Classical Nucleation Theory- Power Remarks
Czech Academy of Sciences Publication Activity Database
Němec, T.; Maršík, František
Kyoto : Maruzen Co., Ltd, 2005 - (Nakahara, M.; Matubayasi, N.; Ueno, M.; Yasuoka, K.; Watanabe, K.), s. 220-225 ISBN 4-621-07596-9. [International Conference on the Properties of Water and Steam /14./. Kyoto (JP), 29.08.2004-03.09.2004] R&D Projects: GA AV ČR(CZ) IBS2076003; GA ČR(CZ) GA101/02/0364 Institutional research plan: CEZ:AV0Z20760514 Keywords : binary * nucleation * power cycle chemistry Subject RIV: BJ - Thermodynamic s
Revision of the classical nucleation theory for supersaturated solutions
Borisenko, Alexander
2015-01-01
During the processes of nucleation and growth of a precipitate cluster from a supersaturated solution, the diffusion flux between the cluster and the solution changes the solute concentration near the cluster-solution interface from its average bulk value. This feature affects the rates of attachment and detachment of solute atoms at the interface and, therefore, alters the entire nucleation kinetics. Unless quite obvious, this effect has been ignored in the classical nucleation theory. To illustrate the results of this new approach, for the case of homogeneous nucleation, we calculate the total solubility (including the contribution from heterophase fluctuations) and the nucleation rate as functions of two parameters of the model and compare these results to the classical ones. One can conclude that discrepancies with the classical nucleation theory are great in the diffusion-limited regime, when the bulk diffusion mobility of solute atoms is small compared to the interfacial one, while in the opposite inter...
Ice Nucleation on Carbon Surface Supports the Classical Theory for Heterogeneous Nucleation
Cabriolu, Raffaela
2015-01-01
The prevalence of heterogeneous nucleation in nature was explained qualitatively by the classical theory for heterogeneous nucleation established over more than 60 years ago, but the quantitative validity and the key conclusions of the theory have remained unconfirmed. Employing the forward flux sampling method and the coarse-grained water model mW, we explicitly computed the heterogeneous ice nucleation rates in the supercooled water on a graphitic surface at various temperatures. The independently calculated ice nucleation rates were found to fit well according to the classical theory for heterogeneous nucleation. The fitting procedure further yields the estimate of the potency factor which measures the ratio of the heterogeneous nucleation barrier to the homogeneous nucleation barrier. Remarkably, the estimated potency factor agrees quantitatively with the volumetric ratio of the critical nuclei between the heterogeneous and homogeneous nucleation. Our numerical study thus provides a strong support to the ...
Refining Predictions of the Classical Nucleation Theory
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš; Maršík, František; Krejčí, A. Petr
Mount Laurel : AAAR, 2006 - (Biswas, P.; Chen, D.; Hering, S.), s. 1599-1600 ISBN 0-9788735-0-5. [IAC 2006 /7./. St. Paul (US), 10.09.2006-15.09.2006] R&D Projects: GA MŠk(CZ) 1P05ME726 Institutional research plan: CEZ:AV0Z20760514 Keywords : binary nucleation * microscopic surface tension Subject RIV: BJ - Thermodynamics
Classical nucleation theory for cavitation processes in water
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš; Maršík, František
Antalya : HEFAT, 2010 - (Meyer, J.), s. 2035-2040 ISBN 978-1-86854-818-7. [International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT2010) /7./. Antalya (TR), 19.07.2010-21.07.2010] R&D Projects: GA ČR(CZ) GA106/08/0557; GA ČR GAP101/10/1819 Institutional research plan: CEZ:AV0Z20760514 Keywords : cavitation * classical nucleation theory * water Subject RIV: BJ - Thermodynamics
Fluctuations, temperature, and detailed balance in classical nucleation theory
Energy Technology Data Exchange (ETDEWEB)
McGraw, R. [Environmental Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973 (United States); LaViolette, R.A. [Idaho National Engineering Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415 (United States)
1995-06-08
The role of temperature in classical nucleation theory is examined. It is shown that while even small clusters are assigned a temperature in the classical theory, this must be a fluctuating quantity. Stochastic simulations of cluster evaporation and growth are presented to track the temperature fluctuations in time. The relation {l_angle}{vert_bar}{delta}{ital T}{vert_bar}{sup 2}{r_angle}={ital kT}{sup @2}{ital d}0/{ital C}{sub {nu}} for the mean square temperature fluctuation is confirmed, where {ital k} is the Boltzmann constant, {ital C}{sub {nu}} is the cluster heat capacity, and {ital T}{sub 0} is the bath temperature. For small capillary drops (50--100 molecules), the resulting rms temperature fluctuations of 10{degree}--20{degree} might be expected to have a significant effect on the nucleation rate. However, the simulations reveal a cluster temperature distribution that is centered several degrees below {ital T}{sub 0}. A theory is presented to explain this effect. To first order, which includes Gaussian fluctuations of the cluster temperature {ital T}, we find that the effective temperature for cluster evaporation is {ital T}{minus}{ital h}/2{ital C}{sub {nu}}, where {ital h} is the latent heat. This temperature correction is precisely that required by detailed balance and results both in a centering of the cluster temperature distribution on {ital T}{sub 0} and a cancellation of any significant effect of temperature fluctuations on the nucleation rate.
