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Sample records for non-equilibrium phase transition

  1. Non-equilibrium phase transitions

    CERN Document Server

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  2. Observables of non-equilibrium phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Tomasik, Boris [Univerzita Mateja Bela, FPV, Banska Bystrica (Slovakia); Ceske vysoke uceni technicke v Praze, FJFI, Prague (Czech Republic); Schulc, Martin; Kopecna, Renata [Ceske vysoke uceni technicke v Praze, FJFI, Prague (Czech Republic); Melo, Ivan [Univerzita Mateja Bela, FPV, Banska Bystrica (Slovakia); Zilinska univerzita, Elektrotechnicka fakulta, Zilina (Slovakia)

    2016-08-15

    A rapidly expanding fireball which undergoes first-order phase transition will supercool and proceed via spinodal decomposition. Hadrons are produced from the individual fragments as well as the left-over matter filling the space between them. Emission from fragments should be visible in rapidity correlations, particularly of protons. In addition to that, even within narrow centrality classes, rapidity distributions will be fluctuating from one event to another in case of fragmentation. This can be identified with the help of the Kolmogorov-Smirnov test. Finally, we present a method which allows to sort events with varying rapidity distributions, in such a way that events with similar rapidity histograms are grouped together. (orig.)

  3. Dynamical Symmetries and Causality in Non-Equilibrium Phase Transitions

    Directory of Open Access Journals (Sweden)

    Malte Henkel

    2015-11-01

    Full Text Available Dynamical symmetries are of considerable importance in elucidating the complex behaviour of strongly interacting systems with many degrees of freedom. Paradigmatic examples are cooperative phenomena as they arise in phase transitions, where conformal invariance has led to enormous progress in equilibrium phase transitions, especially in two dimensions. Non-equilibrium phase transitions can arise in much larger portions of the parameter space than equilibrium phase transitions. The state of the art of recent attempts to generalise conformal invariance to a new generic symmetry, taking into account the different scaling behaviour of space and time, will be reviewed. Particular attention will be given to the causality properties as they follow for co-variant n-point functions. These are important for the physical identification of n-point functions as responses or correlators.

  4. Non-equilibrium physics at a holographic chiral phase transition

    International Nuclear Information System (INIS)

    Evans, Nick; Kim, Keun-young; Kalaydzhyan, Tigran; Kirsch, Ingo

    2010-11-01

    The D3/D7 system holographically describes an N=2 gauge theory which spontaneously breaks a chiral symmetry by the formation of a quark condensate in the presence of a magnetic field. At finite temperature it displays a first order phase transition. We study out of equilibrium dynamics associated with this transition by placing probe D7 branes in a geometry describing a boost-invariant expanding or contracting plasma. We use an adiabatic approximation to track the evolution of the quark condensate in a heated system and reproduce the phase structure expected from equilibrium dynamics. We then study solutions of the full partial differential equation that describes the evolution of out of equilibrium configurations to provide a complete description of the phase transition including describing aspects of bubble formation. (orig.)

  5. Non-equilibrium physics at a holographic chiral phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Nick; Kim, Keun-young [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Kavli Institute for Theoretical Physics China, Beijing (China); Kalaydzhyan, Tigran; Kirsch, Ingo [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2010-11-15

    The D3/D7 system holographically describes an N=2 gauge theory which spontaneously breaks a chiral symmetry by the formation of a quark condensate in the presence of a magnetic field. At finite temperature it displays a first order phase transition. We study out of equilibrium dynamics associated with this transition by placing probe D7 branes in a geometry describing a boost-invariant expanding or contracting plasma. We use an adiabatic approximation to track the evolution of the quark condensate in a heated system and reproduce the phase structure expected from equilibrium dynamics. We then study solutions of the full partial differential equation that describes the evolution of out of equilibrium configurations to provide a complete description of the phase transition including describing aspects of bubble formation. (orig.)

  6. A non-equilibrium phase transition in a dissipative forest model

    International Nuclear Information System (INIS)

    Messer, Joachim A.

    2009-01-01

    The shape of the biostress force for a stressed Lotka-Volterra network is for the first time derived from Lindblad's dissipative dynamics. Numerical solutions for stressed prey-predator systems with limited resources show a threshold. A non-equilibrium phase transition to a phase with ecosystem dying after a few enforced oscillations (waldsterben phase) occurs.

  7. Extra entropy production due to non-equilibrium phase transitions in relativistic heavy ion reactions

    International Nuclear Information System (INIS)

    Csernai, L.P.; Lukacs, B.

    1984-04-01

    In a fluid-dynamical model the extra entropy production is calculated which arises from a non-equilibrium phase transition from nuclear to quark matter. The dynamics of processes producing extra entropy are treated in linear approximation. It is shown that there is a considerable extra entropy production provided the transition is not too fast. In measuring the entropy at the break-up, an excess entropy might signalize the phase transition to a transient quark-gluon plasma. (D.Gy.)

  8. Non-equilibrium phase transitions in a driven-dissipative system of interacting bosons

    Science.gov (United States)

    Young, Jeremy T.; Foss-Feig, Michael; Gorshkov, Alexey V.; Maghrebi, Mohammad F.

    2017-04-01

    Atomic, molecular, and optical systems provide unique opportunities to study simple models of driven-dissipative many-body quantum systems. Typically, one is interested in the resultant steady state, but the non-equilibrium nature of the physics involved presents several problems in understanding its behavior theoretically. Recently, it has been shown that in many of these models, it is possible to map the steady-state phase transitions onto classical equilibrium phase transitions. In the language of Keldysh field theory, this relation typically only becomes apparent after integrating out massive fields near the critical point, leaving behind a single massless field undergoing near-equilibrium dynamics. In this talk, we study a driven-dissipative XXZ bosonic model and discover critical points at which two fields become gapless. Each critical point separates three different possible phases: a uniform phase, an anti-ferromagnetic phase, and a limit cycle phase. Furthermore, a description in terms of an equilibrium phase transition does not seem possible, so the associated phase transitions appear to be inherently non-equilibrium.

  9. Unusual dileptions at RHIC a field theoretic approach based on a non-equilibrium chiral phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, F. [Los Alamos National Labs., NM (United States)

    1997-09-22

    This paper contains viewgraphs on unusual dileptons at Brookhaven RHIC. A field theory approach is used based on a non-equilibrium chiral phase transformation utilizing the schroedinger and Heisenberg picture.

  10. Cosmological QCD phase transition in steady non-equilibrium dissipative Hořava–Lifshitz early universe

    International Nuclear Information System (INIS)

    Khodadi, M.; Sepangi, H.R.

    2014-01-01

    We study the phase transition from quark–gluon plasma to hadrons in the early universe in the context of non-equilibrium thermodynamics. According to the standard model of cosmology, a phase transition associated with chiral symmetry breaking after the electro-weak transition has occurred when the universe was about 1–10 μs old. We focus attention on such a phase transition in the presence of a viscous relativistic cosmological background fluid in the framework of non-detailed balance Hořava–Lifshitz cosmology within an effective model of QCD. We consider a flat Friedmann–Robertson–Walker universe filled with a non-causal and a causal bulk viscous cosmological fluid respectively and investigate the effects of the running coupling constants of Hořava–Lifshitz gravity, λ, on the evolution of the physical quantities relevant to a description of the early universe, namely, the temperature T, scale factor a, deceleration parameter q and dimensionless ratio of the bulk viscosity coefficient to entropy density (ξ)/s . We assume that the bulk viscosity cosmological background fluid obeys the evolution equation of the steady truncated (Eckart) and full version of the Israel–Stewart fluid, respectively. -- Highlights: •In this paper we have studied quark–hadron phase transition in the early universe in the context of the Hořava–Lifshitz model. •We use a flat FRW universe with the bulk viscosity cosmological background fluid obeying the evolution equation of the steady truncated (Eckart) and full version of the Israel–Stewart fluid, respectively

  11. Introduction to the generalized theory of non-equilibrium Cahn-Hilliard phase transitions (Thermodynamic problems in continuum mechanics

    Directory of Open Access Journals (Sweden)

    Eugeniy A. Lukashev

    2017-11-01

    Full Text Available The occurrence of convective currents and their development from regular forms with the subsequent transition to irregular turbulent currents draw attention to the fact that they are responsible for the efficiency of many technological processes of heat and mass transfer. Such technological processes are basic in the chemical, petrochemical, power, metallurgical and other industries. Convective flows arise in liquids and gases in the gravitational field in the presence of spatial inhomogeneity of the density created by the inhomogeneity of the temperature and the concentration of components arising during, for example, chemical reactions or other causes. With increasing temperature difference, the resting liquid loses its stability, which then leads to the appearance of a convective flow (Rayleigh–Bénard instability. A further increase in the temperature difference leads to an instability of the primary convective flow, and the hydrodynamic crisis leads to a heat transfer crisis. The paper reconstructs the early stage of the Rayleigh–Bénard convective instability considered as a nonequilibrium phase transition with the spinodal decomposition (diffusion separation mechanism.

  12. Transport phenomena in a temperaturegradient studied by NEMD. A chemical reaction and a phase transition; non-equilibrium molecular dynamics = NEMD

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jing

    2009-10-15

    In this thesis we used non-equilibrium molecular dynamics (NEMD) to study non-equilibrium behaviors of two irreversible systems, both exposed to large temperature gradients. As modeling systems, we have chosen a simple chemical reaction, 2FreversibleF2, and a liquid-vapor interface of a Lenard-Jones spline fluid. The primary goal of this thesis is to investigate the nature of coupled transfer of heat and mass, and to obtain insight into the underlying molecular mechanisms, dynamic structure and properties of the non-equilibrium systems. Heat and mass transports are central in mechanical as well as in chemical engineering. In order to predict transport properties of such systems, we need to confirm that there is a sound basis for the relevant transport equations. For the purpose, NEMD simulations have been used to study both equilibrium and dynamical behavior of the systems. To model the chemical reaction, Stillinger and Weber's two- and three-body potentials were used. In addition to the two-body potential, the three-body potential is needed in order to sufficiently represent the main features of the reaction. Suitable NEMD techniques with the efficient reaction model were developed to study the fluorine reaction, in both stationary equilibrium and non-equilibrium states. Large temperature gradients were imposed through the boundaries in the NEMD box. With the NEMD simulations, the usefulness and validity of the theory of non-equilibrium thermodynamics (NET) have been investigated. The validity of the assumption of 'local equilibrium' was tested for the chemical reaction in various temperature gradients. Furthermore, the quantitative definitions for the local 'chemical' equilibrium were presented using the results from NEMD. The dynamic properties of the system are governed by the system's entropy production. We gave the expression for the entropy production from NET to define the fluxes and forces in the system. Proper transport

  13. Biological Implications of Dynamical Phases in Non-equilibrium Networks

    Science.gov (United States)

    Murugan, Arvind; Vaikuntanathan, Suriyanarayanan

    2016-03-01

    Biology achieves novel functions like error correction, ultra-sensitivity and accurate concentration measurement at the expense of free energy through Maxwell Demon-like mechanisms. The design principles and free energy trade-offs have been studied for a variety of such mechanisms. In this review, we emphasize a perspective based on dynamical phases that can explain commonalities shared by these mechanisms. Dynamical phases are defined by typical trajectories executed by non-equilibrium systems in the space of internal states. We find that coexistence of dynamical phases can have dramatic consequences for function vs free energy cost trade-offs. Dynamical phases can also provide an intuitive picture of the design principles behind such biological Maxwell Demons.

  14. Homogeneous non-equilibrium two-phase critical flow model

    International Nuclear Information System (INIS)

    Schroeder, J.J.; Vuxuan, N.

    1987-01-01

    An important aspect of nuclear and chemical reactor safety is the ability to predict the maximum or critical mass flow rate from a break or leak in a pipe system. At the beginning of such a blowdown, if the stagnation condition of the fluid is subcooled or slightly saturated thermodynamic non-equilibrium exists in the downstream, e.g. the fluid becomes superheated to a degree determined by the liquid pressure. A simplified non-equilibrium model, explained in this report, is valid for rapidly decreasing pressure along the flow path. It presumes that fluid has to be superheated by an amount governed by physical principles before it starts to flash into steam. The flow is assumed to be homogeneous, i.e. the steam and liquid velocities are equal. An adiabatic flow calculation mode (Fanno lines) is employed to evaluate the critical flow rate for long pipes. The model is found to satisfactorily describe critical flow tests. Good agreement is obtained with the large scale Marviken tests as well as with small scale experiments. (orig.)

  15. Non-equilibrium random matrix theory. Transition probabilities

    International Nuclear Information System (INIS)

    Pedro, Francisco Gil; Westphal, Alexander

    2016-06-01

    In this letter we present an analytic method for calculating the transition probability between two random Gaussian matrices with given eigenvalue spectra in the context of Dyson Brownian motion. We show that in the Coulomb gas language, in large N limit, memory of the initial state is preserved in the form of a universal linear potential acting on the eigenvalues. We compute the likelihood of any given transition as a function of time, showing that as memory of the initial state is lost, transition probabilities converge to those of the static ensemble.

  16. Open problems in non-equilibrium physics

    Energy Technology Data Exchange (ETDEWEB)

    Kusnezov, D.

    1997-09-22

    The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.

  17. Modeling and numerical analysis of non-equilibrium two-phase flows

    International Nuclear Information System (INIS)

    Rascle, P.; El Amine, K.

    1997-01-01

    We are interested in the numerical approximation of two-fluid models of nonequilibrium two-phase flows described by six balance equations. We introduce an original splitting technique of the system of equations. This technique is derived in a way such that single phase Riemann solvers may be used: moreover, it allows a straightforward extension to various and detailed exchange source terms. The properties of the fluids are first approached by state equations of ideal gas type and then extended to real fluids. For the construction of numerical schemes , the hyperbolicity of the full system is not necessary. When based on suitable kinetic unwind schemes, the algorithm can compute flow regimes evolving from mixture to single phase flows and vice versa. The whole scheme preserves the physical features of all the variables which remain in the set of physical states. Several stiff numerical tests, such as phase separation and phase transition are displayed in order to highlight the efficiency of the proposed method. The document is a PhD thesis divided in 6 chapters and two annexes. They are entitled: 1. - Introduction (in French), 2. - Two-phase flow, modelling and hyperbolicity (in French), 3. - A numerical method using upwind schemes for the resolution of two-phase flows without exchange terms (in English), 4. - A numerical scheme for one-phase flow of real fluids (in English), 5. - An upwind numerical for non-equilibrium two-phase flows (in English), 6. - The treatment of boundary conditions (in English), A.1. The Perthame scheme (in English) and A.2. The Roe scheme (in English)

  18. Kinetics of low-temperature transitions and a reaction rate theory from non-equilibrium distributions

    Science.gov (United States)

    Aquilanti, Vincenzo; Coutinho, Nayara Dantas; Carvalho-Silva, Valter Henrique

    2017-03-01

    the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  19. Application of a non-equilibrium drift flux model to two-phase blowdown experiments

    International Nuclear Information System (INIS)

    Kroeger, P.G.

    1976-08-01

    A vapor drift-flux model has been applied to the discharge of two-phase mixtures under choked flow conditions, including equilibrium as well as non-equilibrium vapor generation models. The system of four conservation equations is being solved, using the method of characteristics. Closed form expressions have been obtained for the propagation velocities from approximate solutions of the system's characteristic determinant. Treatment of the phase change front as a discontinuity, similar to the treatment of shocks in single phase gas dynamics, permitted very accurate solutions. Good agreement with experimental data is shown

  20. Entropy analysis on non-equilibrium two-phase flow models

    Energy Technology Data Exchange (ETDEWEB)

    Karwat, H.; Ruan, Y.Q. [Technische Universitaet Muenchen, Garching (Germany)

    1995-09-01

    A method of entropy analysis according to the second law of thermodynamics is proposed for the assessment of a class of practical non-equilibrium two-phase flow models. Entropy conditions are derived directly from a local instantaneous formulation for an arbitrary control volume of a structural two-phase fluid, which are finally expressed in terms of the averaged thermodynamic independent variables and their time derivatives as well as the boundary conditions for the volume. On the basis of a widely used thermal-hydraulic system code it is demonstrated with practical examples that entropy production rates in control volumes can be numerically quantified by using the data from the output data files. Entropy analysis using the proposed method is useful in identifying some potential problems in two-phase flow models and predictions as well as in studying the effects of some free parameters in closure relationships.

  1. Critical pressure of non-equilibrium two-phase critical flow

    International Nuclear Information System (INIS)

    Minzer, U.

    1996-01-01

    Critical pressure is defined as the pressure existing at the exit edge of the piping, when it remains constant despite a decrease in the back. According to this definition the critical pressure is larger than the back pressure and for two-phase conditions below saturation pressure. The two-phase critical pressure has a major influence on the two-phase critical flow characteristics. Therefore it is of High significance in calculations of critical mass flux and critical depressurization rate, which are important in the fields of Nuclear Reactor Safety and Industrial Safety. At the Nuclear Reactor Safety field is useful for estimations of the Reactor Cooling System depressurization, the core coolant level, and the pressure build-up in the containment. In the Industrial Safety field it is helpful for estimating the leakage rate of toxic gases Tom liquefied gas pressure vessels, depressurization of pressure vessels, and explosion conditions due to liquefied gas release. For physical description of non-equilibrium two-phase critical flow it would be convenient to divide the flow into two stages. The first stage is the flow of subcooled liquid at constant temperature and uniform pressure drop (i.e., the case of incompressible fluid and uniform piping cross section). The rapid flow of the liquid causes a delay in the boiling of the liquid, which begins to boil below saturation pressure, at thermal non-equilibrium. The boiling is the beginning of the second stage, characterized by a sharp increase of the pressure drop. The liquid temperature on the second stage is almost constant because most of the energy for vaporization is supplied from the large pressure drop The present work will focus on the two-phase critical pressure of water, since water serves as coolant in the vast majority of nuclear power reactors throughout the world. (author)

  2. A model for non-equilibrium, non-homogeneous two-phase critical flow

    International Nuclear Information System (INIS)

    Bassel, Wageeh Sidrak; Ting, Daniel Kao Sun

    1999-01-01

    Critical two phase flow is a very important phenomena in nuclear reactor technology for the analysis of loss of coolant accident. Several recent papers, Lee and Shrock (1990), Dagan (1993) and Downar (1996) , among others, treat the phenomena using complex models which require heuristic parameters such as relaxation constants or interfacial transfer models. In this paper a mathematical model for one dimensional non equilibrium and non homogeneous two phase flow in constant area duct is developed. The model is constituted of three conservation equations type mass ,momentum and energy. Two important variables are defined in the model: equilibrium constant in the energy equation and the impulse function in the momentum equation. In the energy equation, the enthalpy of the liquid phase is determined by a linear interpolation function between the liquid phase enthalpy at inlet condition and the saturated liquid enthalpy at local pressure. The interpolation coefficient is the equilibrium constant. The momentum equation is expressed in terms of the impulse function. It is considered that there is slip between the liquid and vapor phases, the liquid phase is in metastable state and the vapor phase is in saturated stable state. The model is not heuristic in nature and does not require complex interface transfer models. It is proved numerically that for the critical condition the partial derivative of two phase pressure drop with respect to the local pressure or to phase velocity must be zero.This criteria is demonstrated by numerical examples. The experimental work of Fauske (1962) and Jeandey (1982) were analyzed resulting in estimated numerical values for important parameters like slip ratio, equilibrium constant and two phase frictional drop. (author)

  3. A modified SMAC scheme for a non-equilibrium compressible two-phase fluid

    International Nuclear Information System (INIS)

    Yoon, H. Y.; Jeong, J. J.

    2008-01-01

    Two-phase flows appear in LWRs (light water reactors) in highly complex forms depending on their thermal-hydraulic conditions. System codes have mainly been providing the performance and safety analysis of these complex two-phase phenomena during anticipated transients or accidents. More sophisticated two-phase computational models are needed for a detailed analysis of LWR components such as a reactor vessel core, downcomer, steam generators, etc., enabling more operational margins. In many fluid flow calculations, there are efficient numerical methods like SMAC, ICE and SIMPLE where the mass fluxes from the momentum equation are solved using an assumed pressure field, and the pressure field is corrected based on a continuity. The ICE is similar to SMAC except it can be applied to compressible fluids. SMAC and SIMPLE differ in their degree of implicitness. In all these methods, the energy equations are solved using the mass flux and the pressure from the momentum and continuity equations. However, the pressure fields in a two-phase flow need to be corrected based on energy equation as well as continuity when their thermo-dynamic states are far from an equilibrium state. In this paper, the SMAC method is modified for an application to non-equilibrium two-phase flow, where the phase change term appearing in the continuity equation is implemented in an implicit way for the pressure correction calculation. The compressibility is also considered. The present method is compared to a method, where the energy and continuity equations are coupled simultaneously during the pressure correction step

  4. A modified SMAC scheme for a non-equilibrium compressible two-phase fluid

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, H. Y.; Jeong, J. J. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    Two-phase flows appear in LWRs (light water reactors) in highly complex forms depending on their thermal-hydraulic conditions. System codes have mainly been providing the performance and safety analysis of these complex two-phase phenomena during anticipated transients or accidents. More sophisticated two-phase computational models are needed for a detailed analysis of LWR components such as a reactor vessel core, downcomer, steam generators, etc., enabling more operational margins. In many fluid flow calculations, there are efficient numerical methods like SMAC, ICE and SIMPLE where the mass fluxes from the momentum equation are solved using an assumed pressure field, and the pressure field is corrected based on a continuity. The ICE is similar to SMAC except it can be applied to compressible fluids. SMAC and SIMPLE differ in their degree of implicitness. In all these methods, the energy equations are solved using the mass flux and the pressure from the momentum and continuity equations. However, the pressure fields in a two-phase flow need to be corrected based on energy equation as well as continuity when their thermo-dynamic states are far from an equilibrium state. In this paper, the SMAC method is modified for an application to non-equilibrium two-phase flow, where the phase change term appearing in the continuity equation is implemented in an implicit way for the pressure correction calculation. The compressibility is also considered. The present method is compared to a method, where the energy and continuity equations are coupled simultaneously during the pressure correction step.

  5. Realizing the insulator-to-metal transition in Se-hyperdoped Si via non-equilibrium material processing

    OpenAIRE

    Liu, F.; Prucnal, S.; Berencén, Y.; Zhang, Z.; Yuan, Y.; Liu, Y.; Heller, R.; Boettger, R.; Rebohle, L.; Skorupa, W.; Helm, M.; Zhou, S.

    2017-01-01

    We report on the insulator-to-metal transition in Se-hyperdoped Si layers driven by manipulating the Se concentration via non-equilibrium material processing, i.e. ion implantation followed by millisecond-flash lamp annealing. Electrical transport measurements reveal an increase of carrier concentration and conductivity with increasing Se concentration. For the semi-insulating sample with Se concentrations below the Mott limit, quantitative analysis of the temperature dependence of conductivi...

  6. Numerical Simulation of Non-Equilibrium Two-Phase Wet Steam Flow through an Asymmetric Nozzle

    Directory of Open Access Journals (Sweden)

    Miah Md Ashraful Alam

    2017-11-01

    Full Text Available The present study reported of the numerical investigation of a high-speed wet steam flow through an asymmetric nozzle. The spontaneous non-equilibrium homogeneous condensation of wet steam was numerically modeled based on the classical nucleation theory and droplet growth rate equation combined with the field conservations within the computational fluid dynamics (CFD code of ANSYS Fluent 13.0. The equations describing droplet formations and interphase change were solved sequentially after solving the main flow conservation equations. The calculations were carried out assuming the flow two-dimensional, compressible, turbulent, and viscous. The SST k-ω model was used for modeling the turbulence within an unstructured mesh solver. The validation of numerical model was accomplished, and the results showed a good agreement between the numerical simulation and experimental data. The effect of spontaneous non-equilibrium condensation on the jet and shock structures was revealed, and the condensation shown a great influence on the jet structure.

  7. Realizing the insulator-to-metal transition in Se-hyperdoped Si via non-equilibrium material processing

    Science.gov (United States)

    Liu, Fang; Prucnal, S.; Berencén, Y.; Zhang, Zhitao; Yuan, Ye; Liu, Yu; Heller, R.; Böttger, R.; Rebohle, L.; Skorupa, W.; Helm, M.; Zhou, Shengqiang

    2017-10-01

    We report on the insulator-to-metal transition in Se-hyperdoped Si layers driven by manipulating the Se concentration via non-equilibrium material processing, i.e. ion implantation followed by millisecond-flash lamp annealing. Electrical transport measurements reveal an increase of the carrier concentration and conductivity with the increasing Se concentration. For the semi-insulating sample with Se concentrations below the Mott limit, quantitative analysis of the temperature dependence of the conductivity indicates a variable-range hopping mechanism with an exponent of s  =  1/2 rather than 1/4, which implies a Coulomb gap at the Fermi level. The observed insulator-to-metal transition is attributed to the formation of an intermediate band in the Se-hyperdoped Si layers.

  8. Non-equilibrium effects on the two-phase flow critical phenomenon

    International Nuclear Information System (INIS)

    Sami, S.M.

    1988-01-01

    In the present study, the choking criterion for nonhomogeneous nonequilibrium two phase flow is obtained by solving the two-fluid model conservation equations. The method of characteristics is employed to predict the critical flow conditions. Critical flow is established after the magnitude of the characteristic slopes (velocities). Critical flow conditions are reached when the smallest characteristic slope becomes equal to zero. Several expression are developed to determine the nonequilibrium mass and heat exchanges in terms of the system dependent parameters derivatives. In addition, comprehensive transition flow regime maps are employed in the calculation of interfacial heat and momentum transfer rates. Numerical results reveal that the proposed model reliably predicts the critical two-phase flow phenomenon under different inlet conditions and compares well with other existing models

  9. Non-equilibrium ionization by a periodic electron beam. II. Synthetic Si IV and O IV transition region spectra

    Science.gov (United States)

    Dzifčáková, Elena; Dudík, Jaroslav

    2018-03-01

    Context. Transition region (TR) spectra typically show the Si IV 1402.8 Å line to be enhanced by a factor of 5 or more compared to the neighboring O IV 1401.2 Å, contrary to predictions of ionization equilibrium models and the Maxwellian distribution of particle energies. Non-equilibrium effects in TR spectra are therefore expected. Aims: To investigate the combination of non-equilibrium ionization and high-energy particles, we apply the model of the periodic electron beam, represented by a κ-distribution that recurs at periods of several seconds, to plasma at chromospheric temperatures of 104 K. This simple model can approximate a burst of energy release involving accelerated particles. Methods: Instantaneous time-dependent charge states of silicon and oxygen were calculated and used to synthesize the instantaneous and period-averaged spectra of Si IV and O IV. Results: The electron beam drives the plasma out of equilibrium. At electron densities of Ne = 1010 cm-3, the plasma is out of ionization equilibrium at all times in all cases we considered, while for a higher density of Ne = 1011 cm-3, ionization equilibrium can be reached toward the end of each period, depending on the conditions. In turn, the character of the period-averaged synthetic spectra also depends on the properties of the beam. While the case of κ = 2 results in spectra with strong or even dominant O IV, higher values of κ can approximate a range of observed TR spectra. Spectra similar to typically observed spectra, with the Si IV 1402.8 Å line about a factor 5 higher than O IV 1401.2 Å, are obtained for κ = 3. An even higher value of κ = 5 results in spectra that are exclusively dominated by Si IV, with negligible O IV emission. This is a possible interpretation of the TR spectra of UV (Ellerman) bursts, although an interpretation that requires a density that is 1-3 orders of magnitude lower than for equilibrium estimates. Movies associated to Fig. A.1 are available at http://https://www.aanda.org

  10. Optimization of two-phase R600a ejector geometries using a non-equilibrium CFD model

    International Nuclear Information System (INIS)

    Lee, Moon Soo; Lee, Hoseong; Hwang, Yunho; Radermacher, Reinhard; Jeong, Hee-Moon

    2016-01-01

    Highlights: • Empirical mass transfer coefficient correlation is built based on Weber number. • Developed model is validated in terms of the e and DP. • A set of Pareto solutions is obtained from MOGA based OAAO method. • DP is improved up to 10,379 Pa with the same e of the baseline. • e is enhanced up to 0.782 with the same DP of the baseline case. - Abstract: A vapor compression cycle, which is typically utilized for the heat pump, air conditioning and refrigeration systems, has inherent thermodynamic losses associated with expansion and compression processes. To minimize these losses and improve the energy efficiency of the vapor compression cycle, an ejector can be applied. However, due to the occurrence of complex physics i.e., non-equilibrium flashing compressible flow in the nozzle with possible shock interactions, it has not been feasible to model or optimize the design of a two-phase ejector. In this study, a homogeneous, non-equilibrium, two-phase flow computational fluid dynamics (CFD) model in a commercial code is used with an in-house empirical correlation for the mass transfer coefficient and real gas properties to perform a geometric optimization of a two-phase ejector. The model is first validated with experimental data of an ejector with R600a as the working fluid. After that, the design parameters of the ejector are optimized using multi-objective genetic algorithm (MOGA) based online approximation-assisted optimization (OAAO) approaches to find the maximum performance.

  11. Equilibrium and non-equilibrium cluster phases in colloids with competing interactions

    NARCIS (Netherlands)

    Mani, Ethayaraja; Lechner, Wolfgang; Kegel, Willem K.; Bolhuis, Peter G.

    2014-01-01

    The phase behavior of colloids that interact via competing interactions-short-range attraction and long-range repulsion-is studied by computer simulation. In particular, for a fixed strength and range of repulsion, the effect of the strength of an attractive interaction (ε) on the phase behavior is

  12. Non-equilibrium phase stabilization versus bubble nucleation at a nanoscale-curved Interface

    Science.gov (United States)

    Schiffbauer, Jarrod; Luo, Tengfei

    Using continuum dynamic van der Waals theory in a radial 1D geometry with a Lennard-Jones fluid model, we investigate the nature of vapor bubble nucleation near a heated, nanoscale-curved convex interface. Vapor bubble nucleation and growth are observed for interfaces with sufficiently large radius of curvature while phase stabilization of a superheated fluid layer occurs at interfaces with smaller radius. The hypothesis that the high Laplace pressure required for stable equilibrium of very small bubbles is responsible for phase stability is tested by effectively varying the parameter which controls liquid-vapor surface tension. In doing so, the liquid-vapor surface tension- hence Laplace pressure-is shown to have limited effect on phase stabilization vs. bubble nucleation. However, the strong dependence of nucleation on leading-order momentum transport, i.e. viscous dissipation, near the heated inner surface is demonstrated. We gratefully acknowledge ND Energy for support through the ND Energy Postdoctoral Fellowship program and the Army Research Office, Grant No. W911NF-16-1-0267, managed by Dr. Chakrapani Venanasi.

  13. Non-equilibrium phenomena in confined soft matter irreversible adsorption, physical aging and glass transition at the nanoscale

    CERN Document Server

    2015-01-01

    This book presents cutting-edge experimental and computational results and provides comprehensive coverage on the impact of non-equilibrium structure and dynamics on the properties of soft matter confined to the nanoscale. The book is organized into three main sections: ·         Equilibration and physical aging: by treating non-equilibrium phenomena with the formal methodology of statistical physics in bulk, the analysis of the kinetics of equilibration sheds new light on the physical origin of the non-equilibrium character of thin polymer films. Both the impact of sample preparation and that of interfacial interactions are analyzed using a large set of experiments. A historical overview of the investigation of the non-equilibrium character of thin polymer films is also presented. Furthermore, the discussion focuses on how interfaces and geometrical confinement perturb the pathways and kinetics of equilibrations of soft glasses (a process of tremendous technological interest). ·         Irr...

  14. Gas-Kinetic Navier-Stokes Solver for Hypersonic Flows in Thermal and Chemical Non-Equilibrium, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project proposes to develop a gas-kinetic Navier-Stokes solver for simulation of hypersonic flows in thermal and chemical non-equilibrium. The...

  15. Phase transitions

    CERN Document Server

    Sole, Ricard V; Solé, Ricard V; Solé, Ricard V; Sol, Ricard V; Solé, Ricard V

    2011-01-01

    Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation of diverse ecosystems, the book illustrates the power of simple models to reveal how phase transitions occur. Introductory chapters provide the critical concepts and the simplest mathematical techniques required to study phase transitions. In a series of example-driven chapters, Ricard Solé shows how such concepts and techniques can be applied to the analysis and prediction of complex system behavior, including the origins of ...

  16. Non-equilibrium thermodynamics

    CERN Document Server

    De Groot, Sybren Ruurds

    1984-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  17. Non-equilibrium Economics

    Directory of Open Access Journals (Sweden)

    Katalin Martinás

    2007-02-01

    Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.

  18. Reflection of processes of non-equilibrium two-phase filtration in oil-saturated hierarchical medium in data of active wave geophysical monitoring

    Science.gov (United States)

    Hachay, Olga; Khachay, Andrey; Khachay, Oleg

    2016-04-01

    The processes of oil extraction from deposit are linked with the movement of multi-phase multi-component media, which are characterized by non-equilibrium and non-linear rheological features. The real behavior of layered systems is defined by the complexity of the rheology of moving fluids and the morphology structure of the porous medium, and also by the great variety of interactions between the fluid and the porous medium [Hasanov and Bulgakova, 2003]. It is necessary to take into account these features in order to informatively describe the filtration processes due to the non-linearity, non-equilibrium and heterogeneity that are features of real systems. In this way, new synergetic events can be revealed (namely, a loss of stability when oscillations occur, and the formation of ordered structures). This allows us to suggest new methods for the control and management of complicated natural systems that are constructed on account of these phenomena. Thus the layered system, from which it is necessary to extract the oil, is a complicated dynamical hierarchical system. A comparison is provided of non-equilibrium effects of the influence of independent hydrodynamic and electromagnetic induction on an oil layer and the medium which it surrounds. It is known that by drainage and steeping the hysteresis effect on curves of the relative phase permeability in dependence on the porous medium's water saturation in some cycles of influence (drainage-steep-drainage) is observed. Using the earlier developed 3D method of induction electromagnetic frequency geometric monitoring, we showed the possibility of defining the physical and structural features of a hierarchical oil layer structure and estimating the water saturation from crack inclusions. This effect allows managing the process of drainage and steeping the oil out of the layer by water displacement. An algorithm was constructed for 2D modeling of sound diffraction on a porous fluid-saturated intrusion of a hierarchical

  19. Modeling two-phase flow in a micro-model with local thermal non-equilibrium on the Darcy scale

    NARCIS (Netherlands)

    Nuske, Philipp; Ronneberger, Olaf; Karadimitriou, Nikolaos K.; Helmig, Rainer; Hassanizadeh, S. Majid

    2015-01-01

    Loosening local equilibrium assumptions in two-phase flow in porous media gives rise to new, unknown variables. More specifically, when loosening the local thermal equilibrium assumption, one has to describe the heat transfer between multiple phases, present at the same mathematical point. In this

  20. Aerospace Applications of Non-Equilibrium Plasma

    Science.gov (United States)

    Blankson, Isaiah M.

    2016-01-01

    Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).

  1. Non-equilibrium modelling of distillation

    NARCIS (Netherlands)

    Wesselingh, JA; Darton, R

    1997-01-01

    There are nasty conceptual problems in the classical way of describing distillation columns via equilibrium stages, and efficiencies or HETP's. We can nowadays avoid these problems by simulating the behaviour of a complete column in one go using a non-equilibrium model. Such a model has phase

  2. Two-phase, mass-transport model for direct methanol fuel cells with effect of non-equilibrium evaporation and condensation

    Science.gov (United States)

    Yang, W. W.; Zhao, T. S.

    A two-phase, mass-transport model for liquid-feed direct methanol fuel cells (DMFCs) is developed by taking into account the effect of non-equilibrium evaporation and condensation of methanol and water. The comparison between the present model and other models indicates that the present model yields more reasonable predictions of cell performance. Particularly, it is shown that the models that invoke a thermodynamic-equilibrium assumption between phases will overestimate mass-transport rates of methanol and water, thereby resulting in an inaccurate prediction of cell performance. The parametric study using the present model reveals that the gas coverage at the flow channel-diffusion-layer interface is directly related to the gas-void fraction inside the anode porous region; increasing the gas-void fraction will increase the mass-transfer resistance of methanol and thus lower cell performance. The effects of the geometric dimensions of the cell structure, such as channel width and rib width, on cell performance are also investigated with the model developed in this work.

  3. Non-equilibrium effects evidenced by vibrational spectra during the coil-to-globule transition in poly(N-isopropylacrylamide) subjected to an ultrafast heating-cooling cycle.

    Science.gov (United States)

    Deshmukh, Sanket A; Kamath, Ganesh; Suthar, Kamlesh J; Mancini, Derrick C; Sankaranarayanan, Subramanian K R S

    2014-03-14

    Molecular dynamics simulations in conjunction with finite element calculations are used to explore the conformational dynamics of a thermo-sensitive oligomer, namely poly(N-isopropylacrylamide) (PNIPAM), subjected to an ultra-fast heating-cooling cycle. Finite element (FE) calculations were used to predict the temperature profile resulting from laser-induced heating of the polymer-aqueous system. The heating rate (∼0.6 K ps(-1)) deduced from FE calculations was used to heat an aqueous solution of PNIPAM consisting of 30 monomeric units (30-mer) from 285 K to 315 K. Non-equilibrium effects arising from the ultra-fast heating-cooling cycle results in a hysteresis during the coil-to-globule transition. The corresponding atomic scale conformations were characterized by monitoring the changes in the vibrational spectra, which provided a reliable metric to study the coil-to-globule transition in PNIPAM and vice-versa across the LCST. The vibrational spectra of bonds involving atoms from the oligomer backbone and the various side-groups (amide I, amide II, and the isopropyl group of PNIPAM) of the oligomers were analyzed to study the conformational changes in the oligomer corresponding to the observed hysteresis. The differences in the vibrational spectra calculated at various temperatures during heating and cooling cycles were used to understand the coil-to-globule and globule-to-coil transitions in the PNIPAM oligomer and identify the changes in the relative interactions between various atoms in the backbone and in the side groups of the oligomer with water. The shifts in the computed vibrational spectral peaks and the changes in the intensity of peaks for the different regions of PNIPAM, seen across the LCST during the heating cycle, are in good agreement with previous experimental studies. The changes in the radius of gyration (Rg) and vibrational spectra for amide I and amide II regions of PNIPAM suggest a clear coil-to-globule transition at ∼301 K during the

  4. Equilibrium and non equilibrium in fragmentation

    International Nuclear Information System (INIS)

    Dorso, C.O.; Chernomoretz, A.; Lopez, J.A.

    2001-01-01

    Full text: In this communication we present recent results regarding the interplay of equilibrium and non equilibrium in the process of fragmentation of excited finite Lennard Jones drops. Because the general features of such a potential resemble the ones of the nuclear interaction (fact that is reinforced by the similarity between the EOS of both systems) these studies are not only relevant from a fundamental point of view but also shed light on the problem of nuclear multifragmentation. We focus on the microscopic analysis of the state of the fragmenting system at fragmentation time. We show that the Caloric Curve (i e. the functional relationship between the temperature of the system and the excitation energy) is of the type rise plateau with no vapor branch. The usual rise plateau rise pattern is only recovered when equilibrium is artificially imposed. This result puts a serious question on the validity of the freeze out hypothesis. This feature is independent of the dimensionality or excitation mechanism. Moreover we explore the behavior of magnitudes which can help us determine the degree of the assumed phase transition. It is found that no clear cut criteria is presently available. (Author)

  5. Uniqueness of Specific Interfacial Area–Capillary Pressure–Saturation Relationship Under Non-Equilibrium Conditions in Two-Phase Porous Media Flow

    KAUST Repository

    Joekar-Niasar, Vahid

    2012-02-23

    The capillary pressure-saturation (P c-S w) relationship is one of the central constitutive relationships used in two-phase flow simulations. There are two major concerns regarding this relation. These concerns are partially studied in a hypothetical porous medium using a dynamic pore-network model called DYPOSIT, which has been employed and extended for this study: (a) P c-S w relationship is measured empirically under equilibrium conditions. It is then used in Darcy-based simulations for all dynamic conditions. This is only valid if there is a guarantee that this relationship is unique for a given flow process (drainage or imbibition) independent of dynamic conditions; (b) It is also known that P c-S w relationship is flow process dependent. Depending on drainage and imbibition, different curves can be achieved, which are referred to as "hysteresis". A thermodynamically derived theory (Hassanizadeh and Gray, Water Resour Res 29: 3389-3904, 1993a) suggests that, by introducing a new state variable, called the specific interfacial area (a nw, defined as the ratio of fluid-fluid interfacial area to the total volume of the domain), it is possible to define a unique relation between capillary pressure, saturation, and interfacial area. This study investigates these two aspects of capillary pressure-saturation relationship using a dynamic pore-network model. The simulation results imply that P c-S w relation not only depends on flow process (drainage and imbibition) but also on dynamic conditions for a given flow process. Moreover, this study attempts to obtain the first preliminary insights into the global functionality of capillary pressure-saturation-interfacial area relationship under equilibrium and non-equilibrium conditions and the uniqueness of P c-S w-a nw relationship. © 2012 The Author(s).

  6. Non-equilibrium theory of arrested spinodal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Olais-Govea, José Manuel; López-Flores, Leticia; Medina-Noyola, Magdaleno [Instituto de Física “Manuel Sandoval Vallarta,” Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, SLP (Mexico)

    2015-11-07

    The non-equilibrium self-consistent generalized Langevin equation theory of irreversible relaxation [P. E. Ramŕez-González and M. Medina-Noyola, Phys. Rev. E 82, 061503 (2010); 82, 061504 (2010)] is applied to the description of the non-equilibrium processes involved in the spinodal decomposition of suddenly and deeply quenched simple liquids. For model liquids with hard-sphere plus attractive (Yukawa or square well) pair potential, the theory predicts that the spinodal curve, besides being the threshold of the thermodynamic stability of homogeneous states, is also the borderline between the regions of ergodic and non-ergodic homogeneous states. It also predicts that the high-density liquid-glass transition line, whose high-temperature limit corresponds to the well-known hard-sphere glass transition, at lower temperature intersects the spinodal curve and continues inside the spinodal region as a glass-glass transition line. Within the region bounded from below by this low-temperature glass-glass transition and from above by the spinodal dynamic arrest line, we can recognize two distinct domains with qualitatively different temperature dependence of various physical properties. We interpret these two domains as corresponding to full gas-liquid phase separation conditions and to the formation of physical gels by arrested spinodal decomposition. The resulting theoretical scenario is consistent with the corresponding experimental observations in a specific colloidal model system.

  7. Non-equilibrium thermodynamical description of rhythmic motion patterns of active systems: a canonical-dissipative approach.

    Science.gov (United States)

    Dotov, D G; Kim, S; Frank, T D

    2015-02-01

    We derive explicit expressions for the non-equilibrium thermodynamical variables of a canonical-dissipative limit cycle oscillator describing rhythmic motion patterns of active systems. These variables are statistical entropy, non-equilibrium internal energy, and non-equilibrium free energy. In particular, the expression for the non-equilibrium free energy is derived as a function of a suitable control parameter. The control parameter determines the Hopf bifurcation point of the deterministic active system and describes the effective pumping of the oscillator. In analogy to the equilibrium free energy of the Landau theory, it is shown that the non-equilibrium free energy decays as a function of the control parameter. In doing so, a similarity between certain equilibrium and non-equilibrium phase transitions is pointed out. Data from an experiment on human rhythmic movements is presented. Estimates for pumping intensity as well as the thermodynamical variables are reported. It is shown that in the experiment the non-equilibrium free energy decayed when pumping intensity was increased, which is consistent with the theory. Moreover, pumping intensities close to zero could be observed at relatively slow intended rhythmic movements. In view of the Hopf bifurcation underlying the limit cycle oscillator model, this observation suggests that the intended limit cycle movements were actually more similar to trajectories of a randomly perturbed stable focus. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Non-equilibrium supramolecular polymerization.

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

    2017-09-18

    Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

  9. Non-equilibrium synergistic effects in atmospheric pressure plasmas.

    Science.gov (United States)

    Guo, Heng; Zhang, Xiao-Ning; Chen, Jian; Li, He-Ping; Ostrikov, Kostya Ken

    2018-03-19

    Non-equilibrium is one of the important features of an atmospheric gas discharge plasma. It involves complicated physical-chemical processes and plays a key role in various actual plasma processing. In this report, a novel complete non-equilibrium model is developed to reveal the non-equilibrium synergistic effects for the atmospheric-pressure low-temperature plasmas (AP-LTPs). It combines a thermal-chemical non-equilibrium fluid model for the quasi-neutral plasma region and a simplified sheath model for the electrode sheath region. The free-burning argon arc is selected as a model system because both the electrical-thermal-chemical equilibrium and non-equilibrium regions are involved simultaneously in this arc plasma system. The modeling results indicate for the first time that it is the strong and synergistic interactions among the mass, momentum and energy transfer processes that determine the self-consistent non-equilibrium characteristics of the AP-LTPs. An energy transfer process related to the non-uniform spatial distributions of the electron-to-heavy-particle temperature ratio has also been discovered for the first time. It has a significant influence for self-consistently predicting the transition region between the "hot" and "cold" equilibrium regions of an AP-LTP system. The modeling results would provide an instructive guidance for predicting and possibly controlling the non-equilibrium particle-energy transportation process in various AP-LTPs in future.

  10. Quantum phase transitions

    International Nuclear Information System (INIS)

    Sachdev, S.

    1999-01-01

    Phase transitions are normally associated with changes of temperature but a new type of transition - caused by quantum fluctuations near absolute zero - is possible, and can tell us more about the properties of a wide range of systems in condensed-matter physics. Nature abounds with phase transitions. The boiling and freezing of water are everyday examples of phase transitions, as are more exotic processes such as superconductivity and superfluidity. The universe itself is thought to have passed through several phase transitions as the high-temperature plasma formed by the big bang cooled to form the world as we know it today. Phase transitions are traditionally classified as first or second order. In first-order transitions the two phases co-exist at the transition temperature - e.g. ice and water at 0 deg., or water and steam at 100 deg. In second-order transitions the two phases do not co-exist. In the last decade, attention has focused on phase transitions that are qualitatively different from the examples noted above: these are quantum phase transitions and they occur only at the absolute zero of temperature. The transition takes place at the ''quantum critical'' value of some other parameter such as pressure, composition or magnetic field strength. A quantum phase transition takes place when co-operative ordering of the system disappears, but this loss of order is driven solely by the quantum fluctuations demanded by Heisenberg's uncertainty principle. The physical properties of these quantum fluctuations are quite distinct from those of the thermal fluctuations responsible for traditional, finite-temperature phase transitions. In particular, the quantum system is described by a complex-valued wavefunction, and the dynamics of its phase near the quantum critical point requires novel theories that have no analogue in the traditional framework of phase transitions. In this article the author describes the history of quantum phase transitions. (UK)

  11. Phase diagram and structural evolution of tin/indium (Sn/In) nanosolder particles: from a non-equilibrium state to an equilibrium state.

    Science.gov (United States)

    Shu, Yang; Ando, Teiichi; Yin, Qiyue; Zhou, Guangwen; Gu, Zhiyong

    2017-08-31

    A binary system of tin/indium (Sn/In) in the form of nanoparticles was investigated for phase transitions and structural evolution at different temperatures and compositions. The Sn/In nanosolder particles in the composition range of 24-72 wt% In were synthesized by a surfactant-assisted chemical reduction method under ambient conditions. The morphology and microstructure of the as-synthesized nanoparticles were analyzed by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and X-ray diffraction (XRD). HRTEM and SAED identified InSn 4 and In, with some Sn being detected by XRD, but no In 3 Sn was observed. The differential scanning calorimetry (DSC) thermographs of the as-synthesized nanoparticles exhibited an endothermic peak at around 116 °C, which is indicative of the metastable eutectic melting of InSn 4 and In. When the nanosolders were subjected to heat treatment at 50-225 °C, the equilibrium phase In 3 Sn appeared while Sn disappeared. The equilibrium state was effectively attained at 225 °C. A Tammann plot of the DSC data of the as-synthesized nanoparticles indicated that the metastable eutectic composition is about 62% In, while that of the DSC data of the 225 °C heat-treated nanoparticles yielded a eutectic composition of 54% In, which confirmed the attainment of the equilibrium state at 225 °C. The phase boundaries estimated from the DSC data of heat-treated Sn/In nanosolder particles matched well with those in the established Sn-In equilibrium phase diagram. The phase transition behavior of Sn/In nanosolders leads to a new understanding of binary alloy particles at the nanoscale, and provides important information for their low temperature soldering processing and applications.

  12. Martensitic phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)

    1996-11-01

    Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.

  13. Cosmological phase transitions

    International Nuclear Information System (INIS)

    Kolb, E.W.

    1987-01-01

    If the universe stated from conditions of high temperature and density, there should have been a series of phase transitions associated with spontaneous symmetry breaking. The cosmological phase transitions could have observable consequences in the present Universe. Some of the consequences including the formation of topological defects and cosmological inflation are reviewed here. One of the most important tools in building particle physics models is the use of spontaneous symmetry breaking (SSB). The proposal that there are underlying symmetries of nature that are not manifest in the vacuum is a crucial link in the unification of forces. Of particular interest for cosmology is the expectation that are the high temperatures of the big bang symmetries broken today will be restored, and that there are phase transitions to the broken state. The possibility that topological defects will be produced in the transition is the subject of this section. The possibility that the Universe will undergo inflation in a phase transition will be the subject of the next section. Before discussing the creation of topological defects in the phase transition, some general aspects of high-temperature restoration of symmetry and the development of the phase transition will be reviewed. 29 references, 1 figure, 1 table

  14. Phase transitions modern applications

    CERN Document Server

    Gitterman, Moshe

    2014-01-01

    This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.

  15. Gibbsian Stationary Non-equilibrium States

    Science.gov (United States)

    De Carlo, Leonardo; Gabrielli, Davide

    2017-09-01

    We study the structure of stationary non-equilibrium states for interacting particle systems from a microscopic viewpoint. In particular we discuss two different discrete geometric constructions. We apply both of them to determine non reversible transition rates corresponding to a fixed invariant measure. The first one uses the equivalence of this problem with the construction of divergence free flows on the transition graph. Since divergence free flows are characterized by cyclic decompositions we can generate families of models from elementary cycles on the configuration space. The second construction is a functional discrete Hodge decomposition for translational covariant discrete vector fields. According to this, for example, the instantaneous current of any interacting particle system on a finite torus can be canonically decomposed in a gradient part, a circulation term and an harmonic component. All the three components are associated with functions on the configuration space. This decomposition is unique and constructive. The stationary condition can be interpreted as an orthogonality condition with respect to an harmonic discrete vector field and we use this decomposition to construct models having a fixed invariant measure.

  16. paraelectric phase transition

    Indian Academy of Sciences (India)

    at% of La, x = 3, 5, 6, 10 and 12] have been measured in the frequency range 1 Hz–1 MHz using the vector impedance ... The ferroelectric phase transition is diffuse in nature and broadening of the peak increases with La content. Keywords. PLZT ..... formation from rhombohedral–tetragonal–cubic phase with increase in ...

  17. The potential and flux landscape, Lyapunov function and non-equilibrium thermodynamics for dynamic systems and networks with an application to signal-induced Ca2+ oscillation

    International Nuclear Information System (INIS)

    Xu, Li; Zhang, Feng; Wang, Erkang; Wang, Jin

    2013-01-01

    In this review, we summarize our recent efforts in exploring the non-equilibrium potential and flux landscape for dynamical systems and networks. The driving force of non-equilibrium dynamics can be decomposed into the gradient of the non-equilibrium potential and the divergent free probability flux divided by the steady-state probability distribution. The potential landscape is linked to the probability distribution of the steady state. We found that the intrinsic potential landscape in the zero noise limit is a Lyapunov function. We have defined and quantified the entropy, energy and free energy of the non-equilibrium systems. These can be used for formulating the first law of non-equilibrium thermodynamics. The free energy of the non-equilibrium system is also a Lyapunov function. Therefore, we can use both the intrinsic potential landscape and the free energy to quantify the robustness and global stability of the system. The Lyapunov property provides the formulation for the second law of non-equilibrium thermodynamics. The non-zero probability flux breaks the detailed balance. The two driving forces from the gradient of intrinsic potential landscape and the probability flux are perpendicular to each other under the zero noise limit. We investigate the dynamics of a new biological example of signal-induced Ca 2+ oscillation. We explored the underlying potential landscape which shows a Mexican hat shape attracting the system down to the oscillation ring and the flux which provides the driving force on the ring for coherent and stable oscillation. We explored how the landscape and flux topography change with respect to the system parameters and the relationship to the period of oscillations and how the non-equilibrium free energy changes with respect to different dynamic phases and phase transitions when the system parameters vary. These explain how the system becomes robust and stable under different conditions and can help guide the experiment. (invited article)

  18. Modelling non-equilibrium secondary organic aerosol formation and evaporation with the aerosol dynamics, gas- and particle-phase chemistry kinetic multilayer model ADCHAM

    Science.gov (United States)

    Roldin, P.; Eriksson, A. C.; Nordin, E. Z.; Hermansson, E.; Mogensen, D.; Rusanen, A.; Boy, M.; Swietlicki, E.; Svenningsson, B.; Zelenyuk, A.; Pagels, J.