Microscopic Surface Tension in the Classical Nucleation Theory
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš; Maršík, František
Praha : Institute of Chemical Process Fundamentals ASCR, v.v , Czech Aerosol Society, 2009 - (Smolík, J.; O´Dowd, C.), s. 561-654 ISBN 978-80-02-12161-2. [International Conference Nucleation and Atmospheric Aerosol /18./. Praha (CZ), 10.08.2009-14.08.2009] R&D Projects: GA AV ČR KJB400760701 Institutional research plan: CEZ:AV0Z20760514 Keywords : nucleation theory * multicomponent condensation * surface adsorption Subject RIV: BK - Fluid Dynamics
Limits of the applicability of the classical nucleation theory
Czech Academy of Sciences Publication Activity Database
Kožíšek, Zdeněk; Demo, Pavel; Sveshnikov, Alexey
Valencia: American Scientific Publishers, 2015 - (Kožíšek, Z.; Nitsch, K.; Koman, M.; Behúlová, M.), s. 316-320 ISSN 2164-6627. [Development of Materials Science and Education 2013 (DMSRE23). Kežmarské Žľaby (SK), 09.09.2013-13.09.2013] R&D Projects: GA ČR GAP108/12/0891 Institutional support: RVO:68378271 Keywords : nucleation * encapsulated systems Subject RIV: BM - Solid Matter Physics ; Magnetism
Limits of the applicability of classical nucleation theory
Czech Academy of Sciences Publication Activity Database
Kožíšek, Zdeněk; Demo, Pavel; Sveshnikov, Alexey
Bratislava: Slovak Expert Group of Solid State Chemistry and Physics, 2013 - (Koman, M.; Jorík, V.; Kožíšek, Z.). s. 27 ISBN 978-80-970896-5-8. [Joint Seminar Development of Materials Science in Research and Education /23./. 09.09.2013-13.09.2013, Kežmarské Žĺaby] R&D Projects: GA ČR GAP108/12/0891 Institutional support: RVO:68378271 Keywords : nucleation * phase transition Subject RIV: BM - Solid Matter Physics ; Magnetism http:// dms .fzu.cz/proceedings/ DMS RE23.pdf
Borisenko, Alexander
2016-05-01
During the processes of nucleation and growth of a precipitate cluster from a supersaturated solution, the diffusion flux between the cluster and the solution changes the solute concentration near the cluster-solution interface from its average bulk value. This feature affects the rates of attachment and detachment of solute atoms at the interface, and, therefore, the entire nucleation-growth kinetics is altered. Unless quite obvious, this effect has been ignored in classical nucleation theory. To illustrate the results of this approach, for the case of homogeneous nucleation, we calculate the total solubility and the nucleation rate as functions of two parameters of the model (the reduced interface energy and the inverse second Damköhler number), and we compare these results to the classical ones. One can conclude that discrepancies with classical nucleation theory are great in the diffusion-limited regime, when the rate of bulk diffusion is small compared to the rate of interface reactions, while in the opposite interface-limited case they vanish.
Chen, Xuelian; Schröder, Jan; Hauschild, Stephan; Rosenfeldt, Sabine; Dulle, Martin; Förster, Stephan
2015-10-27
Despite the increasing interest in the applications of functional nanoparticles, a comprehensive understanding of the formation mechanism starting from the precursor reaction with subsequent nucleation and growth is still a challenge. We for the first time investigated the kinetics of gold nanoparticle formation systematically by means of a lab-based in situ small-angle X-ray scattering (SAXS)/wide-angle X-ray scattering (WAXS)/UV-vis absorption spectroscopy experiment using a stopped-flow apparatus. We thus could systematically investigate the influence of all major factors such as precursor concentration, temperature, the presence of stabilizing ligands and cosolvents on the temporal evolution of particle size, size distribution, and optical properties from the early prenucleation state to the late growth phase. We for first time formulated and numerically solved a closed nucleation and growth model including the precursor reaction. We observe that the results can be well described within the framework of classical nucleation and growth theory, including also results of previous studies by other research groups. From the analysis, we can quantitatively derive values for the rate constants of precursor reaction and growth together with their activation free enthalpies. We find the growth process to be surface-reaction limited with negligible influence of Ostwald ripening yielding narrow disperse gold nanoparticles. PMID:26393805
International Nuclear Information System (INIS)
Scaling relations are developed for the number g* of molecules in the critical nucleus and the nucleation barrier height W*. Density functional (DF) calculations for vapor-liquid nucleation confirm these relations and show systematic departure of the ratio W*/g*Δμ from its classical value of 1/2 with increasing difference Δμ in the chemical potential between the supersaturated vapor and bulk condensed phase. Discrepancies between classical and DF nucleation theories and between the classical theory and experiment are interpreted using these results. copyright 1996 The American Physical Society
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš
Vol. 1. Liberec: Technical University of Liberec, 2010 - (Vít, T.; Dančová, P.), s. 439-451 ISBN 978-80-7372-670-6. [International Conference Experimental Fluid Mechanics 2010. Liberec (CZ), 24.11.2010-26.11.2010] R&D Projects: GA ČR GAP101/10/1819; GA ČR GAP101/10/1428 Institutional research plan: CEZ:AV0Z20760514 Keywords : cavitation * nucleation rate * refrigerants Subject RIV: BJ - Thermodynamics
International Nuclear Information System (INIS)
A rigorous thermodynamic formulation of the geometric model for heterogeneous nucleation including line tension effect is missing till date due to the associated mathematical hurdles. In this work, we develop a novel thermodynamic formulation based on Classical Nucleation Theory (CNT), which is supposed to illustrate a systematic and a more plausible analysis for the heterogeneous nucleation on a planar surface including the line tension effect. The appreciable range of the critical microscopic contact angle (θc), obtained from the generalized Young’s equation and the stability analysis, is θ∞ < θc < θ′ for positive line tension and is θM < θc < θ∞ for negative line tension. θ∞ is the macroscopic contact angle, θ′ is the contact angle for which the Helmholtz free energy has the minimum value for the positive line tension, and θM is the local minima of the nondimensional line tension effect for the negative line tension. The shape factor f, which is basically the dimensionless critical free energy barrier, becomes higher for lower values of θ∞ and higher values of θc for positive line tension. The combined effect due to the presence of the triple line and the interfacial areas (fL + fS) in shape factor is always within (0, 3.2), resulting f in the range of (0, 1.7) for positive line tension. A formerly presumed appreciable range for θc(0 < θc < θ∞) is found not to be true when the effect of negative line tension is considered for CNT. Estimation based on the property values of some real fluids confirms the relevance of the present analysis
Sahyoun, Maher; Wex, Heike; Gosewinkel, Ulrich; Šantl-Temkiv, Tina; Nielsen, Niels W.; Finster, Kai; Sørensen, Jens H.; Stratmann, Frank; Korsholm, Ulrik S.
2016-08-01
Bacterial ice-nucleating particles (INP) are present in the atmosphere and efficient in heterogeneous ice-nucleation at temperatures up to -2 °C in mixed-phase clouds. However, due to their low emission rates, their climatic impact was considered insignificant in previous modeling studies. In view of uncertainties about the actual atmospheric emission rates and concentrations of bacterial INP, it is important to re-investigate the threshold fraction of cloud droplets containing bacterial INP for a pronounced effect on ice-nucleation, by using a suitable parameterization that describes the ice-nucleation process by bacterial INP properly. Therefore, we compared two heterogeneous ice-nucleation rate parameterizations, denoted CH08 and HOO10 herein, both of which are based on classical-nucleation-theory and measurements, and use similar equations, but different parameters, to an empirical parameterization, denoted HAR13 herein, which considers implicitly the number of bacterial INP. All parameterizations were used to calculate the ice-nucleation probability offline. HAR13 and HOO10 were implemented and tested in a one-dimensional version of a weather-forecast-model in two meteorological cases. Ice-nucleation-probabilities based on HAR13 and CH08 were similar, in spite of their different derivation, and were higher than those based on HOO10. This study shows the importance of the method of parameterization and of the input variable, number of bacterial INP, for accurately assessing their role in meteorological and climatic processes.
Unification of classical nucleation theories via a unified Itô-Stratonovich stochastic equation.
Durán-Olivencia, Miguel A; Lutsko, James F
2015-09-01
Classical nucleation theory (CNT) is the most widely used framework to describe the early stage of first-order phase transitions. Unfortunately, the different points of view adopted to derive it yield different kinetic equations for the probability density function, e.g., Zeldovich-Frenkel or Becker-Döring-Tunitskii equations. Starting from a phenomenological stochastic differential equation, a unified equation is obtained in this work. In other words, CNT expressions are recovered by selecting one or another stochastic calculus. Moreover, it is shown that the unified CNT thus obtained produces the same Fokker-Planck equation as that from a recent update of CNT [J. F. Lutsko and M. A. Durán-Olivencia, J. Chem. Phys. 138, 244908 (2013)10.1063/1.4811490] when mass transport is governed by diffusion. Finally, we derive a general induction-time expression along with specific approximations of it to be used under different scenarios, in particular, when the mass-transport mechanism is governed by direct impingement, volume diffusion, surface diffusion, or interface transfer. PMID:26465482
Witharana, S; Strobel, S; Kim, H D; McKrell, T; Chang, J -B; Buongiorno, J; Berggren, K K; Chen, L; Ding, Y
2012-01-01
Recently-reported data suggest that bubble nucleation on surfaces with nano-sized features (cavities and posts) may occur close to the thermodynamic saturation temperature. However, according to the traditional theory of heterogeneous bubble nucleation, such low nucleation temperatures are possible only for surfaces with micro-scale cavities. Motivated by this apparent contradiction, we have used infrared thermometry to measure the nucleation temperature of water on custom-fabricated nano- to micro-scale cavities (from 90 nm to 4.5 um in diameter) and posts (from 60 nm to 5 um in diameter), machined on ultra-smooth and clean silicon wafers using electron beam lithography. Our cavity data are in agreement with the predictions of the Young-Laplace equation, thus re-affirming the correctness of the classic view of heterogeneous bubble nucleation, at least for the water-silicon system investigated here. The data also suggest that individual posts of any size have an insignificant effect on bubble nucleation, as e...
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš
Londýn: British & Irish Association for Properties of Water and Steam (BIAPWS) a Institution of Mechanical Engineers, 2013, 063-063. [International Conference on the Properties of Water and Steam /16./ ICPWS. University of Greenwich, Londýn (GB), 01.09.2013-05.09.2013] R&D Projects: GA ČR GAP101/10/1819 Institutional research plan: CEZ:AV0Z20760514 Keywords : ice nucleation * interfacial energy * supercooled water
Comment on "Simple improvements to classical bubble nucleation models"
Schmelzer, Jürn W. P.; Baidakov, Vladimir G.
2016-08-01
A critical analysis of several statements concerning experimental studies, molecular dynamics simulations, and the theoretical interpretation of bubble nucleation processes is performed. In particular, it is shown that the Tolman equation does not supply us, in general, with a satisfactory theoretically founded description of the curvature dependence of the surface tension and the dependence of the steady-state nucleation rate of bubbles and droplets on supersaturation in the framework of classical nucleation theory.
Principles of nucleation theory
International Nuclear Information System (INIS)
The nucleation of small stable species is described in the problem of void growth by discrete rate equations. When gas is being produced the problem reduces to one of calculating the incubation dose for the gas bubble to void transition. A general expression for the steady state nucleation rate is derived for the case when voids are formed by vacancy fluctuations which enable an effective nucleation barrier to be crossed. (author)
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš
2013-01-01
Roč. 583, September (2013), s. 64-68. ISSN 0009-2614 R&D Projects: GA ČR GAP101/10/1819 Institutional research plan: CEZ:AV0Z20760514 Institutional support: RVO:61388998 Keywords : ice nucleation * supercooled water * interfacial energy Subject RIV: BJ - Thermodynamics Impact factor: 1.991, year: 2013 http://www.sciencedirect.com/science/article/pii/S0009261413009913
A nanoscale temperature-dependent heterogeneous nucleation theory
Energy Technology Data Exchange (ETDEWEB)
Cao, Y. Y. [Nanosurface Science and Engineering Research Institute, College of Mechatronics and Control Engineering, Shenzhen University, Shenzhen, 518060 Guangdong (China); Yang, G. W., E-mail: stsygw@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science and Engineering, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou, 510275 Guangdong (China)
2015-06-14
Classical nucleation theory relies on the hypothetical equilibrium of the whole nucleation system, and neglects the thermal fluctuations of the surface; this is because the high entropic gains of the (thermodynamically extensive) surface would lead to multiple stable states. In fact, at the nanometer scale, the entropic gains of the surface are high enough to destroy the stability of the thermal equilibrium during nucleation, comparing with the whole system. We developed a temperature-dependent nucleation theory to elucidate the heterogeneous nucleation process, by considering the thermal fluctuations based on classical nucleation theory. It was found that the temperature not only affected the phase transformation, but also influenced the surface energy of the nuclei. With changes in the Gibbs free energy barrier, nucleation behaviors, such as the nucleation rate and the critical radius of the nuclei, showed temperature-dependent characteristics that were different from those predicted by classical nucleation theory. The temperature-dependent surface energy density of a nucleus was deduced based on our theoretical model. The agreement between the theoretical and experimental results suggested that the developed nucleation theory has the potential to contribute to the understanding and design of heterogeneous nucleation at the nanoscale.