    2014-08-01

    We have developed the novel Aerosol Dynamics, gas- and particle-phase chemistry model for laboratory CHAMber studies (ADCHAM). The model combines the detailed gas-phase Master Chemical Mechanism version 3.2 (MCMv3.2), an aerosol dynamics and particle-phase chemistry module (which considers acid-catalysed oligomerization, heterogeneous oxidation reactions in the particle phase and non-ideal interactions between organic compounds, water and inorganic ions) and a kinetic multilayer module for diffusion-limited transport of compounds between the gas phase, particle surface and particle bulk phase. In this article we describe and use ADCHAM to study (1) the evaporation of liquid dioctyl phthalate (DOP) particles, (2) the slow and almost particle-size-independent evaporation of α-pinene ozonolysis secondary organic aerosol (SOA) particles, (3) the mass-transfer-limited uptake of ammonia (NH3) and formation of organic salts between ammonium (NH4+) and carboxylic acids (RCOOH), and (4) the influence of chamber wall effects on the observed SOA formation in smog chambers. ADCHAM is able to capture the observed α-pinene SOA mass increase in the presence of NH3(g). Organic salts of ammonium and carboxylic acids predominantly form during the early stage of SOA formation. In the smog chamber experiments, these salts contribute substantially to the initial growth of the homogeneously nucleated particles. The model simulations of evaporating α-pinene SOA particles support the recent experimental findings that these particles have a semi-solid tar-like amorphous-phase state. ADCHAM is able to reproduce the main features of the observed slow evaporation rates if the concentration of low-volatility and viscous oligomerized SOA material at the particle surface increases upon evaporation. The evaporation rate is mainly governed by the reversible decomposition of oligomers back to monomers. Finally, we demonstrate that the mass-transfer-limited uptake of condensable organic compounds

  19. A general unified non-equilibrium model for predicting saturated and subcooled critical two-phase flow rates through short and long tubes

    Energy Technology Data Exchange (ETDEWEB)

    Fraser, D.W.H. [Univ. of British Columbia (Canada); Abdelmessih, A.H. [Univ. of Toronto, Ontario (Canada)

    1995-09-01

    A general unified model is developed to predict one-component critical two-phase pipe flow. Modelling of the two-phase flow is accomplished by describing the evolution of the flow between the location of flashing inception and the exit (critical) plane. The model approximates the nonequilibrium phase change process via thermodynamic equilibrium paths. Included are the relative effects of varying the location of flashing inception, pipe geometry, fluid properties and length to diameter ratio. The model predicts that a range of critical mass fluxes exist and is bound by a maximum and minimum value for a given thermodynamic state. This range is more pronounced at lower subcooled stagnation states and can be attributed to the variation in the location of flashing inception. The model is based on the results of an experimental study of the critical two-phase flow of saturated and subcooled water through long tubes. In that study, the location of flashing inception was accurately controlled and adjusted through the use of a new device. The data obtained revealed that for fixed stagnation conditions, the maximum critical mass flux occurred with flashing inception located near the pipe exit; while minimum critical mass fluxes occurred with the flashing front located further upstream. Available data since 1970 for both short and long tubes over a wide range of conditions are compared with the model predictions. This includes test section L/D ratios from 25 to 300 and covers a temperature and pressure range of 110 to 280{degrees}C and 0.16 to 6.9 MPa. respectively. The predicted maximum and minimum critical mass fluxes show an excellent agreement with the range observed in the experimental data.

  20. Referesher Course on Contemporary Non-Equilibrium ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Referesher Course on Contemporary Non-Equilibrium Thermodynamics and Statistical Mechanics. Information and Announcements Volume 15 Issue 7 July 2010 pp 678-678 ...

  1. Non-equilibrium dog-flea model

    Science.gov (United States)

    Ackerson, Bruce J.

    2017-11-01

    We develop the open dog-flea model to serve as a check of proposed non-equilibrium theories of statistical mechanics. The model is developed in detail. Then it is applied to four recent models for non-equilibrium statistical mechanics. Comparison of the dog-flea solution with these different models allows checking claims and giving a concrete example of the theoretical models.

  2. Phase transitions in nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Moretto, L.G.; Phair, L.; Wozniak, G.J.

    1997-08-01

    A critical overview of the low energy phase transitions in nuclei is presented with particular attention to the 2nd (1st) order pairing phase transitions, and to the 1st order liquid-vapor phase transition. The role of fluctuations in washing out these transitions is discussed and illustrated with examples. A robust indicator of phase coexistence in multifragmentation is presented.

  3. Electronic phase transitions

    CERN Document Server

    Kopaev, YuV

    1992-01-01

    Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele

  4. Photoinduced phase transitions

    CERN Document Server

    Nasu, K

    2004-01-01

    A new class of insulating solids was recently discovered. Whenirradiated by a few visible photons, these solids give rise to amacroscopic excited domain that has new structural and electronicorders quite different from the starting ground state. This occurrenceis called "photoinduced phase transition", and this multi-authoredbook reviews recent theoretical and experimental studies of this newphenomenon.

  5. Thermal non equilibrium in two phase flow

    International Nuclear Information System (INIS)

    1989-01-01

    Twenty eight reports presented in the 7th Eurotherm seminar are contained in this publication. They cover the main aspects of the thermodynamics in relation to nuclear systems or having reference to them

  6. Non-Equilibrium Thermodynamics in Multiphase Flows

    CERN Document Server

    Mauri, Roberto

    2013-01-01

    Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...

  7. Understanding quantum phase transitions

    CERN Document Server

    Carr, Lincoln

    2010-01-01

    Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth

  8. Unconventional phase transitions in a constrained single polymer chain

    International Nuclear Information System (INIS)

    Klushin, L I; Skvortsov, A M

    2011-01-01

    Phase transitions were recognized among the most fascinating phenomena in physics. Exactly solved models are especially important in the theory of phase transitions. A number of exactly solved models of phase transitions in a single polymer chain are discussed in this review. These are three models demonstrating the second order phase transitions with some unusual features: two-dimensional model of β-structure formation, the model of coil–globule transition and adsorption of a polymer chain grafted on the solid surface. We also discuss models with first order phase transitions in a single macromolecule which admit not only exact analytical solutions for the partition function with explicit finite-size effects but also the non-equilibrium free energy as a function of the order parameter (Landau function) in closed analytical form. One of them is a model of mechanical desorption of a macromolecule, which demonstrates an unusual first order phase transition with phase coexistence within a single chain. Features of first and second order transitions become mixed here due to phase coexistence which is not accompanied by additional interfacial free energy. Apart from that, there exist several single-chain models belonging to the same class (adsorption of a polymer chain tethered near the solid surface or liquid–liquid interface, and escape transition upon compressing a polymer between small pistons) that represent examples of a highly unconventional first order phase transition with several inter-related unusual features: no simultaneous phase coexistence, and hence no phase boundary, non-concave thermodynamic potential and non-equivalence of conjugate ensembles. An analysis of complex zeros of partition functions upon approaching the thermodynamic limit is presented for models with and without phase coexistence. (topical review)

  9. Universality of phase transition dynamics: topological defects from symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, Wojciech H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Del Campo, Adolfo [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-02-13

    In the course of a non-equilibrium continuous phase transition, the dynamics ceases to be adiabatic in the vicinity of the critical point as a result of the critical slowing down (the divergence of the relaxation time in the neighborhood of the critical point). This enforces a local choice of the broken symmetry and can lead to the formation of topological defects. The Kibble-Zurek mechanism (KZM) was developed to describe the associated nonequilibrium dynamics and to estimate the density of defects as a function of the quench rate through the transition. During recent years, several new experiments investigating formation of defects in phase transitions induced by a quench both in classical and quantum mechanical systems were carried out. At the same time, some established results were called into question. We review and analyze the Kibble-Zurek mechanism focusing in particular on this surge of activity, and suggest possible directions for further progress.

  10. Nonideal plasmas as non-equilibrium media

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E; Valuev, A A; Valuev, I A

    2003-01-01

    Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential stage of the relaxation process are studied for a wide range of ion charge, nonideality parameter and ion mass. A simulation model of the nonideal plasma excited by an electron beam is proposed. An approach is developed to calculate the dynamic structure factor in non-stationary conditions. Instability increment is obtained from MD simulations

  11. Non-equilibrium thermodynamics and physical kinetics

    CERN Document Server

    Bikkin, Halid

    2014-01-01

    This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.

  12. Evolution and non-equilibrium physics

    DEFF Research Database (Denmark)

    Becker, Nikolaj; Sibani, Paolo

    2014-01-01

    We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...

  13. Ultrafast dynamics during the photoinduced phase transition in VO2

    Science.gov (United States)

    Wegkamp, Daniel; Stähler, Julia

    2015-12-01

    The phase transition of VO2 from a monoclinic insulator to a rutile metal, which occurs thermally at TC = 340 K, can also be driven by strong photoexcitation. The ultrafast dynamics during this photoinduced phase transition (PIPT) have attracted great scientific attention for decades, as this approach promises to answer the question of whether the insulator-to-metal (IMT) transition is caused by electronic or crystallographic processes through disentanglement of the different contributions in the time domain. We review our recent results achieved by femtosecond time-resolved photoelectron, optical, and coherent phonon spectroscopy and discuss them within the framework of a selection of latest, complementary studies of the ultrafast PIPT in VO2. We show that the population change of electrons and holes caused by photoexcitation launches a highly non-equilibrium plasma phase characterized by enhanced screening due to quasi-free carriers and followed by two branches of non-equilibrium dynamics: (i) an instantaneous (within the time resolution) collapse of the insulating gap that precedes charge carrier relaxation and significant ionic motion and (ii) an instantaneous lattice potential symmetry change that represents the onset of the crystallographic phase transition through ionic motion on longer timescales. We discuss the interconnection between these two non-thermal pathways with particular focus on the meaning of the critical fluence of the PIPT in different types of experiments. Based on this, we conclude that the PIPT threshold identified in optical experiments is most probably determined by the excitation density required to drive the lattice potential change rather than the IMT. These considerations suggest that the IMT can be driven by weaker excitation, predicting a transiently metallic, monoclinic state of VO2 that is not stabilized by the non-thermal structural transition and, thus, decays on ultrafast timescales.

  14. Hawking–Page phase transition in new massive gravity

    Directory of Open Access Journals (Sweden)

    Shao-Jun Zhang

    2015-07-01

    Full Text Available We consider Hawking–Page phase transition between the BTZ black hole with M≥0 and the thermal soliton with M=−1 in new massive gravity. By comparing the on-shell free energies, we can see that there exists a critical temperature. The thermal soliton is more probable than the black hole below the critical temperature while the black hole is more probable than the thermal soliton above the critical temperature. By consistently constructing the off-shell free energies taking into account the conical singularity, we show that there exist infinite non-equilibrium states connecting the BTZ black hole and the thermal soliton, so that they provide a picture of continuous evolution of the phase transition.

  15. Complex Nonlinearity Chaos, Phase Transitions, Topology Change and Path Integrals

    CERN Document Server

    Ivancevic, Vladimir G

    2008-01-01

    Complex Nonlinearity: Chaos, Phase Transitions, Topology Change and Path Integrals is a book about prediction & control of general nonlinear and chaotic dynamics of high-dimensional complex systems of various physical and non-physical nature and their underpinning geometro-topological change. The book starts with a textbook-like expose on nonlinear dynamics, attractors and chaos, both temporal and spatio-temporal, including modern techniques of chaos–control. Chapter 2 turns to the edge of chaos, in the form of phase transitions (equilibrium and non-equilibrium, oscillatory, fractal and noise-induced), as well as the related field of synergetics. While the natural stage for linear dynamics comprises of flat, Euclidean geometry (with the corresponding calculation tools from linear algebra and analysis), the natural stage for nonlinear dynamics is curved, Riemannian geometry (with the corresponding tools from nonlinear, tensor algebra and analysis). The extreme nonlinearity – chaos – corresponds to th...

  16. Characterization of non equilibrium effects on high quality critical flows

    Energy Technology Data Exchange (ETDEWEB)

    Camelo, E.; Lemonnier, H.; Ochterbeck, J. [Commissariat a l Energie Atomique, Grenoble (France)] [and others

    1995-09-01

    The appropriate design of various pieces of safety equipment such as relief systems, relies on the accurate description of critical flow phenomena. Most of the systems of industrial interest are willing to be described by one-dimensional area-averaged models and a large fraction of them involves multi-component high gas quality flows. Within these circumstances, the flow is very likely to be of an annular dispersed nature and its description by two-fluid models requires various closure relations. Among the most sensitive closures, there is the interfacial area and the liquid entrained fraction. The critical flowrate depends tremendously on the accurate description of the non equilibrium which results from the correctness of the closure equations. In this study, two-component flows are emphasized and non equilibrium results mainly form the differences in the phase velocities. It is therefore of the utmost importance to have reliable data to characterize non equilibrium phenomena and to assess the validity of the closure models. A comprehensive description of air-water nozzle flows, with emphasis on the effect of the nozzle geometry, has been undertaken and some of the results are presented here which helps understanding the overall flow dynamics. Besides the critical flowrate, the presented material includes pressure profiles, droplet size and velocity, liquid film flowrate and liquid film thickness.

  17. Non-equilibrium simulation of CH4 production through the depressurization method from gas hydrate reservoirs

    Science.gov (United States)

    Qorbani, Khadijeh; Kvamme, Bjørn

    2016-04-01

    Natural gas hydrates (NGHs) in nature are formed from various hydrate formers (i.e. aqueous, gas, and adsorbed phases). As a result, due to Gibbs phase rule and the combined first and second laws of thermodynamics CH4-hydrate cannot reach thermodynamic equilibrium in real reservoir conditions. CH4 is the dominant component in NGH reservoirs. It is formed as a result of biogenic degradation of biological material in the upper few hundred meters of subsurface. It has been estimated that the amount of fuel-gas reserve in NGHs exceed the total amount of fossil fuel explored until today. Thus, these reservoirs have the potential to satisfy the energy requirements of the future. However, released CH4 from dissociated NGHs could find its way to the atmosphere and it is a far more aggressive greenhouse gas than CO2, even though its life-time is shorter. Lack of reliable field data makes it difficult to predict the production potential, as well as safety of CH4 production from NGHs. Computer simulations can be used as a tool to investigate CH4 production through different scenarios. Most hydrate simulators within academia and industry treat hydrate phase transitions as an equilibrium process and those which employ the kinetic approach utilize simple laboratory data in their models. Furthermore, it is typical to utilize a limited thermodynamic description where only temperature and pressure projections are considered. Another widely used simplification is to assume only a single route for the hydrate phase transitions. The non-equilibrium nature of hydrate indicates a need for proper kinetic models to describe hydrate dissociation and reformation in the reservoir with respect to thermodynamics variables, CH4 mole-fraction, pressure and temperature. The RetrasoCodeBright (RCB) hydrate simulator has previously been extended to model CH4-hydrate dissociation towards CH4 gas and water. CH4-hydrate is added to the RCB data-base as a pseudo mineral. Phase transitions are treated

  18. Continuous quantum phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Sondhi, S.L. [Department of Physics, Princeton University, Princeton, New Jersey 08544 (United States); Girvin, S.M.; Carini, J.P. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States); Shahar, D. [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    1997-01-01

    A quantum system can undergo a continuous phase transition at the absolute zero of temperature as some parameter entering its Hamiltonian is varied. These transitions are particularly interesting for, in contrast to their classical finite-temperature counterparts, their dynamic and static critical behaviors are intimately intertwined. Considerable insight is gained by considering the path-integral description of the quantum statistical mechanics of such systems, which takes the form of the {ital classical} statistical mechanics of a system in which time appears as an extra dimension. In particular, this allows the deduction of scaling forms for the finite-temperature behavior, which turns out to be described by the theory of finite-size scaling. It also leads naturally to the notion of a temperature-dependent dephasing length that governs the crossover between quantum and classical fluctuations. Using these ideas, a scaling analysis of experiments on Josephson-junction arrays and quantum-Hall-effect systems is presented. {copyright} {ital 1997} {ital The American Physical Society}

  19. Phase transition in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

    2000-01-01

    In this paper we present a review of selected aspects of Phase transitions in finite systems applied in particular to the liquid-gas phase transition in nuclei. We show that the problem of the non existence of boundary conditions can be solved by introducing a statistical ensemble with an averaged constrained volume. In such an ensemble the microcanonical heat capacity becomes negative in the transition region. We show that the caloric curve explicitly depends on the considered transformation of the volume with the excitation energy and so does not bear direct informations on the characteristics of the phase transition. Conversely, partial energy fluctuations are demonstrated to be a direct measure of the equation of state. Since the heat capacity has a negative branch in the phase transition region, the presence of abnormally large kinetic energy fluctuations is a signal of the liquid gas phase transition. (author)

  20. Non-equilibrium and band tailing in organic conductors

    Indian Academy of Sciences (India)

    . Non-equilibrium due to coupling between applied energy and free electrons can be responsible for the exponential relaxation from non-equilibrium to equilibrium. Keywords. Band tailing; organic conductors; IR spectra; electrical resistivity.

  1. Non-equilibrium dynamics of ultracold atoms in optical lattices

    Science.gov (United States)

    Chen, David

    This thesis describes experiments focused on investigating out-of-equilibrium phenomena in the Bose-Hubbard Model and exploring novel cooling techniques for ultracold gases in optical lattices. In the first experiment, we study quenches across the Mott-insulator-to-superfluid quantum phase transition in the 3D Bose-Hubbard Model. The quench is accomplished by continuously tuning the ratio of the Hubbard energies. We observe that the degree of excitation is proportional to the fraction of atoms that cross the phase boundary, and that the amount of excitations and energy produced during the quench have a power-law dependence on the quench rate. These phenomena suggest an excitation process analogous to the mechanism for defect generation in non-equilibrium classical phase transitions. This experiment constitutes the first observation of the Kibble-Zurek mechanism in a quantum quench. We have reported our findings in Ref. [1]. In a second experiment, published in Ref. [2], we investigate dissipation as a method for cooling a strongly interacting gas. We introduce dissipation via a bosonic reservoir to a strongly interacting bosonic gas in the Mott-insulator regime of a 3D spin-dependent optical lattice. The lattice atoms are excited to a higher energy band using laser-induced Bragg transitions. A weakly interacting superfluid comprised of atoms in a state that does not experience the lattice potential acts as a dissipative bath that interacts with the lattice atoms through collisions. We measure the resulting bath-induced decay using the atomic quasimomentum distribution, and we compare the decay rate with predictions from a weakly interacting model with no free parameters. A competing intrinsic decay mechanism arising from collisions between lattice atoms is also investigated. The presence of intrinsic decay can not be accommodated within a non-interacting framework and signals that strong interactions may play a central role in the lattice-atom dynamics. The

  2. Generalized definitions of phase transitions

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Gulminelli, F.

    2001-09-01

    We define a first order phase transition as a bimodality of the event distribution in the space of observations and we show that this is equivalent to a curvature anomaly of the thermodynamical potential and that it implies the Yang Lee behavior of the zeros of the partition sum. Moreover, it allows to study phase transitions out of equilibrium. (authors)

  3. Non-equilibrium many body dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Creutz, M.; Gyulassy, M.

    1997-09-22

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop.

  4. Non-equilibrium many body dynamics

    International Nuclear Information System (INIS)

    Creutz, M.; Gyulassy, M.

    1997-01-01

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop

  5. Magnetic resonance of phase transitions

    CERN Document Server

    Owens, Frank J; Farach, Horacio A

    1979-01-01

    Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also

  6. PREFACE: International Symposium on Non-Equilibrium Soft Matter 2010 International Symposium on Non-Equilibrium Soft Matter 2010

    Science.gov (United States)

    Kawakatsu, T.; Matsuyama, A.; Ohta, T.; Tanaka, H.; Tanaka, S.

    2011-07-01

    dispersions for soft matter photonics I Muševič, M Škarabot and M Humar Solvation effects in phase transitions in soft matter Akira Onuki, Takeaki Araki and Ryuichi Okamoto Non-equilibrium dynamics of 2D liquid crystals driven by transmembrane gas flow Kazuyoshi Seki, Ken Ueda, Yu-ichi Okumura and Yuka Tabe Roles of bond orientational ordering in glass transition and crystallization Hajime Tanaka Shear banding in thixotropic and normal emulsions José Paredes, Noushine Shahidzadeh-Bonn and Daniel Bonn Effects of hydrodynamic interactions in binary colloidal mixtures driven oppositely by oscillatory external fields Adam Wysocki and Hartmut Löwen Onsager's variational principle in soft matter Masao Doi

  7. Non-equilibrium effects of core-cooling and time-dependent internal heating on mantle flush events

    Directory of Open Access Journals (Sweden)

    D. A. Yuen

    1995-01-01

    Full Text Available We have examined the non-equilibrium effects of core-cooling and time-dependent internal-heating on the thermal evolution of the Earth's mantle and on mantle flush events caused by the two major phase transitions. Both two- and three-dimensional models have been employed. The mantle viscosity responds to the secular cooling through changes in the averaged temperature field. A viscosity which decreases algebraically with the average temperature has been considered. The time-dependent internal-heating is prescribed to decrease exponentially with a single decay time. We have studied the thermal histories with initial Rayleigh numbers between 2 x 107 and 108 . Flush events, driven by the non-equilibrium forcings, are much more dramatic than those produced by the equilibrium boundary conditions and constant internal heating. Multiple flush events are found under non-equilibrium conditions in which there is very little internal heating or very fast decay rates of internal-heating. Otherwise, the flush events take place in a relatively continuous fashion. Prior to massive flush events small-scale percolative structures appear in the 3D temperature fields. Time-dependent signatures, such as the surface heat flux, also exhibits high frequency oscillatory patterns prior to massive flush events. These two observations suggest that the flush event may be a self-organized critical phenomenon. The Nusselt number as a function of the time-varying Ra does not follow the Nusselt vs. Rayleigh number power-law relationship based on equilibrium (constant temperature boundary conditions. Instead Nu(t may vary non-monotonically with time because of the mantle flush events. Convective processes in the mantle operate quite differently under non-equilibrium conditions from its behaviour under the usual equilibrium situations.

  8. Phase transitions in surfactant monolayers

    International Nuclear Information System (INIS)

    Casson, B.D.

    1998-01-01

    Two-dimensional phase transitions have been studied in surfactant monolayers at the air/water interface by sum-frequency spectroscopy and ellipsometry. In equilibrium monolayers of medium-chain alcohols C n H 2n+1 OH (n = 9-14) a transition from a two-dimensional crystalline phase to a liquid was observed at temperatures above the bulk melting point. The small population of gauche defects in the solid phase increased only slightly at the phase transition. A model of the hydrocarbon chains as freely rotating rigid rods allowed the area per molecule and chain tilt in the liquid phase to be determined. The area per molecule, chain tilt and density of the liquid phase all increased with increasing chain length, but for each chain length the density was higher than in a bulk liquid hydrocarbon. In a monolayer of decanol adsorbed at the air/water interface a transition from a two-dimensional liquid to a gas was observed. A clear discontinuity in the coefficient of ellipticity as a function of temperature showed that the transition is first-order. This result suggests that liquid-gas phase transitions in surfactant monolayers may be more widespread than once thought. A solid-liquid phase transition has also been studied in mixed monolayers of dodecanol with an anionic surfactant (sodium dodecyl sulphate) and with a homologous series of cationic surfactants (alkyltrimethylammonium bromides: C n TABs, n = 12, 14, 16). The composition and structure of the mixed monolayers was studied above and below the phase transition. At low temperatures the mixed monolayers were as densely packed as a monolayer of pure dodecanol in its solid phase. At a fixed temperature the monolayers under-went a first-order phase transition to form a phase that was less dense and more conformationally disordered. The proportion of ionic surfactant in the mixed monolayer was greatest in the high temperature phase. As the chain length of the C n TAB increased the number of conformational defects

  9. Non-equilibrium in flowing atmospheric plasmas

    International Nuclear Information System (INIS)

    Haas, J.C.M. de.

    1986-01-01

    This thesis deals with the fundamental aspects of two different plasmas applied in technological processes. The first one is the cesium seeded argon plasma in a closed cycle Magnetohydrodynamic (MHD) generator, the second is the thermal argon plasma in a cascade arc with an imposed flow. In Chapter 2 the influence of non-equilibrium on the mass and energy balances of a plasma is worked out. The general theory presented there can be applied to both the plasma in an MHD generator and to the cascade arc with imposed flow. Introductions to these plasmas are given in the Chapters 3 and 6 respectively. These chapters are both followed by two chapters which treat the theoretical and the experimental investigations. The results are summarized in Chapter 9. (Auth.)

  10. Non-equilibrium effects in the plasmas

    International Nuclear Information System (INIS)

    Einfeld, D.

    1975-01-01

    Radial dependences of non-equilibrium effects of a He plasma were studied in a wall-stabilized short-time discharge. The electron density (nsub(e) = 2.5 x 10 22 m -3 ), the electron temperature and the equilibrium shift were determined by calculations of the continuum beam density and the beam densities of one He-I and one He-II line, respectively. In the discharge axis, the overpopulation factors of the ground state of He-I and He-II are about 75. As the distance to the axis increases, they increase for He-I and decrease for He-II. Except for the usual errors of measurement, the overpopulation factors found here correspond to those calculated from the balance equations (Drawin). (orig./AK) [de

  11. Shape characteristics of equilibrium and non-equilibrium fractal clusters.

    Science.gov (United States)

    Mansfield, Marc L; Douglas, Jack F

    2013-07-28

    It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other

  12. Phase transitions and quantum entropy

    International Nuclear Information System (INIS)

    Arrachea, L.; Canosa, N.; Plastino, A.; Portesi, M.; Rossignoli, R.

    1990-01-01

    An examination is made of the possibility to predict phase transitions of the fundamental state of finite quantum system, knowing the quantum entropy of these states, defined on the basis of the information theory. (Author). 7 refs., 3 figs

  13. Phase transition in finite systems

    International Nuclear Information System (INIS)

    Chomaz, Ph.; Duflot, V.; Duflot, V.; Gulminelli, F.

    2000-01-01

    The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)

  14. Phase transition in finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph.; Duflot, V. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Duflot, V.; Gulminelli, F. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France)

    2000-07-01

    The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)

  15. Atomistic Simulation of Non-Equilibrium Phenomena in Hypersonic Flows

    Science.gov (United States)

    Norman, Paul Erik

    The goal of this work is to model the heterogeneous recombination of atomic oxygen on silica surfaces, which is of interest for accurately predicting the heating on vehicles traveling at hypersonic speeds. This is accomplished by creating a finite rate catalytic model, which describes recombination with a set of elementary gas-surface reactions. Fundamental to a description of surface catalytic reactions are the in situ chemical structures on the surface where recombination can occur. Using molecular dynamics simulations with the Reax GSISiO potential, we find that the chemical sites active in direct gas-phase reactions on silica surfaces consist of a small number of specific structures (or defects). The existence of these defects on real silica surfaces is supported by experimental results and the structure and energetics of these defects have been verified with quantum chemical calculations. The reactions in the finite rate catalytic model are based on the interaction of molecular and atomic oxygen with these defects. Trajectory calculations are used to find the parameters in the forward rate equations, while a combination of detailed balance and transition state theory are used to find the parameters in the reverse rate equations. The rate model predicts that the oxygen recombination coefficient is relatively constant at T (300-1000 K), in agreement with experimental results. At T > 1000 K the rate model predicts a drop off in the oxygen recombination coefficient, in disagreement with experimental results, which predict that the oxygen recombination coefficient increases with temperature. A discussion of the possible reasons for this disagreement, including non-adiabatic collision dynamics, variable surface site concentrations, and additional recombination mechanisms is presented. This thesis also describes atomistic simulations with Classical Trajectory Calculation Direction Simulation Monte Carlo (CTC-DSMC), a particle based method for modeling non-equilibrium

  16. Learning phase transitions by confusion

    Science.gov (United States)

    van Nieuwenburg, Evert P. L.; Liu, Ye-Hua; Huber, Sebastian D.

    2017-02-01

    Classifying phases of matter is key to our understanding of many problems in physics. For quantum-mechanical systems in particular, the task can be daunting due to the exponentially large Hilbert space. With modern computing power and access to ever-larger data sets, classification problems are now routinely solved using machine-learning techniques. Here, we propose a neural-network approach to finding phase transitions, based on the performance of a neural network after it is trained with data that are deliberately labelled incorrectly. We demonstrate the success of this method on the topological phase transition in the Kitaev chain, the thermal phase transition in the classical Ising model, and the many-body-localization transition in a disordered quantum spin chain. Our method does not depend on order parameters, knowledge of the topological content of the phases, or any other specifics of the transition at hand. It therefore paves the way to the development of a generic tool for identifying unexplored phase transitions.

  17. Non equilibrium quantum fields in cosmology

    International Nuclear Information System (INIS)

    Paz, J.P.

    1991-01-01

    The authors discuss the general framework used to construct a quantum mechanical model of the inflationary phase transition. The emer-gence of classical behavior in the longwavelength modes of the inflation is one of the facts that these models should address. For some toy examples (in which the inflation interacts with an environment consti-tuted by other fields) decoherence is shown of the modes with physical wavelength greater than the horizon. The authors use an approach based on a master equation. They take advantage of the similarities that exist between the master equation for the toy cosmological models and the one for the simple Quantum Brownian Motion. Recent results are discussed obtained for the general QBM problem (in which the environment has a generic spectral density). (author). 10 refs

  18. Phase transitions in field theory

    International Nuclear Information System (INIS)

    Carvalho, C.A.A. de; Bollini, C.G.; Giambiagi, J.J.

    1984-01-01

    By means of an example for which the effective potential is explicitly calculable (up to the one loop approximation), it is discussed how a phase transition takes place as the temperature is increased and pass from spontaneously broken symmetry to a phase in which the symmetry is restored. (Author) [pt

  19. Extinction phase transitions in a model of ecological and evolutionary dynamics

    Science.gov (United States)

    Barghathi, Hatem; Tackkett, Skye; Vojta, Thomas

    2017-07-01

    We study the non-equilibrium phase transition between survival and extinction of spatially extended biological populations using an agent-based model. We especially focus on the effects of global temporal fluctuations of the environmental conditions, i.e., temporal disorder. Using large-scale Monte-Carlo simulations of up to 3 × 107 organisms and 105 generations, we find the extinction transition in time-independent environments to be in the well-known directed percolation universality class. In contrast, temporal disorder leads to a highly unusual extinction transition characterized by logarithmically slow population decay and enormous fluctuations even for large populations. The simulations provide strong evidence for this transition to be of exotic infinite-noise type, as recently predicted by a renormalization group theory. The transition is accompanied by temporal Griffiths phases featuring a power-law dependence of the life time on the population size.

  20. Phase transitions and neutron scattering

    International Nuclear Information System (INIS)

    Shirane, G.

    1993-01-01

    A review is given of recent advances in neutron scattering studies of solid state physics. I have selected the study of a structural phase transition as the best example to demonstrate the power of neutron scattering techniques. Since energy analysis is relatively easy, the dynamical aspects of a transition can be elucidated by the neutron probe. I shall discuss in some detail current experiments on the 100 K transition in SrTiO 3 , the crystal which has been the paradigm of neutron studies of phase transitions for many years. This new experiment attempts to clarify the relation between the neutron central peak, observed in energy scans, and the two length scales observed in recent x-ray diffraction studies where only scans in momentum space are possible. (author)

  1. Phase transitions and neutron scattering

    International Nuclear Information System (INIS)

    Shirane, G.

    1993-01-01

    A review is given of recent advances in neutron scattering studies of solid state physics. The author has selected the study of a structural phase transition as the best example to demonstrate the power of neutron scattering techniques. Since energy analysis is relatively easy, the dynamical aspects of a transition can be elucidated by the neutron probe. He will discuss in some detail current experiments on the 100K transition in SrTiO 3 , the crystal which has been the paradigm of neutron studies of phase transitions for many years. This new experiment attempts to clarify the relation between the neutron central peak, observed in energy scans, and the two length scales observed in recent x-ray diffraction studies where only scans in momentum space are possible

  2. Incommensurate phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Currat, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1996-11-01

    We review the characteristic aspects of modulated crystals from the point of view of inelastic neutron scattering. We discuss the phenomenological Landau theory of the normal-to-incommensurate displacive instability and its predictions concerning the fluctuation spectrum of the modulated phase. General results on the form of the normal-mode eigenvectors and on the inelastic scattering channels through which they couple to the probe are established using the superspace approach. We illustrate these results on a simple discrete model symmetry and we review available inelastic neutron scattering data on several displacively modulated compounds. (author) 21 figs., 73 refs.

  3. NON-EQUILIBRIUM HELIUM IONIZATION IN AN MHD SIMULATION OF THE SOLAR ATMOSPHERE

    International Nuclear Information System (INIS)

    Golding, Thomas Peter; Carlsson, Mats; Leenaarts, Jorrit

    2016-01-01

    The ionization state of the gas in the dynamic solar chromosphere can depart strongly from the instantaneous statistical equilibrium commonly assumed in numerical modeling. We improve on earlier simulations of the solar atmosphere that only included non-equilibrium hydrogen ionization by performing a 2D radiation-magnetohydrodynamics simulation featuring non-equilibrium ionization of both hydrogen and helium. The simulation includes the effect of hydrogen Lyα and the EUV radiation from the corona on the ionization and heating of the atmosphere. Details on code implementation are given. We obtain helium ion fractions that are far from their equilibrium values. Comparison with models with local thermodynamic equilibrium (LTE) ionization shows that non-equilibrium helium ionization leads to higher temperatures in wavefronts and lower temperatures in the gas between shocks. Assuming LTE ionization results in a thermostat-like behavior with matter accumulating around the temperatures where the LTE ionization fractions change rapidly. Comparison of DEM curves computed from our models shows that non-equilibrium ionization leads to more radiating material in the temperature range 11–18 kK, compared to models with LTE helium ionization. We conclude that non-equilibrium helium ionization is important for the dynamics and thermal structure of the upper chromosphere and transition region. It might also help resolve the problem that intensities of chromospheric lines computed from current models are smaller than those observed

  4. Experimental studies in non-equilibrium physics

    Science.gov (United States)

    Cressman, John Robert, Jr.

    This work is a collection of three experiments aimed at studying different facets of non-equilibrium dynamics. Chapter I concerns strongly compressible turbulence, which turns out to be very different from incompressible turbulence. The focus is on the dispersion of contaminants in such a flow. This type of turbulence can be studied, at very low mach number, by measuring the velocity fields of particles that float on a turbulently stirred body of water. It turns out that in the absence of incompressibility, the turbulence causes particles to cluster rather than to disperse. The implications of the observations are far reaching and include the transport of pollutants on the oceans surface, phytoplankton growth, as well as industrial applications. Chapter II deals with the effects of polymer additives on drag reduction and turbulent suppression, a well-known phenomenon that is not yet understood. In an attempt to simplify the problem, the effects of a polymer additive were investigated in a vortex street formed in a flowing soap film. Measurements suggest that an increase in elongational viscosity is responsible for a substantial reduction in periodic velocity fluctuations. This study also helps to illuminate the mechanism responsible for vortex separation in the wake of a bluff body. Chapter III describes an experiment designed to test a theoretical approach aimed at generalizing the classical fluctuation dissipation theorem (FDT). This theorem applies to systems driven only slightly away from thermal equilibrium, whereas ours, a liquid crystal under-going electroconvection, is so strongly driven, that the FDT does not apply. Both theory and experiment focus on the flux in global power fluctuations. Physical limitations did not permit a direct test of the theory, however it was possible to establish several interesting characteristics of the system: the source of the fluctuations is the transient defect structures that are generated when the system is driven hard

  5. Phase transitions in operational risk.

    Science.gov (United States)

    Anand, Kartik; Kühn, Reimer

    2007-01-01

    In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for the dynamical evolution of order parameters are obtained. Under equilibrium conditions, expressions for the stationary states are also obtained. Consequences of the analytical theory developed are analyzed using phase diagrams. We find coexistence of operational and nonoperational phases, much as in liquid-gas systems. Such systems are susceptible to discontinuous phase transitions from the operational to nonoperational phase via catastrophic breakdown. We find this feature to be robust against variation of the microscopic modeling assumptions.

  6. Critical phase transitions during ablation of atrial fibrillation

    Science.gov (United States)

    Iravanian, Shahriar; Langberg, Jonathan J.

    2017-09-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia with significant morbidity and mortality. Pharmacological agents are not very effective in the management of AF. Therefore, ablation procedures have become the mainstay of AF management. The irregular and seemingly chaotic atrial activity in AF is caused by one or more meandering spiral waves. Previously, we have shown the presence of sudden rhythm organization during ablation of persistent AF. We hypothesize that the observed transitions from a disorganized to an organized rhythm is a critical phase transition. Here, we explore this hypothesis by simulating ablation in an anatomically-correct 3D AF model. In 722 out of 2160 simulated ablation, at least one sudden transition from AF to an organized rhythm (flutter) was noted (33%). They were marked by a sudden decrease in the cycle length entropy and increase in the mean cycle length. At the same time, the number of reentrant wavelets decreased from 2.99 ± 0.06 in AF to 1.76 ± 0.05 during flutter, and the correlation length scale increased from 13.3 ± 1.0 mm to 196.5 ± 86.6 mm (both P < 0.0001). These findings are consistent with the hypothesis that transitions from AF to an anatomical flutter behave as phase transitions in complex non-equilibrium dynamical systems with flutter acting as an absorbing state. Clinically, the facilitation of phase transition should be considered a novel mechanism of ablation and may help to design effective ablation strategies.

  7. Quantum Femtosecond Magnetism: Phase Transition in Step with Light in a Strongly Correlated Manganese Oxide

    Science.gov (United States)

    Wang, Jigang

    2014-03-01

    Research of non-equilibrium phase transitions of strongly correlated electrons is built around addressing an outstanding challenge: how to achieve ultrafast manipulation of competing magnetic/electronic phases and reveal thermodynamically hidden orders at highly non-thermal, femtosecond timescales? Recently we reveal a new paradigm called quantum femtosecond magnetism-photoinduced femtosecond magnetic phase transitions driven by quantum spin flip fluctuations correlated with laser-excited inter-atomic coherent bonding. We demonstrate an antiferromagnetic (AFM) to ferromagnetic (FM) switching during about 100 fs laser pulses in a colossal magneto-resistive manganese oxide. Our results show a huge photoinduced femtosecond spin generation, measured by magnetic circular dichroism, with photo-excitation threshold behavior absent in the picosecond dynamics. This reveals an initial quantum coherent regime of magnetism, while the optical polarization/coherence still interacts with the spins to initiate local FM correlations that compete with the surrounding AFM matrix. Our results thus provide a framework that explores quantum non-equilibrium kinetics to drive phase transitions between exotic ground states in strongly correlated elecrons, and raise fundamental questions regarding some accepted rules, such as free energy and adiabatic potential surface. This work is in collaboration with Tianqi Li, Aaron Patz, Leonidas Mouchliadis, Jiaqiang Yan, Thomas A. Lograsso, Ilias E. Perakis. This work was supported by the National Science Foundation (contract no. DMR-1055352). Material synthesis at the Ames Laboratory was supported by the US Department of Energy-Basic Energy Sciences (contract no. DE-AC02-7CH11358).

  8. Exploring Chemical and Thermal Non-equilibrium in Nitrogen Arcs

    International Nuclear Information System (INIS)

    Ghorui, S; Das, A K

    2012-01-01

    Plasma torches operating with nitrogen are of special importance as they can operate with usual tungsten based refractory electrodes and offer radical rich non-oxidizing high temperature environment for plasma chemistry. Strong gradients in temperature as well as species densities and huge convective fluxes lead to varying degrees of chemical non-equilibrium in associated regions. An axi-symmetric two-temperature chemical non-equilibrium model of a nitrogen plasma torch has been developed to understand the effects of thermal and chemical non-equilibrium in arcs. A 2-D finite volume CFD code in association with a non-equilibrium property routine enabled extraction of steady state self-consistent distributions of various plasma quantities inside the torch under various thermal and chemical non-equilibrium conditions. Chemical non-equilibrium has been incorporated through computation of diffusive and convective fluxes in each finite volume cell in every iteration and associating corresponding thermodynamic and transport properties through the scheme of 'chemical non-equilibrium parameter' introduced by Ghorui et. al. Recombination coefficient data from Nahar et. al. and radiation data from Krey and Morris have been used in the simulation. Results are presented for distributions of temperature, pressure, velocity, current density, electric potential, species densities and chemical non-equilibrium effects. Obtained results are compared with similar results under LTE.

  9. Heavy ion seeks phase transition

    International Nuclear Information System (INIS)

    Ducomet, B.

    1987-11-01

    The emergence of the phase transition language in the context of heavy ion collisions at the so called ''GANIL energies'' (typically 10 - 100 MeV/u) has led us to make more precise some current definitions adopted in statistical mechanics, and used in a much less clear way in the nuclear physics context [fr

  10. Effective field theory with differential operator technique for dynamic phase transition in ferromagnetic Ising model

    International Nuclear Information System (INIS)

    Kinoshita, Takehiro; Fujiyama, Shinya; Idogaki, Toshihiro; Tokita, Masahiko

    2009-01-01

    The non-equilibrium phase transition in a ferromagnetic Ising model is investigated by use of a new type of effective field theory (EFT) which correctly accounts for all the single-site kinematic relations by differential operator technique. In the presence of a time dependent oscillating external field, with decrease of the temperature the system undergoes a dynamic phase transition, which is characterized by the period averaged magnetization Q, from a dynamically disordered state Q = 0 to the dynamically ordered state Q ≠ 0. The results of the dynamic phase transition point T c determined from the behavior of the dynamic magnetization and the Liapunov exponent provided by EFT are improved than that of the standard mean field theory (MFT), especially for the one dimensional lattice where the standard MFT gives incorrect result of T c = 0 even in the case of zero external field.

  11. Controlling competing electronic orders via non-equilibrium acoustic phonons

    Science.gov (United States)

    Schuett, Michael; Orth, Peter; Levchenko, Alex; Fernandes, Rafael

    The interplay between multiple electronic orders is a hallmark of strongly correlated systems displaying unconventional superconductivity. While doping, pressure, and magnetic field are the standard knobs employed to assess these different phases, ultrafast pump-and-probe techniques opened a new window to probe these systems. Recent examples include the ultrafast excitation of coherent optical phonons coupling to electronic states in cuprates and iron pnictides. In this work, we demonstrate theoretically that non-equilibrium acoustic phonons provide a promising framework to manipulate competing electronic phases and favor unconventional superconductivity over other states. In particular, we show that electrons coupled to out-of-equilibrium anisotropic acoustic phonons enter a steady state in which the effective electronic temperature varies around the Fermi surface. Such a momentum-dependent temperature can then be used to selectively heat electronic states that contribute primarily to density-wave instabilities, reducing their competition with superconductivity. We illustrate this phenomenon by computing the microscopic steady-state phase diagram of the iron pnictides, showing that superconductivity is enhanced with respect to the competing antiferromagnetic phase.

  12. Phase transitions and critical phenomena

    CERN Document Server

    Domb, Cyril

    2001-01-01

    The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies.Statistical physics, and more specifically, the theory of transitions between states of matter, more or less defines what we know about 'everyday' matter and its transformations.The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable in

  13. A porous flow approach to model thermal non-equilibrium applicable to melt migration

    Science.gov (United States)

    Schmeling, Harro; Marquart, Gabriele; Grebe, Michael

    2018-01-01

    We develop an approach for heat exchange between a fluid and a solid phase of a porous medium where the temperatures of the fluid and matrix are not in thermal equilibrium. The formulation considers moving of the fluid within a resting or deforming porous matrix in an Eulerian coordinate system. The approach can be applied, for example, to partially molten systems or to brine transport in porous rocks. We start from an existing theory for heat exchange where the energy conservation equations for the fluid and the solid phases are separated and coupled by a heat exchange term. This term is extended to account for the full history of heat exchange. It depends on the microscopic geometry of the fluid phase. For the case of solid containing hot, fluid-filled channels, we derive an expression based on a time-dependent Fourier approach for periodic half-waves. On the macroscopic scale, the temporal evolution of the heat exchange leads to a convolution integral along the flow path of the solid, which simplifies considerably in case of a resting matrix. The evolution of the temperature in both phases with time is derived by inserting the heat exchange term into the energy equations. We explore the effects of thermal non-equilibrium between fluid and solid by considering simple cases with sudden temperature differences between fluid and solid as initial or boundary conditions, and by varying the fluid velocity with respect to the resting porous solid. Our results agree well with an analytical solution for non-moving fluid and solid. The temperature difference between solid and fluid depends on the Peclet number based on the Darcy velocity. For Peclet numbers larger than 1, the temperature difference after one diffusion time reaches 5 per cent of \\tilde{T} or more (\\tilde{T} is a scaling temperature, e.g. the initial temperature difference). Thus, our results imply that thermal non-equilibrium can play an important role for melt migration through partially molten systems

  14. Phase transitions in dense matter

    Science.gov (United States)

    Dexheimer, Veronica; Hempel, Matthias; Iosilevskiy, Igor; Schramm, Stefan

    2017-11-01

    As the density of matter increases, atomic nuclei disintegrate into nucleons and, eventually, the nucleons themselves disintegrate into quarks. The phase transitions (PT's) between these phases can vary from steep first order to smooth crossovers, depending on certain conditions. First-order PT's with more than one globally conserved charge, so-called non-congruent PT's, have characteristic differences compared to congruent PT's. In this conference proceeding we discuss the non-congruence of the quark deconfinement PT at high densities and/or temperatures relevant for heavy-ion collisions, neutron stars, proto-neutron stars, supernova explosions, and compact-star mergers.

  15. Phase Transitions and Free Boundaries

    Science.gov (United States)

    1991-10-31

    V PHASE TRANSITIONS AND FREE BOUNDARIES FINAL REPORT AD -A243 412 DECO 3 1991 WILLARD MILLER, JR. U October 31, 1991 OFFICE OF NAVAL RESEARCH N0014-91...Einstein- University of Michigan Yang/Mills equations Abstract: The only static solution to the vacuum Einstein equations is the celebrated Schwarzschild ...equations to Maxwell’s equations, the only static solution is the Reissner- Nordstr6m metric which is again singular at the origin. Finally, for any gauge

  16. Lattice Stability and Interatomic Potential of Non-equilibrium Warm Dense Gold

    Science.gov (United States)

    Chen, Z.; Mo, M.; Soulard, L.; Recoules, V.; Hering, P.; Tsui, Y. Y.; Ng, A.; Glenzer, S. H.

    2017-10-01

    Interatomic potential is central to the calculation and understanding of the properties of matter. A manifestation of interatomic potential is lattice stability in the solid-liquid transition. Recently, we have used frequency domain interferometry (FDI) to study the disassembly of ultrafast laser heated warm dense gold nanofoils. The FDI measurement is implemented by a spatial chirped single-shot technique. The disassembly of the sample is characterized by the change in phase shift of the reflected probe resulted from hydrodynamic expansion. The experimental data is compared with the results of two-temperature molecular dynamic simulations based on a highly optimized embedded-atom-method (EAM) interatomic potential. Good agreement is found for absorbed energy densities of 0.9 to 4.3MJ/kg. This provides the first demonstration of the applicability of an EAM interatomic potential in the non-equilibrium warm dense matter regime. The MD simulations also reveal the critical role of pressure waves in solid-liquid transition in ultrafast laser heated nanofoils. This work is supported by DOE Office of Science, Fusion Energy Science under FWP 100182, and SLAC LDRD program.

  17. Non-equilibrium statistical mechanics theory for the large scales of geophysical flows

    Science.gov (United States)

    Eric, S.; Bouchet, F.

    2010-12-01

    The aim of any theory of turbulence is to understand the statistical properties of the velocity field. As a huge number of degrees of freedom is involved, statistical mechanics is a natural approach. The self-organization of two-dimensional and geophysical turbulent flows is addressed based on statistical mechanics methods. We discuss classical and recent works on this subject; from the statistical mechanics basis of the theory up to applications to Jupiter’s troposphere and ocean vortices and jets. The equilibrium microcanonical measure is built from the Liouville theorem. Important statistical mechanics concepts (large deviations, mean field approach) and thermodynamic concepts (ensemble inequivalence, negative heat capacity) are briefly explained and used to predict statistical equilibria for turbulent flows. This is applied to make quantitative models of two-dimensional turbulence, the Great Red Spot and other Jovian vortices, ocean jets like the Gulf-Stream, and ocean vortices. A detailed comparison between these statistical equilibria and real flow observations will be discussed. We also present recent results for non-equilibrium situations, for which forces and dissipation are in a statistical balance. As an example, the concept of phase transition allows us to describe drastic changes of the whole system when a few external parameters are changed. F. Bouchet and E. Simonnet, Random Changes of Flow Topology in Two-Dimensional and Geophysical Turbulence, Physical Review Letters 102 (2009), no. 9, 094504-+. F. Bouchet and J. Sommeria, Emergence of intense jets and Jupiter's Great Red Spot as maximum-entropy structures, Journal of Fluid Mechanics 464 (2002), 165-207. A. Venaille and F. Bouchet, Ocean rings and jets as statistical equilibrium states, submitted to JPO F. Bouchet and A. Venaille, Statistical mechanics of two-dimensional and geophysical flows, submitted to Physics Reports Non-equilibrium phase transitions for the 2D Navier-Stokes equations with

  18. Non-Equilibrium Thermodynamics of Self-Replicating Protocells

    DEFF Research Database (Denmark)

    Fellermann, Harold; Corominas-Murtra, Bernat; Hansen, Per Lyngs

    2018-01-01

    We provide a non-equilibrium thermodynamic description of the life-cycle of a droplet based, chemically feasible, system of protocells. By coupling the protocells metabolic kinetics with its thermodynamics, we demonstrate how the system can be driven out of equilibrium to ensure protocell growth...... and replication. This coupling allows us to derive the equations of evolution and to rigorously demonstrate how growth and replication life-cycle can be understood as a non-equilibrium thermodynamic cycle. The process does not appeal to genetic information or inheritance, and is based only on non......-equilibrium physics considerations. Our non-equilibrium thermodynamic description of simple, yet realistic, processes of protocell growth and replication, represents an advance in our physical understanding of a central biological phenomenon both in connection to the origin of life and for modern biology....

  19. Electrolytes: transport properties and non-equilibrium thermodynamics

    International Nuclear Information System (INIS)

    Miller, D.G.

    1980-12-01

    This paper presents a review on the application of non-equilibrium thermodynamics to transport in electrolyte solutions, and some recent experimental work and results for mutual diffusion in electrolyte solutions

  20. Synchronization of Stochastically Coupled Oscillators: Dynamical Phase Transitions and Large Deviations Theory (or Birds and Frogs)

    Science.gov (United States)

    Teodorescu, Razvan

    2009-10-01

    Systems of oscillators coupled non-linearly (stochastically or not) are ubiquitous in nature and can explain many complex phenomena: coupled Josephson junction arrays, cardiac pacemaker cells, swarms or flocks of insects and birds, etc. They are know to have a non-trivial phase diagram, which includes chaotic, partially synchronized, and fully synchronized phases. A traditional model for this class of problems is the Kuramoto system of oscillators, which has been studied extensively for the last three decades. The model is a canonical example for non-equilibrium, dynamical phase transitions, so little understood in physics. From a stochastic analysis point of view, the transition is described by the large deviations principle, which offers little information on the scaling behavior near the critical point. I will discuss a special case of the model, which allows a rigorous analysis of the critical properties of the model, and reveals a new, anomalous scaling behavior in the vicinity of the critical point.

  1. Non-equilibrium dynamics from RPMD and CMD.

    Science.gov (United States)

    Welsch, Ralph; Song, Kai; Shi, Qiang; Althorpe, Stuart C; Miller, Thomas F

    2016-11-28

    We investigate the calculation of approximate non-equilibrium quantum time correlation functions (TCFs) using two popular path-integral-based molecular dynamics methods, ring-polymer molecular dynamics (RPMD) and centroid molecular dynamics (CMD). It is shown that for the cases of a sudden vertical excitation and an initial momentum impulse, both RPMD and CMD yield non-equilibrium TCFs for linear operators that are exact for high temperatures, in the t = 0 limit, and for harmonic potentials; the subset of these conditions that are preserved for non-equilibrium TCFs of non-linear operators is also discussed. Furthermore, it is shown that for these non-equilibrium initial conditions, both methods retain the connection to Matsubara dynamics that has previously been established for equilibrium initial conditions. Comparison of non-equilibrium TCFs from RPMD and CMD to Matsubara dynamics at short times reveals the orders in time to which the methods agree. Specifically, for the position-autocorrelation function associated with sudden vertical excitation, RPMD and CMD agree with Matsubara dynamics up to O(t 4 ) and O(t 1 ), respectively; for the position-autocorrelation function associated with an initial momentum impulse, RPMD and CMD agree with Matsubara dynamics up to O(t 5 ) and O(t 2 ), respectively. Numerical tests using model potentials for a wide range of non-equilibrium initial conditions show that RPMD and CMD yield non-equilibrium TCFs with an accuracy that is comparable to that for equilibrium TCFs. RPMD is also used to investigate excited-state proton transfer in a system-bath model, and it is compared to numerically exact calculations performed using a recently developed version of the Liouville space hierarchical equation of motion approach; again, similar accuracy is observed for non-equilibrium and equilibrium initial conditions.

  2. Thermodynamic chemical energy transfer mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium chemical reactions

    International Nuclear Information System (INIS)

    Roh, Heui-Seol

    2015-01-01

    Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms

  3. Achieving Radiation Tolerance through Non-Equilibrium Grain Boundary Structures.

    Science.gov (United States)

    Vetterick, Gregory A; Gruber, Jacob; Suri, Pranav K; Baldwin, Jon K; Kirk, Marquis A; Baldo, Pete; Wang, Yong Q; Misra, Amit; Tucker, Garritt J; Taheri, Mitra L

    2017-09-25

    Many methods used to produce nanocrystalline (NC) materials leave behind non-equilibrium grain boundaries (GBs) containing excess free volume and higher energy than their equilibrium counterparts with identical 5 degrees of freedom. Since non-equilibrium GBs have increased amounts of both strain and free volume, these boundaries may act as more efficient sinks for the excess interstitials and vacancies produced in a material under irradiation as compared to equilibrium GBs. The relative sink strengths of equilibrium and non-equilibrium GBs were explored by comparing the behavior of annealed (equilibrium) and as-deposited (non-equilibrium) NC iron films on irradiation. These results were coupled with atomistic simulations to better reveal the underlying processes occurring on timescales too short to capture using in situ TEM. After irradiation, NC iron with non-equilibrium GBs contains both a smaller number density of defect clusters and a smaller average defect cluster size. Simulations showed that excess free volume contribute to a decreased survival rate of point defects in cascades occurring adjacent to the GB and that these boundaries undergo less dramatic changes in structure upon irradiation. These results suggest that non-equilibrium GBs act as more efficient sinks for defects and could be utilized to create more radiation tolerant materials in future.