Duplissy, J.; Merikanto, J.; Franchin, A.; Tsagkogeorgas, G.; Kangasluoma, J.; Wimmer, D.; Vuollekoski, H.; Schobesberger, S.; Lehtipalo, K.; Flagan, R. C.; Brus, D.; Donahue, N. M.; Vehkamäki, H.; Almeida, J.; Amorim, A.; Barmet, P.; Bianchi, F.; Breitenlechner, M.; Dunne, E. M.; Guida, R.; Henschel, H.; Junninen, H.; Kirkby, J.; Kürten, A.; Kupc, A.; Määttänen, A.; Makhmutov, V.; Mathot, S.; Nieminen, T.; Onnela, A.; Praplan, A. P.; Riccobono, F.; Rondo, L.; Steiner, G.; Tome, A.; Walther, H.; Baltensperger, U.; Carslaw, K. S.; Dommen, J.; Hansel, A.; Petäjä, T.; Sipilä, M.; Stratmann, F.; Vrtala, A.; Wagner, P. E.; Worsnop, D. R.; Curtius, J.; Kulmala, M.
2016-02-01
We report comprehensive, demonstrably contaminant-free measurements of binary particle formation rates by sulfuric acid and water for neutral and ion-induced pathways conducted in the European Organization for Nuclear Research Cosmics Leaving Outdoor Droplets chamber. The recently developed Atmospheric Pressure interface-time of flight-mass spectrometer was used to detect contaminants in charged clusters and to identify runs free of any contaminants. Four parameters were varied to cover ambient conditions: sulfuric acid concentration (105 to 109 mol cm-3), relative humidity (11% to 58%), temperature (207 K to 299 K), and total ion concentration (0 to 6800 ions cm-3). Formation rates were directly measured with novel instruments at sizes close to the critical cluster size (mobility size of 1.3 nm to 3.2 nm). We compare our results with predictions from Classical Nucleation Theory normalized by Quantum Chemical calculation (QC-normalized CNT), which is described in a companion paper. The formation rates predicted by the QC-normalized CNT were extended from critical cluster sizes to measured sizes using the UHMA2 sectional particle microphysics model. Our results show, for the first time, good agreement between predicted and measured particle formation rates for the binary (neutral and ion-induced) sulfuric acid-water system. Formation rates increase with RH, sulfuric acid, and ion concentrations and decrease with temperature at fixed RH and sulfuric acid concentration. Under atmospheric conditions, neutral particle formation dominates at low temperatures, while ion-induced particle formation dominates at higher temperatures. The good agreement between the theory and our comprehensive data set gives confidence in using the QC-normalized CNT as a powerful tool to study neutral and ion-induced binary particle formation in atmospheric modeling.
Nucleation theory beyond the deterministic limit. I. The nucleation stage.
Dubrovskii, V G; Nazarenko, M V
2010-03-21
This work addresses theory of nucleation and condensation based on the continuous Fokker-Plank type kinetic equation for the distribution of supercritical embryos over sizes beyond the deterministic limit, i.e., keeping the second derivative with respect to size. The first part of the work treats the nucleation stage. It is shown that the size spectrum should be generally obtained by the convolution of the initial distribution with the Gaussian-like Green function with spreading dispersion. It is then demonstrated that the fluctuation-induced effects can be safely neglected at the nucleation stage, where the spectrum broadening due to the nonlinear boundary condition is much larger than the fluctuational one. The crossover between the known triangular and double exponential distributions under different conditions of material influx into the system is demonstrated. Some examples of size distributions at the nucleation stage in different regimes of material influx are also presented. PMID:20331305
Theory and Simulation of Nucleation
Kuipers, J.
2009-01-01
Nucleation is the process where a stable nucleus spontaneously emerges in a metastable environment. Examples of nucleation abound, for instance the formation of droplets in undercooled gasses and of crystals in undercooled liquids. The process is thermally activated and is key to understanding vario
Classical and quantum effective theories
Polonyi, Janos
2014-01-01
A generalization of the action principle of classical mechanics, motivated by the Closed Time Path (CTP) scheme of quantum field theory, is presented to deal with initial condition problems and dissipative forces. The similarities of the classical and the quantum cases are underlined. In particular, effective interactions which describe classical dissipative forces represent the system-environment entanglement. The relation between the traditional effective theories and their CTP extension is briefly discussed and few qualitative examples are mentioned.
Recent developments in the kinetic theory of nucleation.
Ruckenstein, E; Djikaev, Y S
2005-12-30
, but the hierarchy of time scales does allow one to reduce it to the Fokker-Plank equation in the energy space. The new theory provides an equation for the critical radius of a new-phase particle which in the limit of large clusters (low supersaturations) yields the Kelvin equation and hence an expression for the macroscopic surface tension. The theory was illustrated with numerical calculations for a molecular pair interaction potential combining the dispersive attraction with the hard-sphere repulsion. The results for the liquid-to-solid nucleation clearly show that at given supersaturation the nucleation rate depends on the cluster structure (for three cluster structures considered-amorphous, fcc, and icosahedral). For both the liquid-to-solid and vapor-to-liquid nucleation, the predictions of the theory are consistent with the results of classical nucleation theory (CNT) in the limit of large critical clusters (low supersaturations). For small critical clusters the new theory provides higher nucleation rates than CNT. This can be accounted for by the fact that CNT uses the macroscopic interfacial tension which presumably overpredicts the surface tension of small clusters, and hence underpredicts nucleation rates. PMID:16137628
Nucleation theory and growth of nanostructures
Dubrovskii, Vladimir G
2013-01-01
Semiconductor nanostructures such as nanowires are promising building blocks of future nanoelectronic, nanophotonic and nanosensing devices. Their physical properties are primarily determined by the epitaxy process which is rather different from the conventional thin film growth. This book shows how the advanced nucleation theory can be used in modeling of growth properties, morphology and crystal phase of such nanostructures.
Effective binary theory of multi-component nucleation
International Nuclear Information System (INIS)
Classical theory of multi-component nucleation [O. Hirschfelder, J. Chem. Phys. 61, 2690 (1974)] belongs to the class of the so-called intractable problems: it requires computational time which is an exponential function of the number of components N. For a number of systems of practical interest with N > 10, the brute-force use of the classical theory becomes virtually impossible and one has to resort to an effective medium approach. We present an effective binary model which captures important physics of multi-component nucleation. The distinction between two effective species is based on the observation that while all N components contribute to the cluster thermodynamic properties, there is only a part of them which trigger the nucleation process. The proposed 2D-theory takes into account adsorption by means of the Gibbs dividing surface formalism and uses statistical mechanical considerations for the treatment of small clusters. Theoretical predictions for binary-, ternary-, and 14-component mixtures are compared with available experimental data and other models
Identity from classical invariant theory
International Nuclear Information System (INIS)
A simple derivation is given of a well-known relation involving the so-called Cayley Operator of classical invariant theory. The proof is induction-free and independent of Capelli's identity; it makes use only of a known-theorem in the theory of determinants and some elementary combinatorics
Classical theory of algebraic numbers
Ribenboim, Paulo
2001-01-01
Gauss created the theory of binary quadratic forms in "Disquisitiones Arithmeticae" and Kummer invented ideals and the theory of cyclotomic fields in his attempt to prove Fermat's Last Theorem These were the starting points for the theory of algebraic numbers, developed in the classical papers of Dedekind, Dirichlet, Eisenstein, Hermite and many others This theory, enriched with more recent contributions, is of basic importance in the study of diophantine equations and arithmetic algebraic geometry, including methods in cryptography This book has a clear and thorough exposition of the classical theory of algebraic numbers, and contains a large number of exercises as well as worked out numerical examples The Introduction is a recapitulation of results about principal ideal domains, unique factorization domains and commutative fields Part One is devoted to residue classes and quadratic residues In Part Two one finds the study of algebraic integers, ideals, units, class numbers, the theory of decomposition, iner...
Classical theory of radiating strings
Copeland, Edmund J.; Haws, D.; Hindmarsh, M.
1990-01-01
The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.
Scaled nucleation theory for bubble nucleation of lower alkanes
Czech Academy of Sciences Publication Activity Database
Němec, Tomáš
2014-01-01
Roč. 37, č. 111 (2014), s. 69-75. ISSN 1292-8941 R&D Projects: GA ČR GAP101/10/1819; GA ČR GAP101/10/1428 Institutional support: RVO:61388998 Keywords : bubble nucleation * corresponding states * scaled nucleation rate Subject RIV: BJ - Thermodynamics Impact factor: 1.757, year: 2014
Advances In Classical Field Theory
Yahalom, Asher
2011-01-01
Classical field theory is employed by physicists to describe a wide variety of physical phenomena. These include electromagnetism, fluid dynamics, gravitation and quantum mechanics. The central entity of field theory is the field which is usually a multi component function of space and time. Those multi component functions are usually grouped together as vector fields as in the case in electromagnetic theory and fluid dynamics, in other cases they are grouped as tensors as in theories of gravitation and yet in other cases they are grouped as complex functions as in the case of quantum mechanic
Systematic coarse-graining in nucleation theory
International Nuclear Information System (INIS)
In this work, we show that the standard method to obtain nucleation rate-predictions with the aid of atomistic Monte Carlo simulations leads to nucleation rate predictions that deviate 3 − 5 orders of magnitude from the recent brute-force molecular dynamics simulations [Diemand et al., J. Chem. Phys. 139, 074309 (2013)] conducted in the experimental accessible supersaturation regime for Lennard-Jones argon. We argue that this is due to the truncated state space the literature mostly relies on, where the number of atoms in a nucleus is considered the only relevant order parameter. We here formulate the nonequilibrium statistical mechanics of nucleation in an extended state space, where the internal energy and momentum of the nuclei are additionally incorporated. We show that the extended model explains the lack in agreement between the molecular dynamics simulations by Diemand et al. and the truncated state space. We demonstrate additional benefits of using the extended state space; in particular, the definition of a nucleus temperature arises very naturally and can be shown without further approximation to obey the fluctuation law of McGraw and LaViolette. In addition, we illustrate that our theory conveniently allows to extend existing theories to richer sets of order parameters
Systematic coarse-graining in nucleation theory
Schweizer, M.; Sagis, L. M. C.
2015-08-01
In this work, we show that the standard method to obtain nucleation rate-predictions with the aid of atomistic Monte Carlo simulations leads to nucleation rate predictions that deviate 3 - 5 orders of magnitude from the recent brute-force molecular dynamics simulations [Diemand et al., J. Chem. Phys. 139, 074309 (2013)] conducted in the experimental accessible supersaturation regime for Lennard-Jones argon. We argue that this is due to the truncated state space the literature mostly relies on, where the number of atoms in a nucleus is considered the only relevant order parameter. We here formulate the nonequilibrium statistical mechanics of nucleation in an extended state space, where the internal energy and momentum of the nuclei are additionally incorporated. We show that the extended model explains the lack in agreement between the molecular dynamics simulations by Diemand et al. and the truncated state space. We demonstrate additional benefits of using the extended state space; in particular, the definition of a nucleus temperature arises very naturally and can be shown without further approximation to obey the fluctuation law of McGraw and LaViolette. In addition, we illustrate that our theory conveniently allows to extend existing theories to richer sets of order parameters.
Applications of classical detonation theory
Energy Technology Data Exchange (ETDEWEB)
Davis, W.C.
1994-09-01
Classical detonation theory is the basis for almost all calculations of explosive systems. One common type of calculation is of the detailed behavior of inert parts driven by explosive, predicting pressures, velocities, positions, densities, energies, etc as functions of time. Another common application of the theory is predicting the detonation state and expansion isentrope of a new explosive or mixtures, perhaps an explosive that has not yet been made. Both types of calculations are discussed.