  4. Gibbs measures and phase transitions

    CERN Document Server

    Georgii, Hans-Otto

    2011-01-01

    From a review of the first edition: ""This book […] covers in depth a broad range of topics in the mathematical theory of phase transition in statistical mechanics. […] It is in fact one of the author's stated aims that this comprehensive monograph should serve both as an introductory text and as a reference for the expert."" (F. Papangelou, Zentralblatt MATH) The second edition has been extended by a new section on large deviations and some comments on the more recent developments in the area.

  5. Phase transitions and critical phenomena

    CERN Document Server

    Domb, Cyril

    2000-01-01

    The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what m

  6. Light scattering near phase transitions

    CERN Document Server

    Cummins, HZ

    1983-01-01

    Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.

  7. Phase transition in tensor models

    Energy Technology Data Exchange (ETDEWEB)

    Delepouve, Thibault [Laboratoire de Physique Théorique, CNRS UMR 8627, Université Paris Sud,91405 Orsay Cedex (France); Centre de Physique Théorique, CNRS UMR 7644, École Polytechnique,91128 Palaiseau Cedex (France); Gurau, Razvan [Centre de Physique Théorique, CNRS UMR 7644, École Polytechnique,91128 Palaiseau Cedex (France); Perimeter Institute for Theoretical Physics,31 Caroline St. N, N2L 2Y5, Waterloo, ON (Canada)

    2015-06-25

    Generalizing matrix models, tensor models generate dynamical triangulations in any dimension and support a 1/N expansion. Using the intermediate field representation we explicitly rewrite a quartic tensor model as a field theory for a fluctuation field around a vacuum state corresponding to the resummation of the entire leading order in 1/N (a resummation of the melonic family). We then prove that the critical regime in which the continuum limit in the sense of dynamical triangulations is reached is precisely a phase transition in the field theory sense for the fluctuation field.

  8. First principles modeling of hydrocarbons conversion in non-equilibrium plasma

    Energy Technology Data Exchange (ETDEWEB)

    Deminsky, M.A.; Strelkova, M.I.; Durov, S.G.; Jivotov, V.K.; Rusanov, V.D.; Potapkin, B.V. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)

    2001-07-01

    Theoretical justification of catalytic activity of non-equilibrium plasma in hydrocarbons conversion process is presented in this paper. The detailed model of highest hydrocarbons conversion includes the gas-phase reactions, chemistry of the growth of polycyclic aromatic hydrocarbons (PAHs), precursor of soot particles formation, neutral, charged clusters and soot particle formation, ion-molecular gas-phase and heterogeneous chemistry. The results of theoretical analysis are compared with experimental results. (authors)

  9. Dynamical constraints on phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Morawetz, K. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite, 14 - Caen (France)

    2000-07-01

    The numerical solutions of nonlocal and local Boltzmann kinetic equations for the simulation of central heavy ion reactions are parameterized in terms of time dependent thermodynamical variables in the Fermi liquid sense. This allows to discuss dynamical trajectories in phase space. The nonequilibrium state is characterized by non-isobaric, non-isochoric etc conditions, called iso-nothing conditions. Therefore a combination of thermodynamical observables is constructed which allows to locate instabilities and points of possible phase transition in a dynamical sense. We find two different mechanisms of instability, a short time surface - dominated instability and later a spinodal - dominated volume instability. The latter one occurs only if the incident energies are not exceeding much the Fermi energy and might be attributed to spinodal decomposition. Oppositely the fast surface explosion occurs far outside the spinodal and pertains also in the cases where the system develops too fast for suffering the spinodal decomposition and where the system approaches equilibrium outside the spinodal. (author)

  10. Dynamical constraints on phase transitions

    International Nuclear Information System (INIS)

    Morawetz, K.

    2000-01-01

    The numerical solutions of nonlocal and local Boltzmann kinetic equations for the simulation of central heavy ion reactions are parameterized in terms of time dependent thermodynamical variables in the Fermi liquid sense. This allows to discuss dynamical trajectories in phase space. The nonequilibrium state is characterized by non-isobaric, non-isochoric etc conditions, called iso-nothing conditions. Therefore a combination of thermodynamical observables is constructed which allows to locate instabilities and points of possible phase transition in a dynamical sense. We find two different mechanisms of instability, a short time surface - dominated instability and later a spinodal - dominated volume instability. The latter one occurs only if the incident energies are not exceeding much the Fermi energy and might be attributed to spinodal decomposition. Oppositely the fast surface explosion occurs far outside the spinodal and pertains also in the cases where the system develops too fast for suffering the spinodal decomposition and where the system approaches equilibrium outside the spinodal. (author)

  11. Symmetry and Phase Transitions in Nuclei

    International Nuclear Information System (INIS)

    Iachello, F.

    2009-01-01

    Phase transitions in nuclei have received considerable attention in recent years, especially after the discovery that, contrary to expectations, systems at the critical point of a phase transition display a simple structure. In this talk, quantum phase transitions (QPT), i.e. phase transitions that occur as a function of a coupling constant that appears in the quantum Hamiltonian, H, describing the system, will be reviewed and experimental evidence for their occurrence in nuclei will be presented. The phase transitions discussed in the talk will be shape phase transitions. Different shapes have different symmetries, classified by the dynamic symmetries of the Interacting Boson Model, U(5), SU(3) and SO(6). Very recently, the concept of Quantum Phase Transitions has been extended to Excited State Quantum Phase Transitions (ESQPT). This extension will be discussed and some evidence for incipient ESQPT in nuclei will be presented. Systems at the critical point of a phase transition are called 'critical systems'. Approximate analytic formulas for energy spectra and other properties of 'critical nuclei', in particular for nuclei at the critical point of the second order U(5)-SO(6) transition, called E(5), and along the line of first order U(5)-SU(3) transitions, called X(5), will be presented. Experimental evidence for 'critical nuclei' will be also shown. Finally, the microscopic derivation of shape phase transitions in nuclei within the framework of density functional methods will be briefly discussed.(author)

  12. Potential and flux field landscape theory. II. Non-equilibrium thermodynamics of spatially inhomogeneous stochastic dynamical systems

    International Nuclear Information System (INIS)

    Wu, Wei; Wang, Jin

    2014-01-01

    We have established a general non-equilibrium thermodynamic formalism consistently applicable to both spatially homogeneous and, more importantly, spatially inhomogeneous systems, governed by the Langevin and Fokker-Planck stochastic dynamics with multiple state transition mechanisms, using the potential-flux landscape framework as a bridge connecting stochastic dynamics with non-equilibrium thermodynamics. A set of non-equilibrium thermodynamic equations, quantifying the relations of the non-equilibrium entropy, entropy flow, entropy production, and other thermodynamic quantities, together with their specific expressions, is constructed from a set of dynamical decomposition equations associated with the potential-flux landscape framework. The flux velocity plays a pivotal role on both the dynamic and thermodynamic levels. On the dynamic level, it represents a dynamic force breaking detailed balance, entailing the dynamical decomposition equations. On the thermodynamic level, it represents a thermodynamic force generating entropy production, manifested in the non-equilibrium thermodynamic equations. The Ornstein-Uhlenbeck process and more specific examples, the spatial stochastic neuronal model, in particular, are studied to test and illustrate the general theory. This theoretical framework is particularly suitable to study the non-equilibrium (thermo)dynamics of spatially inhomogeneous systems abundant in nature. This paper is the second of a series

  13. On the use of stochastic differential geometry for non-equilibrium thermodynamic modeling and control

    Science.gov (United States)

    Muratore-Ginanneschi, Paolo

    2013-07-01

    We discuss the relevance of geometric concepts in the theory of stochastic differential equations for applications to the theory of non-equilibrium thermodynamics of small systems. In particular, we show how the Eells-Elworthy-Malliavin covariant construction of the Wiener process on a Riemann manifold provides a physically transparent formulation of optimal control problems of finite-time thermodynamic transitions. Based on this formulation, we turn to an evaluative discussion of recent results on optimal thermodynamic control and their interpretation.

  14. Thermal non-equilibrium in heterogeneous media

    CERN Document Server

    de Lemos, Marcelo J S

    2016-01-01

    This book presents, in a self-contained fashion, a series of studies on flow and heat transfer in porous media, in which distinct energy balances are considered for the porous matrix and for the permeating fluid. Detailed mathematical modeling is presented considering both volume and time averaging operators simultaneously applied to the governing equations. System involving combustion in the gaseous phase, moving bed and double-diffusion mechanism are analyzed. Numerical results are presented for each case. In the end, this book contains the description of a tool that might benefit engineers in developing and designing more efficient thermal equipment.

  15. Hypersonic Transition and Turbulence with Non-Equilibrium Thermochemistry

    Science.gov (United States)

    2009-08-31

    unsolved problem in classical physics’ by Nobel-prize winning physicist Richard Feynman . Similar statements regarding the intricacies of turbulence have...jets and turbulence.’ MS thesis (2006). 2. B. M. Riley, J. C. Richard and S. S. Girirnaji. ’Magnetic field effects on axis-switching and notabilities...B. M. Riley, J. C. Richard and S. S. Girirnaji. ’Assessment of magneto-hydrodynamic Lattice-Boltzmann schemes in turbulence and rectangular jets

  16. QCD Phase Transitions, Volume 15

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, T.; Shuryak, E.

    1999-03-20

    The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.

  17. Li-ion batteries: Phase transition

    International Nuclear Information System (INIS)

    Hou Peiyu; Zhang Yantao; Zhang Lianqi; Chu Geng; Gao Jian

    2016-01-01

    Progress in the research on phase transitions during Li + extraction/insertion processes in typical battery materials is summarized as examples to illustrate the significance of understanding phase transition phenomena in Li-ion batteries. Physical phenomena such as phase transitions (and resultant phase diagrams) are often observed in Li-ion battery research and already play an important role in promoting Li-ion battery technology. For example, the phase transitions during Li + insertion/extraction are highly relevant to the thermodynamics and kinetics of Li-ion batteries, and even physical characteristics such as specific energy, power density, volume variation, and safety-related properties. (topical review)

  18. Sound speed during the QCD phase transition

    International Nuclear Information System (INIS)

    Nagasawa, Michiyasu; Yokoyama, Jun'ichi

    1998-01-01

    The Jeans scale is estimated during the coexistence epoch of quark-gluon and hadron phases in the first-order QCD phase transition. It is shown that, contrary to previous claims, reduction of the sound speed is so little that the phase transition does not affect evolution of cosmological density fluctuations appreciably. (author)

  19. Limiting processes in non-equilibrium classical statistical mechanics

    International Nuclear Information System (INIS)

    Jancel, R.

    1983-01-01

    After a recall of the basic principles of the statistical mechanics, the results of ergodic theory, the transient at the thermodynamic limit and his link with the transport theory near the equilibrium are analyzed. The fundamental problems put by the description of non-equilibrium macroscopic systems are investigated and the kinetic methods are stated. The problems of the non-equilibrium statistical mechanics are analyzed: irreversibility and coarse-graining, macroscopic variables and kinetic description, autonomous reduced descriptions, limit processes, BBGKY hierarchy, limit theorems [fr

  20. Convection with local thermal non-equilibrium and microfluidic effects

    CERN Document Server

    Straughan, Brian

    2015-01-01

    This book is one of the first devoted to an account of theories of thermal convection which involve local thermal non-equilibrium effects, including a concentration on microfluidic effects. The text introduces convection with local thermal non-equilibrium effects in extraordinary detail, making it easy for readers newer to the subject area to understand. This book is unique in the fact that it addresses a large number of convection theories and provides many new results which are not available elsewhere. This book will be useful to researchers from engineering, fluid mechanics, and applied mathematics, particularly those interested in microfluidics and porous media.

  1. Consistent simulations of substellar atmospheres and non-equilibrium dust-cloud formation

    OpenAIRE

    Helling, Christiane; Dehn, Matthias; Woitke, Peter; Hauschildt, Peter H.

    2008-01-01

    We aim to understand cloud formation in substellar objects. We combined the non-equilibrium, stationary cloud model of Helling, Woitke & Thi (2008; seed formation, growth, evaporation, gravitational settling, element conservation) with the general-purpose model atmosphere code PHOENIX (radiative transfer, hydrostatic equilibrium, mixing length theory, chemical equilibrium) in order to consistently calculate cloud formation and radiative transfer with their feedback on convection and gas phase...

  2. Many-body quantum electrodynamics networks: Non-equilibrium condensed matter physics with light

    Science.gov (United States)

    Le Hur, Karyn; Henriet, Loïc; Petrescu, Alexandru; Plekhanov, Kirill; Roux, Guillaume; Schiró, Marco

    2016-10-01

    We review recent developments regarding the quantum dynamics and many-body physics with light, in superconducting circuits and Josephson analogues, by analogy with atomic physics. We start with quantum impurity models addressing dissipative and driven systems. Both theorists and experimentalists are making efforts towards the characterization of these non-equilibrium quantum systems. We show how Josephson junction systems can implement the equivalent of the Kondo effect with microwave photons. The Kondo effect can be characterized by a renormalized light frequency and a peak in the Rayleigh elastic transmission of a photon. We also address the physics of hybrid systems comprising mesoscopic quantum dot devices coupled with an electromagnetic resonator. Then, we discuss extensions to Quantum Electrodynamics (QED) Networks allowing one to engineer the Jaynes-Cummings lattice and Rabi lattice models through the presence of superconducting qubits in the cavities. This opens the door to novel many-body physics with light out of equilibrium, in relation with the Mott-superfluid transition observed with ultra-cold atoms in optical lattices. Then, we summarize recent theoretical predictions for realizing topological phases with light. Synthetic gauge fields and spin-orbit couplings have been successfully implemented in quantum materials and with ultra-cold atoms in optical lattices - using time-dependent Floquet perturbations periodic in time, for example - as well as in photonic lattice systems. Finally, we discuss the Josephson effect related to Bose-Hubbard models in ladder and two-dimensional geometries, producing phase coherence and Meissner currents. The Bose-Hubbard model is related to the Jaynes-Cummings lattice model in the large detuning limit between light and matter (the superconducting qubits). In the presence of synthetic gauge fields, we show that Meissner currents subsist in an insulating Mott phase. xml:lang="fr"

  3. Numerical modeling of an alloy droplet deposition with non-equilibrium solidification

    Science.gov (United States)

    Ramanuj, Vimal

    Droplet deposition is a process of extensive relevance to the microfabrication industry. Various bonding and film deposition methods utilize single or multiple droplet impingements on a substrate with subsequent splat formation through simultaneous spreading and solidification. Splat morphology and solidification characteristics play vital roles in determining the final outcome. Experimental methods have limited reach in studying such phenomena owing to the extremely small time and length scales involved. Fundamental understanding of the governing principles of fluid flow, heat transfer and phase change provide effective means of studying such processes through computational techniques. The present study aims at numerically modeling and analyzing the phenomenon of splat formation and phase change in an alloy droplet deposition process. Phase change in alloys occurs non-isothermally and its formulation poses mathematical challenges. A highly non-linear flow field in conjunction with multiple interfaces and convection-diffusion governed phase transition are some of the highlighting features involved in the numerical formulation. Moreover, the non-equilibrium solidification behavior in eutectic systems is of prime concern. The peculiar phenomenon requires special treatments in terms of modeling solid phase species diffusion, liquid phase enrichment during solute partitioning and isothermal eutectic transformation. The flow field is solved using a two-step projection algorithm coupled with enhanced interface modeling schemes. The free surface tracking and reconstruction is achieved through two approaches: VOF-PLIC and CLSVOF to achieve optimum interface accuracy with minimal computational resources. The energy equation is written in terms of enthalpy with an additional source term to account for the phase change. The solidification phenomenon is modeled using a coupled temperature-solute scheme that reflects the microscopic effects arising due to dendritic growth

  4. Some recent developments in non-equilibrium statistical physics

    Indian Academy of Sciences (India)

    for molecular motors and the asymmetric exclusion process which is a basic example of a driven lattice gas. Keywords. Thermodynamics; non-equilibrium mechanics; Brownian motion; molecular motors; Gallavotti–Cohen fluctuation theorem; Jarzynski's work relation. PACS Nos 05.70.Ln; 05.40.-a; 87.16.Nn. 1. Introduction.

  5. Spacecraft Sterilization Using Non-Equilibrium Atmospheric Pressure Plasma

    Science.gov (United States)

    Cooper, Moogega; Vaze, Nachiket; Anderson, Shawn; Fridman, Gregory; Vasilets, Victor N.; Gutsol, Alexander; Tsapin, Alexander; Fridman, Alexander

    2007-01-01

    As a solution to chemically and thermally destructive sterilization methods currently used for spacecraft, non-equilibrium atmospheric pressure plasmas are used to treat surfaces inoculated with Bacillus subtilis and Deinococcus radiodurans. Evidence of significant morphological changes and reduction in viability due to plasma exposure will be presented, including a 4-log reduction of B. subtilis after 2 minutes of dielectric barrier discharge treatment.

  6. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for exclusion models in one dimension with open boundary conditions. For these models, one can also obtain the distribution of the current of particles flowing through the ...

  7. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    For systems in contact with two reservoirs at different densities or with two thermostats at different temperatures, the large deviation function of the density gives a possible way of extending the notion of free energy to non-equilibrium systems. This large deviation function of the density can be calculated explicitly for ...

  8. On the theory of non-equilibrium hydrodynamic fluctuations

    International Nuclear Information System (INIS)

    Peletminskij, S.V.; Plokhov, S.S.; Prikhod'ko, V.I.

    1981-01-01

    Using the method of abbreviated description a microscopic theory of non-equilibrium fluctuations with a great radius of correlations, which permits to study fluctuation kinetics at t>>tausub(r)(tausub(r) is relaxation time) is built. General formula, describing the degree character of approximation to the state of statistical equilibrium of mean values of arbitrary quasilocal operators, are obtained [ru

  9. Classical Orbital Paramagnetism in Non-equilibrium Steady State

    Indian Academy of Sciences (India)

    Avinash A. Deshpande

    2017-09-12

    Sep 12, 2017 ... Classical Orbital Paramagnetism in Non-equilibrium Steady State. AVINASH A. DESHPANDE. ∗ and N. KUMAR. Raman Research Institute, Bangalore 560 080, India. ∗. Corresponding author. E-mail: desh@rri.res.in. MS received 25 March 2017; accepted 31 July 2017; published online 12 September ...

  10. On the forces and fluxes in non-equilibrium thermodynamics

    International Nuclear Information System (INIS)

    Kitahara, Kazuo

    1986-01-01

    A formulation of non-equilibrium thermodynamics of continuum systems based on local equilibrium assumption is reported. Thermodynamic forces are defined from a generalized local entropy and irreversible fluxes are defined as non-advective parts of fluxes of conservative quantities. The validity of the general evolution criterion and its generalization is discussed. (author)

  11. Variation of thermal conductivity of DPPC lipid bilayer membranes around the phase transition temperature.

    Science.gov (United States)

    Youssefian, Sina; Rahbar, Nima; Lambert, Christopher R; Van Dessel, Steven

    2017-05-01

    Given their amphiphilic nature and chemical structure, phospholipids exhibit a strong thermotropic and lyotropic phase behaviour in an aqueous environment. Around the phase transition temperature, phospholipids transform from a gel-like state to a fluid crystalline structure. In this transition, many key characteristics of the lipid bilayers such as structure and thermal properties alter. In this study, we employed atomistic simulation techniques to study the structure and underlying mechanisms of heat transfer in dipalmitoylphosphatidylcholine (DPPC) lipid bilayers around the fluid-gel phase transformation. To investigate this phenomenon, we performed non-equilibrium molecular dynamics simulations for a range of different temperature gradients. The results show that the thermal properties of the DPPC bilayer are highly dependent on the temperature gradient. Higher temperature gradients cause an increase in the thermal conductivity of the DPPC lipid bilayer. We also found that the thermal conductivity of DPPC is lowest at the transition temperature whereby one lipid leaflet is in the gel phase and the other is in the liquid crystalline phase. This is essentially related to a growth in thermal resistance between the two leaflets of lipid at the transition temperature. These results provide significant new insights into developing new thermal insulation for engineering applications. © 2017 The Authors.

  12. Chemical reaction rates and non-equilibrium pressure of reacting gas mixtures in the state-to-state approach

    Energy Technology Data Exchange (ETDEWEB)

    Kustova, Elena V., E-mail: e.kustova@spbu.ru [Department of Mathematics and Mechanics, Saint Petersburg State University, 198504 Universitetskiy pr. 28, Saint Petersburg (Russian Federation); Kremer, Gilberto M., E-mail: kremer@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba (Brazil)

    2014-12-05

    Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N{sub 2} flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure.

  13. HUBBLE-BUBBLE 1. A computer program for the analysis of non-equilibrium flows of water

    International Nuclear Information System (INIS)

    Mather, D.J.

    1978-02-01

    A description is given of the computer program HUBBLE-BUBBLE I which simulates the non-equilibrium flow of water and steam in a pipe. The code is designed to examine the transient flow developing in a pipe containing hot compressed water following the rupture of a retaining diaphragm. Allowance is made for an area change in the pipe. Particular attention is paid to the non-equilibrium development of vapour bubbles and to the transition from a bubble-liquid regime to a droplet-vapour regime. The mathematical and computational model is described together with a summary of the FORTRAN subroutines and listing of data input. (UK)

  14. Coarse-grained Monte Carlo simulations of non-equilibrium systems.

    Science.gov (United States)

    Liu, Xiao; Crocker, John C; Sinno, Talid

    2013-06-28

    We extend the scope of a recent method for generating coarse-grained lattice Metropolis Monte Carlo simulations [X. Liu, W. D. Seider, and T. Sinno, Phys. Rev. E 86, 026708 (2012); and J. Chem. Phys. 138, 114104 (2013)] from continuous interaction potentials to non-equilibrium situations. The original method has been shown to satisfy detailed balance at the coarse scale and to provide a good representation of various equilibrium properties in both atomic and molecular systems. However, we show here that the original method is inconsistent with non-equilibrium trajectories generated by full-resolution Monte Carlo simulations, which, under certain conditions, have been shown to correspond to Langevin dynamics. The modified coarse-grained method is generated by simultaneously biasing the forward and backward transition probability for every possible move, thereby preserving the detailed balance of the original method. The resulting coarse-grained Monte Carlo simulations are shown to provide trajectories that are consistent with overdamped Langevin (Smoluchowski) dynamics using a sequence of simple non-equilibrium examples. We first consider the purely diffusional spreading of a Gaussian pulse of ideal-gas particles and then include an external potential to study the influence of drift. Finally, we validate the method using a more general situation in which the particles interact via a Lennard-Jones interparticle potential.

  15. The Structural Phase Transition in Solid DCN

    DEFF Research Database (Denmark)

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.

    1976-01-01

    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase transition from a tetragonal to an orthorhombic form at 160 K is a first order transition. A transverse acoustic phonon mode, which has the symmetry of the transition was observed at very low...

  16. Locating phase transitions in computationally hard problems

    Indian Academy of Sciences (India)

    automatic planning and models of associative memory among others, all indicate the widespread prevalence of phase transitions in a computational context. It has also been .... depicted by the colour; number of nodes N = 250. Note the sharp inflection corresponding to a phase transition. is an evolution of the system to ...

  17. Late time phase transition as dark energy

    Indian Academy of Sciences (India)

    Abstract. We show that the dark energy field can naturally be described by the scalar condensates of a non-abelian gauge group. This gauge group is unified with the standard model gauge groups and it has a late time phase transition. The small phase transition explains why the positive acceleration of the universe is ...

  18. Scaling Concepts in Describing Continuous Phase Transitions

    Indian Academy of Sciences (India)

    Advanced Scientific. Research, Bengaluru. His research addresses the behaviour of liquids and disordered soft matter, including glassy dynamics and the glass transition, glasses, jamming, and phase transformations in liquids. Phase transitions, like the boiling of water upon increasing temperature, are a part of everyday ...

  19. Phases and phase transitions of S=1 bosons

    Indian Academy of Sciences (India)

    smukerjee

    Quantum phases and phase transitions of bosons. Subroto Mukerjee. Dept. of Physics & Centre for Quantum. Information and Quantum Computing (CQIQC). Indian Institute of Science, Bangalore. 77th annual meeting of the IAS, Nov. 20 2011, PRL Ahmedabad ...

  20. NON-EQUILIBRIUM H{sub 2} FORMATION IN THE EARLY UNIVERSE: ENERGY EXCHANGES, RATE COEFFICIENTS, AND SPECTRAL DISTORTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Coppola, C. M.; Longo, S. [Dipartimento di Chimica, Universita degli Studi di Bari, Via Orabona 4, I-70126 Bari (Italy); D' Introno, R. [Dipartimento di Fisica, Universita degli Studi di Bari, Via Amendola 173, I-70126 Bari (Italy); Galli, D. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Tennyson, J., E-mail: carla.coppola@chimica.uniba.it [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2012-03-01

    Energy exchange processes play a crucial role in the early universe, affecting the thermal balance and the dynamical evolution of the primordial gas. In the present work we focus on the consequences of a non-thermal distribution of the level populations of H{sub 2}: first, we determine the excitation temperatures of vibrational transitions and the non-equilibrium heat transfer; second, we compare the modifications to chemical reaction rate coefficients with respect to the values obtained assuming local thermodynamic equilibrium; and third, we compute the spectral distortions to the cosmic background radiation generated by the formation of H{sub 2} in vibrationally excited levels. We conclude that non-equilibrium processes cannot be ignored in cosmological simulations of the evolution of baryons, although their observational signatures remain below current limits of detection. New fits to the equilibrium and non-equilibrium heat transfer functions are provided.

  1. Phase transitions in solids under high pressure

    CERN Document Server

    Blank, Vladimir Davydovich

    2013-01-01

    Phase equilibria and kinetics of phase transformations under high pressureEquipment and methods for the study of phase transformations in solids at high pressuresPhase transformations of carbon and boron nitride at high pressure and deformation under pressurePhase transitions in Si and Ge at high pressure and deformation under pressurePolymorphic α-ω transformation in titanium, zirconium and zirconium-titanium alloys Phase transformations in iron and its alloys at high pressure Phase transformations in gallium and ceriumOn the possible polymorphic transformations in transition metals under pressurePressure-induced polymorphic transformations in АIBVII compoundsPhase transformations in AIIBVI and AIIIBV semiconductor compoundsEffect of pressure on the kinetics of phase transformations in iron alloysTransformations during deformation at high pressure Effects due to phase transformations at high pressureKinetics and hysteresis in high-temperature polymorphic transformations under pressureHysteresis and kineti...

  2. Non-equilibrium plasma reactor for natrual gas processing

    International Nuclear Information System (INIS)

    Shair, F.H.; Ravimohan, A.L.

    1974-01-01

    A non-equilibrium plasma reactor for natural gas processing into ethane and ethylene comprising means of producing a non-equilibrium chemical plasma wherein selective conversion of the methane in natural gas to desired products of ethane and ethylene at a pre-determined ethane/ethylene ratio in the chemical process may be intimately controlled and optimized at a high electrical power efficiency rate by mixing with a recycling gas inert to the chemical process such as argon, helium, or hydrogen, reducing the residence time of the methane in the chemical plasma, selecting the gas pressure in the chemical plasma from a wide range of pressures, and utilizing pulsed electrical discharge producing the chemical plasma. (author)

  3. Construction of a Non-Equilibrium Thermal Boundary Layer Facility

    Science.gov (United States)

    Biles, Drummond; Ebadi, Alireza; Ma, Allen; White, Christopher

    2015-11-01

    A thermally conductive, electrically heated wall-plate forming the bottom wall of a wind tunnel has been constructed and validation tests have been performed. The wall-plate is a sectioned wall design, where each section is independently heated and controlled. Each section consists of an aluminum 6061 plate, an array of resistive heaters affixed to the bottom of the aluminum plate, and a calcium silicate holder used for thermal isolation. Embedded thermocouples in the aluminum plates are used to monitor the wall temperature and for feedback control of wall heating. The wall-plate is used to investigate thermal transport in both equilibrium and non-equilibrium boundary layers. The non-equilibrium boundary layer flow investigated is oscillatory flow produced by a rotor-stator mechanism placed downstream of the test section of the wind tunnel.

  4. Investigation of Non-Equilibrium Radiation for Earth Entry

    Science.gov (United States)

    Brandis, A. M.; Johnston, C. O.; Cruden, B. A.

    2016-01-01

    For Earth re-entry at velocities between 8 and 11.5 km/s, the accuracy of NASA's computational uid dynamic and radiative simulations of non-equilibrium shock layer radiation is assessed through comparisons with measurements. These measurements were obtained in the NASA Ames Research Center's Electric Arc Shock Tube (EAST) facility. The experiments were aimed at measuring the spatially and spectrally resolved radiance at relevant entry conditions for both an approximate Earth atmosphere (79% N2 : 21% O2 by mole) as well as a more accurate composition featuring the trace species Ar and CO2 (78.08% N2 : 20.95% O2 : 0.04% CO2 : 0.93% Ar by mole). The experiments were configured to target a wide range of conditions, of which shots from 8 to 11.5 km/s at 0.2 Torr (26.7 Pa) are examined in this paper. The non-equilibrium component was chosen to be the focus of this study as it can account for a significant percentage of the emitted radiation for Earth re-entry, and more importantly, non-equilibrium has traditionally been assigned a large uncertainty for vehicle design. The main goals of this study are to present the shock tube data in the form of a non-equilibrium metric, evaluate the level of agreement between the experiment and simulations, identify key discrepancies and to examine critical aspects of modeling non-equilibrium radiating flows. Radiance pro les integrated over discreet wavelength regions, ranging from the Vacuum Ultra Violet (VUV) through to the Near Infra-Red (NIR), were compared in order to maximize both the spectral coverage and the number of experiments that could be used in the analysis. A previously defined non-equilibrium metric has been used to allow comparisons with several shots and reveal trends in the data. Overall, LAURA/HARA is shown to under-predict EAST by as much as 40% and over-predict by as much as 12% depending on the shock speed. DPLR/NEQAIR is shown to under-predict EAST by as much as 50% and over-predict by as much as 20% depending

  5. Non-equilibrium statistical physics with application to disordered systems

    CERN Document Server

    Cáceres, Manuel Osvaldo

    2017-01-01

    This textbook is the result of the enhancement of several courses on non-equilibrium statistics, stochastic processes, stochastic differential equations, anomalous diffusion and disorder. The target audience includes students of physics, mathematics, biology, chemistry, and engineering at undergraduate and graduate level with a grasp of the basic elements of mathematics and physics of the fourth year of a typical undergraduate course. The little-known physical and mathematical concepts are described in sections and specific exercises throughout the text, as well as in appendices. Physical-mathematical motivation is the main driving force for the development of this text. It presents the academic topics of probability theory and stochastic processes as well as new educational aspects in the presentation of non-equilibrium statistical theory and stochastic differential equations.. In particular it discusses the problem of irreversibility in that context and the dynamics of Fokker-Planck. An introduction on fluc...

  6. Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry.

    Science.gov (United States)

    van den Bekerom, Dirk; den Harder, Niek; Minea, Teofil; Gatti, Nicola; Linares, Jose Palomares; Bongers, Waldo; van de Sanden, Richard; van Rooij, Gerard

    2017-08-01

    A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

  7. The dynamics of a thermal non-equilibrium anharmonic oscillator

    OpenAIRE

    Nachbagauer, Herbert

    1995-01-01

    We propose an non-standard method to calculate non-equilibrium physical observables. Considering the generic example of an anharmonic quantum oscillator, we take advantage of the fact that the commutator algebra of second order polynomials in creation/annihilation operators closes. We solve the von~Neumann equation for the density-operator exactly in the mean field approximation and study the time evolution of the particle number and the expectation value .

  8. Fluctuations and large deviations in non-equilibrium systems

    Indian Academy of Sciences (India)

    systems. Keywords. Non-equilibrium systems; large deviations; current fluctuations. PACS Nos 02.50.-r; 05.40.-a; 05.70.Ln; 82.20.-w. 1. Introduction. The goal of this .... The model is defined as a one-dimensional lattice of L sites with open bound- .... In [2] a perturbation theory was developed to calculate µ(λ) in powers of λ.

  9. Ward identity for non-equilibrium Fermi systems

    Czech Academy of Sciences Publication Activity Database

    Velický, B.; Kalvová, Anděla; Špička, Václav

    2008-01-01

    Roč. 77, č. 4 (2008), 041201/1-041201/4 ISSN 1098-0121 R&D Projects: GA ČR GC202/07/J051 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z10100521 Keywords : non-equilibrium * Green’s functions * quantum transport equations * Ward identity Subject RIV: BE - Theoretical Physics Impact factor: 3.322, year: 2008

  10. Non-Equilibrium Radiation from Shock-Heated Air

    Science.gov (United States)

    1991-07-01

    in the availability of data for input parameters shown in Figure 1. The steel driven section is 30 feet and for comparison with predicitons. The major...non-equilibrium aspect of the radiative means of press-scribed, 0.035-inch-thick steel signature arises from the fact that at higher altitudes... CLASIFICATION OF TII PASS 19. (cont.) Further kinetic studies are presently ongoing.3 UNCLASSIFIED3 gaCUm,?, CLAS&IICAION OF THIS PAGE A . APPENDIX B AIAA-90

  11. Non-equilibrium Quasi-Chemical Nucleation Model

    Science.gov (United States)

    Gorbachev, Yuriy E.

    2018-04-01

    Quasi-chemical model, which is widely used for nucleation description, is revised on the basis of recent results in studying of non-equilibrium effects in reacting gas mixtures (Kolesnichenko and Gorbachev in Appl Math Model 34:3778-3790, 2010; Shock Waves 23:635-648, 2013; Shock Waves 27:333-374, 2017). Non-equilibrium effects in chemical reactions are caused by the chemical reactions themselves and therefore these contributions should be taken into account in the corresponding expressions for reaction rates. Corrections to quasi-equilibrium reaction rates are of two types: (a) spatially homogeneous (caused by physical-chemical processes) and (b) spatially inhomogeneous (caused by gas expansion/compression processes and proportional to the velocity divergency). Both of these processes play an important role during the nucleation and are included into the proposed model. The method developed for solving the generalized Boltzmann equation for chemically reactive gases is applied for solving the set of equations of the revised quasi-chemical model. It is shown that non-equilibrium processes lead to essential deviation of the quasi-stationary distribution and therefore the nucleation rate from its traditional form.

  12. States of Water in Non-Equilibrium Glassy Polymers

    Science.gov (United States)

    Davis, Eric; Elabd, Yossef

    2013-03-01

    For many applications (e.g., packaging, medical devices) a deeper fundamental understanding of the molecular nature of water in glassy polymer coatings is of significant interest. In this study, the sorption and diffusion of water in two glassy polymers, poly(methyl methacrylate) (PMMA) and poly(styrene) (PS), were measured with both quartz crystal microbalance (QSM) and time-resolved Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Non-Fickian diffusion was observed in both PMMA and PS using both experimental techniques due to the non-equilibrium state of the polymers. The specific states of water were observed with FTIR-ATR spectroscopy, where dimers exist in PMMA below a critical concentration and larger clusters were observed above this concentration. Contrastingly, water only exists in PS as larger clusters over the entire sorption isotherm. A correlation between the states of water and the diffusive activation energy of water was observed. Additionally, the pseudo-equilibrium water sorption isotherms in PMMA and PS were accurately predicted with the non-equilibrium statistical associating fluid theory (NE-SAFT). We predict that the combination of time-resolved FTIR-ATR spectroscopy and NE-SAFT can be used on other water-glassy polymer systems to provide a molecular understanding of non-equilibrium sorption and diffusion.

  13. Some recent developments in non-equilibrium statistical physics

    Indian Academy of Sciences (India)

    For systems close to thermodynamic equilibrium, linear response theory yields the .... 2.2 Molecular theory of heat and the framework of statistical mechanics ...... The open ASEP undergoes boundary-induced phase transitions: In the large system size limit, the expressions for the current and the density profile become ...

  14. Quantum phase transition with dissipative frustration

    Science.gov (United States)

    Maile, D.; Andergassen, S.; Belzig, W.; Rastelli, G.

    2018-04-01

    We study the quantum phase transition of the one-dimensional phase model in the presence of dissipative frustration, provided by an interaction of the system with the environment through two noncommuting operators. Such a model can be realized in Josephson junction chains with shunt resistances and resistances between the chain and the ground. Using a self-consistent harmonic approximation, we determine the phase diagram at zero temperature which exhibits a quantum phase transition between an ordered phase, corresponding to the superconducting state, and a disordered phase, corresponding to the insulating state with localized superconducting charge. Interestingly, we find that the critical line separating the two phases has a nonmonotonic behavior as a function of the dissipative coupling strength. This result is a consequence of the frustration between (i) one dissipative coupling that quenches the quantum phase fluctuations favoring the ordered phase and (ii) one that quenches the quantum momentum (charge) fluctuations leading to a vanishing phase coherence. Moreover, within the self-consistent harmonic approximation, we analyze the dissipation induced crossover between a first and second order phase transition, showing that quantum frustration increases the range in which the phase transition is second order. The nonmonotonic behavior is reflected also in the purity of the system that quantifies the degree of correlation between the system and the environment, and in the logarithmic negativity as an entanglement measure that encodes the internal quantum correlations in the chain.

  15. The quantum phase-transitions of water

    Science.gov (United States)

    Fillaux, François

    2017-08-01

    It is shown that hexagonal ices and steam are macroscopically quantum condensates, with continuous spacetime-translation symmetry, whereas liquid water is a quantum fluid with broken time-translation symmetry. Fusion and vaporization are quantum phase-transitions. The heat capacities, the latent heats, the phase-transition temperatures, the critical temperature, the molar volume expansion of ice relative to water, as well as neutron scattering data and dielectric measurements are explained. The phase-transition mechanisms along with the key role of quantum interferences and that of Hartley-Shannon's entropy are enlightened. The notions of chemical bond and force-field are questioned.

  16. Numerical analysis of a non equilibrium two-component two-compressible flow in porous media

    KAUST Repository

    Saad, Bilal Mohammed

    2013-09-01

    We propose and analyze a finite volume scheme to simulate a non equilibrium two components (water and hydrogen) two phase flow (liquid and gas) model. In this model, the assumption of local mass non equilibrium is ensured and thus the velocity of the mass exchange between dissolved hydrogen and hydrogen in the gas phase is supposed finite. The proposed finite volume scheme is fully implicit in time together with a phase-by-phase upwind approach in space and it is discretize the equations in their general form with gravity and capillary terms We show that the proposed scheme satisfies the maximum principle for the saturation and the concentration of the dissolved hydrogen. We establish stability results on the velocity of each phase and on the discrete gradient of the concentration. We show the convergence of a subsequence to a weak solution of the continuous equations as the size of the discretization tends to zero. At our knowledge, this is the first convergence result of finite volume scheme in the case of two component two phase compressible flow in several space dimensions.

  17. "Non-equilibrium" block copolymer micelles with glassy cores: a predictive approach based on theory of equilibrium micelles.

    Science.gov (United States)

    Nagarajan, Ramanathan

    2015-07-01

    Micelles generated in water from most amphiphilic block copolymers are widely recognized to be non-equilibrium structures. Typically, the micelles are prepared by a kinetic process, first allowing molecular scale dissolution of the block copolymer in a common solvent that likes both the blocks and then gradually replacing the common solvent by water to promote the hydrophobic blocks to aggregate and create the micelles. The non-equilibrium nature of the micelle originates from the fact that dynamic exchange between the block copolymer molecules in the micelle and the singly dispersed block copolymer molecules in water is suppressed, because of the glassy nature of the core forming polymer block and/or its very large hydrophobicity. Although most amphiphilic block copolymers generate such non-equilibrium micelles, no theoretical approach to a priori predict the micelle characteristics currently exists. In this work, we propose a predictive approach for non-equilibrium micelles with glassy cores by applying the equilibrium theory of micelles in two steps. In the first, we calculate the properties of micelles formed in the mixed solvent while true equilibrium prevails, until the micelle core becomes glassy. In the second step, we freeze the micelle aggregation number at this glassy state and calculate the corona dimension from the equilibrium theory of micelles. The condition when the micelle core becomes glassy is independently determined from a statistical thermodynamic treatment of diluent effect on polymer glass transition temperature. The predictions based on this "non-equilibrium" model compare reasonably well with experimental data for polystyrene-polyethylene oxide diblock copolymer, which is the most extensively studied system in the literature. In contrast, the application of the equilibrium model to describe such a system significantly overpredicts the micelle core and corona dimensions and the aggregation number. The non-equilibrium model suggests ways to

  18. Transition of COM-COP relative phase in a dynamic balance task.

    Science.gov (United States)

    Ko, Ji-Hyun; Challis, John H; Newell, Karl M

    2014-12-01

    The purpose of this study was to investigate whether the coordination between center of mass (COM) and center of pressure (COP) could be a candidate collective variable of a dynamical system that captures the organization of the multi-segmental whole body postural control system. We examined the transition of the COM-COP coordination pattern in a moving platform balance control paradigm. 10 young healthy adults stood on a moving surface of support that within a trial was sinusoidally translated in the anterior-posterior direction continuously scaling up and then down its frequency within the range from 0Hz to 3.0Hz. The COP was derived from a single force platform mounted on the moving surface of support. 4 angular joint motions (ankle, knee, hip, and neck) were measured by a 3D motion analysis system that also allowed COM to be derived. The COM-COP coordination changed from in-phase/anti-phase to anti-phase/in-phase at a certain frequency of the support surface, showed hysteresis as a function of the direction of frequency change and higher variability at the transition region. Conversely, the transition of the ankle-hip coordination consistently occurred at 0.3Hz across subjects with little between or within subject variability as a function of transition frequency and before the COM-COP transition. The findings provide evidence that: (1) the transition of the COM-COP coordination pattern is that of a non-equilibrium phase transition with critical fluctuations and hysteresis; and (2) that COM-COP coupling is a candidate collective variable of the multi-segmental whole body postural control system acting on a redundant postural task. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Spin-Hall effect and emergent antiferromagnetic phase transition in n-Si

    Science.gov (United States)

    Lou, Paul C.; Kumar, Sandeep

    2018-04-01

    Spin current experiences minimal dephasing and scattering in Si due to small spin-orbit coupling and spin-lattice interactions is the primary source of spin relaxation. We hypothesize that if the specimen dimension is of the same order as the spin diffusion length then spin polarization will lead to non-equilibrium spin accumulation and emergent phase transition. In n-Si, spin diffusion length has been reported up to 6 μm. The spin accumulation in Si will modify the thermal transport behavior of Si, which can be detected with thermal characterization. In this study, we report observation of spin-Hall effect and emergent antiferromagnetic phase transition behavior using magneto-electro-thermal transport characterization. The freestanding Pd (1 nm)/Ni80Fe20 (75 nm)/MgO (1 nm)/n-Si (2 μm) thin film specimen exhibits a magnetic field dependent thermal transport and spin-Hall magnetoresistance behavior attributed to Rashba effect. An emergent phase transition is discovered using self-heating 3ω method, which shows a diverging behavior at 270 K as a function of temperature similar to a second order phase transition. We propose that spin-Hall effect leads to the spin accumulation and resulting emergent antiferromagnetic phase transition. We propose that the length scale for Rashba effect can be equal to the spin diffusion length and two-dimensional electron gas is not essential for it. The emergent antiferromagnetic phase transition is attributed to the site inversion asymmetry in diamond cubic Si lattice.

  20. Phase transition phenomenon: A compound measure analysis

    Science.gov (United States)

    Kang, Bo Soo; Park, Chanhi; Ryu, Doojin; Song, Wonho

    2015-06-01

    This study investigates the well-documented phenomenon of phase transition in financial markets using combined information from both return and volume changes within short time intervals. We suggest a new measure for the phase transition behaviour of markets, calculated as a return distribution conditional on local variance in volume imbalance, and show that this measure successfully captures phase transition behaviour under various conditions. We analyse the intraday trade and quote dataset from the KOSPI 200 index futures, which includes detailed information on the original order size and the type of each initiating investor. We find that among these two competing factors, the submitted order size yields more explanatory power on the phenomenon of market phase transition than the investor type.

  1. Phase transition in the hadron gas model

    International Nuclear Information System (INIS)

    Gorenstein, M.I.; Petrov, V.K.; Zinov'ev, G.M.

    1981-01-01

    A class of statistical models of hadron gas allowing an analytical solution is considered. A mechanism of a possible phase transition in such a system is found and conditions for its occurence are determined [ru

  2. Critical behavior in reaction-diffusion systems exhibiting absorbing phase transition

    CERN Document Server

    Ódor, G

    2003-01-01

    Phase transitions of reaction-diffusion systems with site occupation restriction and with particle creation that requires n>1 parents and where explicit diffusion of single particles (A) exists are reviewed. Arguments based on mean-field approximation and simulations are given which support novel kind of non-equilibrium criticality. These are in contradiction with the implications of a suggested phenomenological, multiplicative noise Langevin equation approach and with some of recent numerical analysis. Simulation results for the one and two dimensional binary spreading 2A -> 4A, 4A -> 2A model display a new type of mean-field criticality characterized by alpha=1/3 and beta=1/2 critical exponents suggested in cond-mat/0210615.

  3. Phase Transitions, Diffraction Studies and Marginal Dimensionality

    DEFF Research Database (Denmark)

    Als-Nielsen, Jens Aage

    1985-01-01

    Continuous phase transitions and the associated critical phenomena have been one of the most active areas of research in condensed matter physics for several decades. This short review is only one cut through this huge subject and the author has chosen to emphasize diffraction studies as a basic...... experimental method and illustrate how diffraction experiments have revealed the role of dimensionality in the general classification of phase transitions...

  4. Phase transitions with four-spin interactions

    OpenAIRE

    Lebowitz, Joel L.; Ruelle, David

    2010-01-01

    Using an extended Lee-Yang theorem and GKS correlation inequalities, we prove, for a class of ferromagnetic multi-spin interactions, that they will have a phase transition(and spontaneous magnetization) if, and only if, the external field $h=0$ (and the temperature is low enough). We also show the absence of phase transitions for some nonferromagnetic interactions. The FKG inequalities are shown to hold for a larger class of multi-spin interactions.

  5. Information Geometry of Non-Equilibrium Processes in a Bistable System with a Cubic Damping

    Directory of Open Access Journals (Sweden)

    Rainer Hollerbach

    2017-06-01

    Full Text Available A probabilistic description is essential for understanding the dynamics of stochastic systems far from equilibrium, given uncertainty inherent in the systems. To compare different Probability Density Functions (PDFs, it is extremely useful to quantify the difference among different PDFs by assigning an appropriate metric to probability such that the distance increases with the difference between the two PDFs. This metric structure then provides a key link between stochastic systems and information geometry. For a non-equilibrium process, we define an infinitesimal distance at any time by comparing two PDFs at times infinitesimally apart and sum these distances in time. The total distance along the trajectory of the system quantifies the total number of different states that the system undergoes in time and is called the information length. By using this concept, we investigate the information geometry of non-equilibrium processes involved in disorder-order transitions between the critical and subcritical states in a bistable system. Specifically, we compute time-dependent PDFs, information length, the rate of change in information length, entropy change and Fisher information in disorder-to-order and order-to-disorder transitions and discuss similarities and disparities between the two transitions. In particular, we show that the total information length in order-to-disorder transition is much larger than that in disorder-to-order transition and elucidate the link to the drastically different evolution of entropy in both transitions. We also provide the comparison of the results with those in the case of the transition between the subcritical and supercritical states and discuss implications for fitness.

  6. Phase transitions in two dimensions

    International Nuclear Information System (INIS)

    Henderson, D.

    1980-01-01

    Although a two-dimensional solid with long-range translational order cannot existin the thermodynamic limit (N → ∞, V →∞, N/V finite) macroscopic samples of two-dimensional solids can exist. In this work, stability of the phase was determined by the usuar method of equating the pressure and chemical potential of the phases. (A.C.A.S.) [pt

  7. X-ray scattering studies of non-equilibrium ordering processes

    International Nuclear Information System (INIS)

    Nagler, S.E.

    1991-01-01

    We report on the progress of the project entitled ''X-ray Scattering Studies of Non-Equilibrium Ordering Processes.'' The past year has seen continued progress in the study of kinetic effects in metallic binary alloys and polymers. In addition, work has begun on a low dimensional CDW system: blue bronze. A sample chamber has been constructed to perform small angle neutron scattering measurements on a model quantum system with phase separation: solid He3/He4. Work is continuing on magnetic systems. Planned future experiments include an investigation of crystallization in Rubidium

  8. Extended irreversible thermodynamics and non-equilibrium temperature

    Directory of Open Access Journals (Sweden)

    Casas-Vazquez, Jose'

    2008-02-01

    Full Text Available We briefly review the concept of non-equilibrium temperature from the perspectives of extended irreversible thermodynamics, fluctuation theory, and statistical mechanics. The relations between different proposals are explicitly examined in two especially simple systems: an ideal gas in steady shear flow and a forced harmonic oscillator in a thermal bath. We examine with special detail temperatures related to the average molecular kinetic energy along different spatial directions, to the average configurational energy, to the derivative of the entropy with respect to internal energy, to fluctuation-dissipation relation and discuss their measurement.

  9. The non-equilibrium nature of culinary evolution

    Science.gov (United States)

    Kinouchi, Osame; Diez-Garcia, Rosa W.; Holanda, Adriano J.; Zambianchi, Pedro; Roque, Antonio C.

    2008-07-01

    Food is an essential part of civilization, with a scope that ranges from the biological to the economic and cultural levels. Here, we study the statistics of ingredients and recipes taken from Brazilian, British, French and Medieval cookery books. We find universal distributions with scale invariant behaviour. We propose a copy-mutate process to model culinary evolution that fits our empirical data very well. We find a cultural 'founder effect' produced by the non-equilibrium dynamics of the model. Both the invariant and idiosyncratic aspects of culture are accounted for by our model, which may have applications in other kinds of evolutionary processes.

  10. Cumulants in perturbation expansions for non-equilibrium field theory

    International Nuclear Information System (INIS)

    Fauser, R.

    1995-11-01

    The formulation of perturbation expansions for a quantum field theory of strongly interacting systems in a general non-equilibrium state is discussed. Non-vanishing initial correlations are included in the formulation of the perturbation expansion in terms of cumulants. The cumulants are shown to be the suitable candidate for summing up the perturbation expansion. Also a linked-cluster theorem for the perturbation series with cumulants is presented. Finally a generating functional of the perturbation series with initial correlations is studied. We apply the methods to a simple model of a fermion-boson system. (orig.)

  11. Non-equilibrium steady state in the hydro regime

    Energy Technology Data Exchange (ETDEWEB)

    Pourhasan, Razieh [Science Institute, University of Iceland,Dunhaga 5, 107 Reykjavik (Iceland)

    2016-02-01

    We study the existence and properties of the non-equilibrium steady state which arises by putting two copies of systems at different temperatures into a thermal contact. We solve the problem for the relativistic systems that are described by the energy-momentum of a perfect hydro with general equation of state (EOS). In particular, we examine several simple examples: a hydro with a linear EOS, a holographic CFT perturbed by a relevant operator and a barotropic fluid, i.e., P=P(E). Our studies suggest that the formation of steady state is a universal result of the hydro regime regardless of the kind of fluid.

  12. Visualization of the ultrafast structural phase transitions in warm dense matter

    Science.gov (United States)

    Mo, Mianzhen

    2017-10-01

    It is still a great challenge to obtain real-time atomistic-scale information on the structural phase transitions that lead to warm dense matter state. Recent advances in ultrafast electron diffraction (UED) techniques have opened up exciting prospects to unravel the mechanisms of solid-liquid phase transitions under these extreme non-equilibrium conditions. Here we report on precise measurements of melt time dependency on laser excitation energy density that resolve for the first time the transition from heterogeneous to homogeneous melting. This transition appears in both polycrystalline and single-crystal gold nanofilms with distinct measurable differences. These results test predictions from molecular-dynamics simulations with different interatomic potential models. These data further deliver accurate structure factor data to large wavenumbers that allow us to constrain electron-ion equilibration constants. Our results demonstrate electron-phonon coupling strength much weaker than DFT calculations, and contrary to previous results, provide evidence for bond softening. This work is supported by DOE Office of Science, Fusion Energy Science under FWP 100182, and the DOE BES Accelerator and Detector R&D program.

  13. Phase transitions in crystalline solids 1

    International Nuclear Information System (INIS)

    Walker, J.R.