Classical isodual theory of antimatter
Santilli, R M
1997-01-01
An inspection of the contemporary physics literature reveals that, while matter is treated at all levels of study, from Newtonian mechanics to quantum field theory, antimatter is solely treated at the level of second quantization. For the purpose of initiating the restoration of full equivalence in the treatments of matter and antimatter in due time, in this paper we present a classical representation of antimatter which begins at the primitive Newtonian level with expected images at all subsequent levels. By recalling that charge conjugation of particles into antiparticles is anti-automorphic, the proposed theory of antimatter is based on a new map, called isoduality, which is also anti-automorphic, yet it is applicable beginning at the classical level and then persists at the quantum level. As part of our study, we present novel anti-isomorphic isodual images of the Galilean, special and general relativities and show the compatibility of their representation of antimatter with all available classical experi...
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Based on the classic diffusion controlled nucleation and growth theory, the sympathetic nucleationledgewise growth mechanism of bainite was studied theoretically for Iow carbon Fe-C alloys. The rationality of the occurrence of sympathetic nucleation on the terraces of ledges competing with lateral ledge growth and other sites nucleation was demonstrated by the present work quantitatively. The calculations indicated that Iow reaction temperatures and high carbon concentrations may favor the sympathetic nucleation, thus accounting for the formation of multilayer structures of bainite.
Systematic Coarse-Graining in Nucleation Theory
Schweizer, Marco
2015-01-01
We present a novel approach to nucleation processes based one the GENERIC framework (general equation for the nonequilibrium reversible-irreversible coupling). Solely based on the GENERIC structure of time-evolution equations and thermodynamic consistency arguments of exchange processes between a metastable phase and a nucleating phase, we derive the fundamental dynamics for this phenomenon, based on continuous Fokker-Planck equations. We are readily able to treat non-isothermal nucleation even when the nucleating cores cannot be attributed intensive thermodynamic properties. In addition, we capture the dynamics of the time-dependent metastable phase being continuously expelled from the nucleating phase, and keep rigorous track of the volume corrections to the dynamics. Within our framework the definition of a thermodynamic nuclei temperature is manifest. For the special case of nucleation of a gas phase towards its vapor-liquid coexistence, we illustrate that our approach is capable of reproducing recent lit...
Classical Electron Theory and Conservation Laws
Kiessling, Michael K. -H.
1999-01-01
It is shown that the traditional conservation laws for total charge, energy, linear and angular momentum, hold jointly in classical electron theory if and only if classical electron spin is included as dynamical degree of freedom.
Nucleation theory - Is replacement free energy needed?. [error analysis of capillary approximation
Doremus, R. H.
1982-01-01
It has been suggested that the classical theory of nucleation of liquid from its vapor as developed by Volmer and Weber (1926) needs modification with a factor referred to as the replacement free energy and that the capillary approximation underlying the classical theory is in error. Here, the classical nucleation equation is derived from fluctuation theory, Gibb's result for the reversible work to form a critical nucleus, and the rate of collision of gas molecules with a surface. The capillary approximation is not used in the derivation. The chemical potential of small drops is then considered, and it is shown that the capillary approximation can be derived from thermodynamic equations. The results show that no corrections to Volmer's equation are needed.
A novel approach to the theory of homogeneous and heterogeneous nucleation.
Ruckenstein, Eli; Berim, Gersh O; Narsimhan, Ganesan
2015-01-01
A new approach to the theory of nucleation, formulated relatively recently by Ruckenstein, Narsimhan, and Nowakowski (see Refs. [7-16]) and developed further by Ruckenstein and other colleagues, is presented. In contrast to the classical nucleation theory, which is based on calculating the free energy of formation of a cluster of the new phase as a function of its size on the basis of macroscopic thermodynamics, the proposed theory uses the kinetic theory of fluids to calculate the condensation (W(+)) and dissociation (W(-)) rates on and from the surface of the cluster, respectively. The dissociation rate of a monomer from a cluster is evaluated from the average time spent by a surface monomer in the potential well as obtained from the solution of the Fokker-Planck equation in the phase space of position and momentum for liquid-to-solid transition and the phase space of energy for vapor-to-liquid transition. The condensation rates are calculated using traditional expressions. The knowledge of those two rates allows one to calculate the size of the critical cluster from the equality W(+)=W(-) as well as the rate of nucleation. The developed microscopic approach allows one to avoid the controversial application of classical thermodynamics to the description of nuclei which contain a few molecules. The new theory was applied to a number of cases, such as the liquid-to-solid and vapor-to-liquid phase transitions, binary nucleation, heterogeneous nucleation, nucleation on soluble particles and protein folding. The theory predicts higher nucleation rates at high saturation ratios (small critical clusters) than the classical nucleation theory for both solid-to-liquid as well as vapor-to-liquid transitions. As expected, at low saturation ratios for which the size of the critical cluster is large, the results of the new theory are consistent with those of the classical one. The present approach was combined with the density functional theory to account for the density
Three Approaches to Classical Thermal Field Theory
Gozzi, E.; Penco, R.
2010-01-01
In this paper we study three different functional approaches to classical thermal field theory, which turn out to be the classical counterparts of three well-known different formulations of quantum thermal field theory: the Closed-Time Path (CTP) formalism, the Thermofield Dynamics (TFD) and the Matsubara approach.
Three approaches to classical thermal field theory
Gozzi, E.; Penco, R.
2011-04-01
In this paper we study three different functional approaches to classical thermal field theory, which turn out to be the classical counterparts of three well-known different formulations of quantum thermal field theory: the closed-time path (CTP) formalism, the thermofield dynamics (TFD) and the Matsubara approach.
Classical-field theory of thermal radiation
Rashkovskiy, Sergey A
2016-01-01
In this paper, using the viewpoint that quantum mechanics can be constructed as a classical field theory without any quantization I build a fully classical theory of thermal radiation. Planck's law for the spectral energy density of thermal radiation and the Einstein A-coefficient for spontaneous emission are derived in the framework of classical field theory without using the concept of "photon". It is shown that the spectral energy density of thermal radiation is apparently not a universal function of frequency, as follows from the Planck's law, but depends weakly on the nature of atoms, while Planck's law is valid only as an approximation in the limit of weak excitation of atoms.
Cloud base levels for Jupiter and Venus and the heteromolecular nucleation theory
Stauffer, D.; Kiang, C. S.
1974-01-01
For purified binary gas mixtures like NH3-H2O or HCl-H2O, partial pressures appreciably greater than the two saturation partial pressures are needed to condense the gas mixture into small solution droplets (homogeneous heteromolecular nucleation). Thus without foreign nuclei, clouds are not as easily formed as in the theories of Lewis; the latter should be valid only if large condensation nuclei are available. We calculate here from classical homogeneous heteromolecular nucleation theory the threshold partial pressures necessary to achieve droplet nucleation for the gas mixtures NH3-H2O (Jupiter), HCl-H2O (Venus), H2SO4-H2O (Venus), and C2H5OH-H2O (laboratory).
Classical theory of electric and magnetic fields
Good, Roland H
1971-01-01
Classical Theory of Electric and Magnetic Fields is a textbook on the principles of electricity and magnetism. This book discusses mathematical techniques, calculations, with examples of physical reasoning, that are generally applied in theoretical physics. This text reviews the classical theory of electric and magnetic fields, Maxwell's Equations, Lorentz Force, and Faraday's Law of Induction. The book also focuses on electrostatics and the general methods for solving electrostatic problems concerning images, inversion, complex variable, or separation of variables. The text also explains ma
Classical Electrodynamics in a Unified Theory
Ghose, Partha
2016-01-01
Some consequences of a fully classical unified theory of gravity and electromagnetism are worked out for the electromagnetic sector such as the occurrence of classical light beams with spin and orbital angular momenta that are topologically quantized in units of $q_e q_m=\\sigma$, independent of the beam size. Empirical fits require $\\sigma = \\hbar$. The theory also predicts a generalized coherency matrix whose consequences are testable.
Quantum feedback control and classical control theory
Doherty, Andrew C.; Habib, Salman; Jacobs, Kurt; Mabuchi, Hideo; Tan, Sze M.
1999-01-01
We introduce and discuss the problem of quantum feedback control in the context of established formulations of classical control theory, examining conceptual analogies and essential differences. We describe the application of state-observer-based control laws, familiar in classical control theory, to quantum systems and apply our methods to the particular case of switching the state of a particle in a double-well potential.
FROM CLASSICAL TO EPISTEMIC GAME THEORY
ANDRÉS PEREA
2014-01-01
In this paper, we give a historical overview of the transition from classical game theory to epistemic game theory. To that purpose we will discuss how important notions such as reasoning about the opponents, belief hierarchies, common belief, and the concept of common belief in rationality arose, and gradually entered the game theoretic picture, thereby giving birth to the field of epistemic game theory. We will also address the question why it took game theory so long before it finally inco...
A Classical Introduction to Galois Theory
Newman, Stephen C
2012-01-01
This book provides an introduction to Galois theory and focuses on one central theme - the solvability of polynomials by radicals. Both classical and modern approaches to the subject are described in turn in order to have the former (which is relatively concrete and computational) provide motivation for the latter (which can be quite abstract). The theme of the book is historically the reason that Galois theory was created, and it continues to provide a platform for exploring both classical and modern concepts. This book examines a number of problems arising in the area of classical mathematic
Dynamics of homogeneous nucleation
DEFF Research Database (Denmark)
Toxværd, Søren
2015-01-01
clusters fluctuates, but the mean temperature remains below the temperature in the supersaturated gas until they reach the critical nucleation size. The critical nuclei have, however, a temperature equal to the supersaturated gas. The kinetics of homogeneous nucleation is not only caused by a grow or......The classical nucleation theory for homogeneous nucleation is formulated as a theory for a density fluctuation in a supersaturated gas at a given temperature. But molecular dynamics simulations reveal that it is small cold clusters which initiates the nucleation. The temperature in the nucleating...
Beam structures classical and advanced theories
Carrera, Erasmo; Petrolo, Marco
2011-01-01
Beam theories are exploited worldwide to analyze civil, mechanical, automotive, and aerospace structures. Many beam approaches have been proposed during the last centuries by eminent scientists such as Euler, Bernoulli, Navier, Timoshenko, Vlasov, etc. Most of these models are problem dependent: they provide reliable results for a given problem, for instance a given section and cannot be applied to a different one. Beam Structures: Classical and Advanced Theories proposes a new original unified approach to beam theory that includes practically all classical and advanced models for be
Prototype Theory and Classical Theory:An Explanation and Comparison
Institute of Scientific and Technical Information of China (English)
刘莹
2014-01-01
This paper discusses two different ways to understand categorization, which are classical theory and prototype theory. There is a deep exploration on how to understand categories, and different theoretical backgrounds of the two categorization the⁃ories. Furthermore, it reviews the limitations and advantages of both theories. And the comparison of the theories gives a clearer angle to understand their similarities and differences.
Emergence of classical theories from quantum mechanics
Hajicek, Petr
2012-01-01
Three problems stand in the way of deriving classical theories from quantum mechanics: those of realist interpretation, of classical properties and of quantum measurement. Recently, we have identified some tacit assumptions that lie at the roots of these problems. Thus, a realist interpretation is hindered by the assumption that the only properties of quantum systems are values of observables. If one simply postulates the properties to be objective that are uniquely defined by preparation then all difficulties disappear. As for classical properties, the wrong assumption is that there are arbitrarily sharp classical trajectories. It turns out that fuzzy classical trajectories can be obtained from quantum mechanics by taking the limit of high entropy. Finally, standard quantum mechanics implies that any registration on a quantum system is disturbed by all quantum systems of the same kind existing somewhere in the universe. If one works out systematically how quantum mechanics must be corrected so that there is ...