    1993-09-01

    Many crystalline materials of interest to the Canadian Nuclear Program have the potential to undergo phase transitions in their range of application. During such phase transitions, a representation of the space group of the higher symmetry polymorph softens to induce the transition. This report is the first in a series of reports concerned with the group-theoretic properties of phase transitions in crystalline materials. The object of the research is to identify all spectroscopically-active soft modes for the 230 three-dimensional space groups. Identification of these soft modes will enable a detailed examination of phase transitions in materials of interest to the Canadian Nuclear Program and aid in the optimization of material properties. In this report, the group-theoretic properties of crystal structures and phase transitions are reviewed. It is demonstrated that the problem of extending a group reduces to that of determining its automorphisms. The automorphism groups of the crystallographic and icosahedral point groups are derived using a consistent presentation

  14. An absorbing phase transition from a structured active particle phase

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, Cristobal [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain); Ramos, Francisco [Departamento de Electromagnetismo y Fisica de la Materia and Instituto de Fisica Teorica y Computacional Carlos I, Facultad de Ciencias, Universidad de Granada, 18071 Granada (Spain); Hernandez-GarcIa, Emilio [Instituto Mediterraneo de Estudios Avanzados IMEDEA (CSIC-UIB), Campus de la Universidad de las Islas Baleares, E-07122 Palma de Mallorca (Spain)

    2007-02-14

    In this work we study the absorbing state phase transition of a recently introduced model for interacting particles with neighbourhood-dependent reproduction rates. The novelty of the transition is that as soon as the active phase is reached by increasing a control parameter a periodically arranged structure of particle clusters appears. A numerical study in one and two dimensions shows that the system falls into the directed percolation universality class.

  15. General multi-group macroscopic modeling for thermo-chemical non-equilibrium gas mixtures.

    Science.gov (United States)

    Liu, Yen; Panesi, Marco; Sahai, Amal; Vinokur, Marcel

    2015-04-07

    This paper opens a new door to macroscopic modeling for thermal and chemical non-equilibrium. In a game-changing approach, we discard conventional theories and practices stemming from the separation of internal energy modes and the Landau-Teller relaxation equation. Instead, we solve the fundamental microscopic equations in their moment forms but seek only optimum representations for the microscopic state distribution function that provides converged and time accurate solutions for certain macroscopic quantities at all times. The modeling makes no ad hoc assumptions or simplifications at the microscopic level and includes all possible collisional and radiative processes; it therefore retains all non-equilibrium fluid physics. We formulate the thermal and chemical non-equilibrium macroscopic equations and rate coefficients in a coupled and unified fashion for gases undergoing completely general transitions. All collisional partners can have internal structures and can change their internal energy states after transitions. The model is based on the reconstruction of the state distribution function. The internal energy space is subdivided into multiple groups in order to better describe non-equilibrium state distributions. The logarithm of the distribution function in each group is expressed as a power series in internal energy based on the maximum entropy principle. The method of weighted residuals is applied to the microscopic equations to obtain macroscopic moment equations and rate coefficients succinctly to any order. The model's accuracy depends only on the assumed expression of the state distribution function and the number of groups used and can be self-checked for accuracy and convergence. We show that the macroscopic internal energy transfer, similar to mass and momentum transfers, occurs through nonlinear collisional processes and is not a simple relaxation process described by, e.g., the Landau-Teller equation. Unlike the classical vibrational energy

  16. The Structural Phase Transition in Solid DCN

    DEFF Research Database (Denmark)

    Dietrich, O. W.; Mackenzie, Gordon A.; Pawley, G. S.

    1975-01-01

    Neutron scattering measurements on deuterated hydrogen cyanide have shown that the structural phase change from a tetragonal to an orthorhombic form at 160K is a first-order transition. A transverse acoustic phonon mode, which has the symmetry of the phase change, was observed at very low energies...

  17. Symmetry structure and phase transitions

    Indian Academy of Sciences (India)

    Spontaneous symmetry breaking is one of the most important concepts of all unified gauge theories. The idea that ... stable configurations of gauge and Higgs fields in the form of domain walls, cosmic strings and monopoles on the ..... pressure to balance the surface tension and the pressure of the hadron phase. The quark.

  18. Application of non-equilibrium plasmas in medicine

    Directory of Open Access Journals (Sweden)

    Mojsilović S.

    2012-01-01

    Full Text Available We review the potential of plasma medical applications, the connections to nanotechnologies and the results obtained by our group. A special issue in plasma medicine is the development of the plasma sources that would achieve non-equilibrium at atmospheric pressure in atmospheric gas mixture with no or only marginal heating of the gas, and with desired properties and mechanisms that may be controlled. Our studies have shown that control of radicals or chemically active products of the discharge such as ROS (reactive oxygen species and/or NO may be used to control the growth of the seeds. At the same time specially designed plasma needle and other sources were shown to be efficient to sterilize not only colonies of bacteria but also planctonic samples (microorganisms protected by water or bio films. Finally we have shown that plasma may induce differentiation of stem cells. Non-equilibrium plasmas may be used in detection of different specific markers in medicine. For example proton transfer mass spectroscopy may be employed in detection of volatile organic compounds without their dissociation and thus as a technique for instantaneous measurement of the presence of markers for numerous diseases. [Projekat Ministarstva nauke Republike Srbije, br. ON171037 i br. III41011

  19. Understanding Non-equilibrium Thermodynamics Foundations, Applications, Frontiers

    CERN Document Server

    Jou, David; Lebon, Georgy

    2007-01-01

    This book offers a homogeneous presentation of the many faces of non-equilibrium thermodynamics. The first part is devoted to a description of the nowadays thermodynamic formalism recognized as the classical theory of non-equilibrium processes. This part of the book may serve as a basis to an introductory course dedicated to first-year graduate students in sciences and engineering. The classical description can however not be complete, as it rests on the hypothesis of local equilibrium. This has fostered the development of many theories going beyond local equilibrium and which cannot be put aside. The second part of the book is concerned with these different approaches, and will be of special interest for PhD students and researchers. For the sake of homogeneity, the authors have used the general structure and methods presented in the first part. Indeed, besides their differences, all these formalisms are not closed boxes but present some overlappings and parallelisms which are emphasized in this book. For pe...

  20. NON-EQUILIBRIUM ELECTRONS IN THE OUTSKIRTS OF GALAXY CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Avestruz, Camille; Nagai, Daisuke; Lau, Erwin T. [Department of Physics, Yale University, New Haven, CT 06520 (United States); Nelson, Kaylea, E-mail: camille.avestruz@yale.edu, E-mail: camille.avestruz@yale.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06520 (United States)

    2015-08-01

    The analysis of X-ray and Sunyaev–Zel’dovich measurements of the intracluster medium (ICM) assumes that electrons are in thermal equilibrium with ions in the plasma. However, in the outskirts of galaxy clusters, the electron–ion equilibration timescale can become comparable to the Hubble time, leading to systematic biases in cluster mass estimates and mass-observable scaling relations. To quantify an upper limit of the impact of non-equilibrium electrons, we use a mass-limited sample of simulated galaxy clusters taken from a cosmological simulation with a two-temperature model that assumes the Spitzer equilibration time for the electrons and ions. We show that the temperature bias is more pronounced in more massive and rapidly accreting clusters. For the most extreme case, we find that the bias is of the order of 10% at half of the cluster virial radius and increases to 40% at the edge of the cluster. Gas in filaments is less susceptible to the non-equilibrium effect, leading to azimuthal variations in the temperature bias at large cluster-centric radii. Using mock Chandra observations of simulated clusters, we show that the bias manifests in ultra-deep X-ray observations of cluster outskirts and quantify the resulting biases in hydrostatic mass and cluster temperature derived from these observations. We provide a mass-dependent fitting function for the temperature bias profile, which can be useful for modeling the effect of electron-ion equilibration in galaxy clusters.

  1. Non-equilibrium turbulence scalings in turbulent planar jets

    Science.gov (United States)

    Cafiero, Gioacchino; Vassilicos, John Christos; Turbulence, Mixing; Flow Control Group Team

    2017-11-01

    A revised version of the Townsend George theory, as proposed by Dairay et al. 2015, is applied to the study of turbulent planar jets (Cafiero and Vassilicos 2017). Requiring the self-similarity of only few quantities along with the non-equilibrium dissipation scaling law (Vassilicos 2015), it implies new mean flow and jet width scalings. In particular, the ratio of characteristic cross-stream to centreline streamwise velocities decays as the -1/3 power of streamwise distance in the region where the non-equilibrium dissipation scaling holds. In the definition of Cɛ both in Dairay et al. 2015 and in Cafiero and Vassilicos 2017 the local Reynolds number is based on the local flow width rather than on the integral lengthscale. We verify that the ratio of the integral lengthscale to the flow width is constant, thus enabling the use of the integral flow width in place of the integral lengthscale for defining Cɛ. The importance of this result is twofold: firstly it further strengthens the scalings obtained in the works of Dairay et al. 2015 and Cafiero and Vassilicos 2017; secondly the flow width is immediately accessible by any mean flow measurement, whereas the estimation of the integral lengthscale often requires an additional hypothesis. ERC Advanced Grant 320560.

  2. Mesoscopic non-equilibrium thermodynamic analysis of molecular motors.

    Science.gov (United States)

    Kjelstrup, S; Rubi, J M; Pagonabarraga, I; Bedeaux, D

    2013-11-28

    We show that the kinetics of a molecular motor fueled by ATP and operating between a deactivated and an activated state can be derived from the principles of non-equilibrium thermodynamics applied to the mesoscopic domain. The activation by ATP, the possible slip of the motor, as well as the forward stepping carrying a load are viewed as slow diffusion along a reaction coordinate. Local equilibrium is assumed in the reaction coordinate spaces, making it possible to derive the non-equilibrium thermodynamic description. Using this scheme, we find expressions for the velocity of the motor, in terms of the driving force along the spacial coordinate, and for the chemical reaction that brings about activation, in terms of the chemical potentials of the reactants and products which maintain the cycle. The second law efficiency is defined, and the velocity corresponding to maximum power is obtained for myosin movement on actin. Experimental results fitting with the description are reviewed, giving a maximum efficiency of 0.45 at a myosin headgroup velocity of 5 × 10(-7) m s(-1). The formalism allows the introduction and test of meso-level models, which may be needed to explain experiments.

  3. Microgravity Two-Phase Flow Transition

    Science.gov (United States)

    Parang, M.; Chao, D.

    1999-01-01

    Two-phase flows under microgravity condition find a large number of important applications in fluid handling and storage, and spacecraft thermal management. Specifically, under microgravity condition heat transfer between heat exchanger surfaces and fluids depend critically on the distribution and interaction between different fluid phases which are often qualitatively different from the gravity-based systems. Heat transfer and flow analysis in two-phase flows under these conditions require a clear understanding of the flow pattern transition and development of appropriate dimensionless scales for its modeling and prediction. The physics of this flow is however very complex and remains poorly understood. This has led to various inadequacies in flow and heat transfer modeling and has made prediction of flow transition difficult in engineering design of efficient thermal and flow systems. In the present study the available published data for flow transition under microgravity condition are considered for mapping. The transition from slug to annular flow and from bubbly to slug flow are mapped using dimensionless variable combination developed in a previous study by the authors. The result indicate that the new maps describe the flow transitions reasonably well over the range of the data available. The transition maps are examined and the results are discussed in relation to the presumed balance of forces and flow dynamics. It is suggested that further evaluation of the proposed flow and transition mapping will require a wider range of microgravity data expected to be made available in future studies.

  4. Search for electronic phase separation at quantum phase transitions

    NARCIS (Netherlands)

    Pfleiderer, C.; Böni, P.; Franz, C.; Keller, T.; Neubauer, A.; Niklowitz, P.G.; Schmakat, P.; Schulz, M.; Huang, Y.; Mydosh, J.A.; Vojta, M.; Duncan, W.; Grosche, F.M.; Brando, M.; Deppe, M.; Geibel, C.; Steglich, F.; Krimmel, A.; Loidl, A.

    2010-01-01

    Phase separation and extreme sensitivity to disorder and defects are key features of electronic order near quantum phase transitions. Neutron depolarization imaging and neutron Larmor diffraction are new experimental techniques capable of providing detailed real-space and reciprocal-space

  5. Phase transitions in multiplicative competitive processes

    International Nuclear Information System (INIS)

    Shimazaki, Hideaki; Niebur, Ernst

    2005-01-01

    We introduce a discrete multiplicative process as a generic model of competition. Players with different abilities successively join the game and compete for finite resources. Emergence of dominant players and evolutionary development occur as a phase transition. The competitive dynamics underlying this transition is understood from a formal analogy to statistical mechanics. The theory is applicable to bacterial competition, predicting novel population dynamics near criticality

  6. Supersymmetric electroweak phase transition beyond perturbation theory

    CERN Document Server

    Cline, J M; Cline, James M; Kainulainen, Kimmo

    1996-01-01

    We compute the three-dimensional effective action for the minimal supersymmetric standard model, which describes the light modes of the theory near the finite-temperature electroweak phase transition, keeping the one-loop corrections from the third generation quarks and squarks. Using the lattice results of Kajantie et al. for the phase transition in the same class of 3-D models, we find that the strength of the phase transition is sufficient for electroweak baryogenesis, in much broader regions of parameter space than have been indicated by purely perturbative analyses. In particular we find that, while small values of \\tan\\beta are favored, positive results persist even for arbitrarily large values of \\tan\\beta if the mass of the A^0 boson is between 40 and 100 GeV, a region of parameters which has not been previously identified as being favorable for electroweak baryogenesis.

  7. Late-time cosmological phase transitions

    International Nuclear Information System (INIS)

    Schramm, D.N.

    1990-11-01

    It is shown that the potential galaxy formation and large-scale structure problems of objects existing at high redshifts (Z approx-gt 5), structures existing on scales of 100M pc as well as velocity flows on such scales, and minimal microwave anisotropies (ΔT/T) approx-lt 10 -5 can be solved if the seeds needed to generate structure form in a vacuum phase transition after decoupling. It is argued that the basic physics of such a phase transition is no more exotic than that utilized in the more traditional GUT scale phase transitions, and that, just as in the GUT case, significant random gaussian fluctuations and/or topological defects can form. Scale lengths of ∼100M pc for large-scale structure as well as ∼1 M pc for galaxy formation occur naturally. Possible support for new physics that might be associated with such a late-time transition comes from the preliminary results of the SAGE solar neutrino experiment, implying neutrino flavor mixing with values similar to those required for a late-time transition. It is also noted that a see-saw model for the neutrino masses might also imply a tau neutrino mass that is an ideal hot dark matter candidate. However, in general either hot or cold dark matter can be consistent with a late-time transition. 47 refs., 2 figs

  8. Network traffic behaviour near phase transition point

    Science.gov (United States)

    Lawniczak, A. T.; Tang, X.

    2006-03-01

    We explore packet traffic dynamics in a data network model near phase transition point from free flow to congestion. The model of data network is an abstraction of the Network Layer of the OSI (Open Systems Interconnect) Reference Model of packet switching networks. The Network Layer is responsible for routing packets across the network from their sources to their destinations and for control of congestion in data networks. Using the model we investigate spatio-temporal packets traffic dynamics near the phase transition point for various network connection topologies, and static and adaptive routing algorithms. We present selected simulation results and analyze them.

  9. Exceptional Points and Dynamical Phase Transitions

    Directory of Open Access Journals (Sweden)

    I. Rotter

    2010-01-01

    Full Text Available In the framework of non-Hermitian quantum physics, the relation between exceptional points,dynamical phase transitions and the counter intuitive behavior of quantum systems at high level density is considered. The theoretical results obtained for open quantum systems and proven experimentally some years ago on a microwave cavity, may explain environmentally induce deffects (including dynamical phase transitions, which have been observed in various experimental studies. They also agree(qualitatively with the experimental results reported recently in PT symmetric optical lattices.

  10. Ultrafast demagnetization in Ni: theory of magneto-optics for non-equilibrium electron distributions

    Energy Technology Data Exchange (ETDEWEB)

    Oppeneer, P M [Leibniz-Institute of Solid State and Materials Research, PO Box 27006, D-01171 Dresden (Germany); Liebsch, A [Institut fuer Festkoerperforschung, Forschungszentrum Juelich, D-52425 Juelich (Germany)

    2004-08-04

    The sensitivity of the magneto-optical Kerr response to electronic thermalization processes in ultrafast pump-probe experiments is studied by evaluating the complex conductivity tensor of Ni for non-equilibrium electron distributions. The electronic structure and optical matrix elements are calculated within density functional theory. To account for the electronic redistributions generated by the intense pump-laser pulse during the initial stages of electronic thermalization, two kinds of model electron distributions are considered which mimic the so-called dichroic bleaching or state-blocking effect. Thus, certain optical transitions which are allowed under equilibrium conditions are not accessible to the probe laser. It is shown that the conductivity tensor and the complex Kerr angle can be modified substantially by the non-equilibrium electron distributions. Moreover, in striking contrast to the case for ordinary equilibrium conditions, the Kerr rotation and ellipticity are no longer proportional to the magnetization of the sample. The Kerr response at ultrashort times can therefore not be taken as a measure of demagnetization.

  11. Non-equilibrium dynamics and floral trait interactions shape extant angiosperm diversity.

    Science.gov (United States)

    O'Meara, Brian C; Smith, Stacey D; Armbruster, W Scott; Harder, Lawrence D; Hardy, Christopher R; Hileman, Lena C; Hufford, Larry; Litt, Amy; Magallón, Susana; Smith, Stephen A; Stevens, Peter F; Fenster, Charles B; Diggle, Pamela K

    2016-05-11

    Why are some traits and trait combinations exceptionally common across the tree of life, whereas others are vanishingly rare? The distribution of trait diversity across a clade at any time depends on the ancestral state of the clade, the rate at which new phenotypes evolve, the differences in speciation and extinction rates across lineages, and whether an equilibrium has been reached. Here we examine the role of transition rates, differential diversification (speciation minus extinction) and non-equilibrium dynamics on the evolutionary history of angiosperms, a clade well known for the abundance of some trait combinations and the rarity of others. Our analysis reveals that three character states (corolla present, bilateral symmetry, reduced stamen number) act synergistically as a key innovation, doubling diversification rates for lineages in which this combination occurs. However, this combination is currently less common than predicted at equilibrium because the individual characters evolve infrequently. Simulations suggest that angiosperms will remain far from the equilibrium frequencies of character states well into the future. Such non-equilibrium dynamics may be common when major innovations evolve rarely, allowing lineages with ancestral forms to persist, and even outnumber those with diversification-enhancing states, for tens of millions of years. © 2016 The Author(s).

  12. Dimension changing phase transitions in instanton crystals

    International Nuclear Information System (INIS)

    Kaplunovsky, Vadim; Sonnenschein, Jacob

    2014-01-01

    We investigate lattices of instantons and the dimension-changing transitions between them. Our ultimate goal is the 3D→4D transition, which is holographically dual to the phase transition between the baryonic and the quarkyonic phases of cold nuclear matter. However, in this paper (just as in http://dx.doi.org/10.1007/JHEP11(2012)047) we focus on lower dimensions — the 1D lattice of instantons in a harmonic potential V∝M 2 2 x 2 2 +M 3 2 x 2 2 +M 4 2 x 4 2 , and the zigzag-shaped lattice as a first stage of the 1D→2D transition. We prove that in the low- and moderate-density regimes, interactions between the instantons are dominated by two-body forces. This drastically simplifies finding the ground state of the instantons’ orientations, so we made a numeric scan of the whole orientation space instead of assuming any particular ansatz. We find that depending on the M 2 /M 3 /M 4 ratios, the ground state of instanton orientations can follow a wide variety of patterns. For the straight 1D lattices, we found orientations periodically running over elements of a ℤ 2 , Klein, prismatic, or dihedral subgroup of the SU(2)/ℤ 2 , as well as irrational but link-periodic patterns. For the zigzag-shaped lattices, we detected 4 distinct orientation phases — the anti-ferromagnet, another abelian phase, and two non-abelian phases. Allowing the zigzag amplitude to vary as a function of increasing compression force, we obtained the phase diagrams for the straight and zigzag-shaped lattices in the (force,M 3 /M 4 ), (chemical potential,M 3 /M 4 ), and (density,M 3 /M 4 ) planes. Some of the transitions between these phases are second-order while others are first-order. Our techniques can be applied to other types of non-abelian crystals

  13. Plasma diagnostics of non-equilibrium atmospheric plasma jets

    Science.gov (United States)

    Shashurin, Alexey; Scott, David; Keidar, Michael; Shneider, Mikhail

    2014-10-01

    Intensive development and biomedical application of non-equilibrium atmospheric plasma jet (NEAPJ) facilitates rapid growth of the plasma medicine field. The NEAPJ facility utilized at the George Washington University (GWU) demonstrated efficacy for treatment of various cancer types (lung, bladder, breast, head, neck, brain and skin). In this work we review recent advances of the research conducted at GWU concerned with the development of NEAPJ diagnostics including Rayleigh Microwave Scattering setup, method of streamer scattering on DC potential, Rogowski coils, ICCD camera and optical emission spectroscopy. These tools allow conducting temporally-resolved measurements of plasma density, electrical potential, charge and size of the streamer head, electrical currents flowing though the jet, ionization front propagation speed etc. Transient dynamics of plasma and discharge parameters will be considered and physical processes involved in the discharge will be analyzed including streamer breakdown, electrical coupling of the streamer tip with discharge electrodes, factors determining NEAPJ length, cross-sectional shape and propagation path etc.

  14. Non-equilibrium dissipative supramolecular materials with a tunable lifetime

    Science.gov (United States)

    Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job

    2017-07-01

    Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.

  15. Non-equilibrium steady states in supramolecular polymerization

    Science.gov (United States)

    Sorrenti, Alessandro; Leira-Iglesias, Jorge; Sato, Akihiro; Hermans, Thomas M.

    2017-06-01

    Living systems use fuel-driven supramolecular polymers such as actin to control important cell functions. Fuel molecules like ATP are used to control when and where such polymers should assemble and disassemble. The cell supplies fresh ATP to the cytosol and removes waste products to sustain steady states. Artificial fuel-driven polymers have been developed recently, but keeping them in sustained non-equilibrium steady states (NESS) has proven challenging. Here we show a supramolecular polymer that can be kept in NESS, inside a membrane reactor where ATP is added and waste removed continuously. Assembly and disassembly of our polymer is regulated by phosphorylation and dephosphorylation, respectively. Waste products lead to inhibition, causing the reaction cycle to stop. Inside the membrane reactor, however, waste can be removed leading to long-lived NESS conditions. We anticipate that our approach to obtain NESS can be applied to other stimuli-responsive materials to achieve more life-like behaviour.

  16. Quantum gases finite temperature and non-equilibrium dynamics

    CERN Document Server

    Szymanska, Marzena; Davis, Matthew; Gardiner, Simon

    2013-01-01

    The 1995 observation of Bose-Einstein condensation in dilute atomic vapours spawned the field of ultracold, degenerate quantum gases. Unprecedented developments in experimental design and precision control have led to quantum gases becoming the preferred playground for designer quantum many-body systems. This self-contained volume provides a broad overview of the principal theoretical techniques applied to non-equilibrium and finite temperature quantum gases. Covering Bose-Einstein condensates, degenerate Fermi gases, and the more recently realised exciton-polariton condensates, it fills a gap by linking between different methods with origins in condensed matter physics, quantum field theory, quantum optics, atomic physics, and statistical mechanics. Thematically organised chapters on different methodologies, contributed by key researchers using a unified notation, provide the first integrated view of the relative merits of individual approaches, aided by pertinent introductory chapters and the guidance of ed...

  17. Thermal Non-equilibrium Consistent with Widespread Cooling

    Science.gov (United States)

    Winebarger, A.; Lionello, R.; Mikic, Z.; Linker, J.; Mok, Y.

    2014-01-01

    Time correlation analysis has been used to show widespread cooling in the solar corona; this cooling has been interpreted as a result of impulsive (nanoflare) heating. In this work, we investigate wide-spread cooling using a 3D model for a solar active region which has been heated with highly stratified heating. This type of heating drives thermal non-equilibrium solutions, meaning that though the heating is effectively steady, the density and temperature in the solution are not. We simulate the expected observations in narrowband EUV images and apply the time correlation analysis. We find that the results of this analysis are qualitatively similar to the observed data. We discuss additional diagnostics that may be applied to differentiate between these two heating scenarios.

  18. A non-equilibrium formulation of food security resilience

    Science.gov (United States)

    Vaitla, Bapu

    2017-01-01

    Resilience, the ability to recover from adverse events, is of fundamental importance to food security. This is especially true in poor countries, where basic needs are frequently threatened by economic, environmental and health shocks. An empirically sound formalization of the concept of food security resilience, however, is lacking. Here, we introduce a general non-equilibrium framework for quantifying resilience based on the statistical notion of persistence. Our approach can be applied to any food security variable for which high-frequency time-series data are available. We illustrate our method with per capita kilocalorie availability for 161 countries between 1961 and 2011. We find that resilient countries are not necessarily those that are characterized by high levels or less volatile fluctuations of kilocalorie intake. Accordingly, food security policies and programmes will need to be tailored not only to welfare levels at any one time, but also to long-run welfare dynamics. PMID:28280586

  19. Non-equilibrium stochastic dynamics in continuum: The free case

    Directory of Open Access Journals (Sweden)

    Y.Kondratiev

    2008-12-01

    Full Text Available We study the problem of identification of a proper state-space for the stochastic dynamics of free particles in continuum, with their possible birth and death. In this dynamics, the motion of each separate particle is described by a fixed Markov process M on a Riemannian manifold X. The main problem arising here is a possible collapse of the system, in the sense that, though the initial configuration of particles is locally finite, there could exist a compact set in X such that, with probability one, infinitely many particles will arrive at this set at some time t>0. We assume that X has infinite volume and, for each α���1, we consider the set Θα of all infinite configurations in X for which the number of particles in a compact set is bounded by a constant times the α-th power of the volume of the set. We find quite general conditions on the process M which guarantee that the corresponding infinite particle process can start at each configuration from Θα, will never leave Θα, and has cadlag (or, even, continuous sample paths in the vague topology. We consider the following examples of applications of our results: Brownian motion on the configuration space, free Glauber dynamics on the configuration space (or a birth-and-death process in X, and free Kawasaki dynamics on the configuration space. We also show that if X=Rd, then for a wide class of starting distributions, the (non-equilibrium free Glauber dynamics is a scaling limit of (non-equilibrium free Kawasaki dynamics.

  20. Modeling Inflation Using a Non-Equilibrium Equation of Exchange

    Science.gov (United States)

    Chamberlain, Robert G.

    2013-01-01

    Inflation is a change in the prices of goods that takes place without changes in the actual values of those goods. The Equation of Exchange, formulated clearly in a seminal paper by Irving Fisher in 1911, establishes an equilibrium relationship between the price index P (also known as "inflation"), the economy's aggregate output Q (also known as "the real gross domestic product"), the amount of money available for spending M (also known as "the money supply"), and the rate at which money is reused V (also known as "the velocity of circulation of money"). This paper offers first a qualitative discussion of what can cause these factors to change and how those causes might be controlled, then develops a quantitative model of inflation based on a non-equilibrium version of the Equation of Exchange. Causal relationships are different from equations in that the effects of changes in the causal variables take time to play out-often significant amounts of time. In the model described here, wages track prices, but only after a distributed lag. Prices change whenever the money supply, aggregate output, or the velocity of circulation of money change, but only after a distributed lag. Similarly, the money supply depends on the supplies of domestic and foreign money, which depend on the monetary base and a variety of foreign transactions, respectively. The spreading of delays mitigates the shocks of sudden changes to important inputs, but the most important aspect of this model is that delays, which often have dramatic consequences in dynamic systems, are explicitly incorporated.macroeconomics, inflation, equation of exchange, non-equilibrium, Athena Project

  1. Modification of surfaces and surface layers by non equilibrium processes

    International Nuclear Information System (INIS)

    Beamson, G.; Brennan, W.J.; Clark, D.T.; Howard, J.

    1988-01-01

    Plasmas are examples of non-equilibrium phenomena which are being used increasingly for the synthesis and modification of materials impossible by conventional routes. This paper introduces methods available by describing the construction and characteristics of some equipment used for the production of different types of plasmas and other non-equilibrium phenomena. This includes high energy ion beams. The special features, advantages and disadvantages of the techniques will be described. There are a multitude of potential application relevant to electronic, metallic, ceramic, and polymeric materials. However, scale-up from the laboratory to production equipment depends on establishing a better understanding of both the physics and chemistry of plasma as well as plasma-solid interactions. Examples are given of how such an understanding can be gained. The chemical analysis of polymer surfaces undergoing modification by inert gas, hydrogen or oxygen plasmas is shown to give physical information regarding the relative roles of diffusion of active species, and direct and radiative energy transfer from the plasma. Surface modification by plasma depositing a new material onto an existing substrate is discussed with particular reference to the deposition of amorphous carbon films. Applications of the unique properties of these films are outlined together with our current understanding of these properties based on chemical and physical methods of analysis of both the films and the plasmas producing them. Finally, surface modification by ion beams is briefly illustrated using examples from the electronics and metals industries where the modification has had a largely physical rather than chemical effect on the starting material. (orig.)

  2. Shock wave produced by hadron-quark phase transition in neutron star

    Energy Technology Data Exchange (ETDEWEB)

    Gustavo de Almeida, Luis, E-mail: lgalmeida@cbpf.br [Universidade Federal do Acre – Campus Floresta, Estrada do Canela Fina, km 12, CEP 69980-000, Cruzeiro do Sul, AC (Brazil); Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro, RJ (Brazil); Duarte, Sérgio José Barbosa, E-mail: sbd@cbpf.br [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro, RJ (Brazil); Rodrigues, Hilário, E-mail: harg.astrophys@gmail.com [Centro Federal de Educação Tecnológica Celso Suckow da Fonseca Av. Maracanã, 229, CEP 20271-110, Rio de Janeiro, RJ (Brazil)

    2015-12-17

    In this work we present a schematic description of the detonation wave in hadronic matter inside a neutron star core. We have used a simplified two shells model where the inner shell medium is initially composed of a small lump of strange quark matter surrounded by a large outer shell composed of hadronic matter. We have utilized an equation of state (EOS) based on Relativistic Mean Field Theory with the parameter set NL3 to describe the nuclear and subnuclear phases. We use the MIT bag model to describe the strange quark matter. The hadron-quark phase transition actually induces highly non equilibrium modes, which may become a detonation process (faster) or a burning process (slower). The main purpose of the work is to study the formation of a remnant quark star and the possibility of mass ejection caused by the hadron-quark phase transition. We have found that the total amount of ejected mass is dependant of the bag constant utilized in the strange matter description.

  3. Space Storm as a Dynamical Phase Transition

    Science.gov (United States)

    Wanliss, J. A.

    2006-12-01

    Fluctuations of the DST index were analyzed for several magnetic storms preceded by more than a week of extremely quiet conditions to establish that there is a rapid and unidirectional change in the Hurst scaling exponent at the time of storm onset. That is, the transition is accompanied by the specific signature of a rapid unidirectional change in the temporal fractal scaling of fluctuations in DST, signaling the formation of a new dynamical phase (or mode) which is considerably more organized than the background state. We compare these results to a model of multifractional Brownian motion and suggest that the relatively sudden change from a less correlated to a more correlated pattern of multiscale fluctuations at storm onset can be characterized in terms of nonequilibrium dynamical phase transitions. Initial results show that a dynamical transition in solar wind VBs is correlated with the storm onset for intense storms, suggesting that the transition observed in DST is of external solar wind origin, rather than internal magnetospheric origin. On the other hand, some results show a dynamical transition in solar wind scaling exponents not matched in DST. As well, we also present results for small storms where there is a strong dynamical transition in DST without a similar changes in the VBs scaling statistics. The results for small storms seem to reduce the importance of the solar wind fluctuations but the evidence for the intense storms seems to point to the solar wind as being responsible for providing the scale free properties in the DST fluctuations.

  4. Dynamical quantum phase transitions: a review

    Science.gov (United States)

    Heyl, Markus

    2018-05-01

    Quantum theory provides an extensive framework for the description of the equilibrium properties of quantum matter. Yet experiments in quantum simulators have now opened up a route towards the generation of quantum states beyond this equilibrium paradigm. While these states promise to show properties not constrained by equilibrium principles, such as the equal a priori probability of the microcanonical ensemble, identifying the general properties of nonequilibrium quantum dynamics remains a major challenge, especially in view of the lack of conventional concepts such as free energies. The theory of dynamical quantum phase transitions attempts to identify such general principles by lifting the concept of phase transitions to coherent quantum real-time evolution. This review provides a pedagogical introduction to this field. Starting from the general setting of nonequilibrium dynamics in closed quantum many-body systems, we give the definition of dynamical quantum phase transitions as phase transitions in time with physical quantities becoming nonanalytic at critical times. We summarize the achieved theoretical advances as well as the first experimental observations, and furthermore provide an outlook to major open questions as well as future directions of research.

  5. Scattering theory of topological phase transitions

    NARCIS (Netherlands)

    Fulga, Ion Cosma

    2013-01-01

    This thesis deals with characterizing topological phases as well as the transitions between them, focusing on transport properties and the effects of disorder. In Chapters 2 and 3 we derived scattering matrix expressions for the topological invariants of systems. This approach is oftentimes

  6. Locating phase transitions in computationally hard problems

    Indian Academy of Sciences (India)

    - ity does not seem to justify the .... Although phase transitions occur only in the thermodynamic limit, in the limit of infinitely large systems, as .... composition) for a system in the stochastic theory of adiabatic explosion [17]. In that thermodynamic ...

  7. Magnesium hydrides and their phase transitions

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav

    2016-01-01

    Roč. 41, č. 23 (2016), s. 9769-9773 ISSN 0360-3199 R&D Projects: GA MŠk(CZ) LD13069 Institutional support: RVO:68378271 Keywords : hydrogen * magnesium and transition metal hydrides * crystal structure stability * displacive phase transformations Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.582, year: 2016

  8. Vol. 3: Statistical Physics and Phase Transitions

    International Nuclear Information System (INIS)

    Sitenko, A.

    1993-01-01

    Problems of modern physics and the situation with physical research in Ukraine are considered. Programme of the conference includes scientific and general problems. Its proceedings are published in 6 volumes. The papers presented in this volume refer to statistical physics and phase transition theory

  9. Monte Carlo Simulation of Phase Transitions

    OpenAIRE

    村井, 信行; N., MURAI; 中京大学教養部

    1983-01-01

    In the Monte Carlo simulation of phase transition, a simple heat bath method is applied to the classical Heisenberg model in two dimensions. It reproduces the correlation length predicted by the Monte Carlo renor-malization group and also computed in the non-linear σ model

  10. Dynamical quantum phase transitions: a review.

    Science.gov (United States)

    Heyl, Markus

    2018-02-15

    Quantum theory provides an extensive framework for the description of the equilibrium properties of quantum matter. Yet experiments in quantum simulators have now opened up a route towards the generation of quantum states beyond this equilibrium paradigm. While these states promise to show properties not constrained by equilibrium principles, such as the equal a priori probability of the microcanonical ensemble, identifying the general properties of nonequilibrium quantum dynamics remains a major challenge, especially in view of the lack of conventional concepts such as free energies. The theory of dynamical quantum phase transitions attempts to identify such general principles by lifting the concept of phase transitions to coherent quantum real-time evolution. This review provides a pedagogical introduction to this field. Starting from the general setting of nonequilibrium dynamics in closed quantum many-body systems, we give the definition of dynamical quantum phase transitions as phase transitions in time with physical quantities becoming nonanalytic at critical times. We summarize the achieved theoretical advances as well as the first experimental observations, and furthermore provide an outlook to major open questions as well as future directions of research.

  11. Hysteresis in the phase transition of chocolate

    Science.gov (United States)

    Ren, Ruilong; Lu, Qunfeng; Lin, Sihua; Dong, Xiaoyan; Fu, Hao; Wu, Shaoyi; Wu, Minghe; Teng, Baohua

    2016-01-01

    We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the heating and cooling process, and then established a model to relate the solidification degree to the order parameter. Based on the Landau-Devonshire theory, our model gave a description of the hysteresis phenomenon in chocolate, which lays the foundations for the study of the phase transition behavior of chocolate.

  12. Scaling Concepts in Describing Continuous Phase Transitions

    Indian Academy of Sciences (India)

    these relations was among the main motivations that lead to scal- ing descriptions of behaviour near critical points. Phase Transitions: Preliminaries. The theoretical analyses of critical points, as well as their exposi- tion, have employed simplified models of interacting systems. We follow the same practice here, and define ...

  13. Two phase transitions in Nuclear Physics

    International Nuclear Information System (INIS)

    Bes, D.R.

    1985-01-01

    The status of the art of the problem associated with two phase transitions in the nuclear matter, viz.: the disappearance of the nuclear superfluiditiy with the raising of the rotation velocity and the appearance of an octupolar deformation in the actinide zone, is presented. (L.C.) [pt

  14. Phase transition to QGP matter : confined vs deconfined matter

    CERN Multimedia

    Maire, Antonin

    2015-01-01

    Simplified phase diagram of the nuclear phase transition, from the regular hadronic matter to the QGP phase. The sketch is meant to describe the transition foreseen along the temperature axis, at low baryochemical potential, µB.

  15. The Physics of Structural Phase Transitions

    CERN Document Server

    Fujimoto, Minoru

    2005-01-01

    Phase transitions in which crystalline solids undergo structural changes present an interesting problem in the interplay between the crystal structure and the ordering process that is typically nonlinear. Intended for readers with prior knowledge of basic condensed-matter physics, this book emphasizes the physics behind spontaneous structural changes in crystals. Starting with the relevant thermodynamic principles, the text discusses the nature of order variables in collective motion in structural phase transitions, where a singularity in such a collective mode is responsible for lattice instability as revealed by soft phonons. In this book, critical anomalies at second-order structural transitions are first analyzed with the condensate model. Discussions on the nonlinear ordering mechanism are followed with the soliton theory, thereby interpreting the role of long-range order. Relevant details for nonlinear mathematics are therefore given for minimum necessity. The text also discusses experimental methods fo...

  16. Magnetocaloric materials and first order phase transitions

    DEFF Research Database (Denmark)

    Neves Bez, Henrique

    of the properties of such materials.The experimental characterization of these materials is done through various different methods, such as X-ray diffraction, magnetometry, calorimetry, direct measurements of entropy change, capacitance dilatometry, scanning electron microscopy,energy-dispersive X-ray spectrometry...... shows a paradoxical behavior; the material shows features of both a first order phase transition and of a second order one. Identities as shift of the heat capacity peak and an asymmetric growth of of the entropy change with magnetic field would describe this material transition as a first order one...... temperature and field independent is exaggerated and perhaps cannot be taken.A series of La(Fe,Mn,Si)13Hz with slightly changes in the composition is also evaluated here. This material may present a second order phase transition for large content of Mn and Si, which will become a first order one as the Mn...

  17. Transverse alignment of fibers in a periodically sheared suspension: An absorbing phase transition with a slowly-varying control parameter

    Science.gov (United States)

    Franceschini, Alexandre; Filippidi, Emmanouela; Guazzelli, Elisabeth; Pine, David

    2011-11-01

    Shearing fibers and polymer solutions tends to align particles with the flow direction. Here, we report that neutrally buoyant non-Brownian fibers subjected to oscillatory shear are observed to align perpendicular to the flow. This alignment occurs over a finite range of strain amplitudes and is governed by a subtle interplay between fiber orientation and short-range interactions through an athermal (non-equilibrium) process known as random organization. For a given strain amplitude and concentration, the mean field orientation defines a time-dependant control parameter that can drive the suspension through an absorbing phase transition. The slow drift of the control parameter does not influence the class of the transition. The measured critical threshold and exponents are consistent with the one reported for sphere suspensions. This work was supported by the NSF through the NYU MRSEC, Award DMR:0820341. Additional support was provided by a Lavoisier Fellowship (AF) and from the Onassis Foundation (EF).

  18. The second-order description of rotational non-equilibrium effects in polyatomic gases

    Science.gov (United States)

    Myong, Rho Shin

    2017-11-01

    The conventional description of gases is based on the physical laws of conservation (mass, momentum, and energy) in conjunction with the first-order constitutive laws, the two-century old so-called Navier-Stokes-Fourier (NSF) equation based on a critical assumption made by Stokes in 1845 that the bulk viscosity vanishes. While the Stokes' assumption is certainly legitimate in the case of dilute monatomic gases, ever increasing evidences, however, now indicate that such is not the case, in particular, in the case of polyatomic gases-like nitrogen and carbon dioxide-far-from local thermal equilibrium. It should be noted that, from room temperature acoustic attenuation data, the bulk viscosity for carbon dioxide is three orders of magnitude larger than its shear viscosity. In this study, this fundamental issue in compressible gas dynamics is revisited and the second-order constitutive laws are derived by starting from the Boltzmann-Curtiss kinetic equation. Then the topology of the second-order nonlinear coupled constitutive relations in phase space is investigated. Finally, the shock-vortex interaction problem where the strong interaction of two important thermal (translational and rotational) non-equilibrium phenomena occurs is considered in order to highlight the rotational non-equilibrium effects in polyatomic gases. This work was supported by the National Research Foundation of South Korea (NRF 2017-R1A2B2-007634).

  19. Time-dependent non-equilibrium dielectric response in QM/continuum approaches

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Feizhi; Lingerfelt, David B.; Li, Xiaosong, E-mail: benedetta.mennucci@unipi.it, E-mail: li@chem.washington.edu [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Mennucci, Benedetta, E-mail: benedetta.mennucci@unipi.it, E-mail: li@chem.washington.edu [Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa (Italy)

    2015-01-21

    The Polarizable Continuum Models (PCMs) are some of the most inexpensive yet successful methods for including the effects of solvation in quantum-mechanical calculations of molecular systems. However, when applied to the electronic excitation process, these methods are restricted to dichotomously assuming either that the solvent has completely equilibrated with the excited solute charge density (infinite-time limit), or that it retains the configuration that was in equilibrium with the solute prior to excitation (zero-time limit). This renders the traditional PCMs inappropriate for resolving time-dependent solvent effects on non-equilibrium solute electron dynamics like those implicated in the instants following photoexcitation of a solvated molecular species. To extend the existing methods to this non-equilibrium regime, we herein derive and apply a new formalism for a general time-dependent continuum embedding method designed to be propagated alongside the solute’s electronic degrees of freedom in the time domain. Given the frequency-dependent dielectric constant of the solvent, an equation of motion for the dielectric polarization is derived within the PCM framework and numerically integrated simultaneously with the time-dependent Hartree fock/density functional theory equations. Results for small molecular systems show the anticipated dipole quenching and electronic state dephasing/relaxation resulting from out-of-phase charge fluctuations in the dielectric and embedded quantum system.

  20. Computational advances in transition phase analysis

    International Nuclear Information System (INIS)

    Morita, K.; Kondo, S.; Tobita, Y.; Shirakawa, N.; Brear, D.J.; Fischer, E.A.

    1994-01-01

    In this paper, historical perspective and recent advances are reviewed on computational technologies to evaluate a transition phase of core disruptive accidents in liquid-metal fast reactors. An analysis of the transition phase requires treatment of multi-phase multi-component thermohydraulics coupled with space- and energy-dependent neutron kinetics. Such a comprehensive modeling effort was initiated when the program of SIMMER-series computer code development was initiated in the late 1970s in the USA. Successful application of the latest SIMMER-II in USA, western Europe and Japan have proved its effectiveness, but, at the same time, several areas that require further research have been identified. Based on the experience and lessons learned during the SIMMER-II application through 1980s, a new project of SIMMER-III development is underway at the Power Reactor and Nuclear Fuel Development Corporation (PNC), Japan. The models and methods of SIMMER-III are briefly described with emphasis on recent advances in multi-phase multi-component fluid dynamics technologies and their expected implication on a future reliable transition phase analysis. (author)

  1. Structural Phase Transition in Adipic Acid

    Science.gov (United States)

    Srinivasa Gopalan, R.; Kumaradhas, P.; Kulkarni, G. U.

    1999-11-01

    The structure of adipic acid undergoing phase transition at ∼136 K has been investigated using single-crystal x-ray diffraction. On lowering the temperature, the a parameter of the room temperature monoclinic cell decreases by ∼0.25 Å. Accompanying the transition, the b parameter nearly triples while a reverts back to the room temperature value. Two-thirds of the molecules in the structure loses center of symmetry. Packing diagrams of the high- and low-temperature phases on superposition reveal that there exist alternating domains perpendicular to the b direction, which contain molecules with and without symmetry. Unsymmetric molecules show displacements along the ac diagonal. Intermolecular hydrogen contacts involving carboxylic oxygens and the methylene hydrogens seem to increase interchain interactions in the low-temperature phase.

  2. Energy transition and phasing out nuclear

    International Nuclear Information System (INIS)

    Laponche, Bernard

    2013-05-01

    In the first part of this report, the author outlines and comments the need of an energy transition in the world: overview of world challenges (world energy consumption and its constraints, a necessary energy transition, new actors and new responsibilities), and describes the German example of an energy transition policy. In the second part, he presents and discusses the main reasons for phasing out nuclear: description of a nuclear plant operation (fission and chain reaction, heat production, production of radioactive elements, how to stop a nuclear reactor), safety and risk issues (protection arrangements, risk and consequence of a nuclear accident), issue of radioactive wastes, relationship between civil techniques and proliferation of nuclear weapons. In a third part, the author proposes an overview of the energy issue in France: final energy consumption, electricity production and consumption, primary energy consumption, characteristics of the French energy system (oil dependency, electricity consumption, and high share of nuclear energy in electricity production). In a last part, the author addresses the issue of energy transition in a perspective of phasing out nuclear: presentation of the Negawatt scenario, assessments made by Global Chance, main programmes of energy transition

  3. Phase transition signals of finite systems

    International Nuclear Information System (INIS)

    Duflot-Flandrois, Veronique

    2001-01-01

    Phase transitions are universal properties of interacting matter. They are well described if the considered system is infinite, by using standard thermodynamics. But in the case of small systems like atomic nuclei, this formalism cannot be applied anymore. Our aim is to propose a statistical mechanics approach in order to define the thermodynamical features of small open systems subject to non-saturating forces. We concentrate in particular on the definition and characterization for such systems of phase transitions belonging to the liquid gas universality class. Theoretical and experimental observables are defined to signal the occurrence and the order of this transition without any ambiguity. One of the most relevant and experimentally accessible observables consists in the study of kinetic energy fluctuations for a fixed value of the total deposited energy. In a first order phase transition such fluctuations become anomaly high and at the same time the size distribution appears to behave critically. All our results are obtained within numerical simulations of the lattice gas model with a nearest neighbors attractive interaction. Finally we check the influence of non-saturating forces, developing the specific example of the Coulomb interaction in the nucleus. Future improvements and perspectives at this work consist in the analysis of specific effects occurring in nuclei: isospin and quantum mechanics. (author) [fr

  4. Dynamical versus equilibrium properties of the QCD phase transition: A holographic perspective

    Science.gov (United States)

    Rougemont, Romulo; Critelli, Renato; Noronha-Hostler, Jacquelyn; Noronha, Jorge; Ratti, Claudia

    2017-07-01

    We employ an Einstein-Maxwell-Dilaton (EMD) holographic model, which is known to be in good agreement with lattice results for the QCD equation of state with (2 +1 ) flavors and physical quark masses, to investigate the temperature and baryon chemical potential dependence of the susceptibilities, conductivities, and diffusion coefficients associated with baryon, electric, and strangeness conserved charges. We also determine how the bulk and shear viscosities of the plasma vary in the plane of temperature and baryon chemical potential. The diffusion of conserved charges and the hydrodynamic viscosities in a baryon rich quark-gluon plasma are found to be suppressed with respect to the zero net baryon case. The transition temperatures associated with equilibrium and non-equilibrium quantities are determined as a function of the baryon chemical potential for the first time. Because of the crossover nature of the QCD phase transition even at moderately large values of the chemical potential, we find that the transition temperatures associated with different quantities are spread in the interval between 130-200 MeV and they all decrease with increasing baryon chemical potential.

  5. Space storm as a phase transition

    Science.gov (United States)

    Wanliss, J. A.; Dobias, P.

    2007-04-01

    Fluctuations of the SYM-H index were analyzed for several space storms preceded by more than a week of extremely quiet conditions to establish that there was a rapid and unidirectional change in the Hurst scaling exponent at the time of storm onset. That is, the transition was accompanied by the specific signature of a rapid unidirectional change in the temporal fractal scaling of fluctuations in SYM-H, signaling the formation of a new dynamical phase (or mode) which was considerably more organized than the background state. We compare these results to a model of multifractional Brownian motion and suggest that the relatively sudden change from a less correlated to a more correlated pattern of multiscale fluctuations at storm onset can be characterized in terms of nonequilibrium dynamical phase transitions. The results show that a dynamical transition in solar wind VB is correlated with the storm onset for intense storms, suggesting that the dynamical transition observed in SYM-H is of external solar wind origin, rather than internal magnetospheric origin. However, some results showed a dynamical transition in solar wind scaling exponents not matched by similar transitions in SYM-H. In other instances, we observed some small storms where there was a strong dynamical transition in SYM-H without similar changes in the VB scaling statistics, suggesting that changes were due to internal magnetospheric processes. In summary, the results for intense storms points to the solar wind as being responsible for providing the scale free properties in the SYM-H fluctuations but the evidence for small storms clearly limit the importance of the solar wind fluctuations; their interaction is more complex than simple causality.

  6. About the dynamics of structural phase transitions

    International Nuclear Information System (INIS)

    Medeiros, J.T.N.

    1975-01-01

    The dynamics of structural phase transitions with a fourth order interaction between the soft phonon fields is studied in the 1/n approximation, using many body methods at finite temperatures. Two limits are considered: high transition temperature T sub(c) (classical limit) and T sub(c) = 0 (quantum limit). The dynamical contribution to the critical coefficient eta of the correlation function is calculated in these limits. It is found that there is no dynamical contribution to eta in the classical limit, whereas in the quantum limit eta is non-zero only for dimensions of the system d [pt

  7. Observation of a many-body dynamical phase transition with a 53-qubit quantum simulator

    Science.gov (United States)

    Zhang, J.; Pagano, G.; Hess, P. W.; Kyprianidis, A.; Becker, P.; Kaplan, H.; Gorshkov, A. V.; Gong, Z.-X.; Monroe, C.

    2017-11-01

    A quantum simulator is a type of quantum computer that controls the interactions between quantum bits (or qubits) in a way that can be mapped to certain quantum many-body problems. As it becomes possible to exert more control over larger numbers of qubits, such simulators will be able to tackle a wider range of problems, such as materials design and molecular modelling, with the ultimate limit being a universal quantum computer that can solve general classes of hard problems. Here we use a quantum simulator composed of up to 53 qubits to study non-equilibrium dynamics in the transverse-field Ising model with long-range interactions. We observe a dynamical phase transition after a sudden change of the Hamiltonian, in a regime in which conventional statistical mechanics does not apply. The qubits are represented by the spins of trapped ions, which can be prepared in various initial pure states. We apply a global long-range Ising interaction with controllable strength and range, and measure each individual qubit with an efficiency of nearly 99 per cent. Such high efficiency means that arbitrary many-body correlations between qubits can be measured in a single shot, enabling the dynamical phase transition to be probed directly and revealing computationally intractable features that rely on the long-range interactions and high connectivity between qubits.

  8. Phase transitions in Pareto optimal complex networks.

    Science.gov (United States)

    Seoane, Luís F; Solé, Ricard

    2015-09-01

    The organization of interactions in complex systems can be described by networks connecting different units. These graphs are useful representations of the local and global complexity of the underlying systems. The origin of their topological structure can be diverse, resulting from different mechanisms including multiplicative processes and optimization. In spatial networks or in graphs where cost constraints are at work, as it occurs in a plethora of situations from power grids to the wiring of neurons in the brain, optimization plays an important part in shaping their organization. In this paper we study network designs resulting from a Pareto optimization process, where different simultaneous constraints are the targets of selection. We analyze three variations on a problem, finding phase transitions of different kinds. Distinct phases are associated with different arrangements of the connections, but the need of drastic topological changes does not determine the presence or the nature of the phase transitions encountered. Instead, the functions under optimization do play a determinant role. This reinforces the view that phase transitions do not arise from intrinsic properties of a system alone, but from the interplay of that system with its external constraints.

  9. A Comparison of the Computation Times of Thermal Equilibrium and Non-equilibrium Models of Droplet Field in a Two-Fluid Three-Field Model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ik Kyu; Cho, Heong Kyu; Kim, Jong Tae; Yoon, Han Young; Jeong, Jae Jun

    2007-12-15

    A computational model for transient, 3 dimensional 2 phase flows was developed by using 'unstructured-FVM-based, non-staggered, semi-implicit numerical scheme' considering the thermally non-equilibrium droplets. The assumption of the thermally equilibrium between liquid and droplets of previous studies was not used any more, and three energy conservation equations for vapor, liquid, liquid droplets were set up. Thus, 9 conservation equations for mass, momentum, and energy were established to simulate 2 phase flows. In this report, the governing equations and a semi-implicit numerical sheme for a transient 1 dimensional 2 phase flows was described considering the thermally non-equilibrium between liquid and liquid droplets. The comparison with the previous model considering the thermally non-equilibrium between liquid and liquid droplets was also reported.

  10. Non equilibrium thermodynamics with internal variables in Kluitenberg's theory

    Directory of Open Access Journals (Sweden)

    Ciancio, Vincenzo

    2008-02-01

    Full Text Available We show a method to verify experimentally some inequalities which occur for phenomenological coefficients in the thermodynamical model for dielectric relaxation and viscoanelastic media developed in the ambit of non-equilibrium thermodynamic Kluitenberg's theory. In particular, for dielectric relaxation we assume a sinusoidal form for induction vector (extensive variable: cause, the electric field (intensive variable: effect inside the system, which depends on unknown phenomenological coefficients, has been obtained by integration. Then we compare it with a similar form of the electric field obtained by experimental considerations, where well known experimentally determinable coefficients appear. We carry out dielectric measurements on PMMA and PVC at different frequencies and fixed temperature in order to obtain the phenomenological coefficients as functions of the frequency. For viscoanelastic media we consider the relative rheological equation and we compare the solution of this equation with a well known expression of the stress obtained, by experimentally considerations, in the linear response theory. This comparison will be able to determine the phenomenological an state coefficients as function of frequency dependent quantities experimentally measurable. This method will be applied to polymeric materials as Polyisobutilene.

  11. Non-equilibrium phenomena near vapor-liquid interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kryukov, Alexei; Levashov, Vladimir; Puzina, Yulia [Moscow Power Engineering Institute, Moscow (Russian Federation)

    2013-08-01

    Written by experts in the field. This book presents information on the development of a non-equilibrium approach to the study of heat and mass transfer problems using vapor-liquid interfaces, and demonstrates its application to a broad range of problems. In the process, the following peculiarities become apparent: 1. At vapor condensation on the interface from gas-vapor mixture, non-condensable components can lock up the interface surface and condensation stops completely. 2. At the evolution of vapor film on the heater in superfluid helium (He-II), the boiling mass flux density from the vapor-liquid interface is effectively zero at the macroscopic scale. 3. In problems concerning the motion of He-II bridges inside capillaries filled by vapor, in the presence of axial heat flux the He-II bridge cannot move from the heater as would a traditional liquid, but in the opposite direction instead. Thus the heater attracts the superfluid helium bridge. 4. The shape of liquid-vapor interface at film boiling on the axis-symmetric heaters immersed in liquid greatly depends on heat flux in the interface. Thus a new type of hydrostatic problems appears when in contrast to traditional statements the shape of the liquid-vapor interface has a complex profile with a point of inflection and a smooth exit on a free liquid surface.

  12. Calculating zeros: Non-equilibrium free energy calculations

    International Nuclear Information System (INIS)

    Oostenbrink, Chris; Gunsteren, Wilfred F. van

    2006-01-01

    Free energy calculations on three model processes with theoretically known free energy changes have been performed using short simulation times. A comparison between equilibrium (thermodynamic integration) and non-equilibrium (fast growth) methods has been made in order to assess the accuracy and precision of these methods. The three processes have been chosen to represent processes often observed in biomolecular free energy calculations. They involve a redistribution of charges, the creation and annihilation of neutral particles and conformational changes. At very short overall simulation times, the thermodynamic integration approach using discrete steps is most accurate. More importantly, reasonable accuracy can be obtained using this method which seems independent of the overall simulation time. In cases where slow conformational changes play a role, fast growth simulations might have an advantage over discrete thermodynamic integration where sufficient sampling needs to be obtained at every λ-point, but only if the initial conformations do properly represent an equilibrium ensemble. From these three test cases practical lessons can be learned that will be applicable to biomolecular free energy calculations

  13. Geometry and symmetry in non-equilibrium thermodynamic systems

    Science.gov (United States)

    Sonnino, Giorgio

    2017-06-01

    The ultimate aim of this series of works is to establish the closure equations, valid for thermodynamic systems out from the Onsager region, and to describe the geometry and symmetry in thermodynamic systems far from equilibrium. Geometry of a non-equilibrium thermodynamic system is constructed by taking into account the second law of thermodynamics and by imposing the validity of the Glansdorff-Prigogine Universal Criterion of Evolution. These two constraints allow introducing the metrics and the affine connection of the Space of the Thermodynamic Forces, respectively. The Lie group associated to the nonlinear Thermodynamic Coordinate Transformations (TCT) leaving invariant both the entropy production σ and the Glansdorff-Prigogine dissipative quantity P, is also described. The invariance under TCT leads to the formulation of the Thermodynamic Covariance Principle (TCP): The nonlinear closure equations, i.e. the flux-force relations, must be covariant under TCT. In other terms, the fundamental laws of thermodynamics should be manifestly covariant under transformations between the admissible thermodynamic forces (i.e. under TCT). The symmetry properties of a physical system are intimately related to the conservation laws characterizing the thermodynamic system. Noether's theorem gives a precise description of this relation. The macroscopic theory for closure relations, based on this geometrical description and subject to the TCP, is referred to as the Thermodynamic Field Theory (TFT). This theory ensures the validity of the fundamental theorems for systems far from equilibrium.

  14. Non-Equilibrium Water-Glassy Polymer Dynamics

    Science.gov (United States)

    Davis, Eric; Minelli, Matteo; Baschetti, Marco; Sarti, Giulio; Elabd, Yossef

    2012-02-01

    For many applications (e.g., medical implants, packaging), an accurate assessment and fundamental understanding of the dynamics of water-glassy polymer interactions is of great interest. In this study, sorption and diffusion of pure water in several glassy polymers films, such as poly(styrene) (PS), poly(methyl methacrylate) (PMMA), poly(lactide) (PLA), were measured over a wide range of vapor activities and temperatures using several experimental techniques, including quartz spring microbalance (QSM), quartz crystal microbalance (QCM), and time-resolved Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy. Non-Fickian behavior (diffusion-relaxation phenomena) was observed by all three techniques, while FTIR-ATR spectroscopy also provides information about the distribution of the states of water and water transport mechanisms on a molecular-level. Specifically, the states of water are significantly different in PS compared to PMMA and PLA. Additionally, a purely predictive non-equilibrium lattice fluid (NELF) model was applied to predict the sorption isotherms of water in these glassy polymers.

  15. Non-Equilibrium Turbulence and Two-Equation Modeling

    Science.gov (United States)

    Rubinstein, Robert

    2011-01-01

    Two-equation turbulence models are analyzed from the perspective of spectral closure theories. Kolmogorov theory provides useful information for models, but it is limited to equilibrium conditions in which the energy spectrum has relaxed to a steady state consistent with the forcing at large scales; it does not describe transient evolution between such states. Transient evolution is necessarily through nonequilibrium states, which can only be found from a theory of turbulence evolution, such as one provided by a spectral closure. When the departure from equilibrium is small, perturbation theory can be used to approximate the evolution by a two-equation model. The perturbation theory also gives explicit conditions under which this model can be valid, and when it will fail. Implications of the non-equilibrium corrections for the classic Tennekes-Lumley balance in the dissipation rate equation are drawn: it is possible to establish both the cancellation of the leading order Re1/2 divergent contributions to vortex stretching and enstrophy destruction, and the existence of a nonzero difference which is finite in the limit of infinite Reynolds number.

  16. Non-equilibrium statistical thermodynamics of neutron gas in reactor

    International Nuclear Information System (INIS)

    Hayasaka, Hideo

    1977-01-01

    The thermodynamic structures of non-equilibrium steady states of highly rarefied neutron gas in various media are considered for the irreversible processes owing to creative and destructive reactions of neutrons with nuclei of these media and supply from the external sources. Under the so-called clean and cold condition in reactor, the medium is regarded virtually as offering the different chemical potential fields for each subsystem of a steady neutron gas system. The fluctuations around a steady state are considered in a Markovian-Gaussian process. The generalized Einstein relations are derived for stationary neutron gas systems. The forces and flows of neutron gases in a medium are defined upon the general stationary solution of the Fokker-Planck equation. There exist the symmetry of the kinetic coefficients, and the minimum entropy production upon neutron-nuclear reactions. The distribution functions in various media are determined by each corresponding extremum condition under the vanishing of changes of the respective total entropies in the Gibbs equation. (auth.)

  17. Non-Equilibrium Properties from Equilibrium Free Energy Calculations

    Science.gov (United States)

    Pohorille, Andrew; Wilson, Michael A.

    2012-01-01

    Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.

  18. Controlling Non-Equilibrium Structure Formation on the Nanoscale.

    Science.gov (United States)

    Buchmann, Benedikt; Hecht, Fabian Manfred; Pernpeintner, Carla; Lohmueller, Theobald; Bausch, Andreas R

    2017-12-06

    Controlling the structure formation of gold nanoparticle aggregates is a promising approach towards novel applications in many fields, ranging from (bio)sensing to (bio)imaging to medical diagnostics and therapeutics. To steer structure formation, the DNA-DNA interactions of DNA strands that are coated on the surface of the particles have become a valuable tool to achieve precise control over the interparticle potentials. In equilibrium approaches, this technique is commonly used to study particle crystallization and ligand binding. However, regulating the structural growth processes from the nano- to the micro- and mesoscale remains elusive. Here, we show that the non-equilibrium structure formation of gold nanoparticles can be stirred in a binary heterocoagulation process to generate nanoparticle clusters of different sizes. The gold nanoparticles are coated with sticky single stranded DNA and mixed at different stoichiometries and sizes. This not only allows for structural control but also yields access to the optical properties of the nanoparticle suspensions. As a result, we were able to reliably control the kinetic structure formation process to produce cluster sizes between tens of nanometers up to micrometers. Consequently, the intricate optical properties of the gold nanoparticles could be utilized to control the maximum of the nanoparticle suspension extinction spectra between 525 nm and 600 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Transition phase in LMFBR hypothetical accidents

    International Nuclear Information System (INIS)

    Ostensen, R.W.; Henninger, R.J.; Jackson, J.F.

    1976-01-01

    Mechanistic analyses of transient-under-cooling accidents have led in some cases to a mild initiating phase instead of a direct hydrodynamic disassembly of the core. The fuel is then trapped in the core by the strong mechanical surroundings and blockages formed by refrozen cladding steel and/or fuel. The formation of fuel blockages has been verified experimentally. The bottled-up core will boil on fission and decay heat, with steel as the working fluid. Boil-up in a churn turbulent flow regime may prevent recriticality due to fuel recompaction. Ultimate fuel removal from the core is probably by a two-phase blow-down after permanent leakage paths are opened. However, a vigorous recriticality can not be precluded. Reactors with void coefficients larger than that in CRBR are more likely to disassemble in the initiating phase, so the transition phase may be unique to small cores

  20. Equilibrium and Non-Equilibrium Condensation Phenomena in Tuneable 3D and 2D Bose Gases

    Science.gov (United States)

    2016-04-01

    AFRL-AFOSR-UK-TR-2016-0009 Equilibrium and non- equilibrium condensation phenomena in tuneable 3D and 2D Bose gases Zoran Hadzibabic THE CHANCELLOR...31-Aug-2015 4. TITLE AND SUBTITLE Equilibrium and non- equilibrium condensation phenomena in tuneable 3D and 2D Bose gases 5a. CONTRACT NUMBER... equilibrium and non- equilibrium many-body phenomena, trapping ultracold atomic gases in different geometries including both 3 and 2 spatial dimensions

  1. Gravitational Waves from a Dark Phase Transition.

    Science.gov (United States)

    Schwaller, Pedro

    2015-10-30

    In this work, we show that a large class of models with a composite dark sector undergo a strong first order phase transition in the early Universe, which could lead to a detectable gravitational wave signal. We summarize the basic conditions for a strong first order phase transition for SU(N) dark sectors with n_{f} flavors, calculate the gravitational wave spectrum and show that, depending on the dark confinement scale, it can be detected at eLISA or in pulsar timing array experiments. The gravitational wave signal provides a unique test of the gravitational interactions of a dark sector, and we discuss the complementarity with conventional searches for new dark sectors. The discussion includes the twin Higgs and strongly interacting massive particle models as well as symmetric and asymmetric composite dark matter scenarios.

  2. Electroweak monopoles and the electroweak phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Arunasalam, Suntharan; Kobakhidze, Archil [The University of Sydney, ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, Sydney, NSW (Australia)

    2017-07-15

    We consider an isolated electroweak monopole solution within the Standard Model with a nonlinear Born-Infeld extension of the hypercharge gauge field. Monopole (and dyon) solutions in such an extension are regular and their masses are predicted to be proportional to the Born-Infeld mass parameter. We argue that cosmological production of electroweak monopoles may delay the electroweak phase transition and make it more strongly first order for monopole masses M >or similar 9.3 . 10{sup 3} TeV, while the nucleosynthesis constraints on the abundance of relic monopoles impose the bound M phase transition. (orig.)

  3. Phase transitions and elementary-particle physics

    International Nuclear Information System (INIS)

    Creutz, M.

    1981-01-01

    The reason physicists have recently taken an intense interest in the statistical mechanics of certain lattice models is reviewed. Phase transitions in these systems are of direct relevance to whether the gauge theory of interacting quarks and gluons can prevent the quark as appearing as a free isolated object. Monte Carlo simulation techniques have given the strongest evidence for the confinement phenomenon and are beginning to make numerical predictions in strong interaction physics

  4. Gravitation, phase transitions, and the big bang

    International Nuclear Information System (INIS)

    Krauss, L.M.

    1982-01-01

    Introduced here is a model of the early universe based on the possibility of a first-order phase transition involving gravity, and arrived at by a consideration of instabilities in the semiclassical theory. The evolution of the system is very different from the standard Friedmann-Robertson-Walker big-bang scenario, indicating the potential importance of semiclassical finite-temperature gravitational effects. Baryosynthesis and monopole production in this scenario are also outlined

  5. Modelling and simulation of equilibrium and non-equilibrium solidification in laser spot welding

    Science.gov (United States)

    Reddy, Pradeep; Patel, Virendra; Yadav, Anshul; Patel, Sushil; Kumar, Arvind

    2018-02-01

    In this work, rapid solidification in laser welding is studied by solving transient, coupled, governing equations of mass, momentum and energy conservation using a fixed-grid, finite volume methodology. The solidification process in laser welding occurs with high cooling rates involving rapid solidification kinetics. The non-equilibrium phase change is accounted at the solid-liquid interface of the weld pool and it is assumed that heterogeneous nucleation occurs instantaneously when the temperature in the melt pool reaches the nucleation temperature. Simulation results of laser welding with undercooling and without undercooling are compared. It is found that the melt pool width is larger in the case of undercooling case, however, the maximum temperature in the weld pool is higher in the case of without undercooling case.

  6. Real-time powder diffraction studies of energy materials under non-equilibrium conditions

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Vanessa K.; Auckett, Josie E.; Pang, Wei-Kong

    2017-09-01

    Energy materials form the central part of energy devices. An essential part of their function is the ability to reversibly host charge or energy carriers, and analysis of their phase composition and structure in real time under non-equilibrium conditions is mandatory for a full understanding of their atomic-scale functional mechanism. Real-time powder diffraction is increasingly being applied for this purpose, forming a critical step in the strategic chemical engineering of materials with improved behaviour. This topical review gives examples of real-time analysis using powder diffraction of rechargeable battery electrodes and porous sorbent materials used for the separation and storage of energy-relevant gases to demonstrate advances in the insights which can be gained into their atomic-scale function.

  7. Phase transitions of ε-HNIW in compound systems

    Directory of Open Access Journals (Sweden)

    Jing-yuan Zhang

    2016-05-01

    Full Text Available The heat-induced phase transitions of ε-HNIW, both neat and coated with various additives used in plastic bonded explosives, were investigated using powder X-ray diffraction and differential scanning calorimetry. It was found that ε-HNIW, after being held at 70°C for 60h, remained in the ε-phase. Applying other conditions, various phase transition parameters were determined, including Tc (the critical phase transition temperature, T50 (the temperature at which 50% of the phase transition is complete and T180 (the percentage of γ-HNIW present in samples heated to 180°C. According to the above three parameters, additives were divided into three categories: those that delay phase transition, those that raise the critical temperature and the transition rate, and those that promote the phase transition. Based on the above data, a phase transition mechanism is proposed.

  8. Compact Stars with Sequential QCD Phase Transitions.

    Science.gov (United States)

    Alford, Mark; Sedrakian, Armen

    2017-10-20

    Compact stars may contain quark matter in their interiors at densities exceeding several times the nuclear saturation density. We explore models of such compact stars where there are two first-order phase transitions: the first from nuclear matter to a quark-matter phase, followed at a higher density by another first-order transition to a different quark-matter phase [e.g., from the two-flavor color-superconducting (2SC) to the color-flavor-locked (CFL) phase]. We show that this can give rise to two separate branches of hybrid stars, separated from each other and from the nuclear branch by instability regions, and, therefore, to a new family of compact stars, denser than the ordinary hybrid stars. In a range of parameters, one may obtain twin hybrid stars (hybrid stars with the same masses but different radii) and even triplets where three stars, with inner cores of nuclear matter, 2SC matter, and CFL matter, respectively, all have the same mass but different radii.

  9. Second-order phase transitions of pure substances

    NARCIS (Netherlands)

    Schaftenaar, H.P.C.

    2009-01-01

    In this report we are dealing with the thermodynamic theory of second-order phase transitions or continuous transitions of unary systems. The first classification of these phase transitions is due to Ehrenfest (1933), based on chemical potentials. First-order transitions are changes in which the

  10. Spontaneous ordering against an external field in non-equilibrium systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Avella, J C; Eguiluz, V M; San Miguel, M [IFISC (CSIC-UIB), Instituto de Fisica Interdisciplinar y Sistemas Complejos, Campus Universitat Illes Balears, E-07122 Palma de Mallorca (Spain); Cosenza, M G [Centro de Fisica Fundamental, Universidad de Los Andes, Merida, Merida 5251 (Venezuela, Bolivarian Republic of)], E-mail: juancarlos@ifisc.uib-csic.es

    2010-01-15

    We study the collective behavior of non-equilibrium systems subjected to an external field with a dynamics characterized by the existence of non-interacting states. Aiming at exploring the generality of the results, we consider two types of model according to the nature of their state variables: (i) a vector model, where interactions are proportional to the overlap between the states, and (ii) a scalar model, where interactions depend on the distance between states. The phase space is numerically characterized for each model in a fully connected network and in random and scale-free networks. For both models, the system displays three phases: two ordered phases, one parallel to the field and another orthogonal to the field, and one disordered phase. By placing the particles on a small-world network, we show that an ordered phase in a state different from the one imposed by the field is possible because of the long-range interactions that exist in fully connected, random and scale-free networks. This phase does not exist in a regular lattice and emerges when long-range interactions are included in a small-world network.

  11. Phase transitions in shocked porous quartz

    Science.gov (United States)

    Akin, M. C.; Crum, R. S.; Lind, J.; Pagan, D. C.; Homel, M. A.; Hurley, R. C.; Herbold, E. B.

    2017-06-01

    The presence of porosity in granular media provides the means to probe regions of the phase diagram that do not coincide with the principal Hugoniot. In particular, the potential for increased heating is likely to lead to observable changes in phase boundaries. 55% dense quartz and forsterite were prepared by tap filling. These samples were shock compressed using the two stage light gas gun at DCS-APS to examine the impact of the increased porosity on the phase boundary. Here we discuss the observed changes to phase in quartz and forsterite compared to the fully dense materials, the effects of porosity upon compaction and phase transitions, and the implications for constructing the phase diagram. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Work was supported by LLNL's LDRD program under Grant 16-ERD-010. The Dynamic Compression Sector (35) is supported by Department of Energy / National Nuclear Security Administration under Award Number DE-NA0002442. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357.

  12. The transition to chaotic phase synchronization

    Science.gov (United States)

    Mosekilde, E.; Laugesen, J. L.; Zhusubaliyev, Zh. T.

    2012-08-01

    The transition to chaotic phase synchronization for a periodically driven spiral-type chaotic oscillator is known to involve a dense set of saddle-node bifurcations. By following the synchronization transition through the cascade of period-doubling bifurcations in a forced Rössler system, this paper describes how these saddle-node bifurcations arise and how their characteristic cyclic organisation develops. We identify the cycles that are involved in the various saddle-node bifurcations and descibe how the formation of multi-layered resonance cycles in the synchronization domain is related to the torus doubling bifurcations that take place outside this domain. By examining a physiology-based model of the blood flow regulation to the individual functional unit (nephron) of the kidney we demonstrate how a similar bifurcation structure may arise in this system as a response to a periodically varying arterial blood pressure. The paper finally discusses how an alternative transition to chaotic phase synchronization may occur in the mutual synchronization of two chaotically oscillating period-doubling systems.

  13. Casimir amplitudes in topological quantum phase transitions.

    Science.gov (United States)

    Griffith, M A; Continentino, M A

    2018-01-01

    Topological phase transitions constitute a new class of quantum critical phenomena. They cannot be described within the usual framework of the Landau theory since, in general, the different phases cannot be distinguished by an order parameter, neither can they be related to different symmetries. In most cases, however, one can identify a diverging length at these topological transitions. This allows us to describe them using a scaling approach and to introduce a set of critical exponents that characterize their universality class. Here we consider some relevant models of quantum topological transitions associated with well-defined critical exponents that are related by a quantum hyperscaling relation. We extend to these models a finite-size scaling approach based on techniques for calculating the Casimir force in electromagnetism. This procedure allows us to obtain universal Casimir amplitudes at their quantum critical points. Our results verify the validity of finite-size scaling in these systems and confirm the values of the critical exponents obtained previously.

  14. Casimir amplitudes in topological quantum phase transitions

    Science.gov (United States)

    Griffith, M. A.; Continentino, M. A.

    2018-01-01

    Topological phase transitions constitute a new class of quantum critical phenomena. They cannot be described within the usual framework of the Landau theory since, in general, the different phases cannot be distinguished by an order parameter, neither can they be related to different symmetries. In most cases, however, one can identify a diverging length at these topological transitions. This allows us to describe them using a scaling approach and to introduce a set of critical exponents that characterize their universality class. Here we consider some relevant models of quantum topological transitions associated with well-defined critical exponents that are related by a quantum hyperscaling relation. We extend to these models a finite-size scaling approach based on techniques for calculating the Casimir force in electromagnetism. This procedure allows us to obtain universal Casimir amplitudes at their quantum critical points. Our results verify the validity of finite-size scaling in these systems and confirm the values of the critical exponents obtained previously.

  15. Phase stability of transition metals and alloys

    International Nuclear Information System (INIS)

    Hixson, R.S.; Schiferl, D.; Wills, J.M.; Hill, M.A.

    1997-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project was focused on resolving unexplained differences in calculated and measured phase transition pressures in transition metals. Part of the approach was to do new, higher accuracy calculations of transmission pressures for group 4B and group 6B metals. Theory indicates that the transition pressures for these baseline metals should change if alloyed with a d-electron donor metal, and calculations done using the Local Density Approximation (LDA) and the Virtual Crystal Approximation (VCA) indicate that this is true. Alloy systems were calculated for Ti, Zr and Hf based alloys with various solute concentrations. The second part of the program was to do new Diamond Anvil Cell (DAC) measurements to experimentally verify calculational results. Alloys were prepared for these systems with grain size suitable for Diamond Anvil Cell experiments. Experiments were done on pure Ti as well as Ti-V and Ti-Ta alloys. Measuring unambiguous transition pressures for these systems proved difficult, but a new technique developed yielded good results

  16. Scale invariance from phase transitions to turbulence

    CERN Document Server

    Lesne, Annick

    2012-01-01

    During a century, from the Van der Waals mean field description (1874) of gases to the introduction of renormalization group (RG techniques 1970), thermodynamics and statistical physics were just unable to account for the incredible universality which was observed in numerous critical phenomena. The great success of RG techniques is not only to solve perfectly this challenge of critical behaviour in thermal transitions but to introduce extremely useful tools in a wide field of daily situations where a system exhibits scale invariance. The introduction of scaling, scale invariance and universality concepts has been a significant turn in modern physics and more generally in natural sciences. Since then, a new "physics of scaling laws and critical exponents", rooted in scaling approaches, allows quantitative descriptions of numerous phenomena, ranging from phase transitions to earthquakes, polymer conformations, heartbeat rhythm, diffusion, interface growth and roughening, DNA sequence, dynamical systems, chaos ...

  17. Quantum phase transitions in matrix product states

    International Nuclear Information System (INIS)

    Zhu Jingmin

    2008-01-01

    We present a new general and much simpler scheme to construct various quantum phase transitions (QPTs) in spin chain systems with matrix product ground states. By use of the scheme we take into account one kind of matrix product state (MPS) QPT and provide a concrete model. We also study the properties of the concrete example and show that a kind of QPT appears, accompanied by the appearance of the discontinuity of the parity absent block physical observable, diverging correlation length only for the parity absent block operator, and other properties which are that the fixed point of the transition point is an isolated intermediate-coupling fixed point of renormalization flow and the entanglement entropy of a half-infinite chain is discontinuous. (authors)

  18. Quantum Phase Transitions in Matrix Product States

    International Nuclear Information System (INIS)

    Jing-Min, Zhu

    2008-01-01

    We present a new general and much simpler scheme to construct various quantum phase transitions (QPTs) in spin chain systems with matrix product ground states. By use of the scheme we take into account one kind of matrix product state (MPS) QPT and provide a concrete model. We also study the properties of the concrete example and show that a kind of QPT appears, accompanied by the appearance of the discontinuity of the parity absent block physical observable, diverging correlation length only for the parity absent block operator, and other properties which are that the fixed point of the transition point is an isolated intermediate-coupling fixed point of renormalization flow and the entanglement entropy of a half-infinite chain is discontinuous

  19. On the definition of equilibrium and non-equilibrium states in dynamical systems

    OpenAIRE

    Akimoto, Takuma

    2008-01-01

    We propose a definition of equilibrium and non-equilibrium states in dynamical systems on the basis of the time average. We show numerically that there exists a non-equilibrium non-stationary state in the coupled modified Bernoulli map lattice.

  20. Phases and phase transitions in the algebraic microscopic shell model

    Directory of Open Access Journals (Sweden)

    Georgieva A. I.

    2016-01-01

    Full Text Available We explore the dynamical symmetries of the shell model number conserving algebra, which define three types of pairing and quadrupole phases, with the aim to obtain the prevailing phase or phase transition for the real nuclear systems in a single shell. This is achieved by establishing a correspondence between each of the pairing bases with the Elliott’s SU(3 basis that describes collective rotation of nuclear systems. This allows for a complete classification of the basis states of different number of particles in all the limiting cases. The probability distribution of the SU(3 basis states within theirs corresponding pairing states is also obtained. The relative strengths of dynamically symmetric quadrupole-quadrupole interaction in respect to the isoscalar, isovector and total pairing interactions define a control parameter, which estimates the importance of each term of the Hamiltonian in the correct reproduction of the experimental data for the considered nuclei.

  1. Behavior of Triple Langmuir Probes in Non-Equilibrium Plasmas

    Science.gov (United States)

    Polzin, Kurt A.; Ratcliffe, Alicia C.

    2018-01-01

    The triple Langmuir probe is an electrostatic probe in which three probe tips collect current when inserted into a plasma. The triple probe differs from a simple single Langmuir probe in the nature of the voltage applied to the probe tips. In the single probe, a swept voltage is applied to the probe tip to acquire a waveform showing the collected current as a function of applied voltage (I-V curve). In a triple probe three probe tips are electrically coupled to each other with constant voltages applied between each of the tips. The voltages are selected such that they would represent three points on the single Langmuir probe I-V curve. Elimination of the voltage sweep makes it possible to measure time-varying plasma properties in transient plasmas. Under the assumption of a Maxwellian plasma, one can determine the time-varying plasma temperature T(sub e)(t) and number density n(sub e)(t) from the applied voltage levels and the time-histories of the collected currents. In the present paper we examine the theory of triple probe operation, specifically focusing on the assumption of a Maxwellian plasma. Triple probe measurements have been widely employed for a number of pulsed and timevarying plasmas, including pulsed plasma thrusters (PPTs), dense plasma focus devices, plasma flows, and fusion experiments. While the equilibrium assumption may be justified for some applications, it is unlikely that it is fully justifiable for all pulsed and time-varying plasmas or for all times during the pulse of a plasma device. To examine a simple non-equilibrium plasma case, we return to basic governing equations of probe current collection and compute the current to the probes for a distribution function consisting of two Maxwellian distributions with different temperatures (the two-temperature Maxwellian). A variation of this method is also employed, where one of the Maxwellians is offset from zero (in velocity space) to add a suprathermal beam of electrons to the tail of the

  2. Role of non-equilibrium conformations on driven polymer translocation.

    Science.gov (United States)

    Katkar, H H; Muthukumar, M

    2018-01-14

    assuming a constant effective velocity of translocation, it is found that for flexible (ssDNA and synthetic) polymers with N K Kuhn segments, the condition ⟨τ⟩/N K equilibrium to non-equilibrium behavior would occur at N K ∼ O(1000).

  3. Phase transitions in de Sitter space

    Directory of Open Access Journals (Sweden)

    Alexander Vilenkin

    1983-10-01

    Full Text Available An effective potential in de Sitter space is calculated for a model of two interacting scalar fields in one-loop approximation and in a self-consistent approximation which takes into account an infinite set of diagrams. Various approaches to renormalization in de Sitter space are discussed. The results are applied to analyze the phase transition in the Hawking-Moss version of the inflationary universe scenario. Requiring that inflation is sufficiently large, we derive constraints on the parameters of the model.

  4. Chiral phase transition from string theory.

    Science.gov (United States)

    Parnachev, Andrei; Sahakyan, David A

    2006-09-15

    The low energy dynamics of a certain D-brane configuration in string theory is described at weak t'Hooft coupling by a nonlocal version of the Nambu-Jona-Lasinio model. We study this system at finite temperature and strong t'Hooft coupling, using the string theory dual. We show that for sufficiently low temperatures chiral symmetry is broken, while for temperatures larger then the critical value, it gets restored. We compute the latent heat and observe that the phase transition is of the first order.

  5. Traders' behavioral coupling and market phase transition

    Science.gov (United States)

    Ma, Rong; Zhang, Yin; Li, Honggang

    2017-11-01

    Traditional economic theory is based on the assumption that traders are completely independent and rational; however, trading behavior in the real market is often coupled by various factors. This paper discusses behavioral coupling based on the stock index in the stock market, focusing on the convergence of traders' behavior, its effect on the correlation of stock returns and market volatility. We find that the behavioral consensus in the stock market, the correlation degree of stock returns, and the market volatility all exhibit significant phase transitions with stronger coupling.

  6. Phase Transitions of Thermoelectric TAGS-85

    OpenAIRE

    Kumar, Anil; Vermeulen, Paul A.; Kooi, Bart J.; Rao, Jiancun; van Eijck, Lambert; Schwarzmueller, Stefan; Oeckler, Oliver; Blake, Graeme R.

    2017-01-01

    The alloys (GeTe)x(AgSbTe2)100–x, commonly known as TAGS-x, are among the best performing p-type thermoelectric materials for the composition range 80 ≤ x ≤ 90 and in the temperature range 200–500 °C. They adopt a rhombohedrally distorted rocksalt structure at room temperature and are reported to undergo a reversible phase transition to a cubic structure at ∼250 °C. However, we show that, for the optimal x = 85 composition (TAGS-85), both the structural and thermoelectric properties are highl...

  7. A Note on Holography and Phase Transitions

    Directory of Open Access Journals (Sweden)

    Marc Bellon

    2011-01-01

    Full Text Available Focusing on the connection between the Landau theory of second-order phase transitions and the holographic approach to critical phenomena, we study diverse field theories in an anti de Sitter black hole background. Through simple analytical approximations, solutions to the equations of motion can be obtained in closed form which give rather good approximations of the results obtained using more involved numerical methods. The agreement we find stems from rather elementary considerations on perturbation of Schrödinger equations.

  8. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Lu, X., E-mail: luxinpei@hotmail.com [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Naidis, G.V. [Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412 (Russian Federation); Laroussi, M. [Plasma Engineering & Medicine Institute, Old Dominion University, Norfolk, VA 23529 (United States); Reuter, S. [Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald (Germany); Graves, D.B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720 (United States); Ostrikov, K. [Institute for Future Environments, Queensland University of Technology, Brisbane, QLD 4000 (Australia); School of Physics, Chemistry, and Mechanical Engineering, Queensland University of Technology, Brisbane, QLD 4000 (Australia); Commonwealth Scientific and Industrial Research Organization, P.O.Box 218, Lindfield, NSW 2070 (Australia); School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-05-04

    Non-equilibrium atmospheric-pressure plasmas have recently become a topical area of research owing to their diverse applications in health care and medicine, environmental remediation and pollution control, materials processing, electrochemistry, nanotechnology and other fields. This review focuses on the reactive electrons and ionic, atomic, molecular, and radical species that are produced in these plasmas and then transported from the point of generation to the point of interaction with the material, medium, living cells or tissues being processed. The most important mechanisms of generation and transport of the key species in the plasmas of atmospheric-pressure plasma jets and other non-equilibrium atmospheric-pressure plasmas are introduced and examined from the viewpoint of their applications in plasma hygiene and medicine and other relevant fields. Sophisticated high-precision, time-resolved plasma diagnostics approaches and techniques are presented and their applications to monitor the reactive species and plasma dynamics in the plasma jets and other discharges, both in the gas phase and during the plasma interaction with liquid media, are critically reviewed. The large amount of experimental data is supported by the theoretical models of reactive species generation and transport in the plasmas, surrounding gaseous environments, and plasma interaction with liquid media. These models are presented and their limitations are discussed. Special attention is paid to biological effects of the plasma-generated reactive oxygen and nitrogen (and some other) species in basic biological processes such as cell metabolism, proliferation, survival, etc. as well as plasma applications in bacterial inactivation, wound healing, cancer treatment and some others. Challenges and opportunities for theoretical and experimental research are discussed and the authors’ vision for the emerging convergence trends across several disciplines and application domains is presented to

  9. Miscellaneous results on the electroweak phase transition

    International Nuclear Information System (INIS)

    Ilgenfritz, E.M.; Schiller, A.

    1994-12-01

    We present new 4-D Monte Carlo results characterizing the strength of the finite temperature phase transition for Higgs/W mass ratios 1.0 and 0.6, obtained on isotropic lattices mainly with N s = 16, N t = 2. We discuss the distribution of a gauge invariant block spin order parameter, estimating the Higgs condensate Φ c at T c . We use the Potvin/Rebbi method in order to find the interface tension α/T c 3 . We demonstrate how the multi-histogram method (giving free energy differences) can be used to avoid the limiting procedure δ K → 0. From pure-phase histograms at K c , extrapolated with the help of this method, we estimate the latent heat Δε/T c 4 . Actual time series at lower Higgs mass require blocking in order to determine the jump of the lattice observables. (orig.)

  10. Transitional Phenomena on Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Wójcik Tadeusz M.

    2014-03-01

    Full Text Available One of the most significant problem with technology development is transferring of large heat fluxes, which requires constant heat transfer temperature (in the specified temperature range. This problem concern mainly the nuclear energetics, space technologies, military technologies and most of all electronics containing integrated circuits with very large scale of integrations. Intensive heat transfer and thermal energy storage are possible by the use of phase change materials (PCMs. In the paper there are presented preliminary results of research on the use of liquid-gas (L-G PCMs and solid-solid phase change materials (S-S PCMs. For L-G PCMs the boiling characteristics were determined by increasing and decreasing the heat flux, which for certain sets of structural parameters of the heating surface and the physical properties of the liquid induce a variety of forms of transitional phenomena. Thermal energy storage is much more effective when using PCMs than sensible heat.

  11. The onset of double diffusive convection in a viscoelastic fluid-saturated porous layer with non-equilibrium model.

    Directory of Open Access Journals (Sweden)

    Zhixin Yang

    Full Text Available The onset of double diffusive convection in a viscoelastic fluid-saturated porous layer is studied when the fluid and solid phase are not in local thermal equilibrium. The modified Darcy model is used for the momentum equation and a two-field model is used for energy equation each representing the fluid and solid phases separately. The effect of thermal non-equilibrium on the onset of double diffusive convection is discussed. The critical Rayleigh number and the corresponding wave number for the exchange of stability and over-stability are obtained, and the onset criterion for stationary and oscillatory convection is derived analytically and discussed numerically.

  12. Influence of dimensionality on phase transition in VO2 nanocrystals

    Directory of Open Access Journals (Sweden)

    Blagojević V.A.

    2013-01-01

    Full Text Available Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65°C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials. [Projekat Ministarstva nauke Republike Srbije, br. 142015

  13. Heat capacity characterization at phase transition temperature of Agl superionic

    International Nuclear Information System (INIS)

    Widowati, Arie

    2000-01-01

    The phase transition of Agl superionic conductor was investigated by calorometric. A single phase transition was found at (153±5) o C which corresponds to the α - β transition. Calorimetric measurement showed an anomalously high heat capacity with a large discontinues change in the Arrhenius plot, was found above the transition temperature of β - α phase. The maximum heat capacity was found to be ±19.7 cal/gmol. Key words : superionic conductor, thermal capacity

  14. Phase transitions and doping in semiconductor nanocrystals

    Science.gov (United States)

    Sahu, Ayaskanta

    impurities (or doping) allows further control over the electrical and optical properties of nanocrystals. However, while impurity doping in bulk semiconductors is now routine, doping of nanocrystals remains challenging. In particular, evidence for electronic doping, in which additional electrical carriers are introduced into the nanocrystals, has been very limited. Here, we adopt a new approach to electronic doping of nanocrystals. We utilize a partial cation exchange to introduce silver impurities into cadmium selenide (CdSe) and lead selenide (PbSe) nanocrystals. Results indicate that the silver-doped CdSe nanocrystals show a significant increase in fluorescence intensity, as compared to pure CdSe nanocrystals. We also observe a switching from n- to p-type doping in the silver-doped CdSe nanocrystals with increased silver amounts. Moreover, the silver-doping results in a change in the conductance of both PbSe and CdSe nanocrystals and the magnitude of this change depends on the amount of silver incorporated into the nanocrystals. In the bulk, silver chalcogenides (Ag2E, E=S, Se, and Te) possess a wide array of intriguing properties, including superionic conductivity. In addition, they undergo a reversible temperature-dependent phase transition which induces significant changes in their electronic and ionic properties. While most of these properties have been examined extensively in bulk, very few studies have been conducted at the nanoscale. We have recently developed a versatile synthesis that yields colloidal silver chalcogenide nanocrystals. Here, we study the size dependence of their phase-transition temperatures. We utilize differential scanning calorimetry and in-situ X-ray diffraction analyses to observe the phase transition in nanocrystal assemblies. We observe a significant deviation from the bulk alpha (low-temperature) to beta (high-temperature) phase-transition temperature when we reduce their size to a few nanometers. Hence, these nanocrystals provide great

  15. A non-equilibrium model for soil heating and moisture transport during extreme surface heating: The soil (heat-moisture-vapor) HMV-Model Version

    Science.gov (United States)

    William Massman

    2015-01-01

    Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMVmodel, a 1-D (one-dimensional) non-equilibrium (liquid- vapor phase change)...

  16. QCD PHASE TRANSITIONS-VOLUME 15.

    Energy Technology Data Exchange (ETDEWEB)

    SCHAFER,T.

    1998-11-04

    The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some. efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.

  17. Phase transitions in Ge-Sb phase change materials

    International Nuclear Information System (INIS)

    Raoux, Simone; Virwani, Kumar; Cabral, Cyril Jr.; Krusin-Elbaum, Lia; Jordan-Sweet, Jean L.; Hitzbleck, Martina; Salinga, Martin; Madan, Anita; Pinto, Teresa L.

    2009-01-01

    Thin films of the phase change material Ge-Sb with Ge concentrations between 7.3 and 81.1 at. % were deposited by cosputtering from elemental targets. Their crystallization behavior was studied using time-resolved x-ray diffraction, Auger electron spectroscopy, differential scanning calorimetry, x-ray reflectivity, profilometry, optical reflectivity, and resistivity versus temperature measurements. It was found that the crystallization temperature increases with Ge content. Calculations of the glass transition temperature (which is a lower limit for the crystallization temperature T x ) also show an increase with Ge concentration closely tracking the measured values of T x . For low Ge content samples, Sb x-ray diffraction peaks occurred during a heating ramp at lower temperature than Ge diffraction peaks. The appearance of Ge peaks is related to Ge precipitation and agglomeration. For Ge concentrations of 59.3 at. % and higher, Sb and Ge peaks occurred at the same temperature. Upon crystallization, film mass density and optical reflectivity increase as well as electrical contrast (ratio of resistivity in amorphous phase to crystalline phase) all showed a maximum for the eutectic alloy (14.5 at. % Ge). For the alloy with 59.3 at. % Ge there was very little change in any of these parameters, while the alloy with 81.1 at. % Ge behaved opposite to a typical phase change alloy and showed reduced mass density and reflectivity and increased resistivity

  18. Wilson loop's phase transition probed by non-local observable

    Directory of Open Access Journals (Sweden)

    Hui-Ling Li

    2018-04-01

    Full Text Available In order to give further insights into the holographic Van der Waals phase transition, it would be of great interest to investigate the behavior of Wilson loop across the holographic phase transition for a higher dimensional hairy black hole. We offer a possibility to proceed with a numerical calculation in order to discussion on the hairy black hole's phase transition, and show that Wilson loop can serve as a probe to detect a phase structure of the black hole. Furthermore, for a first order phase transition, we calculate numerically the Maxwell's equal area construction; and for a second order phase transition, we also study the critical exponent in order to characterize the Wilson loop's phase transition.

  19. Non-equilibrium plasma chemistry at high pressure and its applications

    International Nuclear Information System (INIS)

    Bai Xiyao; Zhang Zhitao; Bai Mindong; Zhu Qiaoying

    2000-01-01

    A review is presented of research and development of gas discharge and non-equilibrium plasma including, new ideas of non-equilibrium plasma at high gas pressure. With special technology, strong electric fields (>400 Td) can be achieved by which electrons are accelerated suddenly, becoming high energy electrons (> 10 eV) at high pressure. On impact with the electrons, the gas molecules dissociate into ions, atomic ions, atoms and free radicals, and new substances or molecules can be synthesized through custom design. Chemical reaction difficult to achieve by conventional method can be realized or accelerated. Non-equilibrium plasma chemistry at high pressure has wide application prospects

  20. Deep Neural Network Detects Quantum Phase Transition

    Science.gov (United States)

    Arai, Shunta; Ohzeki, Masayuki; Tanaka, Kazuyuki

    2018-03-01

    We detect the quantum phase transition of a quantum many-body system by mapping the observed results of the quantum state onto a neural network. In the present study, we utilized the simplest case of a quantum many-body system, namely a one-dimensional chain of Ising spins with the transverse Ising model. We prepared several spin configurations, which were obtained using repeated observations of the model for a particular strength of the transverse field, as input data for the neural network. Although the proposed method can be employed using experimental observations of quantum many-body systems, we tested our technique with spin configurations generated by a quantum Monte Carlo simulation without initial relaxation. The neural network successfully identified the strength of transverse field only from the spin configurations, leading to consistent estimations of the critical point of our model Γc = J.

  1. Thermal equilibrium during the electroweak phase transition

    International Nuclear Information System (INIS)

    Tetradis, N.

    1991-12-01

    The effective potential for the standard model develops a barrier, at temperatures around the electroweak scale, which separates the minimum at zero field and a deeper non-zero minimum. This could create out of equilibrium conditions by inducing the localization of the Higgs field in a metastable state around zero. In this picture vacuum decay would occur through bubble nucleation. I show that there is an upper bound on the Higgs mass for the above scenario to be realized. The barrier must be high enough to prevent thermal fluctuations of the Higgs expectation value from establishing thermal equilibrium between the two minima. The upper bound is estimated to be lower than the experimental lower limit. This is also imposes constraints on extensions of the standard model constructed in order to generate a strongly first order phase transition. (orig.)

  2. Kinetics of the chiral phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Hees, Hendrik van [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany); Frankfurt Institute for Advanced Studies (FIAS), Frankfurt (Germany); Wesp, Christian; Meistrenko, Alex; Greiner, Carsten [Johann-Wolfgang-Goethe-Universitaet Frankfurt, Institut fuer Theoretische Physik, Frankfurt (Germany)

    2016-07-01

    We simulate the kinetics of the chiral phase transition in hot and dense strongly interacting matter within a novel kinetic-theory approach. Employing an effective linear σ model for quarks, σ mesons, and pions we treat the quarks within a test-particle ansatz for solving the Boltzmann transport equation and the mesons in terms of classical fields. The decay-recombination processes like σ <-> anti q+q are treated using a kind of wave-particle dualism using the exact conservation of energy and momentum. After demonstrating the correct thermodynamic limit for particles and fields in a ''box calculation'' we apply the simulation to the dynamics of an expanding fireball similar to the medium created in ultrarelativistic heavy-ion collisions.

  3. Quantum phase transitions in Bose-Fermi systems

    International Nuclear Information System (INIS)

    Petrellis, D.; Leviatan, A.; Iachello, F.

    2011-01-01

    Research highlights: → We study quantum phase transitions in a system of N bosons and a single-j fermion. → Classical order parameters and correlation diagrams of quantum levels are determined. → The odd fermion strongly influences the location and nature of the phase transition. → Experimental evidence for the U(5)-SU(3) transition in odd-even nuclei is presented. - Abstract: Quantum phase transitions in a system of N bosons with angular momentum L = 0, 2 (s, d) and a single fermion with angular momentum j are investigated both classically and quantum mechanically. It is shown that the presence of the odd fermion strongly influences the location and nature of the phase transition, especially the critical value of the control parameter at which the phase transition occurs. Experimental evidence for the U(5)-SU(3) (spherical to axially-deformed) transition in odd-even nuclei is presented.

  4. Magnetically ordered phase near transition to Bose-glass phase

    Science.gov (United States)

    Syromyatnikov, A. V.; Sizanov, A. V.

    2017-01-01

    We discuss a magnetically ordered ("superfluid") phase near quantum transition to the Bose-glass phase in a simple modeling system, a Heisenberg antiferromagnet with spatial dimension d >2 in an external magnetic field with disorder in exchange coupling constants. Our analytical consideration is based on hydrodynamic description of long-wavelength excitations. Results obtained are valid in the entire critical region near the quantum critical point (QCP), allowing us to describe a possible crossover from one critical behavior to another. We demonstrate that the system behaves in full agreement with predictions by M. P. Fisher et al. [Phys. Rev. B 40, 546 (1989), 10.1103/PhysRevB.40.546] in close vicinity to the QCP. We find as an extension to that analysis that the anomalous dimension η =2 -d and β =ν d /2 , where β and ν are critical exponents of the order parameter and the correlation length, respectively. The density of states per spin of low-energy localized excitations is found to be independent of d ("superuniversal"). We show that many recent experimental and numerical results obtained in various three-dimensional (3D) systems can be described by our formulas using percolation critical exponents. Then, it is a possibility that a percolation critical regime arises in the ordered phase in some 3D systems not very close to the QCP.

  5. Multiple phase transitions in palmitoleic acid under the pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kos, A; Siegoczynski, R M; Rostocki, A J; Tefelski, D B; Kosciesza, R; Wieja, K [Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw (Poland)], E-mail: aldona@if.pw.edu.pl

    2008-07-15

    Long unsaturated carbon chain liquids exhibit a phase transition under a high pressure. We have investigated the phase transition in palmitoleic acid as a representative of this group not researched yet. A temperature, a relative permittivity and a dissipation factor have been measured, while the pressure was applied. We have also observed the transmitted and the scattered IR light. These parameters allowed us to find phase transitions that occurred due to the pressure. Especially the behavior of the temperature indicates several phase transitions during compression. Above certain pressure the liquid becomes opaque, it is connected with most significant phase transition that occurs around 177 MPa. We have observed asymmetry of intensity of the scattered light, which is much stronger during decompression. Observed multiple phase transitions are not present in other acids investigated by us.

  6. Characteristics of the chiral phase transition in nonlocal quark models

    International Nuclear Information System (INIS)

    Gomez Dumm, D. Gomez; Scoccola, N.N.

    2005-01-01

    The characteristics of the chiral phase transition are analyzed within the framework of chiral quark models with nonlocal interactions in the mean-field approximation. In the chiral limit, we develop a semianalytic framework that allows us to explicitly determine the phase transition curve, the position of the critical points, some relevant critical exponents, etc. For the case of finite current quark masses, we show the behavior of various thermodynamical and chiral response functions across the phase transition

  7. Gravitational waves from global second order phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Jr, John T. Giblin [Department of Physics, Kenyon College, 201 North College Rd, Gambier, OH 43022 (United States); Price, Larry R.; Siemens, Xavier; Vlcek, Brian, E-mail: giblinj@kenyon.edu, E-mail: larryp@caltech.edu, E-mail: siemens@gravity.phys.uwm.edu, E-mail: bvlcek@uwm.edu [Center for Gravitation and Cosmology, Department of Physics, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, WI 53201 (United States)

    2012-11-01

    Global second-order phase transitions are expected to produce scale-invariant gravitational wave spectra. In this manuscript we explore the dynamics of a symmetry-breaking phase transition using lattice simulations. We explicitly calculate the stochastic gravitational wave background produced during the transition and subsequent self-ordering phase. We comment on this signal as it compares to the scale-invariant spectrum produced during inflation.

  8. Non-equilibrium concentration fluctuations in binary liquids with realistic boundary conditions.

    Science.gov (United States)

    Ortiz de Zárate, J M; Kirkpatrick, T R; Sengers, J V

    2015-09-01

    Because of the spatially long-ranged nature of spontaneous fluctuations in thermal non-equilibrium systems, they are affected by boundary conditions for the fluctuating hydrodynamic variables. In this paper we consider a liquid mixture between two rigid and impervious plates with a stationary concentration gradient resulting from a temperature gradient through the Soret effect. For liquid mixtures with large Lewis and Schmidt numbers, we are able to obtain explicit analytical expressions for the intensity of the non-equilibrium concentration fluctuations as a function of the frequency ω and the wave number q of the fluctuations. In addition we elucidate the spatial dependence of the intensity of the non-equilibrium fluctuations responsible for a non-equilibrium Casimir effect.

  9. Non-equilibrium thermodynamics of radiation-induced processes in solids

    International Nuclear Information System (INIS)

    Yurov, V.M.; Eshchanov, A.N.; Kuketaev, A.T.; Sidorenya, Yu.S.

    2005-01-01

    In the paper an item about a defect system response in solids on external action (temperature, pressure, light, etc.) from the point of view of non-equilibrium statistical thermodynamics is considered

  10. Non-Equilibrium Heavy Flavored Hadron Yields from Chemical Equilibrium Strangeness-Rich QGP

    OpenAIRE

    Kuznetsova, Inga; Rafelski, Johann

    2008-01-01

    The yields of heavy flavored hadrons emitted from strangeness-rich QGP are evaluated within chemical non-equilibrium statistical hadronization model, conserving strangeness, charm, and entropy yields at hadronization.

  11. RareNoise: non-equilibrium effects in detectors of gravitational waves

    Energy Technology Data Exchange (ETDEWEB)

    Conti, L [INFN, Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Bonaldi, M [Istituto di Fotonica e Nanotecnologie, CNR-Fondazione Bruno Kessler, 38100 Povo, Trento (Italy); Rondoni, L, E-mail: Livia.Conti@pd.infn.i [Dip. di Matematica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2010-04-21

    The RareNoise project investigates non-equilibrium effects in gravitational wave detectors. We illustrate the physics behind the project and the planned project development, involving experimental, numerical and theoretical research.

  12. Non-equilibrium reactive flux: A unified framework for slow and fast reaction kinetics.

    Science.gov (United States)

    Bose, Amartya; Makri, Nancy

    2017-10-21

    The flux formulation of reaction rate theory is recast in terms of the expectation value of the reactive flux with an initial condition that corresponds to a non-equilibrium, factorized reactant density. In the common case of slow reactive processes, the non-equilibrium expression reaches the plateau regime only slightly slower than the equilibrium flux form. When the reactants are described by a single quantum state, as in the case of electron transfer reactions, the factorized reactant density describes the true initial condition of the reactive process. In such cases, the time integral of the non-equilibrium flux expression yields the reactant population as a function of time, allowing characterization of the dynamics in cases where there is no clear separation of time scales and thus a plateau regime cannot be identified. The non-equilibrium flux offers a unified approach to the kinetics of slow and fast chemical reactions and is ideally suited to mixed quantum-classical methods.

  13. Fragmentation function in non-equilibrium QCD using closed-time path integral formalism

    International Nuclear Information System (INIS)

    Nayak, Gouranga C.

    2009-01-01

    In this paper we implement the Schwinger-Keldysh closed-time path integral formalism in non-equilibrium QCD in accordance to the definition of the Collins-Soper fragmentation function. We consider a high-p T parton in QCD medium at initial time τ 0 with an arbitrary non-equilibrium (non-isotropic) distribution function f(vector (p)) fragmenting to a hadron. We formulate the parton-to-hadron fragmentation function in non-equilibrium QCD in the light-cone quantization formalism. It may be possible to include final-state interactions with the medium via a modification of the Wilson lines in this definition of the non-equilibrium fragmentation function. This may be relevant to the study of hadron production from a quark-gluon plasma at RHIC and LHC. (orig.)

  14. Non-equilibrium dynamics of open systems and fluctuation-dissipation theorems

    Czech Academy of Sciences Publication Activity Database

    Špička, Václav; Velický, B.; Kalvová, Anděla

    2017-01-01

    Roč. 65, 6-8 (2017), s. 1-23, č. článku 1700032. ISSN 0015-8208 Institutional support: RVO:68378271 Keywords : non-equilibrium * fluctuation-dissipation theorems * non-equilibrium Greens function * transient and steady state magnetic current * molecular bridge Subject RIV: BE - Theoretical Physics OBOR OECD: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Impact factor: 2.434, year: 2016

  15. Note: local thermal conductivities from boundary driven non-equilibrium molecular dynamics simulations.

    Science.gov (United States)

    Bresme, F; Armstrong, J

    2014-01-07

    We report non-equilibrium molecular dynamics simulations of heat transport in models of molecular fluids. We show that the "local" thermal conductivities obtained from non-equilibrium molecular dynamics simulations agree within numerical accuracy with equilibrium Green-Kubo computations. Our results support the local equilibrium hypothesis for transport properties. We show how to use the local dependence of the thermal gradients to quantify the thermal conductivity of molecular fluids for a wide range of thermodynamic states using a single simulation.

  16. A Tightly Coupled Non-Equilibrium Magneto-Hydrodynamic Model for Inductively Coupled RF Plasmas

    Science.gov (United States)

    2016-02-29

    Journal Article 3. DATES COVERED (From - To) 12 May 2015 – 06 Oct 2015 4. TITLE AND SUBTITLE A Tightly Coupled Non- Equilibrium Magneto-Hydrodynamic...development a tightly coupled magneto-hydrodynamic model for Inductively Coupled Radio- Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE...effects are described based on a hybrid State-to-State (StS) approach. A multi-temperature formulation is used to account for thermal non- equilibrium

  17. The phase transition of RDX under hydrostatic and ramp compression

    Science.gov (United States)

    Zheng, Xianxu; Zhang, Zhaohui; Zhao, Jun; Zeng, Daipeng; Zeng, Yangyang; Zhang, Xu

    2017-06-01

    The thermodynamic state of explosive was highly dependent on the phase transition structure and phase transition of explosive crystal. However, the phase transition details of explosive have never been characterized sufficiently under different compression conditions. In this study, both the hydrostatic and ramp compression were performed to examine the phase transition of RDX crystal. Based on our experimental results, we confirmed the α- γ phase transition onset around 4 GPa under hydrostatic compression, which agree with the published literature very well. In the ramp compression experiment, a 260 ns ramp compression up to 30 GPa was generated to compress the RDX single crystal along 020 crystal axis, the PDV signal indicated that the phase transition was induced around 2.8 GPa, and the phase transition induction time was about several tens nanoseconds. Our preliminary experiments suggest that the phase transition pressure of RDX have great relation with the compression history, that probably means the phase transition mechanism were quite different between the hydrostatic and ramp compression.

  18. Modeling the Non-Equilibrium Process of the Chemical Adsorption of Ammonia on GaN(0001) Reconstructed Surfaces Based on Steepest-Entropy-Ascent Quantum Thermodynamics.

    Science.gov (United States)

    Kusaba, Akira; Li, Guanchen; von Spakovsky, Michael R; Kangawa, Yoshihiro; Kakimoto, Koichi

    2017-08-15

    Clearly understanding elementary growth processes that depend on surface reconstruction is essential to controlling vapor-phase epitaxy more precisely. In this study, ammonia chemical adsorption on GaN(0001) reconstructed surfaces under metalorganic vapor phase epitaxy (MOVPE) conditions (3Ga-H and N ad -H + Ga-H on a 2 × 2 unit cell) is investigated using steepest-entropy-ascent quantum thermodynamics (SEAQT). SEAQT is a thermodynamic-ensemble based, first-principles framework that can predict the behavior of non-equilibrium processes, even those far from equilibrium where the state evolution is a combination of reversible and irreversible dynamics. SEAQT is an ideal choice to handle this problem on a first-principles basis since the chemical adsorption process starts from a highly non-equilibrium state. A result of the analysis shows that the probability of adsorption on 3Ga-H is significantly higher than that on N ad -H + Ga-H. Additionally, the growth temperature dependence of these adsorption probabilities and the temperature increase due to the heat of reaction is determined. The non-equilibrium thermodynamic modeling applied can lead to better control of the MOVPE process through the selection of preferable reconstructed surfaces. The modeling also demonstrates the efficacy of DFT-SEAQT coupling for determining detailed non-equilibrium process characteristics with a much smaller computational burden than would be entailed with mechanics-based, microscopic-mesoscopic approaches.

  19. Pressure induced phase transitions in ceramic compounds containing tetragonal zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, R.G.; Pfeiffer, G.; Paesler, M.A.

    1988-12-01

    Stabilized tetragonal zirconia compounds exhibit a transformation toughening process in which stress applied to the material induces a crystallographic phase transition. The phase transition is accompanied by a volume expansion in the stressed region thereby dissipating stress and increasing the fracture strength of the material. The hydrostatic component of the stress required to induce the phase transition can be investigated by the use of a high pressure technique in combination with Micro-Raman spectroscopy. The intensity of Raman lines characteristic for the crystallographic phases can be used to calculate the amount of material that has undergone the transition as a function of pressure. It was found that pressures on the order of 2-5 kBar were sufficient to produce an almost complete transition from the original tetragonal to the less dense monoclinic phase; while a further increase in pressure caused a gradual reversal of the transition back to the original tetragonal structure.

  20. Quantum phase transitions of strongly correlated electron systems

    International Nuclear Information System (INIS)

    Imada, Masatoshi

    1998-01-01

    Interacting electrons in solids undergo various quantum phase transitions driven by quantum fluctuations. The quantum transitions take place at zero temperature by changing a parameter to control quantum fluctuations rather than thermal fluctuations. In contrast to classical phase transitions driven by thermal fluctuations, the quantum transitions have many different features where quantum dynamics introduces a source of intrinsic fluctuations tightly connected with spatial correlations and they have been a subject of recent intensive studies as we see below. Interacting electron systems cannot be fully understood without deep analyses of the quantum phase transitions themselves, because they are widely seen and play essential roles in many phenomena. Typical and important examples of the quantum phase transitions include metal-insulator transitions, (2, 3, 4, 5, 6, 7, 8, 9) metal-superconductor transitions, superconductor-insulator transitions, magnetic transitions to antiferromagnetic or ferromagnetic phases in metals as well as in Mott insulators, and charge ordering transitions. Here, we focus on three different types of transitions

  1. Non-equilibrium phonon generation and detection in microstructure devices

    KAUST Repository

    Hertzberg, J. B.

    2011-01-01

    We demonstrate a method to excite locally a controllable, non-thermal distribution of acoustic phonon modes ranging from 0 to ∼200 GHz in a silicon microstructure, by decay of excited quasiparticle states in an attached superconducting tunnel junction (STJ). The phonons transiting the structure ballistically are detected by a second STJ, allowing comparison of direct with indirect transport pathways. This method may be applied to study how different phonon modes contribute to the thermal conductivity of nanostructures. © 2011 American Institute of Physics.

  2. Highly birefringent crystal for Raman transitions with phase modulators

    Science.gov (United States)

    Arias, Nieves; Abediyeh, Vahide; Hamzeloui, Saeed; Jeronimo-Moreno, Yasser; Gomez, Eduardo

    2016-05-01

    We present a system to excite Raman transitions with minimum phase noise. The system uses a phase modulator to generate the phase locked beams required for the transition. We use a long calcite crystal to filter out one of the sidebands, avoiding the cancellation that appears at high detunings for phase modulation. The measured phase noise is limited by the quality of the microwave synthesizer. We use the calcite crystal a second time to produce a co-propagating Raman pair with perpendicular polarizations to drive velocity insensitive Raman transitions. Support from CONACYT and Fundacion Marcos Moshinsky.

  3. Van der Waals phase transition in the framework of holography

    Directory of Open Access Journals (Sweden)

    Xiao-Xiong Zeng

    2017-01-01

    Full Text Available Phase structure of the quintessence Reissner–Nordström–AdS black hole is probed by the nonlocal observables such as holographic entanglement entropy and two point correlation function. Our result shows that, as the case of the thermal entropy, both the observables exhibit the Van der Waals-like phase transition. To reinforce this conclusion, we further check the equal area law for the first order phase transition and critical exponent of the heat capacity for the second order phase transition. We also discuss the effect of the state parameter on the phase structure of the nonlocal observables.

  4. Van der Waals phase transition in the framework of holography

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Xiao-Xiong, E-mail: xxzeng@itp.ac.cn [State School of Material Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Li, Li-Fang, E-mail: lilf@itp.ac.cn [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-01-10

    Phase structure of the quintessence Reissner–Nordström–AdS black hole is probed by the nonlocal observables such as holographic entanglement entropy and two point correlation function. Our result shows that, as the case of the thermal entropy, both the observables exhibit the Van der Waals-like phase transition. To reinforce this conclusion, we further check the equal area law for the first order phase transition and critical exponent of the heat capacity for the second order phase transition. We also discuss the effect of the state parameter on the phase structure of the nonlocal observables.

  5. Phase transitions in a gas of anyons

    International Nuclear Information System (INIS)

    MacKenzie, R.; Nebia-Rahal, F.; Paranjape, M. B.; Richer, J.

    2010-01-01

    We continue our numerical Monte Carlo simulation of a gas of closed loops on a 3 dimensional lattice, however, now in the presence of a topological term added to the action which corresponds to the total linking number between the loops. We compute the linking number using a novel approach employing certain notions from knot theory. Adding the topological term converts the particles into anyons. Interpreting the model as an effective theory that describes the 2+1-dimensional Abelian Higgs model in the asymptotic strong-coupling regime, the topological linking number simply corresponds to the addition to the action of the Chern-Simons term. The system continues to exhibit a phase transition as a function of the vortex mass as it becomes small. We find the following new results. The Chern-Simons term has no effect on the Wilson loop. On the other hand, it does effect the 't Hooft loop of a given configuration, adding the linking number of the 't Hooft loop with all of the dynamical vortex loops. We find the unexpected result that both the Wilson loop and the 't Hooft loop exhibit a perimeter law even though there are no massless particles in the theory, in both phases of the theory. It should be noted that our method suffers from numerical instabilities if the coefficient of the Chern-Simons term is too large; thus, we have restricted our results to small values of this parameter. Furthermore, interpreting the lattice loop gas as an effective theory describing the Abelian Higgs model is only known to be true in the infinite coupling limit; for strong but finite coupling this correspondence is only a conjecture, the validity of which is beyond the scope of this article.

  6. Flow reactor studies of non-equilibrium plasma-assisted oxidation of n-alkanes.

    Science.gov (United States)

    Tsolas, Nicholas; Lee, Jong Guen; Yetter, Richard A

    2015-08-13

    The oxidation of n-alkanes (C1-C7) has been studied with and without the effects of a nanosecond, non-equilibrium plasma discharge at 1 atm pressure from 420 to 1250 K. Experiments have been performed under nearly isothermal conditions in a flow reactor, where reactive mixtures are diluted in Ar to minimize temperature changes from chemical reactions. Sample extraction performed at the exit of the reactor captures product and intermediate species and stores them in a multi-position valve for subsequent identification and quantification using gas chromatography. By fixing the flow rate in the reactor and varying the temperature, reactivity maps for the oxidation of fuels are achieved. Considering all the fuels studied, fuel consumption under the effects of the plasma is shown to have been enhanced significantly, particularly for the low-temperature regime (T<800 K). In fact, multiple transitions in the rates of fuel consumption are observed depending on fuel with the emergence of a negative-temperature-coefficient regime. For all fuels, the temperature for the transition into the high-temperature chemistry is lowered as a consequence of the plasma being able to increase the rate of fuel consumption. Using a phenomenological interpretation of the intermediate species formed, it can be shown that the active particles produced from the plasma enhance alkyl radical formation at all temperatures and enable low-temperature chain branching for fuels C3 and greater. The significance of this result demonstrates that the plasma provides an opportunity for low-temperature chain branching to occur at reduced pressures, which is typically observed at elevated pressures in thermal induced systems. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  7. Optimal Data-Driven Estimation of Generalized Markov State Models for Non-Equilibrium Dynamics

    Directory of Open Access Journals (Sweden)

    Péter Koltai

    2018-02-01

    Full Text Available There are multiple ways in which a stochastic system can be out of statistical equilibrium. It might be subject to time-varying forcing; or be in a transient phase on its way towards equilibrium; it might even be in equilibrium without us noticing it, due to insufficient observations; and it even might be a system failing to admit an equilibrium distribution at all. We review some of the approaches that model the effective statistical behavior of equilibrium and non-equilibrium dynamical systems, and show that both cases can be considered under the unified framework of optimal low-rank approximation of so-called transfer operators. Particular attention is given to the connection between these methods, Markov state models, and the concept of metastability, further to the estimation of such reduced order models from finite simulation data. All these topics bear an important role in, e.g., molecular dynamics, where Markov state models are often and successfully utilized, and which is the main motivating application in this paper. We illustrate our considerations by numerical examples.

  8. Modeling of thermodynamic non-equilibrium flows around cylinders and in channels

    Science.gov (United States)

    Sinha, Avick; Gopalakrishnan, Shiva

    2017-11-01

    Numerical simulations for two different types of flash-boiling flows, namely shear flow (flow through a de-Laval nozzle) and free shear flow (flow past a cylinder) are carried out in the present study. The Homogenous Relaxation Model (HRM) is used to model the thermodynamic non-equilibrium process. It was observed that the vaporization of the fluid stream, which was initially maintained at a sub-cooled state, originates at the nozzle throat. This is because the fluid accelerates at the vena-contracta and subsequently the pressure falls below the saturation vapor pressure, generating a two-phase mixture in the diverging section of the nozzle. The mass flow rate at the nozzle was found to decrease with the increase in fluid inlet temperature. A similar phenomenon also occurs for the free shear case due to boundary layer separation, causing a drop in pressure behind the cylinder. The mass fraction of vapor is maximum at rear end of the cylinder, where the size of the wake is highest. As the back pressure is reduced, severe flashing behavior was observed. The numerical simulations were validated against available experimental data. The authors gratefully acknowledge funding from the public-private partnership between DST, Confederation of Indian Industry and General Electric Pvt. Ltd.

  9. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands.

    Science.gov (United States)

    Valente, Luis M; Phillimore, Albert B; Etienne, Rampal S

    2015-08-01

    Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. © 2015 The Authors Ecology Letters published by John Wiley & Sons Ltd and CNRS.

  10. Interaction of non-equilibrium phonons with electron-hole plasmas in germanium

    International Nuclear Information System (INIS)

    Kirch, S.J.

    1985-01-01

    This thesis presents results of experiments on the interaction of phonons and photo-excited electron-hole plasmas in Ge at low temperature. The first two studies involved the low-temperature fluid phase known as the electron-hole liquid (EHL). The third study involved a wider range of temperatures and includes the higher temperature electron-hole plasma (EHP). In the first experiment, superconducting tunnel junctions are used to produce quasi-monochromatic phonons, which propagate through the EHL. The magnitude of the absorption of these non-equilibrium phonons gives a direct measure of the coupling constant, the deformation potential. In the second experiment, the nonequilibrium phonons are generated by laser excitation of a metal film. An unusual sample geometry allows examination of the EHL-phonon interaction near the EHL excitation surface. This coupling is examined for both cw and pulsed EHL excitation. In the third experiment, the phonons are byproducts of the photo-excited carrier thermalization. The spatial, spectral and temporal dependence of the recombination luminescence is examined. A phonon wind force is observed to dominate the transport properties of the EHL and the EHP. These carriers are never observed to move faster than the phonon velocity even during the laser pulse

  11. Thermodynamics of pairing phase transition in nuclei

    International Nuclear Information System (INIS)

    Karim, Afaque; Ahmad, Shakeb

    2014-01-01

    The pairing gaps, pairing energy, heat capacity and entropy are calculated within BCS (Bardeen- Cooper-Schrieffer) based quasi particle approach, including thermal fluctuations on pairing field within pairing model for all nuclei (light, medium, heavy and super heavy nuclei). Quasi particles approach in BCS theory was introduced and reformulated to study various properties. For thermodynamic behavior of nuclei at finite temperatures, the anomalous averages of creation and annihilation operators are introduced. It is solved self consistently at finite temperatures to obtain BCS Hamiltonian. After doing unitary transformation, we obtained the Hamiltonian in the diagonal form. Thus, one gets temperature dependence gap parameter and pairing energy for nuclei. Moreover, the energy at finite temperatures is the sum of the condensation energy and the thermal energy of fermionic quasi particles. With the help of BCS Hamiltonian, specific heat, entropy and free energy are calculated for different nuclei. In this paper the gap parameter occupation number and pairing energy as a function of temperature which is important for all the light, medium, heavy and super heavy nuclei is calculated. Moreover, the various thermo dynamical quantities like specific heat, entropy and free energy is also obtained for different nuclei. Thus, the thermodynamics of pairing phase transition in nuclei is studied

  12. Molecular simulation of non-equilibrium methane hydrate decomposition process

    Energy Technology Data Exchange (ETDEWEB)

    Bagherzadeh, S.Alireza; Englezos, Peter [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, V6T 1Z3 (Canada); Alavi, Saman, E-mail: saman.alavi@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6 (Canada); Ripmeester, John A., E-mail: john.ripmeester@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6 (Canada)

    2012-01-15

    Graphical abstract: Highlights: > Decomposition of methane hydrate is studied with molecular dynamics simulations. > Simulations are performed under adiabatic conditions (no thermostats). > The effects of heat and mass transfer during the decomposition are observed. > Temperature gradients are established as the hydrate decomposes. > Intrinsic reaction kinetics picture of hydrate dissociation is revisited. - Abstract: We recently performed constant energy molecular dynamics simulations of the endothermic decomposition of methane hydrate in contact with water to study phenomenologically the role of mass and heat transfer in the decomposition rate [S. Alavi, J.A. Ripmeester, J. Chem. Phys. 132 (2010) 144703]. We observed that with the progress of the decomposition front temperature gradients are established between the remaining solid hydrate and the solution phases. In this work, we provide further quantitative macroscopic and molecular level analysis of the methane hydrate decomposition process with an emphasis on elucidating microscopic details and how they affect the predicted rate of methane hydrate decomposition in natural methane hydrate reservoirs. A quantitative criterion is used to characterize the decomposition of the hydrate phase at different times. Hydrate dissociation occurs in a stepwise fashion with rows of sI cages parallel to the interface decomposing simultaneously. The correlations between decomposition times of subsequent layers of the hydrate phase are discussed.

  13. Non-Equilibrium Containerless Solidification of Aluminum-Nickel Alloys

    Science.gov (United States)

    Ilbagi, Arash

    More than 90% of all metallic materials are manufactured starting from their liquid state. Designing the solid structure produced during solidification can have major savings in downstream processing. Rapid solidification yields significant enhancement in properties through refined microstructure, reduced microsegregation and the formation of metastable phases. To control the microstructure obtained from rapid solidification and attain desired properties, understanding of effects of processing parameters, in particular cooling rate and undercooling on microstructure evolution is required. In the case of peritectic reaction this understanding is lacking. In this dissertation, the effect of cooling rate on the peritectic reactions occurring in the binary Al-Ni system is investigated. Impulse Atomization technique was used to produce rapidly solidified particles of Al-36 wt%Ni and Al-50wt%Ni. The effect of cooling rate on the microstructure evolution and phase fractions achieved after solidification was studied. Also, porosity formation in the atomized particles was investigated and the effect of processing parameters on the amount and distribution of porosity was analyzed. For characterization, neutron diffraction, X-ray micro-tomography, electron and optical microscopy were utilized. The results showed that in both Al-36 wt%Ni and Al-50 wt%Ni, cooling rate has a significant effect on the formation of microstructure, phase fractions and metastable phase formation. It was shown that at different cooling rate ii regimes different mechanisms are responsible for the changes observed in the phase fractions. Using X-Ray tomography, multiple nucleation sites were observed in large particles, while smaller particles contained only a single nucleation site. Also, porosity within the particles was quantified and the distribution of porosity with regard to the nucleation site and cooling rate is discussed. The distribution of porosity within the small particles and large

  14. Phase transition in L-alaninium oxalate by photoacoustics

    Indian Academy of Sciences (India)

    Unknown

    TG and DTA mea- surements were first carried out to identify any transitions. The calorimetric techniques such as DSC, TG and DTA are generally used to study the phase transition. But,. Ganguly and Rao (1981) reported from their PA study on. La2CuO4 that there would be a weak transition at 553 K but they could not see ...

  15. A grain boundary phase transition in Si–Au

    International Nuclear Information System (INIS)

    Ma, Shuailei; Meshinchi Asl, Kaveh; Tansarawiput, Chookiat; Cantwell, Patrick R.; Qi, Minghao; Harmer, Martin P.; Luo, Jian

    2012-01-01

    A grain boundary transition from a bilayer to an intrinsic (nominally clean) boundary is observed in Si–Au. An atomically abrupt transition between the two complexions (grain boundary stabilized phases) implies the occurrence of a first-order interfacial phase transition associated with a discontinuity in the interfacial excess. This observation supports a grain-boundary complexion theory with broad applications. This transition is atypical in that the monolayer complexion is absent. A model is proposed to explain the bilayer stabilization and the origin of this complexion transition.

  16. On the theory of phase transitions in polypeptides

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2008-01-01

    We suggest a theoretical method based on the statistical mechanics for treating the alpha-helix random coil transition in polypeptides. This process is considered as a first-order-like phase transition. The developed theory is free of model parameters and is based solely on fundamental physical...... principles. We apply the developed formalism for the description of thermodynamical properties of alanine polypeptides of different length. We analyze the essential thermodynamical properties of the system such as heat capacity, phase transition temperature and latent heat of the phase transition...

  17. Thermal non-equilibrium heat transfer in a porous cavity in the presence of bio-chemical heat source

    Directory of Open Access Journals (Sweden)

    Nazari Mohsen

    2015-01-01

    Full Text Available This paper is concerned with thermal non-equilibrium natural convection in a square cavity filled with a porous medium in the presence of a biomass which is transported in the cavity. The biomass can consume a secondary moving substrate. The physics of the presented problem is related to the analysis of heat and mass transfer in a composting process that controlled by internal heat generation. The intensity of the bio-heat source generated in the cavity is equal to the rate of consumption of the substrate by the biomass. It is assumed that the porous medium is homogeneous and isotropic. A two-field model that represents the fluid and solid phase temperature fields separately is used for energy equation. A simplified Monod model is introduced along with the governing equations to describe the consumption of the substrate by the biomass. In other word, the transient biochemical heat source which is dependent on a solute concentration is considered in the energy equations. Investigation of the biomass activity and bio-chemical heat generation in the case of thermal non-equilibrium assumption has not been considered in the literature and they are open research topics. The effects of thermal non-equilibrium model on heat transfer, flow pattern and biomass transfer are investigated. The effective parameters which have a direct impact on the generated bio-chemical heat source are also presented. The influences of the non-dimensional parameters such as fluid-to-solid conductivity ratio on the temperature distribution are presented.

  18. Role of multistability in the transition to chaotic phase synchronization

    DEFF Research Database (Denmark)

    Postnov, D.E.; Vadivasova, T.E.; Sosnovtseva, Olga

    1999-01-01

    In this paper we describe the transition to phase synchronization for systems of coupled nonlinear oscillators that individually follow the Feigenbaum route to chaos. A nested structure of phase synchronized regions of different attractor families is observed. With this structure, the transition...... using Rössler systems and model maps are given. ©1999 American Institute of Physics....

  19. Local discontinuous Galerkin methods for phase transition problems

    NARCIS (Netherlands)

    Tian, Lulu

    2015-01-01

    In this thesis we develop a local discontinuous Galerkin (LDG) finite element method to solve mathematical models for phase transitions in solids and fluids. The first model we study is called a viscosity-capillarity (VC) system associated with phase transitions in elastic bars and Van der Waals

  20. Structural phase transitions and piezoelectric anomalies in ordered ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 4. Structural phase transitions and piezoelectric anomalies in ordered Sc0.5Ga0.5N alloys ... This alloy is found to exhibit a tremendous piezoelectric response, associated with a phase transition from nonpolar 63/(6h) space group to a polar ...

  1. Phase transitions in liquids with directed intermolecular bonding

    OpenAIRE

    Son, L.; Ryltcev, R.

    2005-01-01

    Liquids with quasi - chemical bonding between molecules are described in terms of vertex model. It is shown that this bonding results in liquid - liquid phase transition, which occurs between phases with different mean density of intermolecular bonds. The transition may be suggested to be a universal phenomena for those liquids.

  2. Supercooling across first-order phase transitions in vortex matter

    Indian Academy of Sciences (India)

    Hysteresis in cycling through first-order phase transitions in vortex matter, akin to the well-studied phenomenon of supercooling of water, has been discussed in literature. Hysteresis can be seen while varying either temperature or magnetic field (and thus the density of vortices). Our recent work on phase transitions with ...

  3. High-density QCD phase transitions inside neutron stars: Glitches ...

    Indian Academy of Sciences (India)

    2017-10-09

    Oct 9, 2017 ... ... of different high-density phases and associated phase transitions. We study effectsof density fluctuations during transitions with and without topological defect production and study the effect on pulsar timings due to changing moment of inertia of the star. We also discuss gravitational wave production due ...

  4. Electroweak phase transition and some related phenomena–a brief

    Indian Academy of Sciences (India)

    In this article, we give a bird's eye view of the research on electroweak phase transition and some related phenomena, viz., cosmological baryogenesis, electroweak bubble dynamics and generation of gravitationalwaves. Our presentation revolves around the observation that a strong first-order electroweak phase transition ...

  5. Model for pairing phase transition in atomic nuclei

    International Nuclear Information System (INIS)

    Schiller, A.; Guttormsen, M.; Hjorth-Jensen, M.; Rekstad, J.; Siem, S.

    2002-01-01

    A model is developed which allows the investigation and classification of the pairing phase transition in atomic nuclei. The regions of the parameter space are discussed for which a pairing phase transition can be observed. The model parameters include number of particles, attenuation of pairing correlations with increasing seniority, single-particle level spacing, and pairing gap parameter

  6. Thermodynamic phase transition of a black hole in rainbow gravity

    Directory of Open Access Journals (Sweden)

    Zhong-Wen Feng

    2017-09-01

    Full Text Available In this letter, using the rainbow functions that were proposed by Magueijo and Smolin, we investigate the thermodynamics and the phase transition of rainbow Schwarzschild black hole. First, we calculate the rainbow gravity corrected Hawking temperature. From this modification, we then derive the local temperature, free energy, and other thermodynamic quantities in an isothermal cavity. Finally, we analyze the critical behavior, thermodynamic stability, and phase transition of the rainbow Schwarzschild black hole. The results show that the rainbow gravity can stop the Hawking radiation in the final stages of black holes' evolution and lead to the remnants of black holes. Furthermore, one can observe that the rainbow Schwarzschild black hole has one first-order phase transition, two second-order phase transitions, and three Hawking–Page-type phase transitions in the framework of rainbow gravity theory.

  7. Thermodynamic phase transition of a black hole in rainbow gravity

    Science.gov (United States)

    Feng, Zhong-Wen; Yang, Shu-Zheng

    2017-09-01

    In this letter, using the rainbow functions that were proposed by Magueijo and Smolin, we investigate the thermodynamics and the phase transition of rainbow Schwarzschild black hole. First, we calculate the rainbow gravity corrected Hawking temperature. From this modification, we then derive the local temperature, free energy, and other thermodynamic quantities in an isothermal cavity. Finally, we analyze the critical behavior, thermodynamic stability, and phase transition of the rainbow Schwarzschild black hole. The results show that the rainbow gravity can stop the Hawking radiation in the final stages of black holes' evolution and lead to the remnants of black holes. Furthermore, one can observe that the rainbow Schwarzschild black hole has one first-order phase transition, two second-order phase transitions, and three Hawking-Page-type phase transitions in the framework of rainbow gravity theory.

  8. Baryon inhomogeneity from the cosmic quark-hadron phase transition

    International Nuclear Information System (INIS)

    Kurki-Suonio, H.

    1991-01-01

    We discuss the generation of inhomogeneity in the baryon-number density during the cosmic quark-hadron phase transition. We use a simple model with thin-wall phase boundaries and ideal-gas equations of state. The nucleation of the phase transition introduces a new distance scale into the universe which will be the scale of the generated inhomogeneity. We review the estimate of this scale. During the transition baryon number is likely to collect onto a layer at the phase boundary. These layers may in the end be deposited as small regions of very high baryon density. 21 refs., 1 fig

  9. Simulation of non-equilibrium many body electrons in RTD

    Directory of Open Access Journals (Sweden)

    A. H. Rezvani

    2001-06-01

    Full Text Available   We inspected the exact solution of double barrier quantum well. The choice of proper boundary conditions has been taken into account. We eveluated the mechanism of resonant in this device. The density correlation matrix was calculated by using the exact solution of the time-dependent generalized nonlinear Schrodinger equation in the presence of electron-electron interaction. The result shows that there is no correlation dependence among the electrons at the equilibrium between contact regions. After biasing, we have calculated the density correlation matrix in the transient and steady state. The results of our calculations show the oscillatory plasmon current in the state of transient, while in the steaby state the correlation among the phase of electrons observed to be oscillatory in the whole region of the device.

  10. The equation of state with non-equilibrium methods

    Directory of Open Access Journals (Sweden)

    Nada Alessandro

    2018-01-01

    Full Text Available Jarzynski’s equality provides an elegant and powerful tool to directly compute differences in free energy in Monte Carlo simulations and it can be readily extended to lattice gauge theories to compute a large set of physically interesting observables. In this talk we present a novel technique to determine the thermodynamics of stronglyinteracting matter based on this relation, which allows for a direct and efficient determination of the pressure using out-of-equilibrium Monte Carlo simulations on the lattice. We present results for the equation of state of the SU(3 Yang-Mills theory in the confined and deconfined phases. Finally, we briefly discuss the generalization of this method for theories with fermions, with particular focus on the equation of state of QCD.

  11. CO2 Capture from Flue Gas by Phase Transitional Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Liang Hu

    2009-06-30

    A novel absorption process called Phase Transitional Absorption was invented. What is the Phase Transitional Absorption? Phase Transitional Absorption is a two or multi phase absorption system, CO{sub 2} rich phase and CO{sub 2} lean phase. During Absorption, CO{sub 2} is accumulated in CO{sub 2} rich phase. After separating the two phases, CO{sub 2} rich phase is forward to regeneration. After regeneration, the regenerated CO{sub 2} rich phase combines CO{sub 2} lean phase to form absorbent again to complete the cycle. The advantage for Phase Transitional Absorption is obvious, significantly saving on regeneration energy. Because CO{sub 2} lean phase was separated before regeneration, only CO{sub 2} rich phase was forward to regeneration. The absorption system we developed has the features of high absorption rate, high loading and working capacity, low corrosion, low regeneration heat, no toxic to environment, etc. The process evaluation shows that our process is able to save 80% energy cost by comparing with MEA process.

  12. Generic two-phase coexistence in the quadratic contact process

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiaofang [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    This thesis focuses on the demonstration of the existence of and analysis of phenomena related to the discontinuous non-equilibrium phase transition between an active (or reactive) state and a poisoned (or extinguished) state occurring in a stochastic lattice-gas realization of Schloegl’s second model for autocatalysis.

  13. Field-control, phase-transitions, and life’s emergence

    Directory of Open Access Journals (Sweden)

    Gargi eMitra-Delmotte

    2012-10-01

    Full Text Available Instances of critical-like characteristics in living systems at each organizational level (bio-molecules to ecosystems as well as the spontaneous emergence of computation (Langton, do suggest the relevance of self-organized criticality (SOC. But extrapolating complex bio-systems to life’s origins, brings up a paradox: how could simple organics-- lacking the ‘soft matter’ response properties of today’s complex bio-molecules--have dissipated energy from primordial reactions (eventually reducing CO2 in a controlled manner for their ‘ordering’? Nevertheless, a causal link of life’s macroscopic irreversible dynamics to the microscopic reversible laws of statistical mechanics is indicated via the ‘functional-takeover’ of a soft magnetic scaffold by organics (c.f. Cairns-Smith’s crystal-scaffold. A field-controlled structure offers a mechanism for bootstrapping-- bottom-up assembly with top-down control: its super-paramagnetic colloidal components obey reversible dynamics, but its dissipation of magnetic (H-field energy for aggregation breaks time-reversal symmetry. The responsive adjustments of the controlled (host mineral system to environmental changes would bring about mutual coupling between random organic sets supported by it; here the generation of long-range correlations within organic (guest networks could include SOC-like mechanisms. And, such cooperative adjustments enable the selection of the functional configuration by altering the inorganic dipolar network’s capacity to assist a spontaneous process. A non-equilibrium dynamics could now drive the kinetically-oriented system (trimming the phase-space via sterically-coupled organics towards a series of phase-transitions with appropriate organic replacements taking-over its functions. Where available, experiments are cited in support of these speculations and for designing appropriate tests.

  14. Phase Transitions In M-Theory And F-Theory

    OpenAIRE

    Witten, Edward

    1996-01-01

    Phase transitions are studied in $M$-theory and $F$-theory. In $M$-theory compactification to five dimensions on a Calabi-Yau, there are topology-changing transitions similar to those seen in conformal field theory, but the non-geometrical phases known in conformal field theory are absent. At boundaries of moduli space where such phases might have been expected, the moduli space ends, by a conventional or unconventional physical mechanism. The unconventional mechanisms, which roughly involve ...

  15. Causal kinetic equation of non-equilibrium plasmas

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2017-05-01

    Full Text Available Statistical plasma theory far from thermal equilibrium is subject to Liouville's equation, which is at the base of the BBGKY hierarchical approach to plasma kinetic theory, from which, in the absence of collisions, Vlasov's equation follows. It is also at the base of Klimontovich's approach which includes single-particle effects like spontaneous emission. All these theories have been applied to plasmas with admirable success even though they suffer from a fundamental omission in their use of the electrodynamic equations in the description of the highly dynamic interactions in many-particle conglomerations. In the following we extend this theory to taking into account that the interaction between particles separated from each other at a distance requires the transport of information. Action needs to be transported and thus, in the spirit of the direct-interaction theory as developed by Wheeler and Feynman (1945, requires time. This is done by reference to the retarded potentials. We derive the fundamental causal Liouville equation for the phase space density of a system composed of a very large number of charged particles. Applying the approach of Klimontovich (1967, we obtain the retarded time evolution equation of the one-particle distribution function in plasmas, which replaces Klimontovich's equation in cases when the direct-interaction effects have to be taken into account. This becomes important in all systems where the distance between two points |Δq| ∼ ct is comparable to the product of observation time and light velocity, a situation which is typical in cosmic physics and astrophysics.

  16. The thickness dependence of the phase transition temperature in PVDF

    Energy Technology Data Exchange (ETDEWEB)

    Mai, M. [Institute of Electrical Engineering Physics, Saarland University, D-66123 Saarbruecken (Germany); Fridkin, V. [Institute of Crystallography of Russian Academy of Sciences, 119333 Moscow (Russian Federation); Martin, B., E-mail: b.martin@mx.uni-saarland.de [Institute of Electrical Engineering Physics, Saarland University, D-66123 Saarbruecken (Germany); Leschhorn, A.; Kliem, H. [Institute of Electrical Engineering Physics, Saarland University, D-66123 Saarbruecken (Germany)

    2013-07-15

    It was found recently that in the Langmuir–Blodgett ultrathin vinylidene fluoride (PVDF) films there is ferroelectric phase transition of the first order. Earlier in the bulk PVDF this phase transition was not observed because the melting temperature of this ferroelectric polymer (∼170 °C) is lower than the point of the possible phase transition. Therefore this polymer was treated for a long time as pyroelectric. In the present work we investigate PVDF Langmuir–Blodgett films at the nanoscale and the film thickness interval, where ferroelectric phase transition disappears and transition from ferroelectric to pyroelectric state takes place. This phenomenon is explained by the finite-size effect at the nanoscale using Landau–Ginzburg–Devonshire (LGD) theory and by the Weiss mean field model.

  17. The electroweak phase transition in the Inert Doublet Model

    Energy Technology Data Exchange (ETDEWEB)

    Blinov, Nikita [Department of Physics, University of California Santa Cruz,1156 High St, Santa Cruz, CA 95064 (United States); Santa Cruz Institute for Particle Physics,1156 High St, Santa Cruz, CA 95064 (United States); Theory Department, TRIUMF,4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia,Vancouver, BC V6T 1Z1 (Canada); Profumo, Stefano; Stefaniak, Tim [Department of Physics, University of California Santa Cruz,1156 High St, Santa Cruz, CA 95064 (United States); Santa Cruz Institute for Particle Physics,1156 High St, Santa Cruz, CA 95064 (United States)

    2015-07-21

    We study the strength of a first-order electroweak phase transition in the Inert Doublet Model (IDM), where particle dark matter (DM) is comprised of the lightest neutral inert Higgs boson. We improve over previous studies in the description and treatment of the finite-temperature effective potential and of the electroweak phase transition. We focus on a set of benchmark models inspired by the key mechanisms in the IDM leading to a viable dark matter particle candidate, and illustrate how to enhance the strength of the electroweak phase transition by adjusting the masses of the yet undiscovered IDM Higgs states. We argue that across a variety of DM masses, obtaining a strong enough first-order phase transition is a generic possibility in the IDM. We find that due to direct dark matter searches and collider constraints, a sufficiently strong transition and a thermal relic density matching the universal DM abundance is possible only in the Higgs funnel regime.

  18. The electroweak phase transition in the Inert Doublet Model

    Energy Technology Data Exchange (ETDEWEB)

    Blinov, Nikita; Profumo, Stefano; Stefaniak, Tim, E-mail: nblinov@triumf.ca, E-mail: profumo@ucsc.edu, E-mail: tistefan@ucsc.edu [Department of Physics, University of California Santa Cruz, 1156 High St, Santa Cruz, CA 95064 (United States)

    2015-07-01

    We study the strength of a first-order electroweak phase transition in the Inert Doublet Model (IDM), where particle dark matter (DM) is comprised of the lightest neutral inert Higgs boson. We improve over previous studies in the description and treatment of the finite-temperature effective potential and of the electroweak phase transition. We focus on a set of benchmark models inspired by the key mechanisms in the IDM leading to a viable dark matter particle candidate, and illustrate how to enhance the strength of the electroweak phase transition by adjusting the masses of the yet undiscovered IDM Higgs states. We argue that across a variety of DM masses, obtaining a strong enough first-order phase transition is a generic possibility in the IDM. We find that due to direct dark matter searches and collider constraints, a sufficiently strong transition and a thermal relic density matching the universal DM abundance is possible only in the Higgs funnel regime.

  19. Nonequilibrium topological phase transitions in two-dimensional optical lattices

    Science.gov (United States)

    Nakagawa, Masaya; Kawakami, Norio

    2014-01-01

    Recently, concepts of topological phases of matter are extended to nonequilibrium systems, especially periodically driven systems. In this paper, we construct an example which shows nonequilibrium topological phase transitions using ultracold fermions in optical lattices. We show that the Rabi oscillation has the possibility to induce nonequilibrium topological phases which are classified into time-reversal-invariant topological insulators for a two-orbital model of alkaline-earth-metal atoms. Furthermore, we study the nonequilibrium topological phases using time-dependent Schrieffer-Wolff-type perturbation theory, and we obtain an analytical expression to describe the topological phase transitions from a high-frequency limit of external driving fields.

  20. Replacing leads by self-energies using non-equilibrium Green's functions

    International Nuclear Information System (INIS)

    Michael, Fredrick; Johnson, M.D.

    2003-01-01

    Open quantum systems consist of semi-infinite leads which transport electrons to and from the device of interest. We show here that within the non-equilibrium Green's function technique for continuum systems, the leads can be replaced by simple c-number self-energies. Our starting point is an approach for continuum systems developed by Feuchtwang. The reformulation developed here is simpler to understand and carry out than the somewhat unwieldly manipulations typical in the Feuchtwang method. The self-energies turn out to have a limited variability: the retarded self-energy Σ r depends on the arbitrary choice of internal boundary conditions, but the non-equilibrium self-energy or scattering function Σ which determines transport is invariant for a broad class of boundary conditions. Expressed in terms of these self-energies, continuum non-equilibrium transport calculations take a particularly simple form similar to that developed for discrete systems

  1. Non-equilibrium scaling analysis of the Kondo model with voltage bias

    International Nuclear Information System (INIS)

    Fritsch, Peter; Kehrein, Stefan

    2009-01-01

    The quintessential description of Kondo physics in equilibrium is obtained within a scaling picture that shows the buildup of Kondo screening at low temperature. For the non-equilibrium Kondo model with a voltage bias, the key new feature are decoherence effects due to the current across the impurity. In the present paper, we show how one can develop a consistent framework for studying the non-equilibrium Kondo model within a scaling picture of infinitesimal unitary transformations (flow equations). Decoherence effects appear naturally in third order of the β-function and dominate the Hamiltonian flow for sufficiently large voltage bias. We work out the spin dynamics in non-equilibrium and compare it with finite temperature equilibrium results. In particular, we report on the behavior of the static spin susceptibility including leading logarithmic corrections and compare it with the celebrated equilibrium result as a function of temperature.

  2. Beyond the second law entropy production and non-equilibrium systems

    CERN Document Server

    Lineweaver, Charles; Niven, Robert; Regenauer-Lieb, Klaus

    2014-01-01

    The Second Law, a cornerstone of thermodynamics, governs the average direction of dissipative, non-equilibrium processes. But it says nothing about their actual rates or the probability of fluctuations about the average. This interdisciplinary book, written and peer-reviewed by international experts, presents recent advances in the search for new non-equilibrium principles beyond the Second Law, and their applications to a wide range of systems across physics, chemistry and biology. Beyond The Second Law brings together traditionally isolated areas of non-equilibrium research and highlights potentially fruitful connections between them, with entropy production playing the unifying role. Key theoretical concepts include the Maximum Entropy Production principle, the Fluctuation Theorem, and the Maximum Entropy method of statistical inference. Applications of these principles are illustrated in such diverse fields as climatology, cosmology, crystal growth morphology, Earth system science, environmental physics, ...

  3. Non-equilibrium assembly of microtubules: from molecules to autonomous chemical robots.

    Science.gov (United States)

    Hess, H; Ross, Jennifer L

    2017-09-18

    Biological systems have evolved to harness non-equilibrium processes from the molecular to the macro scale. It is currently a grand challenge of chemistry, materials science, and engineering to understand and mimic biological systems that have the ability to autonomously sense stimuli, process these inputs, and respond by performing mechanical work. New chemical systems are responding to the challenge and form the basis for future responsive, adaptive, and active materials. In this article, we describe a particular biochemical-biomechanical network based on the microtubule cytoskeletal filament - itself a non-equilibrium chemical system. We trace the non-equilibrium aspects of the system from molecules to networks and describe how the cell uses this system to perform active work in essential processes. Finally, we discuss how microtubule-based engineered systems can serve as testbeds for autonomous chemical robots composed of biological and synthetic components.

  4. Non-equilibrium versus equilibrium emission of complex fragments from hot nuclei

    International Nuclear Information System (INIS)

    Viola, V.E.; Kwiatkowski, K.; Yennello, S.; Fields, D.E.

    1989-01-01

    The relative contributions of equilibrium and non-equilibrium mechanisms for intermediate-mass fragment emission have been deduced for Z=3-14 fragments formed in 3 He- and 14 N-induced reactions on Ag and Au targets. Complete inclusive excitation function measurements have been performed for 3 He projectiles from E/A=67 to 1,200 MeV and for 14 N from E/A=20 to 50 MeV. The data are consistent with a picture in which equilibrated emission is important at the lowest energies, but with increasing bombarding energy the cross sections are increasingly dominated by non-equilibrium processes. Non-equilibrium emission is also shown to be favored for light fragments relative to heavy fragments. These results are supported by coincidence studies of intermediate-mass fragments tagged by linear momentum transfer measurements

  5. Discontinuity of maximum entropy inference and quantum phase transitions

    International Nuclear Information System (INIS)

    Chen, Jianxin; Ji, Zhengfeng; Yu, Nengkun; Zeng, Bei; Li, Chi-Kwong; Poon, Yiu-Tung; Shen, Yi; Zhou, Duanlu

    2015-01-01

    In this paper, we discuss the connection between two genuinely quantum phenomena—the discontinuity of quantum maximum entropy inference and quantum phase transitions at zero temperature. It is shown that the discontinuity of the maximum entropy inference of local observable measurements signals the non-local type of transitions, where local density matrices of the ground state change smoothly at the transition point. We then propose to use the quantum conditional mutual information of the ground state as an indicator to detect the discontinuity and the non-local type of quantum phase transitions in the thermodynamic limit. (paper)

  6. Phase transition of pure zirconia under irradiation: A textbook example

    Energy Technology Data Exchange (ETDEWEB)

    Simeone, D. [CEA/Saclay, DEN/DMN/SRMA/LA2M, F-91191 Gif sur Yvette (France)]. E-mail: david.simeone@cea.fr; Baldinozzi, G. [Laboratoire de Structures, Proprietes et Modelisation des Solides, UMR CNRS 8580 Ecole Centrale Paris, F-92295 Chatenay Malabry (France); Gosset, D. [CEA/Saclay, DEN/DMN/SRMA/LA2M, F-91191 Gif sur Yvette (France); Le Caer, S. [CEA/Saclay, DSM/DRECAM/SCM/URA 331 CNRS, F-91191 Gif sur Yvette (France)

    2006-09-15

    One of the most important goals in ceramic and materials science is to be able to design materials with specific properties. Irradiation seems to be a powerful tool for the design of advanced ceramics because of its ability to modify over different scales the microstructure of solids. Nowadays, it is clearly proved that irradiation induces order-disorder phase transitions in metallic alloys and in some ceramics. In this paper, we show that a displacive phase transition can also be induced by irradiation. Based on many experimental facts, a microscopic model is proposed to explain the displacive phase transition observed in this material after irradiation. Defects, produced in the oxygen sublattice, induce important strain fields on a nanometric scale. This strain field can be handled as a secondary order parameter within the Landau theory approach, leading to a decrease of the phase transition temperature and thus quenching the high temperature tetragonal phase.

  7. Thermodynamic model of nonequilibrium phase transitions.

    Science.gov (United States)

    Martyushev, L M; Konovalov, M S

    2011-07-01

    Within the scope of a thermodynamic description using the maximum entropy production principle, transitions from one nonequilibrium (kinetic) regime to another are considered. It is shown that in the case when power-law dependencies of thermodynamic flux on force are similar for two regimes, only a transition accompanied by a positive jump of thermodynamic flux is possible between them. It is found that the difference in powers of the dependencies of thermodynamic fluxes on forces results in a number of interesting nonequilibrium transitions between kinetic regimes, including the reentrant one with a negative jump of thermodynamic flux.

  8. Do phase transitions survive binomial reducibility and thermal scaling?

    International Nuclear Information System (INIS)

    Moretto, L.G.; Phair, L.; Wozniak, G.J.

    1996-05-01

    First order phase transitions are described in terms of the microcanonical and canonical ensemble, with special attention to finite size effects. Difficulties in interpreting a 'caloric curve' are discussed. A robust parameter indicating phase coexistence (univariance) or single phase (bivariance) is extracted for charge distributions. 9 refs., 4 figs

  9. Do phase transitions survive binomial reducibility and thermal scaling?

    Energy Technology Data Exchange (ETDEWEB)

    Moretto, L.G.; Phair, L.; Wozniak, G.J.

    1996-05-01

    First order phase transitions are described in terms of the microcanonical and canonical ensemble, with special attention to finite size effects. Difficulties in interpreting a `caloric curve` are discussed. A robust parameter indicating phase coexistence (univariance) or single phase (bivariance) is extracted for charge distributions. 9 refs., 4 figs.

  10. X-RAY SIGNATURES OF NON-EQUILIBRIUM IONIZATION EFFECTS IN GALAXY CLUSTER ACCRETION SHOCK REGIONS

    International Nuclear Information System (INIS)

    Wong, Ka-Wah; Sarazin, Craig L.; Ji Li

    2011-01-01

    The densities in the outer regions of clusters of galaxies are very low, and the collisional timescales are very long. As a result, heavy elements will be under-ionized after they have passed through the accretion shock. We have studied systematically the effects of non-equilibrium ionization for relaxed clusters in the ΛCDM cosmology using one-dimensional hydrodynamic simulations. We found that non-equilibrium ionization effects do not depend on cluster mass, but depend strongly on redshift which can be understood by self-similar scaling arguments. The effects are stronger for clusters at lower redshifts. We present X-ray signatures such as surface brightness profiles and emission lines in detail for a massive cluster at low redshift. In general, soft emission (0.3-1.0 keV) is enhanced significantly by under-ionization, and the enhancement can be nearly an order of magnitude near the shock radius. The most prominent non-equilibrium ionization signature we found is the O VII and O VIII line ratio. The ratios for non-equilibrium ionization and collisional ionization equilibrium models are different by more than an order of magnitude at radii beyond half of the shock radius. These non-equilibrium ionization signatures are equally strong for models with different non-adiabatic shock electron heating efficiencies. We have also calculated the detectability of the O VII and O VIII lines with the future International X-ray Observatory (IXO). Depending on the line ratio measured, we conclude that an exposure of ∼130-380 ks on a moderate-redshift, massive regular cluster with the X-ray Microcalorimeter Spectrometer (XMS) on the IXO will be sufficient to provide a strong test for the non-equilibrium ionization model.

  11. Phase transition in a modified square Josephson-junction array

    CERN Document Server

    Han, J

    1999-01-01

    We study the phase transition in a modified square proximity-coupled Josephson-junction array with small superconducting islands at the center of each plaquette. We find that the modified square array undergoes a Kosterlitz-Thouless-Berezinskii-like phase transition, but at a lower temperature than the simple square array with the same single-junction critical current. The IV characteristics, as well as the phase transition, resemble qualitatively those of a disordered simple square array. The effects of the presence of the center islands in the modified square array are discussed.

  12. Novel phase transitions in B-site doped manganites

    International Nuclear Information System (INIS)

    Popovic, Z.V.; Cantarero, A.; Thijssen, W.H.A.; Paunovic, N.; Dohcevic-Mitrovic, Z.; Sapina, F.

    2005-01-01

    We have examined the infrared reflectivity and the electrical resistivity of La 1- x [Sr(Ba)] x Mn 1- z [Cu(Zn)] z O 3 samples in ferromagnetic metallic and insulator regime. Several phase transitions are observed, the most obvious being the transition from a ferromagnetic metallic to a ferromagnetic insulator phase that is related to the formation of short-range orbitally ordered domains. The temperature T 1 of the phase transition is dependent on doping concentration and for optimally doped samples (∼32% of Mn 4+ ions) we have found T 1 ∼0.93 T C

  13. On the chiral phase transition in the linear sigma model

    International Nuclear Information System (INIS)

    Tran Huu Phat; Nguyen Tuan Anh; Le Viet Hoa

    2003-01-01

    The Cornwall- Jackiw-Tomboulis (CJT) effective action for composite operators at finite temperature is used to investigate the chiral phase transition within the framework of the linear sigma model as the low-energy effective model of quantum chromodynamics (QCD). A new renormalization prescription for the CJT effective action in the Hartree-Fock (HF) approximation is proposed. A numerical study, which incorporates both thermal and quantum effect, shows that in this approximation the phase transition is of first order. However, taking into account the higher-loop diagrams contribution the order of phase transition is unchanged. (author)

  14. Trapped ion system for sympathetic cooling and non-equilibrium dynamics

    Science.gov (United States)

    Doret, Charlie; Jubin, Sierra; Stevenson, Sarah

    2017-04-01

    Atomic systems are superbly suited to the study of non-equilibrium dynamics. These systems' exquisite isolation from environmental perturbations leads to long relaxation times that enable exploration of far-from-equilibrium phenomena. We present progress towards trapping chains of multiple co-trapped calcium isotopes geared towards measuring thermal equilibration and sympathetic cooling rates. We also discuss plans for future experiments in non-equilibrium statistical mechanics, including exploration of the quantum-to-classical crossover between ballistic transport and diffusive, Fourier's Law conduction. This work is supported by Cottrell College Science Award from the Research Corporation for Science Advancement and by Williams College.

  15. Frontier of plasma physics. 'Research network on non-equilibrium and extreme state plasmas'

    International Nuclear Information System (INIS)

    Itoh, Sanae-I.; Fujisawa, Akihide; Kodama, Ryosuke; Sato, Motoyasu; Tanaka, Kazuo A.; Hatakeyama, Rikizo; Itoh, Kimitaka

    2011-01-01

    Plasma physics and fusion science have been applied to a wide variety of plasmas such as nuclear fusion plasmas, high-energy-density plasmas, processing plasmas and nanobio- plasmas. They are pioneering science and technology frontiers such as new energy sources and new functional materials. A large project 'research network on non-equilibrium and extreme state plasmas' is being proposed to reassess individual plasma researches from a common view of the non-equilibrium extreme plasma and to promote collaboration among plasma researchers all over the country. In the present review, recent collaborative works related to this project are being introduced. (T.I.)

  16. One-loop calculation in time-dependent non-equilibrium thermo field dynamics

    International Nuclear Information System (INIS)

    Umezawa, H.; Yamanaka, Y.

    1989-01-01

    This paper is a review on the structure of thermo field dynamics (TFD) in which the basic concepts such as the thermal doublets, the quasi-particles and the self-consistent renormalization are presented in detail. A strong emphasis is put on the computational scheme. A detailed structure of this scheme is illustrated by the one-loop calculation in a non-equilibrium time-dependent process. A detailed account of the one-loop calculation has never been reported anywhere. The role of the self-consistent renormalization is explained. The equilibrium TFD is obtained as the long-time limit of non-equilibrium TFD. (author)

  17. Wall ablation of heated compound-materials into non-equilibrium discharge plasmas

    Science.gov (United States)

    Wang, Weizong; Kong, Linghan; Geng, Jinyue; Wei, Fuzhi; Xia, Guangqing

    2017-02-01

    The discharge properties of the plasma bulk flow near the surface of heated compound-materials strongly affects the kinetic layer parameters modeled and manifested in the Knudsen layer. This paper extends the widely used two-layer kinetic ablation model to the ablation controlled non-equilibrium discharge due to the fact that the local thermodynamic equilibrium (LTE) approximation is often violated as a result of the interaction between the plasma and solid walls. Modifications to the governing set of equations, to account for this effect, are derived and presented by assuming that the temperature of the electrons deviates from that of the heavy particles. The ablation characteristics of one typical material, polytetrafluoroethylene (PTFE) are calculated with this improved model. The internal degrees of freedom as well as the average particle mass and specific heat ratio of the polyatomic vapor, which strongly depends on the temperature, pressure and plasma non-equilibrium degree and plays a crucial role in the accurate determination of the ablation behavior by this model, are also taken into account. Our assessment showed the significance of including such modifications related to the non-equilibrium effect in the study of vaporization of heated compound materials in ablation controlled arcs. Additionally, a two-temperature magneto-hydrodynamic (MHD) model accounting for the thermal non-equilibrium occurring near the wall surface is developed and applied into an ablation-dominated discharge for an electro-thermal chemical launch device. Special attention is paid to the interaction between the non-equilibrium plasma and the solid propellant surface. Both the mass exchange process caused by the wall ablation and plasma species deposition as well as the associated momentum and energy exchange processes are taken into account. A detailed comparison of the results of the non-equilibrium model with those of an equilibrium model is presented. The non-equilibrium results

  18. Extension of CE/SE method to non-equilibrium dissociating flows

    KAUST Repository

    Wen, C.Y.

    2017-12-08

    In this study, the hypersonic non-equilibrium flows over rounded nose geometries are numerically investigated by a robust conservation element and solution element (CE/SE) code, which is based on hybrid meshes consisting of triangular and quadrilateral elements. The dissociating and recombination chemical reactions as well as the vibrational energy relaxation are taken into account. The stiff source terms are solved by an implicit trapezoidal method of integration. Comparison with laboratory and numerical cases are provided to demonstrate the accuracy and reliability of the present CE/SE code in simulating hypersonic non-equilibrium flows.

  19. Non-Equilibrium Thermodynamic Chemistry and the Composition of the Atmosphere of Mars

    Science.gov (United States)

    Levine, J. S.; Summers, M. E.

    2003-01-01

    A high priority objective of the Mars Exploration Program is to Determine if life exists today (MEPAG Goal I, Objective A). The measurement of gases of biogenic origin may be an approach to detect the presence of microbial life on the surface or subsurface of Mars. Chemical thermodynamic calculations indicate that on both Earth and Mars, certain gases should exist in extremely low concentrations, if at all. Microbial metabolic activity is an important non-equilibrium chemistry process on Earth, and if microbial life exists on Mars, may be an important nonequilibrium chemistry process on Mars. The non-equilibrium chemistry of the atmosphere of Mars is discussed in this paper.

  20. Note: Local thermal conductivities from boundary driven non-equilibrium molecular dynamics simulations

    International Nuclear Information System (INIS)

    Bresme, F.; Armstrong, J.

    2014-01-01

    We report non-equilibrium molecular dynamics simulations of heat transport in models of molecular fluids. We show that the “local” thermal conductivities obtained from non-equilibrium molecular dynamics simulations agree within numerical accuracy with equilibrium Green-Kubo computations. Our results support the local equilibrium hypothesis for transport properties. We show how to use the local dependence of the thermal gradients to quantify the thermal conductivity of molecular fluids for a wide range of thermodynamic states using a single simulation

  1. Non-equilibrium surface tension of the vapour-liquid interface of active Lennard-Jones particles

    Science.gov (United States)

    Paliwal, Siddharth; Prymidis, Vasileios; Filion, Laura; Dijkstra, Marjolein

    2017-08-01

    We study a three-dimensional system of self-propelled Brownian particles interacting via the Lennard-Jones potential. Using Brownian dynamics simulations in an elongated simulation box, we investigate the steady states of vapour-liquid phase coexistence of active Lennard-Jones particles with planar interfaces. We measure the normal and tangential components of the pressure tensor along the direction perpendicular to the interface and verify mechanical equilibrium of the two coexisting phases. In addition, we determine the non-equilibrium interfacial tension by integrating the difference of the normal and tangential components of the pressure tensor and show that the surface tension as a function of strength of particle attractions is well fitted by simple power laws. Finally, we measure the interfacial stiffness using capillary wave theory and the equipartition theorem and find a simple linear relation between surface tension and interfacial stiffness with a proportionality constant characterized by an effective temperature.

  2. Quantum phase transitional patterns of nuclei

    International Nuclear Information System (INIS)

    Dai Lianrong; Wang Lixing; Pan Feng; Zhong Weiwei; Liu Qi

    2013-01-01

    With the framework of Interacting Boson Model (IBM), transitional patterns from the spherical to the axially deformed limit of the IBM with a schematic Hamiltonian are studied by replacing the SU (3) quadrupole-quadrupole term with O (6) cubic interaction. But, we use the two schemes to investigate some energy ratios and B (E2) ratios for different bosons N = 8 and N = 20. The results show that with the increasing of the numbers of bosons, the transitional behaviors can be enhanced; the transitional behaviors are very similar in the two schemes. However, there are some distinctive differences for some quantities across the entire transitional region, such as energy levels and ratios, B (E2) values and ratios, and expectation values of the shape variables. Generally speaking, the transition is smoother and the nuclear shape is less well defined in the new scheme. Then we apply the two schemes to the critical point symmetry candidate, such as 152 Sm, and find the overall fitting quality of the UQ scheme is better than that of the U (5)-SU (3) scheme, especially for the inter-band E2 transitions in 152 Sm. (authors)

  3. Quantum phase transitions in random XY spin chains

    International Nuclear Information System (INIS)

    Bunder, J.E.; McKenzie, R.H.

    2000-01-01

    Full text: The XY spin chain in a transverse field is one of the simplest quantum spin models. It is a reasonable model for heavy fermion materials such as CeCu 6-x Au x . It has two quantum phase transitions: the Ising transition and the anisotropic transition. Quantum phase transitions occur at zero temperature. We are investigating what effect the introduction of randomness has on these quantum phase transitions. Disordered systems which undergo quantum phase transitions can exhibit new universality classes. The universality class of a phase transition is defined by the set of critical exponents. In a random system with quantum phase transitions we can observe Griffiths-McCoy singularities. Such singularities are observed in regions which have no long range order, so they are not classified as critical regions, yet they display phenomena normally associated with critical points, such as a diverging susceptibility. Griffiths-McCoy phases are due to rare regions with stronger than! average interactions and may be present far from the quantum critical point. We show how the random XY spin chain may be mapped onto a random Dirac equation. This allows us to calculate the density of states without making any approximations. From the density of states we can describe the conditions which should allow a Griffiths-McCoy phase. We find that for the Ising transition the dynamic critical exponent, z, is not universal. It is proportional to the disorder strength and inversely proportional to the energy gap, hence z becomes infinite at the critical point where the energy gap vanishes

  4. Pressure-induced phase transition in a ternary microemulsion system

    International Nuclear Information System (INIS)

    Nagao, Michihiro; Seto, Hideki

    2002-01-01

    Static and dynamic structure of a ternary microemulsion system including AOT (Aerosol-OT; dioctyl sulfosuccinate sodium salt) were investigated in order to clarify the mechanism of the structural phase transition induced by pressure. From the static measurement by means of small-angle x-ray and neutron scattering (SAXS and SANS), it was observed that the dense water-in-oil droplet structure at ambient temperature and pressure transformed to two-phase coexistence with the lamellar phase and the bicontinuous phase with increasing pressure as the case of increasing temperature. The characteristic features of pressure-induced phase transition were quite similar to the temperature-induced one below the phase transition temperature and pressure, however, above the transition temperature and pressure, they were different. From the dynamical measurement by means of the neutron spin echo (NSE), membrane dynamics at high-pressure phase was observed completely different from the high temperature phase. The result showed that with increasing temperature the membrane became flexible and, on the other hand, it became rigid with increasing pressure. These differences suggested the different mechanism of the pressure-induced phase transition from the temperature-induced one. (author)

  5. Enhanced configurational sampling with hybrid non-equilibrium molecular dynamics-Monte Carlo propagator

    Science.gov (United States)

    Suh, Donghyuk; Radak, Brian K.; Chipot, Christophe; Roux, Benoît

    2018-01-01

    Molecular dynamics (MD) trajectories based on classical equations of motion can be used to sample the configurational space of complex molecular systems. However, brute-force MD often converges slowly due to the ruggedness of the underlying potential energy surface. Several schemes have been proposed to address this problem by effectively smoothing the potential energy surface. However, in order to recover the proper Boltzmann equilibrium probability distribution, these approaches must then rely on statistical reweighting techniques or generate the simulations within a Hamiltonian tempering replica-exchange scheme. The present work puts forth a novel hybrid sampling propagator combining Metropolis-Hastings Monte Carlo (MC) with proposed moves generated by non-equilibrium MD (neMD). This hybrid neMD-MC propagator comprises three elementary elements: (i) an atomic system is dynamically propagated for some period of time using standard equilibrium MD on the correct potential energy surface; (ii) the system is then propagated for a brief period of time during what is referred to as a "boosting phase," via a time-dependent Hamiltonian that is evolved toward the perturbed potential energy surface and then back to the correct potential energy surface; (iii) the resulting configuration at the end of the neMD trajectory is then accepted or rejected according to a Metropolis criterion before returning to step 1. A symmetric two-end momentum reversal prescription is used at the end of the neMD trajectories to guarantee that the hybrid neMD-MC sampling propagator obeys microscopic detailed balance and rigorously yields the equilibrium Boltzmann distribution. The hybrid neMD-MC sampling propagator is designed and implemented to enhance the sampling by relying on the accelerated MD and solute tempering schemes. It is also combined with the adaptive biased force sampling algorithm to examine. Illustrative tests with specific biomolecular systems indicate that the method can yield

  6. QCD phase transition in Brans-Dicke cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Atazadeh, K. [Shahid Beheshti University G. C., Evin, Department of Physics, Tehran (Iran, Islamic Republic of)

    2011-04-15

    In the standard picture of cosmology, when the universe was about 10 {mu}sec old it underwent a transition from quark phase to hadron one, being associated with a chiral symmetry breaking after the electro weak transition. We assume that this transition was of crossover and study the evolution of the Universe in the context of Brans-Dicke theory. The evolution of physical quantities relevant to the physical description of the early Universe, namely, the energy density, temperature and the scale factor, are studied within an effective model of lattice QCD for high temperature and also we consider in the context of hadronic resonance gas model those parameters at low temperature. We show that for different values of Brans-Dicke coupling, {omega}, a phase transition occurs and results in decreasing of the effective temperature of the quark-gluon plasma during the process of quark-hadron phase transition. (orig.)

  7. Research for the energy turnaround. Phase transitions actively shape. Contributions

    International Nuclear Information System (INIS)

    Szczepanski, Petra; Wunschick, Franziska; Martin, Niklas

    2015-01-01

    The Annual Conference 2014 of the Renewable Energy Research Association was held in Berlin on 6 and 7 November 2014. This book documents the contributions of the conference on research for the energy turnaround, phase transitions actively shape. After an introduction and two contributions to the political framework, the contributions to the economic phases of the energy transition, the phase of the current turn, the phases of social energy revolution, the stages of heat turnaround (Waermewende), and the stages of the mobility turn deal with the stages of development of the energy system. Finally, the Research Association Renewable Energy is briefly presented. [de

  8. Electroweak phase transition in a model with gauged lepton number

    International Nuclear Information System (INIS)

    Aranda, Alfredo; Jiménez, Enrique; Vaquera-Araujo, Carlos A.

    2015-01-01

    In this work we study the electroweak phase transition in a model with gauged lepton number. Here, a family of vector-like leptons is required in order to cancel the gauge anomalies. Furthermore, these leptons can play an important role in the transition process. We find that this framework is able to provide a strong transition, but only for a very limited number of cases.

  9. A framework for modelling gene regulation which accommodates non-equilibrium mechanisms.

    Science.gov (United States)

    Ahsendorf, Tobias; Wong, Felix; Eils, Roland; Gunawardena, Jeremy

    2014-12-05

    Gene regulation has, for the most part, been quantitatively analysed by assuming that regulatory mechanisms operate at thermodynamic equilibrium. This formalism was originally developed to analyse the binding and unbinding of transcription factors from naked DNA in eubacteria. Although widely used, it has made it difficult to understand the role of energy-dissipating, epigenetic mechanisms, such as DNA methylation, nucleosome remodelling and post-translational modification of histones and co-regulators, which act together with transcription factors to regulate gene expression in eukaryotes. Here, we introduce a graph-based framework that can accommodate non-equilibrium mechanisms. A gene-regulatory system is described as a graph, which specifies the DNA microstates (vertices), the transitions between microstates (edges) and the transition rates (edge labels). The graph yields a stochastic master equation for how microstate probabilities change over time. We show that this framework has broad scope by providing new insights into three very different ad hoc models, of steroid-hormone responsive genes, of inherently bounded chromatin domains and of the yeast PHO5 gene. We find, moreover, surprising complexity in the regulation of PHO5, which has not yet been experimentally explored, and we show that this complexity is an inherent feature of being away from equilibrium. At equilibrium, microstate probabilities do not depend on how a microstate is reached but, away from equilibrium, each path to a microstate can contribute to its steady-state probability. Systems that are far from equilibrium thereby become dependent on history and the resulting complexity is a fundamental challenge. To begin addressing this, we introduce a graph-based concept of independence, which can be applied to sub-systems that are far from equilibrium, and prove that history-dependent complexity can be circumvented when sub-systems operate independently. As epigenomic data become increasingly

  10. Phase transition of bismuth telluride thin films grown by MBE

    DEFF Research Database (Denmark)

    Fülöp, Attila; Song, Yuxin; Charpentier, Sophie

    2014-01-01

    A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formation...

  11. Phase transition in L-alaninium oxalate by photoacoustics

    Indian Academy of Sciences (India)

    Phase transition in L-alaninium oxalate is studied by using TG, DTA and photoacoustic spectroscopy. A sharp transition at 378 K by photoacoustics is observed whereas at the same temperature the endothermic energy change observed by TG and DTA is not very sharp. This is discussed in detail with reference to the other ...

  12. Phase transitions, interfacial fluctuations and hidden symmetries for ...

    Indian Academy of Sciences (India)

    Fluids adsorbed at micro-patterned and geometrically structured substrates can exhibit novel phase transitions and interfacial fluctuation effects distinct from those characteristic of wetting at planar, homogeneous walls. We review recent theoretical progress in this area paying particular attention to filling transitions pertinent ...

  13. Quantum Shape-Phase Transitions in Finite Nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.

    2007-01-01

    Quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Critical-point Hamiltonians for first- and second-order transitions are identified by resolving them into intrinsic and collective parts. Suitable wave functions and finite-N estimates for observables at the critical-points are derived

  14. Quantum Shape-Phase Transitions in Finite Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2007-05-15

    Quantum shape-phase transitions in finite nuclei are considered in the framework of the interacting boson model. Critical-point Hamiltonians for first- and second-order transitions are identified by resolving them into intrinsic and collective parts. Suitable wave functions and finite-N estimates for observables at the critical-points are derived.

  15. The QCD phase transitions: From mechanism to observables

    Energy Technology Data Exchange (ETDEWEB)

    Shuryak, E.V.

    1997-09-22

    This paper contains viewgraphs on quantum chromodynamic phase transformations during heavy ion collisions. Some topics briefly described are: finite T transitions of I molecule pairs; finite density transitions of diquarks polymers; and the softtest point of the equation of state as a source of discontinuous behavior as a function of collision energy or centrality.

  16. Signals of a phase transition in nuclear breakup

    International Nuclear Information System (INIS)

    Campi, X.

    1987-01-01

    We show that nuclei break up like finite systems that exhibit a clean phase transition in infinite size. This is done by studying conditional moments of the fragment multiplicities, the largest fragment size produced by event and its fluctuations. The nature of this smooth phase transition cannot be determined from the available experimental data. The ''critical point'' is reached when the energy deposited in the nucleus is 90% of its binding energy

  17. Baryogenesis via leptonic CP-violating phase transition

    Science.gov (United States)

    Pascoli, Silvia; Turner, Jessica; Zhou, Ye-Ling

    2018-05-01

    We propose a new mechanism to generate a lepton asymmetry based on the vacuum CP-violating phase transition (CPPT). This approach differs from classical thermal leptogenesis as a specific seesaw model, and its UV completion, need not be specified. The lepton asymmetry is generated via the dynamically realised coupling of the Weinberg operator during the phase transition. This mechanism provides a connection with low-energy neutrino observables.

  18. Partial dynamical symmetry at critical points of quantum phase transitions.

    Science.gov (United States)

    Leviatan, A

    2007-06-15

    We show that partial dynamical symmetries can occur at critical points of quantum phase transitions, in which case underlying competing symmetries are conserved exactly by a subset of states, and mix strongly in other states. Several types of partial dynamical symmetries are demonstrated with the example of critical-point Hamiltonians for first- and second-order transitions in the framework of the interacting boson model, whose dynamical symmetries correspond to different shape phases in nuclei.

  19. Partial Dynamical Symmetry at Critical Points of Quantum Phase Transitions

    International Nuclear Information System (INIS)

    Leviatan, A.

    2007-01-01

    We show that partial dynamical symmetries can occur at critical points of quantum phase transitions, in which case underlying competing symmetries are conserved exactly by a subset of states, and mix strongly in other states. Several types of partial dynamical symmetries are demonstrated with the example of critical-point Hamiltonians for first- and second-order transitions in the framework of the interacting boson model, whose dynamical symmetries correspond to different shape phases in nuclei

  20. Hadronization during quark-gluon plasma phase transition

    International Nuclear Information System (INIS)

    Mohanty, A.K.; Kataria, S.K.

    1996-01-01

    The hadron multiplicity distributions and factorial moments are studied in the framework of Landau theory of phase transitions. The factorial moments show a scaling law with a scaling exponent ν which characterizes the intermittency properties of the hadron phase for T c (or T t ) where T c (or T t ) is the transition temperature for second (or first) order transition. The scaling exponent ν is weakly dependent on the free energy parameters as well as on temperature. It is shown that ν remains practically constant in the hadron phase for which T c or T t whether the transition is second order or first order of second kind where the free energy expansion includes cubic term. This universality in the scaling exponent is also maintained above T c over a wide range of temperature even if the transition is strongly first order of first kind where the free energy expansion has only even order coefficients, except around the critical temperature T t where T t approx-gt T c . Therefore, the scaling exponent ν is rather more universal and only indicates the presence of a possible phase transition. It is further shown that the hadron multiplicity distribution is quite sensitive to the free energy parameters. The study of hadron multiplicity distribution at various resolution or bin size reveals more information about the dynamics of the phase transition. The calculated hadron multiplicity distributions are also compared with the negative binomial distribution, often used to explain the experimental multiplicity distributions. copyright 1996 The American Physical Society

  1. Jet quenching and gluon to hadron fragmentation function in non-equilibrium QCD at RHIC and LHC

    International Nuclear Information System (INIS)

    Nayak, G.C.

    2017-01-01

    Theoretical understanding of the observed jet quenching measurements at RHIC and LHC is challenging in QCD because it requires understanding of parton to hadron fragmentation function in non-equilibrium QCD. In this paper, by using closed-time path integral formalism, we derive the gauge invariant definition of the gluon to hadron fragmentation function in non-equilibrium QCD which is consistent with factorization theorem in non-equilibrium QCD from first principles.

  2. Liquid-liquid phase transition and glass transition in a monoatomic model system.

    Science.gov (United States)

    Xu, Limei; Buldyrev, Sergey V; Giovambattista, Nicolas; Stanley, H Eugene

    2010-01-01

    We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

  3. Modelling non-equilibrium thermodynamic systems from the speed-gradient principle.

    Science.gov (United States)

    Khantuleva, Tatiana A; Shalymov, Dmitry S

    2017-03-06

    The application of the speed-gradient (SG) principle to the non-equilibrium distribution systems far away from thermodynamic equilibrium is investigated. The options for applying the SG principle to describe the non-equilibrium transport processes in real-world environments are discussed. Investigation of a non-equilibrium system's evolution at different scale levels via the SG principle allows for a fresh look at the thermodynamics problems associated with the behaviour of the system entropy. Generalized dynamic equations for finite and infinite number of constraints are proposed. It is shown that the stationary solution to the equations, resulting from the SG principle, entirely coincides with the locally equilibrium distribution function obtained by Zubarev. A new approach to describe time evolution of systems far from equilibrium is proposed based on application of the SG principle at the intermediate scale level of the system's internal structure. The problem of the high-rate shear flow of viscous fluid near the rigid plane plate is discussed. It is shown that the SG principle allows closed mathematical models of non-equilibrium processes to be constructed.This article is part of the themed issue 'Horizons of cybernetical physics'. © 2017 The Author(s).

  4. Leaching from MSWI bottom ash: Evaluation of non-equilibrium in column percolation experiments

    DEFF Research Database (Denmark)

    Hyks, Jiri; Astrup, Thomas; Christensen, Thomas Højlund

    2009-01-01

    -equilibrium-induced changes in the solubility control. Despite both physical and chemical non-equilibrium, the Columns were found to provide adequate information for readily soluble compounds (i.e., Na, Cl-, and K) and solubility-controlled elements (i.e., Ca, SO42-, Ba, Si, Al, Zn, and Pb). The leaching Of Cu and Ni...

  5. Lyapunov Functions, Stationary Distributions, and Non-equilibrium Potential for Reaction Networks

    DEFF Research Database (Denmark)

    Anderson, David F; Craciun, Gheorghe; Gopalkrishnan, Manoj

    2015-01-01

    We consider the relationship between stationary distributions for stochastic models of reaction systems and Lyapunov functions for their deterministic counterparts. Specifically, we derive the well-known Lyapunov function of reaction network theory as a scaling limit of the non-equilibrium potent...

  6. Non-equilibrium reacting gas flows kinetic theory of transport and relaxation processes

    CERN Document Server

    Nagnibeda, Ekaterina; Nagnibeda, Ekaterina

    2009-01-01

    This volume develops the kinetic theory of transport phenomena and relaxation processes in the flows of reacting gas mixtures. The theory is applied to the modeling of non-equilibrium flows behind strong shock waves, in the boundary layer, and in nozzles.

  7. Thermodynamics of Growth, Non-Equilibrium Thermodynamics of Bacterial Growth : The Phenomenological and the Mosaic Approach

    NARCIS (Netherlands)

    Westerhoff, Hans V.; Lolkema, Juke S.; Otto, Roel; Hellingwerf, K

    1982-01-01

    Microbial growth is analyzed in terms of mosaic and phenomenological non-equilibrium thermodynamics. It turns out that already existing parameters devised to measure bacterial growth, such as YATP, µ, and Qsubstrate, have as thermodynamic equivalents flow ratio, output flow and input flow. With this

  8. The Matrix model, a driven state variables approach to non-equilibrium thermodynamics

    NARCIS (Netherlands)

    Jongschaap, R.J.J.

    2001-01-01

    One of the new approaches in non-equilibrium thermodynamics is the so-called matrix model of Jongschaap. In this paper some features of this model are discussed. We indicate the differences with the more common approach based upon internal variables and the more sophisticated Hamiltonian and GENERIC

  9. Present and Future Experiments in Non-equilibrium Reactor Antineutrino Energy Spectrum

    OpenAIRE

    Kopeikin, V. I.; Mikaelyan, L. A.

    2005-01-01

    Considerable efforts that have been undertaken in the recent years in low energy antineutrino experiments require further systematic investigations in line of reactor antineutrino spectroscopy as a metrological basis of these experiments. We consider some effects associated with the non-equilibrium of reactor antineutrino radiation and residual antineutrino emission from spent reactor fuel in contemporary antineutrino experiments.

  10. Improvements on non-equilibrium and transport Green function techniques: The next-generation TRANSIESTA

    DEFF Research Database (Denmark)

    Papior, Nick Rübner; Lorente, Nicolás; Frederiksen, Thomas

    2017-01-01

    We present novel methods implemented within the non-equilibrium Green function code (NEGF) TRANSIESTA based on density functional theory (DFT). Our flexible, next-generation DFT–NEGF code handles devices with one or multiple electrodes (Ne≥1) with individual chemical potentials and electronic tem...

  11. Non-equilibrium between ions and electrons inside hot spots from National Ignition Facility experiments

    Directory of Open Access Journals (Sweden)

    Zhengfeng Fan

    2017-01-01

    Full Text Available The non-equilibrium between ions and electrons in the hot spot can relax the ignition conditions in inertial confinement fusion [Fan et al., Phys. Plasmas 23, 010703 (2016], and obvious ion-electron non-equilibrium could be observed by our simulations of high-foot implosions when the ion-electron relaxation is enlarged by a factor of 2. On the other hand, in many shots of high-foot implosions on the National Ignition Facility, the observed X-ray enhancement factors due to ablator mixing into the hot spot are less than unity assuming electrons and ions have the same temperature [Meezan et al., Phys. Plasmas 22, 062703 (2015], which is not self-consistent because it can lead to negative ablator mixing into the hot spot. Actually, this non-consistency implies ion-electron non-equilibrium within the hot spot. From our study, we can infer that ion-electron non-equilibrium exists in high-foot implosions and the ion temperature could be ∼9% larger than the equilibrium temperature in some NIF shots.

  12. Mean flow structure of non-equilibrium boundary layers with adverse ...

    Indian Academy of Sciences (India)

    Marušic and Perry for non-equilibrium adverse pressure gradient layers. It is observed that structure of turbulence for this flow is well-described by these two laws. From the known structure of turbulence eddy viscosity for the flow under consideration is calculated. Self similarity in eddy viscosity is observed in the wall region.

  13. On radial stationary solutions to a model of non-equilibrium growth

    Czech Academy of Sciences Publication Activity Database

    Escudero, C.; Hakl, Robert; Peral, I.; Torres, P.J.

    2013-01-01

    Roč. 24, č. 3 (2013), s. 437-453 ISSN 0956-7925 Institutional support: RVO:67985840 Keywords : non-equilibrium growth * radial solutions * variational methods Subject RIV: BA - General Mathematics Impact factor: 1.081, year: 2013 http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8897362

  14. Stochastic pumping of non-equilibrium steady-states: how molecules adapt to a fluctuating environment.

    Science.gov (United States)

    Astumian, R D

    2018-01-11

    In the absence of input energy, a chemical reaction in a closed system ineluctably relaxes toward an equilibrium state governed by a Boltzmann distribution. The addition of a catalyst to the system provides a way for more rapid equilibration toward this distribution, but the catalyst can never, in and of itself, drive the system away from equilibrium. In the presence of external fluctuations, however, a macromolecular catalyst (e.g., an enzyme) can absorb energy and drive the formation of a steady state between reactant and product that is not determined solely by their relative energies. Due to the ubiquity of non-equilibrium steady states in living systems, the development of a theory for the effects of external fluctuations on chemical systems has been a longstanding focus of non-equilibrium thermodynamics. The theory of stochastic pumping has provided insight into how a non-equilibrium steady-state can be formed and maintained in the presence of dissipation and kinetic asymmetry. This effort has been greatly enhanced by a confluence of experimental and theoretical work on synthetic molecular machines designed explicitly to harness external energy to drive non-equilibrium transport and self-assembly.

  15. Non-equilibrium effects in copper vapor laser pumped Nd 3+doped ...

    Indian Academy of Sciences (India)

    Photoacoustic (PA) spectra, observed under CVL pump condition had shown that the CVL induced changes were not due to photoinduced valence change, and that the CVL pumping creates highly favorable conditions for non-equilibrium population distribution in the excited electronic states. The complete disappearance ...

  16. Non-equilibrium dynamics of single polymer adsorption to solid surfaces

    NARCIS (Netherlands)

    Panja, D.; Barkema, G.T.; Kolomeisky, A.B.

    2009-01-01

    The adsorption of polymers to surfaces is crucial for understanding many fundamental processes in nature. Recent experimental studies indicate that the adsorption dynamics is dominated by non-equilibrium effects. We investigate the adsorption of a single polymer of length N to a planar solid surface

  17. Phase transitions and critical behaviour for charged black holes

    International Nuclear Information System (INIS)

    Carlip, S; Vaidya, S

    2003-01-01

    We investigate the thermodynamics of a four-dimensional charged black hole in a finite cavity in asymptotically flat and asymptotically de Sitter spaces. In each case, we find a Hawking-Page-like phase transition between a black hole and a thermal gas very much like the known transition in asymptotically anti-de Sitter space. For a 'supercooled' black hole - a thermodynamically unstable black hole below the critical temperature for the Hawking-Page phase transition - the phase diagram has a line of first-order phase transitions that terminates in a second-order point. For the asymptotically flat case, we calculate the critical exponents at the second-order phase transition and find that they exactly match the known results for a charged black hole in anti-de Sitter space. We find strong evidence for similar phase transitions for the de Sitter black hole as well. Thus many of the thermodynamic features of charged anti-de Sitter black holes do not really depend on asymptotically anti-de Sitter boundary conditions; the thermodynamics of charged black holes is surprisingly universal

  18. Problem-solving phase transitions during team collaboration

    DEFF Research Database (Denmark)

    Wiltshire, Travis; Butner, Jonathan E.; Fiore, Stephen M.

    2017-01-01

    ) with dynamical systems theory suggesting that when a system is undergoing a phase transition it should exhibit a peak in entropy and that entropy levels should also relate to team performance. Communications from 40 teams that collaborated on a complex problem were coded for occurrence of problem......-solving processes. We applied a sliding window entropy technique to each team's communications and specified criteria for (a) identifying data points that qualify as peaks and (b) determining which peaks were robust. We used multilevel modeling, and provide a qualitative example, to evaluate whether phases exhibit...... phases. Peaks in entropy thus corresponded to qualitative shifts in teams’ CPS communications, providing empirical evidence that teams exhibit phase transitions during CPS. Also, lower average levels of entropy at the phase transition points predicted better CPS performance. We specify future directions...

  19. Entropy and baryon number conservation in the deconfinement phase transition

    International Nuclear Information System (INIS)

    Leonidov, A.; Redlich, K.; Satz, H.; Suhonen, E.; Weber, G.

    1994-01-01

    The conservation of entropy and baryon number in the deconfinement phase transition is studied in the framework of the bag model. In the standard construction of the equilibrium phase transition from a quark-gluon plasma into a hadron gas a subsequent dilution and reheating of the system on the phase boundary is necessary to preserve the entropy and baryon number conservation. We propose modifying the bag pressure to depend explicitly on temperature and baryon chemical potential. It is shown that this modification is sufficient to construct a model in agreement with the Gibbs equilibrium criteria for a phase transition, while simultaneously assuring entropy and baryon number conservation on the phase boundary. Within this model the quark-gluon plasma hadronizes at a fixed temperature and chemical potential

  20. Continuum model of non-equilibrium solvation and solvent effect on ultra-fast processes

    International Nuclear Information System (INIS)

    Li Xiangyuan; Fu Kexiang; Zhu Quan

    2006-01-01

    In the past 50 years, non-equilibrium solvation theory for ultra-fast processes such as electron transfer and light absorption/emission has attracted particular interest. A great deal of research efforts was made in this area and various models which give reasonable qualitative descriptions for such as solvent reorganization energy in electron transfer and spectral shift in solution, were developed within the framework of continuous medium theory. In a series of publications by the authors, we clarified that the expression of the non-equilibrium electrostatic free energy that is at the dominant position of non-equilibrium solvation and serves as the basis of various models, however, was incorrectly formulated. In this work, the authors argue that reversible charging work integration was inappropriately applied in the past to an irreversible path linking the equilibrium or the non-equilibrium state. Because the step from the equilibrium state to the nonequilibrium state is factually thermodynamically irreversible, the conventional expression for non-equilibrium free energy that was deduced in different ways is unreasonable. Here the authors derive the non-equilibrium free energy to a quite different form according to Jackson integral formula. Such a difference throws doubts to the models including the famous Marcus two-sphere model for solvent reorganization energy of electron transfer and the Lippert-Mataga equation for spectral shift. By introducing the concept of 'spring energy' arising from medium polarizations, the energy constitution of the non-equilibrium state is highlighted. For a solute-solvent system, the authors separate the total electrostatic energy into different components: the self-energies of solute charge and polarized charge, the interaction energy between them and the 'spring energy' of the solvent polarization. With detailed reasoning and derivation, our formula for non-equilibrium free energy can be reached through different ways. Based on the

  1. Density Functional Theory for Phase-Ordering Transitions

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jianzhong [Univ. of California, Riverside, CA (United States)

    2016-03-30

    Colloids display astonishing structural and dynamic properties that can be dramatically altered by modest changes in the solution condition or an external field. This complex behavior stems from a subtle balance of colloidal forces and intriguing mesoscopic and macroscopic phase transitions that are sensitive to the processing conditions and the dispersing environment. Whereas the knowledge on the microscopic structure and phase behavior of colloidal systems at equilibrium is now well-advanced, quantitative predictions of the dynamic properties and the kinetics of phase-ordering transitions in colloids are not always realized. Many important mesoscopic and off-equilibrium colloidal states remain poorly understood. The proposed research aims to develop a new, unifying approach to describe colloidal dynamics and the kinetics of phase-ordering transitions based on accomplishments from previous work for the equilibrium properties of both uniform and inhomogeneous systems and on novel concepts from the state-of-the-art dynamic density functional theory. In addition to theoretical developments, computational research is designed to address a number of fundamental questions on phase-ordering transitions in colloids, in particular those pertinent to a competition of the dynamic pathways leading to various mesoscopic structures, off-equilibrium states, and crystalline phases. By providing a generic theoretical framework to describe equilibrium, metastable as well as non-ergodic phase transitions concurrent with the colloidal self-assembly processes, accomplishments from this work will have major impacts on both fundamental research and technological applications.

  2. Polymer Semiflexibility Induces Nonuniversal Phase Transitions in Diblock Copolymers

    Science.gov (United States)

    Mao, Shifan; MacPherson, Quinn; Spakowitz, Andrew J.

    2018-02-01

    The order-disorder phase transition and the associated phase diagrams of semiflexible diblock copolymers are investigated using the wormlike chain model, incorporating concentration fluctuations. The free energy up to quartic order in concentration fluctuations is developed with chain-rigidity-dependent coefficients, evaluated using our exact results for the wormlike chain model, and a one-loop renormalization treatment is used to account for fluctuation effects. The chain length N and the monomer aspect ratio α directly control the strength of immiscibility (defined by the Flory-Huggins parameter χ ) at the order-disorder transition and the resulting microstructures at different chemical compositions fA. When monomers are infinitely thin (i.e., large aspect ratio α ), the finite chain length N lowers the χ N at the phase transition. However, fluctuation effects become important when chains have a finite radius, and a decrease in the chain length N elevates the χ N at the phase transition. Phase diagrams of diblock copolymers over a wide range of N and α are calculated based on our fluctuation theory. We find that both finite N and α enhance the stability of the lamellar phase above the order-disorder transition. Our results demonstrate that polymer semiflexibility plays a dramatic role in the phase behavior, even for large chain lengths (e.g., N ≈100 ).

  3. Analysis of non-equilibrium phenomena in inductively coupled plasma generators

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Panesi, M., E-mail: mpanesi@illinois.edu [University of Illinois at Urbana-Champaign, Urbana, Illinois 61822 (United States); Lani, A. [Von Karman Institute for Fluid Dynamics, Rhode-Saint-Genèse (Belgium)

    2016-07-15

    This work addresses the modeling of non-equilibrium phenomena in inductively coupled plasma discharges. In the proposed computational model, the electromagnetic induction equation is solved together with the set of Navier-Stokes equations in order to compute the electromagnetic and flow fields, accounting for their mutual interaction. Semi-classical statistical thermodynamics is used to determine the plasma thermodynamic properties, while transport properties are obtained from kinetic principles, with the method of Chapman and Enskog. Particle ambipolar diffusive fluxes are found by solving the Stefan-Maxwell equations with a simple iterative method. Two physico-mathematical formulations are used to model the chemical reaction processes: (1) A Local Thermodynamics Equilibrium (LTE) formulation and (2) a thermo-chemical non-equilibrium (TCNEQ) formulation. In the TCNEQ model, thermal non-equilibrium between the translational energy mode of the gas and the vibrational energy mode of individual molecules is accounted for. The electronic states of the chemical species are assumed in equilibrium with the vibrational temperature, whereas the rotational energy mode is assumed to be equilibrated with translation. Three different physical models are used to account for the coupling of chemistry and energy transfer processes. Numerical simulations obtained with the LTE and TCNEQ formulations are used to characterize the extent of non-equilibrium of the flow inside the Plasmatron facility at the von Karman Institute. Each model was tested using different kinetic mechanisms to assess the sensitivity of the results to variations in the reaction parameters. A comparison of temperatures and composition profiles at the outlet of the torch demonstrates that the flow is in non-equilibrium for operating conditions characterized by pressures below 30 000 Pa, frequency 0.37 MHz, input power 80 kW, and mass flow 8 g/s.

  4. Ab initio theory of helix <-> coil phase transition

    DEFF Research Database (Denmark)

    Yakubovich, Alexander V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2008-01-01

    In this paper, we suggest a theoretical method based on the statistical mechanics for treating the alpha-helix random coil transition in alanine polypeptides. We consider this process as a first-order phase transition and develop a theory which is free of model parameters and is based solely...... on fundamental physical principles. It describes essential thermodynamical properties of the system such as heat capacity, the phase transition temperature and others from the analysis of the polypeptide potential energy surface calculated as a function of two dihedral angles, responsible for the polypeptide...

  5. An objective indicator for two-phase flow pattern transition

    International Nuclear Information System (INIS)

    Hervieua, E.; Seleghim, P. Jr.

    1998-01-01

    This work concerns the development of a methodology the objective of which is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. During the first time, the efforts focused on: (1) the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; (2) the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; and (3) the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. During the second time, in order to verify the fundamental assumption, a series of experiments were conducted, the objective of which was to demonstrate the correlation between unstationarity and regime transition. The unstationarity degree was quantified by calculating the Gabor's transform time-frequency covariance of the impedance probe signals. Furthermore, the phenomenology of each transition was characterized by the joint moments and entropy. The results clearly show that the regime transitions are correlated with local time-frequency covariance peaks, which demonstrates that these regime transitions are characterized by a loss of stationarity. Consequently, the time-frequency covariance constitutes an objective two-phase flow regime transition indicator. (orig.)

  6. An objective indicator for two-phase flow pattern transition

    International Nuclear Information System (INIS)

    Hervieu, E.; Seleghim, P. Jr.

    1998-01-01

    This work concerns the development of a methodology which objective is to characterize and diagnose two-phase flow regime transitions. The approach is based on the fundamental assumption that a transition flow is less stationary than a flow with an established regime. In a first time, the efforts focused on: the design and construction of an experimental loop, allowing to reproduce the main horizontal two-phase flow patterns, in a stable and controlled way; the design and construction of an electrical impedance probe, providing an imaged information of the spatial phase distribution in the pipe; the systematic study of the joint time-frequency and time-scale analysis methods, which permitted to define an adequate parameter quantifying the unstationarity degree. In a second time, in order to verify the fundamental assumption, a series of experiments were conducted, which objective was to demonstrate the correlation between unstationarity and regime transition. The unstationarity degree was quantified by calculating the Gabor's transform time-frequency covariance of the impedance probe signals. Furthermore, the phenomenology of each transition was characterized by the joint moments and entropy. The results clearly show that the regime transitions are correlated with local time-frequency covariance peaks, which demonstrates that these regime transitions are characterized by a loss of stationarity. Consequently, the time-frequency covariance constitutes an objective two-phase flow regime transition indicator. (author)

  7. Combining the GW formalism with the polarizable continuum model: A state-specific non-equilibrium approach

    Science.gov (United States)

    Duchemin, Ivan; Jacquemin, Denis; Blase, Xavier

    2016-04-01

    We have implemented the polarizable continuum model within the framework of the many-body Green's function GW formalism for the calculation of electron addition and removal energies in solution. The present formalism includes both ground-state and non-equilibrium polarization effects. In addition, the polarization energies are state-specific, allowing to obtain the bath-induced renormalisation energy of all occupied and virtual energy levels. Our implementation is validated by comparisons with ΔSCF calculations performed at both the density functional theory and coupled-cluster single and double levels for solvated nucleobases. The present study opens the way to GW and Bethe-Salpeter calculations in disordered condensed phases of interest in organic optoelectronics, wet chemistry, and biology.

  8. Combining the GW formalism with the polarizable continuum model: A state-specific non-equilibrium approach

    Energy Technology Data Exchange (ETDEWEB)

    Duchemin, Ivan, E-mail: ivan.duchemin@cea.fr [INAC, SP2M/L-Sim, CEA/UJF Cedex 09, 38054 Grenoble (France); Jacquemin, Denis [Laboratoire CEISAM - UMR CNR 6230, Université de Nantes, 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3 (France); Institut Universitaire de France, 1 rue Descartes, 75005 Paris Cedex 5 (France); Blase, Xavier [CNRS, Inst. NÉEL, F-38000 Grenoble (France); Univ. Grenoble Alpes, Inst. NÉEL, F-38000 Grenoble (France)

    2016-04-28

    We have implemented the polarizable continuum model within the framework of the many-body Green’s function GW formalism for the calculation of electron addition and removal energies in solution. The present formalism includes both ground-state and non-equilibrium polarization effects. In addition, the polarization energies are state-specific, allowing to obtain the bath-induced renormalisation energy of all occupied and virtual energy levels. Our implementation is validated by comparisons with ΔSCF calculations performed at both the density functional theory and coupled-cluster single and double levels for solvated nucleobases. The present study opens the way to GW and Bethe-Salpeter calculations in disordered condensed phases of interest in organic optoelectronics, wet chemistry, and biology.

  9. New numerical method to study phase transitions and its applications

    International Nuclear Information System (INIS)

    Lee, Jooyoung; Kosterlitz, J.M.

    1991-11-01

    We present a powerful method of identifying the nature of transitions by numerical simulation of finite systems. By studying the finite size scaling properties of free energy barrier between competing states, we can identify unambiguously a weak first order transition even when accessible system sizes are L/ξ < 0.05 as in the five state Potts model in two dimensions. When studying a continuous phase transition we obtain quite accurate estimates of critical exponents by treating it as a field driven first order transition. The method has been successfully applied to various systems

  10. On the phase transition nature in compressible Ising models

    International Nuclear Information System (INIS)

    Ota, A.T.

    1985-01-01

    The phase transition phenomenon is analysed in a compressible ferromagnetic Ising model at null field, through the mean-field approximation. The model studied is d-dimensional under the magnetic point of view and one-dimensional under the elastic point of view. This is achieved keeping the compressive interactions among the ions and rejecting annealing forces completely. The exchange parameter J is linear and the elastic potential quadratic in relation to the microscopic shifts of the lattice. In the one-dimensional case, this model shows no phase transition. In the two-dimensional case, the role of the S i spin of the i-the ion is crucial: a) for spin 1/2 the transitions are of second order; b) for spin 1, desides the second order transitions there is a three-critical point and a first-order transitions line. (L.C.) [pt

  11. No Hawking-Page phase transition in three dimensions

    International Nuclear Information System (INIS)

    Myung, Y.S.

    2005-01-01

    We investigate whether or not the Hawking-Page phase transition is possible to occur in three dimensions. Starting with the simplest class of Lanczos-Lovelock action, thermodynamic behavior of all AdS-type black holes without charge falls into two classes: Schwarzschild-AdS black holes in even dimensions and Chern-Simons black holes in odd dimensions. The former class can provide the Hawking-Page transition between Schwarzschild-AdS black holes and thermal AdS space. On the other hand, the latter class is exceptional and thus the Hawking-Page transition is hard to occur. In three dimensions, a second-order phase transition might occur between the non-rotating BTZ black hole and the massless BTZ black hole (thermal AdS space), instead of the first-order Hawking-Page transition between the non-rotating BTZ black hole and thermal AdS space

  12. Signatures of Quantum Phase Transitions via Quantum Information Theoretic Measures

    Science.gov (United States)

    Bose, I.; Tribedi, A.

    Quantum phase transitions (QPTs) in many body systems occur at T = 0 brought about by tuning a non-thermal parameter, e.g. pressure, chemical composition or external magnetic field [1, 2]. In a QPT, the ground state wave function undergoes qualitative changes at the transition point. The transition is driven by quantum fluctuations whereas ordinary phase transitions occurring at nonzero temperatures are driven by thermal fluctuations. Like a thermal phase transition, a QPT can be first order, second order or higher order. The thermal critical point, associated with a second-order phase transition, is characterized by the presence of thermal fluctuations on all length scales resulting in a divergent correlation length. The free energy and the thermodynamic functions develop singularities as temperature Trightarrow T_{textrm{c}} , the critical temperature. At the quantum critical point (QCP), quantum fluctuations occur on all length scales leading to a divergent correlation length. The ground state and related physical quantities become non-analytic as the tuning parameter g tends to the critical value g c . The influence of QPTs extends into the finite T part of the phase diagram so that experimental detection of QPTs is possible.

  13. Complexity and phase transitions in a holographic QCD model

    Science.gov (United States)

    Zhang, Shao-Jun

    2018-04-01

    Applying the "Complexity = Action" conjecture, we study the holographic complexity close to crossover/phase transition in a holographic QCD model proposed by Gubser et al. This model can realize three types of phase transition, crossover or first and second order, depending on the parameters of the dilaton potential. The re-scaled late-time growth rate of holographic complexity density for the three cases is calculated. Our results show that it experiences a fast drop/jump close to the critical point while approaching constants far beyond the critical temperature. Moreover, close to the critical temperature, it shows a behavior characterizing the type of the transition. These features suggest that the growth rate of the holographic complexity may be used as a good parameter to characterize the phase transition. The Lloyd's bound is always satisfied for the cases we considered but only saturated for the conformal case.

  14. Structural phase transitions and topological defects in ion Coulomb crystals

    Energy Technology Data Exchange (ETDEWEB)

    Partner, Heather L. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Nigmatullin, Ramil [Institute of Quantum Physics, Ulm Univ., Ulm (Germany); Burgermeister, Tobias [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Keller, Jonas [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Pyka, Karsten [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany); Plenio, Martin B. [Center for Integrated Quantum Science and Technology, Ulm Univ., Ulm, (Germany):Institute for Theoretical Physics, Ulm Univ.,Ulm, (Germany); Retzker, Alex [Racah Institute of Physics, The Hebrew University of Jerusalem, Givat Ram (Israel); Zurek, Wojciech Hubert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); del Campo, Adolfo [Univ. of Massachusetts, Amherst, MA (United States). Dept. of Physics; Mehlstaubler, Tanja E. [Physikalisch-Technische Bundesanstalt, Braunschweig (Germany)

    2014-11-19

    We use laser-cooled ion Coulomb crystals in the well-controlled environment of a harmonic radiofrequency ion trap to investigate phase transitions and defect formation. Topological defects in ion Coulomb crystals (kinks) have been recently proposed for studies of nonlinear physics with solitons and as carriers of quantum information. Defects form when a symmetry breaking phase transition is crossed non-adiabatically. For a second order phase transition, the Kibble-Zurek mechanism predicts that the formation of these defects follows a power law scaling in the rate of the transition. We demonstrate a scaling of defect density and describe kink dynamics and stability. We further discuss the implementation of mass defects and electric fields as first steps toward controlled kink preparation and manipulation.

  15. The Physics of Phase Transitions Concepts and Applications

    CERN Document Server

    Papon, Pierre; Meijer, Paul H.E

    2006-01-01

    The physics of phase transitions is an important area at the crossroads of several fields that play central roles in materials sciences. In this second edition, new developments had been included which came up in the states of matter physics, in particular in the domain of nanomaterials and atomic Bose-Einstein condensates where progress is accelerating. The presentation of several chapters had been improved by bringing better information on some phase transition mechanisms and by illustrating them with new application examples. This work deals with all classes of phase transitions in fluids and solids. It contains chapters on evaporation, melting, solidification, magnetic transitions, critical phenomena, superconductivity, etc., and is intended for graduate students in physics and engineering; for scientists it will serve both as an introduction and an overview. End-of-chapter problems and complete answers are included.

  16. Phase transitions in nuclear matter and consequences for neutron stars

    International Nuclear Information System (INIS)

    Kaempfer, B.

    1983-04-01

    Estimates of the minimal bombarding energy necessary to reach the quark gluon phase in heavy ion collisions are presented within a hydrodynamical scenario. Further, the consequences of first-order phase transitions from nuclear/neutron matter to pion-condensed matter or quark matter are discussed for neutron stars. (author)

  17. Observation of phase transitions in spreading activation networks.

    Science.gov (United States)

    Shrager, J; Hogg, T; Huberman, B A

    1987-05-29

    Phase transitions, similar to those seen in physical systems, are observed in spreading activation networks. Such networks are used both in theories of cognition and in artificial intelligence applications. This result confirms a predicted abrupt behavioral change as either the topology of the network or the activation parameters are varied across phase boundaries.

  18. Supercooling across first-order phase transitions in vortex matter

    Indian Academy of Sciences (India)

    Abstract. Hysteresis in cycling through first-order phase transitions in vortex matter, akin to the well-studied phenomenon of supercooling of water, has been discussed in literature. Hysteresis can be seen while varying either temperature T or magnetic field H (and thus the density of vortices). Our recent work on phase ...

  19. Chiral phase transitions in quantum chromodynamics at finite ...

    Indian Academy of Sciences (India)

    cedure the phase structure of gauge theories. At finite temperature/density, however, we should seriously ask whether the preceding results [1] of the DS equation analysis on the chiral phase transition could be relied on being the real consequences of thermal gauge theories. This is because in previous analyses the ...

  20. Commensurate-incommensurate phase transition in the deformed crystal

    International Nuclear Information System (INIS)

    Parlinski, K.; Watanabe, Y.; Ohno, K.; Kawazoe, Y.

    1995-01-01

    Using simple orthorhombic microscopic model the commensurate-incommensurate phase transition has been studied. Coupling of the order parameter with spontaneous strain may lead to process which uses the ferroelastic domain walls to introduce the discommensurations to the incommensurate phase. (author). 4 refs, 1 fig

  1. Phase transitions and topological excitations in hypergauge theories

    International Nuclear Information System (INIS)

    Nencka-Ficek, H.

    1985-01-01

    The problems connected with the phase structure of antisymmetric tensor gauge fields are investigated. (s+1)-dimensional hyperloops cannot be constructed in (s+1)-dimensional lattices. This is the cause of a lack of phase transitions in the U(1) theories with fields being sth-kind gauge invariant in the (s+1)-dimensional lattice

  2. The Physics of Weldpool Formation: Phase Transition Process In ...

    African Journals Online (AJOL)

    ... phase transition took place but did not significantly alter the microstructure of the weldment. This study also supports the claims made by different investigators about the different heat treatments given to metals to determine a particular hardenability level. This heat treatment process is an indicator of phase change.

  3. Molecular-dynamics study of propane-hydrate dissociation: Fluctuation-dissipation and non-equilibrium analysis.

    Science.gov (United States)

    Ghaani, Mohammad Reza; English, Niall J

    2018-03-21

    Equilibrium and non-equilibrium molecular-dynamics (MD) simulations have been performed to investigate thermal-driven break-up of planar propane-hydrate interfaces in contact with liquid water over the 260-320 K range. Two types of hydrate-surface water-lattice molecular termination were adopted, at the hydrate edge with water, for comparison: a 001-direct surface cleavage and one with completed cages. Statistically significant differences in melting temperatures and initial break-up rates were observed between both interface types. Dissociation rates were observed to be strongly dependent on temperature, with higher rates at larger over-temperatures vis-à-vis melting. A simple coupled mass and heat transfer model, developed previously, was applied to fit the observed dissociation profiles, and this helps us to identify clearly two distinct hydrate-decomposition régimes; following a highly temperature-dependent break-up phase, a second well-defined stage is essentially independent of temperature, in which the remaining nanoscale, de facto two-dimensional system's lattice framework is intrinsically unstable. Further equilibrium MD-analysis of the two-phase systems at their melting point, with consideration of the relaxation times gleaned from the auto-correlation functions of fluctuations in a number of enclathrated guest molecules, led to statistically significant differences between the two surface-termination cases; a consistent correlation emerged in both cases between the underlying, non-equilibrium, thermal-driven dissociation rates sampled directly from melting with that from an equilibrium-MD fluctuation-dissipation approach.

  4. The crystal structure and the phase transitions of pyridinium trifluoromethanesulfonate

    International Nuclear Information System (INIS)

    Jesariew, Dominik; Ilczyszyn, Maria M; Pietraszko, Adam

    2014-01-01

    The calorimetric and optical studies and the structural properties of pyridinium trifluoromethanesulfonate (abbreviated as PyHOTf) are reported. A sequence of four fully reversible solid–solid phase transitions, at 223.0, 309.0, 359.9 and 394.3 K, has been discovered. The phase transition sequence was confirmed by x-ray diffraction data. The crystal structures of three phases (V, IV and III) have been determined from the single crystal x-ray diffraction data. Structural properties of the high temperature phases are characterized using powder x-ray diffraction data measured in the 290–425 K temperature range. The structural changes triggered by the temperature change are discussed in relation to the phase transitions. Two low temperature phases (V and IV) belong to the P4 3 2 1 2 space group of the tetragonal system. The intermediate phases (III and II) are monoclinic and the prototype high temperature phase (I) is a pseudo-cubic (tetragonal) one. The low temperature phases (V and IV) are well ordered. The crystal structure of intermediate (III and II) and prototype (I) phases are characterized by high disorder of the pyridinium cations and triflate anions. (papers)

  5. Dynamical phase transitions and temporal orthogonality in one-dimensional hard-core bosons: from the continuum to the lattice

    Science.gov (United States)

    Fogarty, Thomás; Usui, Ayaka; Busch, Thomas; Silva, Alessandro; Goold, John

    2017-11-01

    We investigate the dynamics of the rate function and of local observables after a quench in models which exhibit phase transitions between a superfluid and an insulator in their ground states. Zeros of the return probability, corresponding to singularities of the rate functions, have been suggested to indicate the emergence of dynamical criticality and we address the question of whether such zeros can be tied to the dynamics of physically relevant observables and hence order parameters in the systems. For this we first numerically analyze the dynamics of a hard-core boson gas in a one-dimensional waveguide when a quenched lattice potential is commensurate with the particle density. Such a system can undergo a pinning transition to an insulating state and we find non-analytic behavior in the evolution of the rate function which is indicative of dynamical phase transitions. In addition, we perform simulations of the time dependence of the momentum distribution and compare the periodicity of this collapse and revival cycle to that of the non-analyticities in the rate function: the two are found to be closely related only for deep quenches. We then confirm this observation by analytic calculations on a closely related discrete model of hard-core bosons in the presence of a staggered potential and find expressions for the rate function for the quenches. By extraction of the zeros of the survival amplitude we uncover a non-equilibrium timescale for the emergence of non-analyticities and discuss its relationship with the dynamics of the experimentally relevant parity operator.

  6. Phase transitions in biogenic amorphous calcium carbonate.

    Science.gov (United States)

    Gong, Yutao U T; Killian, Christopher E; Olson, Ian C; Appathurai, Narayana P; Amasino, Audra L; Martin, Michael C; Holt, Liam J; Wilt, Fred H; Gilbert, P U P A

    2012-04-17

    Crystalline biominerals do not resemble faceted crystals. Current explanations for this property involve formation via amorphous phases. Using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), here we examine forming spicules in embryos of Strongylocentrotus purpuratus sea urchins, and observe a sequence of three mineral phases: hydrated amorphous calcium carbonate (ACC · H(2)O) → dehydrated amorphous calcium carbonate (ACC) → calcite. Unexpectedly, we find ACC · H(2)O-rich nanoparticles that persist after the surrounding mineral has dehydrated and crystallized. Protein matrix components occluded within the mineral must inhibit ACC · H(2)O dehydration. We devised an in vitro, also using XANES-PEEM, assay to identify spicule proteins that may play a role in stabilizing various mineral phases, and found that the most abundant occluded matrix protein in the sea urchin spicules, SM50, stabilizes ACC · H(2)O in vitro.

  7. Theoretical Predictions of Phase Transitions at Ultra-high Pressures

    Science.gov (United States)

    Boates, Brian

    2013-06-01

    We present ab initio calculations of the high-pressure phase diagrams of important planetary materials such as CO2, MgSiO3, and MgO. For CO2, we predict a series of distinct liquid phases over a wide pressure (P) and temperature (T) range, including a first-order transition to a dense polymer liquid. We have computed finite-temperature free energies of liquid and solid CO2 phases to determine the melting curve beyond existing measurements and investigate possible phase separation transitions. The interaction of these phase boundaries with the mantle geotherm will also be discussed. Furthermore, we find evidence for a vast pressure-temperature regime where molten MgSiO3 decomposes into liquid SiO2 and solid MgO, with a volume change of approximately 1.2 percent. The demixing transition is driven by the crystallization of MgO ? the reaction only occurs below the high-pressure MgO melting curve. The predicted transition pressure at 10,000 K is in close proximity to an anomaly reported in recent laser-driven shock experiments of MgSiO3. We also present new results for the high-pressure melting curve of MgO and its B1-B2 solid phase transition, with a triple point near 364 GPa and 12,000 K.

  8. Quantum phase transitions of a disordered antiferromagnetic topological insulator

    Science.gov (United States)

    Baireuther, P.; Edge, J. M.; Fulga, I. C.; Beenakker, C. W. J.; Tworzydło, J.

    2014-01-01

    We study the effect of electrostatic disorder on the conductivity of a three-dimensional antiferromagnetic insulator (a stack of quantum anomalous Hall layers with staggered magnetization). The phase diagram contains regions where the increase of disorder first causes the appearance of surface conduction (via a topological phase transition), followed by the appearance of bulk conduction (via a metal-insulator transition). The conducting surface states are stabilized by an effective time-reversal symmetry that is broken locally by the disorder but restored on long length scales. A simple self-consistent Born approximation reliably locates the boundaries of this so-called "statistical" topological phase.

  9. High pressure structural phase transition of neodymium mono pnictides

    International Nuclear Information System (INIS)

    Pagare, Gitanjali; Ojha, P.; Sanyal, S.P.; Aynyas, Mahendra

    2007-01-01

    We have investigated theoretically the high-pressure structural phase transition of two neodymium mono NdX (X=As, Sb) using an interionic potential theory with necessary modification to include the effect of Coulomb screening by the delocalized f electrons of Nd ion. These compounds exhibits first order crystallographic phase transition from their NaCl (B 1 ) phase to body centered tetragonal (BCT) at 27 GPa and 15.3 GPa respectively. We also calculated the Nd-Nd distance as a function of pressure. (author)

  10. Shear induced phase transitions induced in edible fats

    Science.gov (United States)

    Mazzanti, Gianfranco; Welch, Sarah E.; Marangoni, Alejandro G.; Sirota, Eric B.; Idziak, Stefan H. J.

    2003-03-01

    The food industry crystallizes fats under different conditions of temperature and shear to obtain products with desired crystalline phases. Milk fat, palm oil, cocoa butter and chocolate were crystallized from the melt in a temperature controlled Couette cell. Synchrotron x-ray diffraction studies were conducted to examine the role of shear on the phase transitions seen in edible fats. The shear forces on the crystals induced acceleration of the alpha to beta-prime phase transition with increasing shear rate in milk fat and palm oil. The increase was slow at low shear rates and became very strong above 360 s-1. In cocoa butter the acceleration between beta-prime-III and beta-V phase transition increased until a maximum of at 360 s-1, and then decreased, showing competition between enhanced heat transfer and viscous heat generation.

  11. Generalized transport model for phase transition with memory

    International Nuclear Information System (INIS)

    Chen, Chi; Ciucci, Francesco

    2013-01-01

    A general model for phenomenological transport in phase transition is derived, which extends Jäckle and Frisch model of phase transition with memory and the Cahn–Hilliard model. In addition to including interfacial energy to account for the presence of interfaces, we introduce viscosity and relaxation contributions, which result from incorporating memory effect into the driving potential. Our simulation results show that even without interfacial energy term, the viscous term can lead to transient diffuse interfaces. From the phase transition induced hysteresis, we discover different energy dissipation mechanism for the interfacial energy and the viscosity effect. In addition, by combining viscosity and interfacial energy, we find that if the former dominates, then the concentration difference across the phase boundary is reduced; conversely, if the interfacial energy is greater then this difference is enlarged.

  12. Magnetism and Microstructure Characterization of Phase Transitions in a Steel

    Directory of Open Access Journals (Sweden)

    M. Güler

    2014-01-01

    Full Text Available We present phase transitions in a low carbon steel according to existing phases and their magnetism. Scanning electron microscope employed research to clarify and evaluate the microstructural details. Additionally, we utilized from Mössbauer spectroscopy for magnetic characteristics of different existed phases. Scanning electron microscope examinations showed that the pure state of the steel was fully in the ferrite phase with equiaxed grains. Moreover, subsequent heat treatments on the studied steel also ensured the first austenite and then pearlite phase formation. Mössbauer spectroscopy of these phases appeared as a paramagnetic single-line absorption peak for the austenite phase and ferromagnetic six-line spectra for both ferrite and pearlite phases. From Mössbauer data, we determined that the internal magnetic fields of ferrite and pearlite phases were as 32.2 Tesla and 31.3 Tesla, respectively.

  13. Non-equilibrium thermodynamics, heat transport and thermal waves in laminar and turbulent superfluid helium

    Science.gov (United States)

    Mongiovì, Maria Stella; Jou, David; Sciacca, Michele

    2018-01-01

    This review paper puts together some results concerning non equilibrium thermodynamics and heat transport properties of superfluid He II. A one-fluid extended model of superfluid helium, which considers heat flux as an additional independent variable, is presented, its microscopic bases are analyzed, and compared with the well known two-fluid model. In laminar situations, the fundamental fields are density, velocity, absolute temperature, and heat flux. Such a theory is able to describe the thermomechanical phenomena, the propagation of two sounds in liquid helium, and of fourth sound in superleak. It also leads in a natural way to a two-fluid model on purely macroscopical grounds and allows a small amount of entropy associated with the superfluid component. Other important features of liquid He II arise in rotating situations and in superfluid turbulence, both characterized by the presence of quantized vortices (thin vortex lines whose circulation is restricted by a quantum condition). Such vortices have a deep influence on the transport properties of superfluid helium, as they increase very much its thermal resistance. Thus, heat flux influences the vortices which, in turn, modify the heat flux. The dynamics of vortex lines is the central topic in turbulent superfluid helium. The model is generalized to take into account the vortices in different cases of physical interest: rotating superfluids, counterflow superfluid turbulence, combined counterflow and rotation, and mass flow in addition to heat flow. To do this, the averaged vortex line density per unit volume L, is introduced and its dynamical equations are considered. Linear and non-linear evolution equations for L are written for homogeneous and inhomogeneous, isotropic and anisotropic situations. Several physical experiments are analyzed and the influence of vortices on the effective thermal conductivity of turbulent superfluid helium is found. Transitions from laminar to turbulent flows, from diffusive to

  14. Effects of single particle on shape phase transitions and phase coexistence in odd-even nuclei

    Science.gov (United States)

    Yu, Xiang-Ru; Hu, Jing; Li, Xiao-Xue; An, Si-Yu; Zhang, Yu

    2018-02-01

    A classical analysis of shape phase transitions and phase coexistence in odd-even nuclei has been performed in the framework of the interacting boson-fermion model. The results indicate that the effects of a single particle may influence different types of transitions in different ways. Especially, it is revealed that phase coexistence can clearly emerge in the critical region and thus be taken as a indicator of the shape phase transitions in odd-even nuclei. Supported by National Natural Science Foundation of China (11375005)

  15. Phase transitions: the lattice QCD approach

    International Nuclear Information System (INIS)

    Gavai, R.V.

    1986-01-01

    Recent results in the field of finite temperature lattice quantum chromodynamics (QCD) are presented with special emphasis on comparison of the different methods used to incorporate the dynamical fermions. Attempts to obtain a nonperturbative estimate of the velocity of sound in both the hadronic and quark-gluon phase are summarized along with the results. 15 refs., 7 figs

  16. Kinetics of silica-phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, C.J.

    1993-07-01

    In addition to the stable silica polymorph quartz, several metastable silica phases are present in Yucca Mountain. The conversion of these phases to quartz is accompanied by volume reduction and a decrease in the aqueous silica activity, which may destabilize clinoptilolite and mordenite. The primary reaction sequence for the silica phases is from opal or glass to disordered opal-CT, followed by ordering of the opal-CT and finally by the crystallization of quartz. The ordering of opal-CT takes place in the solid state, whereas the conversion of opal-CT takes place through dissolution-reprecipitation involving the aqueous phase. It is proposed that the rate of conversion of opal-CT to quartz is controlled by diffusion of defects out of a disordered surface layer formed on the crystallizing quartz. The reaction rates are observed to be dependent on temperature, pressure, degree of supersaturation, and pH. Rate equations selected from the literature appear to be consistent with observations at Yucca Mountain.

  17. Non-equilibrium Thermodynamic Dissolution Theory for Multi-Component Solid/Liquid Surfaces Involving Surface Adsorption and Radiolysis Kinetics

    International Nuclear Information System (INIS)

    Stout, R B

    2001-01-01

    A theoretical expression is developed for the dissolution rate response for multi-component radioactive materials that have surface adsorption kinetics and radiolysis kinetics when wetted by a multi-component aqueous solution. An application for this type of dissolution response is the performance evaluation of multi-component spent nuclear fuels (SNFs) for long term interim storage and for geological disposition. Typically, SNF compositions depend on initial composition, uranium oxide and metal alloys being most common, and on reactor burnup which results in a wide range of fission product and actinide concentrations that decay by alpha, beta, and gamma radiation. These compositional/burnup ranges of SNFs, whether placed in interim storage or emplaced in a geologic repository, will potentially be wetted by multi-component aqueous solutions, and these solutions may be further altered by radiolytic aqueous species due to three radiation fields. The solid states of the SNFs are not thermodynamically stable when wetted and will dissolve, with or without radiolysis. The following development of a dissolution theory is based on a non-equilibrium thermodynamic analysis of energy reactions and energy transport across a solid-liquid phase change discontinuity that propagates at a quasi-steady, dissolution velocity. The integral form of the energy balance equation is used for this spatial surface discontinuity analysis. The integral formulation contains internal energy functional of classical thermodynamics for both the SNFs' solid state and surface adsorption species, and the adjacent liquid state, which includes radiolytic chemical species. The steady-state concentrations of radiolytic chemical species are expressed by an approximate analysis of the decay radiation transport equation. For purposes of illustration a modified Temkin adsorption isotherm was assumed for the surface adsorption kinetics on an arbitrary, finite area of the solid-liquid dissolution interface. For

  18. Study of the phase transition dynamics of the L to H transition

    International Nuclear Information System (INIS)

    Moyer, R.A.; Rhodes, T.L.; Rettig, C.L.

    1997-12-01

    A highly radiating zone (MARFE) just above the divertor X-point has been used to access the marginal transition regime P sep ∼ P thres to study the existence of a critical point for the L to H transition. Phase transition models predict that at the critical point, the transition duration increases and the plasma parameters vary continuously between L-mode and H-mode. In these experiments, the L to H transition duration increased 50--100 times over fast transitions. However, the evolution of E r shear, edge density gradient, H-mode pedestal, and fluctuations is essentially unchanged from that in fast transitions. The only difference is in the speed with which and the degree to which the fluctuation amplitudes are transiently reduced. This difference is understandable in terms of the time scales for fluctuation amplitude reduction (≤ 100 micros) and edge pressure gradient increase (several ms), provided the edge fluctuations are pressure-gradient driven

  19. Quantum Phase Transition and Entanglement in Topological Quantum Wires.

    Science.gov (United States)

    Cho, Jaeyoon; Kim, Kun Woo

    2017-06-05

    We investigate the quantum phase transition of the Su-Schrieffer-Heeger (SSH) model by inspecting the two-site entanglements in the ground state. It is shown that the topological phase transition of the SSH model is signified by a nonanalyticity of local entanglement, which becomes discontinuous for finite even system sizes, and that this nonanalyticity has a topological origin. Such a peculiar singularity has a universal nature in one-dimensional topological phase transitions of noninteracting fermions. We make this clearer by pointing out that an analogous quantity in the Kitaev chain exhibiting the identical nonanalyticity is the local electron density. As a byproduct, we show that there exists a different type of phase transition, whereby the pattern of the two-site entanglements undergoes a sudden change. This transition is characterised solely by quantum information theory and does not accompany the closure of the spectral gap. We analyse the scaling behaviours of the entanglement in the vicinities of the transition points.

  20. Enthalpy of phase transition and prediction of phase Equilibria in systems of glycols and glycol ethers

    OpenAIRE

    Esina, Zoya; Miroshnikov, Aleksandr; Korchuganova, Margarita

    2014-01-01

    The PCEAS model was used to study the liquid-solid and liquid-vapor phase transitions at constant pressure in systems containing glycols and glycol ethers. This method is based on minimizing the excess Gibbs energy over the solvation parameter, which takes into account the processes of association of molecules in various phases. To compute the diagrams, the data on enthalpy and phase transition temperatures of pure components are required, while the information about the interactions in the b...

  1. Antiferrodistortive phase transitions and ground state of PZT ceramics

    International Nuclear Information System (INIS)

    Pandey, Dhananjai

    2013-01-01

    The ground state of the technologically important Pb(Zr x Ti (1-x) )O 3 , commonly known as PZT, ceramics is currently under intense debate. The phase diagram of this material shows a morphotropic phase boundary (MPB) for x∼0.52 at 300K, across which a composition induced structural phase transition occurs leading to maximization of the piezoelectric properties. In search for the true ground state of the PZT in the MPB region, Beatrix Noheda and coworkers first discovered a phase transition from tetragonal (space group P4mm) to an M A type monoclinic phase (space group Cm) at low temperatures for x=0.52. Soon afterwards, we discovered yet another low temperature phase transition for the same composition in which the M A type (Cm) monoclinic phase transforms to another monoclinic phase with Cc space group. We have shown that the Cm to Cc phase transition is an antiferrodistortive (AFD) transition involving tilting of oxygen octahedra leading to unit cell doubling and causing appearance of superlattice reflections which are observable in the electron and neutron diffraction patterns only and not in the XRD patterns, as a result of which Noheda and coworkers missed the Cc phase in their synchrotron XRD studies at low temperatures. Our findings were confirmed by leading groups using neutron, TEM, Raman and high pressure diffraction studies. The first principles calculations also confirmed that the true ground state of PZT in the MPB region has Cc space group. However, in the last couple of years, the Cc space group of the ground state has become controversial with an alternative proposal of R3c as the space group of the ground state phase which is proposed to coexist with the metastable Cm phase. In order to resolve this controversy, we recently revisited the issue using pure PZT and 6% Sr 2+ substituted PZT, the latter samples show larger tilt angle on account of the reduction in the average cationic radius at the Pb 2+ site. Using high wavelength neutrons and high

  2. Ordering phenomena and non-equilibrium properties of lattice gas models

    International Nuclear Information System (INIS)

    Fiig, T.

    1994-03-01

    This report falls within the general field of ordering processes and non-equilibrium properties of lattice gas models. The theory of diffuse scattering of lattice gas models originating from a random distribution of clusters is considered. We obtain relations between the diffuse part of the structure factor S dif (q), the correlation function C(r), and the size distribution of clusters D(n). For a number of distributions we calculate S dif (q) exactly in one dimension, and discuss the possibility for a Lorentzian and a Lorentzian square lineshape to arise. We discuss the two- and three-dimensional oxygen ordering processes in the high T c superconductor YBa 2 Cu 3 O 6+x based on a simple anisotropic lattice gas model. We calculate the structural phase diagram by Monte Carlo simulation and compared the results with experimental data. The structure factor of the oxygen ordering properties has been calculated in both two and three dimensions by Monte Carlo simulation. We report on results obtained from large scale computations on the Connection Machine, which are in excellent agreement with recent neutron diffraction data. In addition we consider the effect of the diffusive motion of metal-ion dopants on the oxygen ordering properties on YBa 2 Cu 3 O 6+x . The stationary properties of metastability in long-range interaction models are studied by application of a constrained transfer matrix (CTM) formalism. The model considered, which exhibits several metastable states, is an extension of the Blume Capel model to include weak long-range interactions. We show, that the decay rate of the metastable states is closely related to the imaginary part of the equilibrium free-energy density obtained from the CTM formalism. We discuss a class of lattice gas model for dissipative transport in the framework of a Langevin description, which is capable of producing power law spectra for the density fluctuations. We compare with numerical results obtained from simulations of a

  3. Generalized Metropolis acceptance criterion for hybrid non-equilibrium molecular dynamics-Monte Carlo simulations.

    Science.gov (United States)

    Chen, Yunjie; Roux, Benoît

    2015-01-14

    A family of hybrid simulation methods that combines the advantages of Monte Carlo (MC) with the strengths of classical molecular dynamics (MD) consists in carrying out short non-equilibrium MD (neMD) trajectories to generate new configurations that are subsequently accepted or rejected via an MC process. In the simplest case where a deterministic dynamic propagator is used to generate the neMD trajectories, the familiar Metropolis acceptance criterion based on the change in the total energy ΔE, min[1, exp{-βΔE}], guarantees that the hybrid algorithm will yield the equilibrium Boltzmann distribution. However, the functional form of the acceptance probability is more complex when the non-equilibrium switching process is generated via a non-deterministic stochastic dissipative propagator coupled to a heat bath. Here, we clarify the conditions under which the Metropolis criterion remains valid to rigorously yield a proper equilibrium Boltzmann distribution within hybrid neMD-MC algorithm.

  4. Development of a Thermo-chemical Non-equilibrium Solver for Hypervelocity Flows

    Science.gov (United States)

    Balasubramanian, R.; Anandhanarayanan, K.

    2015-04-01

    In the present study, a three dimensional flowsolver is indigenously developed to numerically simulate hypervelocity thermal and chemical non equilibrium reactive air flow past flight vehicles. The two-temperature, five species, seventeen reactions, thermo-chemical non equilibrium, non-ionizing, air-chemistry model of Park is implemented in a compressible viscous code CERANS and solved in the finite volume framework. The energy relaxation is addressed by a conservation equation for the vibrational energy of the gas mixture resulting in the evaluation of its vibrational temperature. The AUSM-PW+ numerical flux function has been used for modeling the convective fluxes and a central differencing approximation is used for modeling the diffusive fluxes. The flowsolver had been validated for specifically chosen test cases with inherent flow complexities of non-ionizing hypervelocity thermochemical nonequilibrium flows and results obtained are in good agreement with results available in open literature.

  5. Investigation on non-equilibrium x-ray emission spectra from laser produced plasmas

    International Nuclear Information System (INIS)

    Pei Wenbing; Chang Tieqiang; Zhang Jun

    1995-01-01

    A statistical method for the ion configuration probability distribution in non-LTE plasmas based on the average-ion model is described. In this method, the ion configuration probabilities are obtained from the average level population probabilities of the ions according to the binomial distribution. The non-equilibrium ion configuration distribution and X-ray spectra emitted from Au plasmas produced by 1.06 μm laser are studied. The calculated X-ray emission spectra are in the same energy band range as the experimental results. We discuss the non-equilibrium characteristics of X-ray emission, and show that the contributions of the multiply excited ions to X-ray emission are important

  6. Shear Viscosity of Benzene, Toluene, and p-Xylene by Non-equilibrium Molecular Dynamics Simulations

    International Nuclear Information System (INIS)

    Lee, Song Hi

    2004-01-01

    Green and Kubo showed that the phenomenological coefficients describing many transport processes and time dependent phenomena in general could be written as integrals over a certain type of function called a time correlation function. The Green-Kubo formulas are the formal expressions for hydrodynamic field variables and some of the thermodynamic properties in terms of the microscopic variables of an N-particle system. The identification of microscopic expressions for macroscopic variables is made by a process of comparison of the conservation equations of hydrodynamics with the microscopic equations of change for conserved densities. The importance of these formulas is three-fold: they provide an obvious method for calculating transport coefficients using computer simulation, a convenient starting point for constructing analytic theories for non-equilibrium processes, and an essential information for designing non-equilibrium molecular dynamics (NEMD) algorithm.

  7. Dynamics of unstable sound waves in a non-equilibrium medium at the nonlinear stage

    Science.gov (United States)

    Khrapov, Sergey; Khoperskov, Alexander

    2018-03-01

    A new dispersion equation is obtained for a non-equilibrium medium with an exponential relaxation model of a vibrationally excited gas. We have researched the dependencies of the pump source and the heat removal on the medium thermodynamic parameters. The boundaries of sound waves stability regions in a non-equilibrium gas have been determined. The nonlinear stage of sound waves instability development in a vibrationally excited gas has been investigated within CSPH-TVD and MUSCL numerical schemes using parallel technologies OpenMP-CUDA. We have obtained a good agreement of numerical simulation results with the linear perturbations dynamics at the initial stage of the sound waves growth caused by instability. At the nonlinear stage, the sound waves amplitude reaches the maximum value that leads to the formation of shock waves system.

  8. Optimal response to non-equilibrium disturbances under truncated Burgers-Hopf dynamics

    Science.gov (United States)

    Thalabard, Simon; Turkington, Bruce

    2017-04-01

    We model and compute the average response of truncated Burgers-Hopf dynamics to finite perturbations away from the Gibbs equipartition energy spectrum using a dynamical optimization framework recently conceptualized in a series of papers. Non-equilibrium averages are there approximated in terms of geodesic paths in probability space that ‘best-fit’ the Liouvillean dynamics over a family of quasi-equilibrium trial densities. By recasting the geodesic principle as an optimal control problem, we solve numerically for the non-equilibrium responses using an augmented Lagrangian, non-linear conjugate gradient descent method. For moderate perturbations, we find an excellent agreement between the optimal predictions and the direct numerical simulations of the truncated Burgers-Hopf dynamics. In this near-equilibrium regime, we argue that the optimal response theory provides an approximate yet predictive counterpart to fluctuation-dissipation identities.

  9. Non-equilibrium behaviour in coacervate-based protocells under electric-field-induced excitation

    Science.gov (United States)

    Yin, Yudan; Niu, Lin; Zhu, Xiaocui; Zhao, Meiping; Zhang, Zexin; Mann, Stephen; Liang, Dehai

    2016-02-01

    Although numerous strategies are now available to generate rudimentary forms of synthetic cell-like entities, minimal progress has been made in the sustained excitation of artificial protocells under non-equilibrium conditions. Here we demonstrate that the electric field energization of coacervate microdroplets comprising polylysine and short single strands of DNA generates membrane-free protocells with complex, dynamical behaviours. By confining the droplets within a microfluidic channel and applying a range of electric field strengths, we produce protocells that exhibit repetitive cycles of vacuolarization, dynamical fluctuations in size and shape, chaotic growth and fusion, spontaneous ejection and sequestration of matter, directional capture of solute molecules, and pulsed enhancement of enzyme cascade reactions. Our results highlight new opportunities for the study of non-equilibrium phenomena in synthetic protocells, provide a strategy for inducing complex behaviour in electrostatically assembled soft matter microsystems and illustrate how dynamical properties can be activated and sustained in microcompartmentalized media.

  10. Acoustics of permeable heterogeneous materials with local non-equilibrium pressure states

    Science.gov (United States)

    Venegas, Rodolfo; Boutin, Claude

    2018-03-01

    The key idea developed in this work is the enforcement of local non-equilibrium pressure states in permeable materials by means of introducing geometrical and/or material heterogeneities. The two-scale asymptotic method of homogenisation is used to derive the macroscopic equations that describe sound propagation in the investigated class of materials. This allowed us to conclude that, at the leading order, the macroscopic fluid flow is mostly determined by that occurring in the most permeable fluid network. In contrast, the effective compressibility of the saturating fluid is modified by the non-equilibrium pressure states occurring in the different much less permeable local heterogeneities of the materials. The theory is exemplified by introducing an analytical model for the acoustical properties of a perforated microporous matrix with cylindrical microporous inclusions co-axially inserted in the perforations. The experimental validation of the theory is also provided.

  11. Multi-Group Maximum Entropy Model for Translational Non-Equilibrium

    Science.gov (United States)

    Jayaraman, Vegnesh; Liu, Yen; Panesi, Marco

    2017-01-01

    The aim of the current work is to describe a new model for flows in translational non- equilibrium. Starting from the statistical description of a gas proposed by Boltzmann, the model relies on a domain decomposition technique in velocity space. Using the maximum entropy principle, the logarithm of the distribution function in each velocity sub-domain (group) is expressed with a power series in molecular velocity. New governing equations are obtained using the method of weighted residuals by taking the velocity moments of the Boltzmann equation. The model is applied to a spatially homogeneous Boltzmann equation with a Bhatnagar-Gross-Krook1(BGK) model collision operator and the relaxation of an initial non-equilibrium distribution to a Maxwellian is studied using the model. In addition, numerical results obtained using the model for a 1D shock tube problem are also reported.

  12. Theoretical investigation of shock stand-off distance for non-equilibrium flows over spheres

    KAUST Repository

    Shen, Hua

    2018-02-20

    We derived a theoretical solution of the shock stand-off distance for a non-equilibrium flow over spheres based on Wen and Hornung’s solution and Olivier’s solution. Compared with previous approaches, the main advantage of the present approach is allowing an analytic solution without involving any semi-empirical parameter for the whole non-equilibrium flow regimes. The effects of some important physical quantities therefore can be fully revealed via the analytic solution. By combining the current solution with Ideal Dissociating Gas (IDG) model, we investigate the effects of free stream kinetic energy and free stream dissociation level (which can be very different between different facilities) on the shock stand-off distance.

  13. Topological phases and phase transitions in magnets and ice

    NARCIS (Netherlands)

    Keesman, R.

    2017-01-01

    The main focus of this Thesis is the behaviour of two-dimensional materials, namely (anti)-ferromagnetic materials in the first two chapters, which show topological phases, and energetic square ice in the third and fourth chapter. The magnetic materials are of interest in part due to foreseen

  14. Experimental First Order Pairing Phase Transition in Atomic Nuclei

    International Nuclear Information System (INIS)

    Moretto, L G; Larsen, A C; Giacoppo, F; Guttormsen, M; Siem, S

    2015-01-01

    The natural log of experimental nuclear level densities at low energy is linear with energy. This can be interpreted in terms of a nearly 1st order phase transition from a superfluid to an ideal gas of quasi particles. The transition temperature coincides with the BCS critical temperature and yields gap parameters in good agreement with the values extracted from even- odd mass differences from rotational states. This converging evidence supports the relevance of the BCS theory to atomic nuclei

  15. Gravitational radiation from first-order phase transitions

    International Nuclear Information System (INIS)

    Child, Hillary L.; Giblin, John T. Jr.

    2012-01-01

    It is believed that first-order phase transitions at or around the GUT scale will produce high-frequency gravitational radiation. This radiation is a consequence of the collisions and coalescence of multiple bubbles during the transition. We employ high-resolution lattice simulations to numerically evolve a system of bubbles using only scalar fields, track the anisotropic stress during the process and evolve the metric perturbations associated with gravitational radiation. Although the radiation produced during the bubble collisions has previously been estimated, we find that the coalescence phase enhances this radiation even in the absence of a coupled fluid or turbulence. We comment on how these simulations scale and propose that the same enhancement should be found at the Electroweak scale; this modification should make direct detection of a first-order electroweak phase transition easier

  16. Chirality Quantum Phase Transition in Noncommutative Dirac Oscillator

    International Nuclear Information System (INIS)

    Wang Shao-Hua; Hou Yu-Long; Jing Jian; Wang Qing; Long Zheng-Wen

    2014-01-01

    The charged Dirac oscillator on a noncommutative plane coupling to a uniform perpendicular magnetic held is studied in this paper. We map the noncommutative plane to a commutative one by means of Bopp shift and study this problem on the commutative plane. We find that this model can be mapped onto a quantum optics model which contains Anti—Jaynes—Cummings (AJC) or Jaynes—Cummings (JC) interactions when a dimensionless parameter ζ (which is the function of the intensity of the magnetic held) takes values in different regimes. Furthermore, this model behaves as experiencing a chirality quantum phase transition when the dimensionless parameter ζ approaches the critical point. Several evidences of the chirality quantum phase transition are presented. We also study the non-relativistic limit of this model and find that a similar chirality quantum phase transition takes place in its non-relativistic limit. (physics of elementary particles and fields)

  17. Novel phase transitions in B-site doped manganites

    Energy Technology Data Exchange (ETDEWEB)

    Popovic, Z.V. [Institute of Physics, P.O. Box 68, 11080 Belgrade/Zemun (Serbia and Montenegro)]. E-mail: zoran.popovic@phy.bg.ac.yu; Cantarero, A. [Materials Science Institute, University of Valencia, P.O. Box 22085, 46071 Valencia (Spain); Thijssen, W.H.A. [Kamerlingh Onnes Laboratorium, Leiden University, Postbus 9504, 2300 RA Leiden (Netherlands); Paunovic, N. [Institute of Physics, P.O. Box 68, 11080 Belgrade/Zemun (Serbia and Montenegro); Dohcevic-Mitrovic, Z. [Institute of Physics, P.O. Box 68, 11080 Belgrade/Zemun (Serbia and Montenegro); Sapina, F. [Materials Science Institute, University of Valencia, P.O. Box 22085, 46071 Valencia (Spain)

    2005-04-30

    We have examined the infrared reflectivity and the electrical resistivity of La{sub 1-} {sub x} [Sr(Ba)] {sub x} Mn{sub 1-} {sub z} [Cu(Zn)] {sub z} O{sub 3} samples in ferromagnetic metallic and insulator regime. Several phase transitions are observed, the most obvious being the transition from a ferromagnetic metallic to a ferromagnetic insulator phase that is related to the formation of short-range orbitally ordered domains. The temperature T {sub 1} of the phase transition is dependent on doping concentration and for optimally doped samples ({approx}32% of Mn{sup 4+} ions) we have found T {sub 1}{approx}0.93 T {sub C}.

  18. Phase-transition-like behaviour of quantum games

    CERN Document Server

    Du Jiang Feng; Xu Xiao Dong; Zhou Xian Yi; Han Rong Dian

    2003-01-01

    The discontinuous dependence of the properties of a quantum game on its entanglement has been shown to be very much like phase transitions viewed in the entanglement-payoff diagram (J Du et al 2002 Phys. Rev. Lett. 88 137902). In this paper we investigate such phase-transition-like behaviour of quantum games, by suggesting a method which would help to illuminate the origin of such a kind of behaviour. For the particular case of the generalized Prisoners' Dilemma, we find that, for different settings of the numerical values in the payoff table, even though the classical game behaves the same, the quantum game exhibits different and interesting phase-transition-like behaviour.

  19. Phase-transition-like behaviour of quantum games

    International Nuclear Information System (INIS)

    Du Jiangfeng; Li Hui; Xu Xiaodong; Zhou Xianyi; Han Rongdian

    2003-01-01

    The discontinuous dependence of the properties of a quantum game on its entanglement has been shown to be very much like phase transitions viewed in the entanglement-payoff diagram (J Du et al 2002 Phys. Rev. Lett. 88 137902). In this paper we investigate such phase-transition-like behaviour of quantum games, by suggesting a method which would help to illuminate the origin of such a kind of behaviour. For the particular case of the generalized Prisoners' Dilemma, we find that, for different settings of the numerical values in the payoff table, even though the classical game behaves the same, the quantum game exhibits different and interesting phase-transition-like behaviour

  20. A MATLAB GUI to study Ising model phase transition

    Science.gov (United States)

    Thornton, Curtislee; Datta, Trinanjan

    We have created a MATLAB based graphical user interface (GUI) that simulates the single spin flip Metropolis Monte Carlo algorithm. The GUI has the capability to study temperature and external magnetic field dependence of magnetization, susceptibility, and equilibration behavior of the nearest-neighbor square lattice Ising model. Since the Ising model is a canonical system to study phase transition, the GUI can be used both for teaching and research purposes. The presence of a Monte Carlo code in a GUI format allows easy visualization of the simulation in real time and provides an attractive way to teach the concept of thermal phase transition and critical phenomena. We will also discuss the GUI implementation to study phase transition in a classical spin ice model on the pyrochlore lattice.

  1. Gravitational radiation from first-order phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Child, Hillary L.; Giblin, John T. Jr., E-mail: childh@kenyon.edu, E-mail: giblinj@kenyon.edu [Department of Physics, Kenyon College, 201 North College Road, Gambier, OH 43022 (United States)

    2012-10-01

    It is believed that first-order phase transitions at or around the GUT scale will produce high-frequency gravitational radiation. This radiation is a consequence of the collisions and coalescence of multiple bubbles during the transition. We employ high-resolution lattice simulations to numerically evolve a system of bubbles using only scalar fields, track the anisotropic stress during the process and evolve the metric perturbations associated with gravitational radiation. Although the radiation produced during the bubble collisions has previously been estimated, we find that the coalescence phase enhances this radiation even in the absence of a coupled fluid or turbulence. We comment on how these simulations scale and propose that the same enhancement should be found at the Electroweak scale; this modification should make direct detection of a first-order electroweak phase transition easier.

  2. Phase-transition-like behaviour of quantum games

    Energy Technology Data Exchange (ETDEWEB)

    Du Jiangfeng [Department of Modern Physics, University of Science and Technology of China, Hefei, 230027 (China); Li Hui [Department of Modern Physics, University of Science and Technology of China, Hefei, 230027 (China); Xu Xiaodong [Harrison M Randall Laboratory of Physics, University of Michigan, Ann Arbor, MI 48109-1120 (United States); Zhou Xianyi [Department of Modern Physics, University of Science and Technology of China, Hefei, 230027 (China); Han Rongdian [Department of Modern Physics, University of Science and Technology of China, Hefei, 230027 (China)

    2003-06-13

    The discontinuous dependence of the properties of a quantum game on its entanglement has been shown to be very much like phase transitions viewed in the entanglement-payoff diagram (J Du et al 2002 Phys. Rev. Lett. 88 137902). In this paper we investigate such phase-transition-like behaviour of quantum games, by suggesting a method which would help to illuminate the origin of such a kind of behaviour. For the particular case of the generalized Prisoners' Dilemma, we find that, for different settings of the numerical values in the payoff table, even though the classical game behaves the same, the quantum game exhibits different and interesting phase-transition-like behaviour.

  3. Non-equilibrium carrier efect in the optical properties of semiconductors

    International Nuclear Information System (INIS)

    Teschke, O.

    1980-01-01

    The time-resolved reflectivity of picosecond pulses from optically excited carrier distributions can provide important information about the energy relaxation rates of hot electrons and holes in semiconductors. the basic optical properties of non-equilibrium carrier distributions of GaAs are discussed. A semi-empirical analysis of the reflectivity spectrum is presented and the contributions of different effects are estimated. The results are in qualitative agreement with recent experiments employing dye lasers. (Author) [pt

  4. Electrolytes supramolecular interactions and non-equilibrium phenomena in concentrated solutions

    CERN Document Server

    Aseyev, Georgii Georgievich

    2014-01-01

    Electrolyte solutions play a key role in traditional chemical industry processes as well as other sciences such as hydrometallurgy, geochemistry, and crystal chemistry. Knowledge of electrolyte solutions is also key in oil and gas exploration and production, as well as many other environmental engineering endeavors. Until recently, a gap existed between the electrolyte solution theory dedicated to diluted solutions, and the theory, practice, and technology involving concentrated solutions.Electrolytes: Supramolecular Interactions and Non-Equilibrium Phenomena in Concentrated Solutions addresse

  5. Non-equilibrium Thermodynamics and the Production of Entropy Life, Earth, and Beyond

    CERN Document Server

    Kleidon, Axel

    2005-01-01

    The present volume studies the application of concepts from non-equilibrium thermodynamics to a variety of research topics. Emphasis is on the Maximum Entropy Production (MEP) principle and applications to Geosphere-Biosphere couplings. Written by leading researchers form a wide range of background, the book proposed to give a first coherent account of an emerging field at the interface of thermodynamics, geophysics and life sciences.

  6. A non-equilibrium model for soil heating and evaporation under extreme conditions

    Science.gov (United States)

    Massman, W. J.

    2014-12-01

    Extreme heating of soils during fires can have long-term and irreversible consequences and given the increasing use of prescribed fire by land managers and the increasing probability of wildfires associated with global warming, one approach to improving understanding of these consequences is to better understand and model the dynamics of the coupled heat, (liquid) moisture, and vapor transport in soils during extreme heating events. The present study describes a model developed to simulate non-equilibrium soil evaporation and the transport of heat, moisture, and water vapor under conditions during fires where the surface heating of the soil often ranges between 10,000 and 100,000 Wm-2 for several minutes to several hours. The Hertz-Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. Model performance is tested against laboratory measurements of soil temperature and moisture changes. Testing the present model with different formulations for soil hydraulic conductivity, water retention curve, water activity, and the non-equilibrium evaporative source term, indicates that virtually all the model's successes result from the use of a temperature dependent condensation coefficient in the evaporative source term, a rather surprising and unexpected result. On the other hand, the model solution is not a completely faithful representation of the laboratory data. Nevertheless, this new non-equilibrium model circumvents many of the problems that plagued an equilibrium model developed for the same purpose (Massman 2012: Water Resources Research 48, WR011710) and provides a much more physically realistic simulation than the earlier model. Finally, the present model should provide insight into modeling of heat and mass transport and evaporation, not only during high temperature and low moisture conditions, but for modeling these soil processes under less extreme environmental conditions as well.

  7. Stochastic relaxational dynamics applied to finance: towards non-equilibrium option pricing theory

    OpenAIRE

    Otto, Matthias

    1999-01-01

    Non-equilibrium phenomena occur not only in physical world, but also in finance. In this work, stochastic relaxational dynamics (together with path integrals) is applied to option pricing theory. A recently proposed model (by Ilinski et al.) considers fluctuations around this equilibrium state by introducing a relaxational dynamics with random noise for intermediate deviations called ``virtual'' arbitrage returns. In this work, the model is incorporated within a martingale pricing method for ...

  8. Measurement of Radiative Non-Equilibrium for Air Shocks Between 7-9 Km/s

    Science.gov (United States)

    Cruden, Brett A.; Brandis, Aaron M.

    2016-01-01

    This paper describes a recent characterization of non-equilibrium radiation for shock speeds between 7 and 9 km/s in the NASA Ames Electric Arc Shock Tube (EAST) Facility. Data is spectrally resolved from 190- 1450 nm and spatially resolved behind the shock front. Comparisons are made to DPLR/NEQAIR simulations using different modeling options and recommendations for future study are made based on these comparisons.

  9. Broken detailed balance and non-equilibrium dynamics in living systems: a review.

    Science.gov (United States)

    Gnesotto, Federico; Mura, Federica; Gladrow, Jannes; Broedersz, Chase

    2018-03-05

    Living systems operate far from thermodynamic equilibrium. Enzymatic activity can induce broken detailed balance at the molecular scale. This molecular scale breaking of detailed balance is crucial to achieve biological functions such as high-fidelity transcription and translation, sensing, adaptation, biochemical patterning, and force generation. While biological systems such as motor enzymes violate detailed balance at the molecular scale, it remains unclear how non-equilibrium dynamics manifests at the mesoscale in systems that are driven through the collective activity of many motors. Indeed, in several cellular systems the presence of non-equilibrium dynamics is not always evident at large scales. For example, in the cytoskeleton or in chromosomes one can observe stationary stochastic processes that appear at first glance thermally driven. This raises the question how non-equilibrium fluctuations can be discerned from thermal noise. We discuss approaches that have recently been developed to address this question, including methods based on measuring the extent to which the system violates the fluctuation-dissipation theorem. We also review applications of this approach to reconstituted cytoskeletal networks, the cytoplasm of living cells, and cell membranes. Furthermore, we discuss a more recent approach to detect actively driven dynamics, which is based on inferring broken detailed balance. This constitutes a non-invasive method that uses time-lapse microscopy data, and can be applied to a broad range of systems in cells and tissue. We discuss the ideas underlying this method and its application to several examples including flagella, primary cilia, and cytoskeletal networks. Finally, we briefly discuss recent developments in stochastic thermodynamics and non-equilibrium statistical mechanics, which offer new perspectives to understand the physics of living systems. . © 2018 IOP Publishing Ltd.

  10. Structural and topological phase transitions on the German Stock Exchange

    Science.gov (United States)

    Wiliński, M.; Sienkiewicz, A.; Gubiec, T.; Kutner, R.; Struzik, Z. R.

    2013-12-01

    We find numerical and empirical evidence for dynamical, structural and topological phase transitions on the (German) Frankfurt Stock Exchange (FSE) in the temporal vicinity of the worldwide financial crash. Using the Minimal Spanning Tree (MST) technique, a particularly useful canonical tool of the graph theory, two transitions of the topology of a complex network representing the FSE were found. The first transition is from a hierarchical scale-free MST representing the stock market before the recent worldwide financial crash, to a superstar-like MST decorated by a scale-free hierarchy of trees representing the market’s state for the period containing the crash. Subsequently, a transition is observed from this transient, (meta)stable state of the crash to a hierarchical scale-free MST decorated by several star-like trees after the worldwide financial crash. The phase transitions observed are analogous to the ones we obtained earlier for the Warsaw Stock Exchange and more pronounced than those found by Onnela-Chakraborti-Kaski-Kertész for the S&P 500 index in the vicinity of Black Monday (October 19, 1987) and also in the vicinity of January 1, 1998. Our results provide an empirical foundation for the future theory of dynamical, structural and topological phase transitions on financial markets.

  11. Validation of vibration-dissociation coupling models in hypersonic non-equilibrium separated flows

    Science.gov (United States)

    Shoev, G.; Oblapenko, G.; Kunova, O.; Mekhonoshina, M.; Kustova, E.

    2018-03-01

    The validation of recently developed models of vibration-dissociation coupling is discussed in application to numerical solutions of the Navier-Stokes equations in a two-temperature approximation for a binary N2/N flow. Vibrational-translational relaxation rates are computed using the Landau-Teller formula generalized for strongly non-equilibrium flows obtained in the framework of the Chapman-Enskog method. Dissociation rates are calculated using the modified Treanor-Marrone model taking into account the dependence of the model parameter on the vibrational state. The solutions are compared to those obtained using traditional Landau-Teller and Treanor-Marrone models, and it is shown that for high-enthalpy flows, the traditional and recently developed models can give significantly different results. The computed heat flux and pressure on the surface of a double cone are in a good agreement with experimental data available in the literature on low-enthalpy flow with strong thermal non-equilibrium. The computed heat flux on a double wedge qualitatively agrees with available data for high-enthalpy non-equilibrium flows. Different contributions to the heat flux calculated using rigorous kinetic theory methods are evaluated. Quantitative discrepancy of numerical and experimental data is discussed.

  12. Entropy generation of viscous dissipative flow in thermal non-equilibrium porous media with thermal asymmetries

    International Nuclear Information System (INIS)

    Chee, Yi Shen; Ting, Tiew Wei; Hung, Yew Mun

    2015-01-01

    The effect of thermal asymmetrical boundaries on entropy generation of viscous dissipative flow of forced convection in thermal non-equilibrium porous media is analytically studied. The two-dimensional temperature, Nusselt number and entropy generation contours are analysed comprehensively to provide insights into the underlying physical significance of the effect on entropy generation. By incorporating the effects of viscous dissipation and thermal non-equilibrium, the first-law and second-law characteristics of porous-medium flow are investigated via various pertinent parameters, i.e. heat flux ratio, effective thermal conductivity ratio, Darcy number, Biot number and averaged fluid velocity. For the case of symmetrical wall heat flux, an optimum condition with a high Nusselt number and a low entropy generation is identified at a Darcy number of 10 −4 , providing an ideal operating condition from the second-law aspect. This type of heat and fluid transport in porous media covers a wide range of engineering applications, involving porous insulation, packed-bed catalytic process in nuclear reactors, filtration transpiration cooling, and modelling of transport phenomena of microchannel heat sinks. - Highlights: • Effects of thermal asymmetries on convection in porous-medium are studied. • Exergetic effectiveness of porous media with thermal asymmetries is investigated. • 2-D temperature, Nusselt number and entropy generation contours are analyzed. • Significance of viscous dissipation in entropy generation is scrutinized. • Significance of thermal non-equilibrium in entropy generation is studied

  13. The efficiency of driving chemical reactions by a physical non-equilibrium is kinetically controlled.

    Science.gov (United States)

    Göppel, Tobias; Palyulin, Vladimir V; Gerland, Ulrich

    2016-07-27

    An out-of-equilibrium physical environment can drive chemical reactions into thermodynamically unfavorable regimes. Under prebiotic conditions such a coupling between physical and chemical non-equilibria may have enabled the spontaneous emergence of primitive evolutionary processes. Here, we study the coupling efficiency within a theoretical model that is inspired by recent laboratory experiments, but focuses on generic effects arising whenever reactant and product molecules have different transport coefficients in a flow-through system. In our model, the physical non-equilibrium is represented by a drift-diffusion process, which is a valid coarse-grained description for the interplay between thermophoresis and convection, as well as for many other molecular transport processes. As a simple chemical reaction, we consider a reversible dimerization process, which is coupled to the transport process by different drift velocities for monomers and dimers. Within this minimal model, the coupling efficiency between the non-equilibrium transport process and the chemical reaction can be analyzed in all parameter regimes. The analysis shows that the efficiency depends strongly on the Damköhler number, a parameter that measures the relative timescales associated with the transport and reaction kinetics. Our model and results will be useful for a better understanding of the conditions for which non-equilibrium environments can provide a significant driving force for chemical reactions in a prebiotic setting.

  14. Two-temperature chemically non-equilibrium modelling of an air supersonic ICP

    Energy Technology Data Exchange (ETDEWEB)

    El Morsli, Mbark; Proulx, Pierre [Laboratoire de Modelisation de Procedes Chimiques par Ordinateur Oppus, Departement de Genie Chimique, Universite de Sherbrooke (Ciheam) J1K 2R1 (Canada)

    2007-08-21

    In this work, a non-equilibrium mathematical model for an air inductively coupled plasma torch with a supersonic nozzle is developed without making thermal and chemical equilibrium assumptions. Reaction rate equations are written, and two coupled energy equations are used, one for the calculation of the translational-rotational temperature T{sub hr} and one for the calculation of the electro-vibrational temperature T{sub ev}. The viscous dissipation is taken into account in the translational-rotational energy equation. The electro-vibrational energy equation also includes the pressure work of the electrons, the Ohmic heating power and the exchange due to elastic collision. Higher order approximations of the Chapman-Enskog method are used to obtain better accuracy for transport properties, taking advantage of the most recent sets of collisions integrals available in the literature. The results obtained are compared with those obtained using a chemical equilibrium model and a one-temperature chemical non-equilibrium model. The influence of the power and the pressure chamber on the chemical and thermal non-equilibrium is investigated.

  15. Post-CHF heat transfer: a non-equilibrium, relaxation model

    International Nuclear Information System (INIS)

    Jones, O.C. Jr.; Zuber, N.

    1977-01-01

    Existing phenomenological models of heat transfer in the non-equilibrium, liquid-deficient, dispersed flow regime can sometimes predict the thermal behavior fairly well but are quite complex, requiring coupled simultaneous differential equations to describe the axial gradients of mass and energy along with those of droplet acceleration and size. In addition, empirical relations are required to express the droplet breakup and increased effective heat transfer due to holdup. This report describes the development of a different approach to the problem. It is shown that the non-equilibrium component of the total energy can be expressed as a first order, inhomogeneous relaxation equation in terms of one variable coefficient termed the Superheat Relaxation number. A demonstration is provided to show that this relaxation number can be correlated using local variables in such a manner to allow the single non-equilibrium equation to accurately calculate the effects of mass velocity and heat flux along with tube length, diameter, and critical quality for equilibrium qualities from 0.13 to over 3.0

  16. The effect of non-equilibrium metal cooling on the interstellar medium

    Science.gov (United States)

    Capelo, Pedro R.; Bovino, Stefano; Lupi, Alessandro; Schleicher, Dominik R. G.; Grassi, Tommaso

    2018-04-01

    By using a novel interface between the modern smoothed particle hydrodynamics code GASOLINE2 and the chemistry package KROME, we follow the hydrodynamical and chemical evolution of an isolated galaxy. In order to assess the relevance of different physical parameters and prescriptions, we constructed a suite of 10 simulations, in which we vary the chemical network (primordial and metal species), how metal cooling is modelled (non-equilibrium versus equilibrium; optically thin versus thick approximation), the initial gas metallicity (from 10 to 100 per cent solar), and how molecular hydrogen forms on dust. This is the first work in which metal injection from supernovae, turbulent metal diffusion, and a metal network with non-equilibrium metal cooling are self-consistently included in a galaxy simulation. We find that properly modelling the chemical evolution of several metal species and the corresponding non-equilibrium metal cooling has important effects on the thermodynamics of the gas, the chemical abundances, and the appearance of the galaxy: the gas is typically warmer, has a larger molecular-gas mass fraction, and has a smoother disc. We also conclude that, at relatively high metallicity, the choice of molecular-hydrogen formation rates on dust is not crucial. Moreover, we confirm that a higher initial metallicity produces a colder gas and a larger fraction of molecular gas, with the low-metallicity simulation best matching the observed molecular Kennicutt-Schmidt relation. Finally, our simulations agree quite well with observations that link star formation rate to metal emission lines.

  17. Infinite cascades of phase transitions in the classical Ising chain

    Science.gov (United States)

    Timonin, P. N.; Chitov, Gennady Y.

    2017-12-01

    We report exact results on one of the best studied models in statistical physics: the classical antiferromagnetic Ising chain in a magnetic field. We show that the model possesses an infinite cascade of thermal phase transitions (also known as disorder lines or geometric phase transitions). The phase transition is signaled by a change of asymptotic behavior of the nonlocal string-string correlation functions when their monotonic decay becomes modulated by incommensurate oscillations. The transitions occur for rarefied (m -periodic) strings with arbitrary odd m . We propose a duality transformation which maps the Ising chain onto the m -leg Ising tube with nearest-neighbor couplings along the legs and the plaquette four-spin interactions of adjacent legs. Then the m -string correlation functions of the Ising chain are mapped onto the two-point spin-spin correlation functions along the legs of the m -leg tube. We trace the origin of these cascades of phase transitions to the lines of the Lee-Yang zeros of the Ising chain in m -periodic complex magnetic field, allowing us to relate these zeros to the observable (and potentially measurable) quantities.

  18. The quark-hadron phase transition and primordial nucleosynthesis

    Science.gov (United States)

    Hogan, Craig J.

    1987-01-01

    After presenting the current view of the processes taking place during the cosmological transition from 'quark soup' to normal hadron matter, attention is given to what happens to cosmological nucleosynthesis in the presence of small-scale baryon inhomogeneities. The QCD phase transition is among the plausible sources of this inhomogeneity. It is concluded that the formation of primordial 'quark nuggets' and other cold exotica requires very low entropy regions at the outset, and that even the more modest nonlinearities perturbing nucleosynthesis probably require some ingredient in addition to a quiescent, mildly supercooled transition.

  19. Crystal-liquid-gas phase transitions and thermodynamic similarity

    CERN Document Server

    Skripov, Vladimir P; Schmelzer, Jurn W P

    2006-01-01

    Professor Skripov obtained worldwide recognition with his monograph ""Metastable liquids"", published in English by Wiley & Sons. Based upon this work and another monograph published only in Russia, this book investigates the behavior of melting line and the properties of the coexisting crystal and liquid phase of simple substances across a wide range of pressures, including metastable states of the coexisting phases. The authors derive new relations for the thermodynamic similarity for liquid-vapour phase transition, as well as describing solid-liquid, liquid-vapor and liquid-liquid phase tra

  20. Phase transitions in glassy systems via convolutional neural networks

    Science.gov (United States)

    Fang, Chao

    Machine learning is a powerful approach commonplace in industry to tackle large data sets. Most recently, it has found its way into condensed matter physics, allowing for the first time the study of, e.g., topological phase transitions and strongly-correlated electron systems. The study of spin glasses is plagued by finite-size effects due to the long thermalization times needed. Here we use convolutional neural networks in an attempt to detect a phase transition in three-dimensional Ising spin glasses. Our results are compared to traditional approaches.