Lagrangian formulation of classical BMT-theory
International Nuclear Information System (INIS)
Full text: The most popular classical theory of electron has been formulated by Bargmann, Michel and Telegdi (BMT) in 1959. The BMT equations give classical relativistic description of a charged particle with spin and anomalous magnetic momentum moving in homogeneous electro-magnetic field. This allows to study spin dynamics of polarized beams in uniform fields. In particular, first experimental measurements of muon anomalous magnetic momentum were done using changing of helicity predicted by BMT equations. Surprisingly enough, a systematic formulation and the analysis of the BMT theory are absent in literature. In the present work we particularly fill this gap by deducing Lagrangian formulation (variational problem) for BMT equations. Various equivalent forms of Lagrangian will be discussed in details. An advantage of the obtained classical model is that the Lagrangian action describes a relativistic spinning particle without Grassmann variables, for both free and interacting cases. This implies also the possibility of canonical quantization. In the interacting case, an arbitrary electromagnetic background may be considered, which generalizes the BMT theory formulated to the case of homogeneous fields. The classical model has two local symmetries, which gives an interesting example of constrained classical dynamics. It is surprising, that the case of vanishing anomalous part of the magnetic momentum is naturally highlighted in our construction. (author)
Classical theory of the hydrogen atom
Rashkovskiy, Sergey
2016-01-01
It is shown that all of the basic properties of the hydrogen atom can be consistently described in terms of classical electrodynamics instead of taking the electron to be a particle; we consider an electrically charged classical wave field, an "electron wave", which is held in a limited region of space by the electrostatic field of the proton. It is shown that quantum mechanics must be considered to be not a theory of particles but a classical field theory in the spirit of classical electrodynamics. In this case, we are not faced with difficulties in interpreting the results of the theory. In the framework of classical electrodynamics, all of the well-known regularities of the spontaneous emission of the hydrogen atom are obtained, which is usually derived in the framework of quantum electrodynamics. It is shown that there are no discrete states and discrete energy levels of the atom: the energy of the atom and its states change continuously. An explanation of the conventional corpuscular-statistical interpre...
"Scars" connect classical and quantum theory
Monteiro, T
1990-01-01
Chaotic systems are unstable and extremely sensitive to initial condititions. So far, scientists have been unable to demonstrate that the same kind of behaviour exists in quantum or microscopic systems. New connections have been discovered though between classical and quantum theory. One is the phenomena of 'scars' which cut through the wave function of a particle (1 page).
The classical theory of fields electromagnetism
Helrich, Carl S
2012-01-01
The study of classical electromagnetic fields is an adventure. The theory is complete mathematically and we are able to present it as an example of classical Newtonian experimental and mathematical philosophy. There is a set of foundational experiments, on which most of the theory is constructed. And then there is the bold theoretical proposal of a field-field interaction from James Clerk Maxwell. This textbook presents the theory of classical fields as a mathematical structure based solidly on laboratory experiments. Here the student is introduced to the beauty of classical field theory as a gem of theoretical physics. To keep the discussion fluid, the history is placed in a beginning chapter and some of the mathematical proofs in the appendices. Chapters on Green’s Functions and Laplace’s Equation and a discussion of Faraday’s Experiment further deepen the understanding. The chapter on Einstein’s relativity is an integral necessity to the text. Finally, chapters on particle motion and waves in a dis...
Quantum field theory from classical statistics
Wetterich, C
2011-01-01
An Ising-type classical statistical model is shown to describe quantum fermions. For a suitable time-evolution law for the probability distribution of the Ising-spins our model describes a quantum field theory for Dirac spinors in external electromagnetic fields, corresponding to a mean field approximation to quantum electrodynamics. All quantum features for the motion of an arbitrary number of electrons and positrons, including the characteristic interference effects for two-fermion states, are described by the classical statistical model. For one-particle states in the non-relativistic approximation we derive the Schr\\"odinger equation for a particle in a potential from the time evolution law for the probability distribution of the Ising-spins. Thus all characteristic quantum features, as interference in a double slit experiment, tunneling or discrete energy levels for stationary states, are derived from a classical statistical ensemble. Concerning the particle-wave-duality of quantum mechanics, the discret...
Optimal search behavior and classic foraging theory
International Nuclear Information System (INIS)
Random walk methods and diffusion theory pervaded ecological sciences as methods to analyze and describe animal movement. Consequently, statistical physics was mostly seen as a toolbox rather than as a conceptual framework that could contribute to theory on evolutionary biology and ecology. However, the existence of mechanistic relationships and feedbacks between behavioral processes and statistical patterns of movement suggests that, beyond movement quantification, statistical physics may prove to be an adequate framework to understand animal behavior across scales from an ecological and evolutionary perspective. Recently developed random search theory has served to critically re-evaluate classic ecological questions on animal foraging. For instance, during the last few years, there has been a growing debate on whether search behavior can include traits that improve success by optimizing random (stochastic) searches. Here, we stress the need to bring together the general encounter problem within foraging theory, as a mean for making progress in the biological understanding of random searching. By sketching the assumptions of optimal foraging theory (OFT) and by summarizing recent results on random search strategies, we pinpoint ways to extend classic OFT, and integrate the study of search strategies and its main results into the more general theory of optimal foraging.
Emergence of classical theories from quantum mechanics
International Nuclear Information System (INIS)
Three problems stand in the way of deriving classical theories from quantum mechanics: those of realist interpretation, of classical properties and of quantum measurement. Recently, we have identified some tacit assumptions that lie at the roots of these problems. Thus, a realist interpretation is hindered by the assumption that the only properties of quantum systems are values of observables. If one simply postulates the properties to be objective that are uniquely defined by preparation then all difficulties disappear. As for classical properties, the wrong assumption is that there are arbitrarily sharp classical trajectories. It turns out that fuzzy classical trajectories can be obtained from quantum mechanics by taking the limit of high entropy. Finally, standard quantum mechanics implies that any registration on a quantum system is disturbed by all quantum systems of the same kind existing somewhere in the universe. If one works out systematically how quantum mechanics must be corrected so that there is no such disturbance, one finds a new interpretation of von Neumann's 'first kind of dynamics', and so a new way to a solution of the quantum measurement problem. The present paper gives a very short review of this work.
Emergence of classical theories from quantum mechanics
Hájíček, P.
2012-05-01
Three problems stand in the way of deriving classical theories from quantum mechanics: those of realist interpretation, of classical properties and of quantum measurement. Recently, we have identified some tacit assumptions that lie at the roots of these problems. Thus, a realist interpretation is hindered by the assumption that the only properties of quantum systems are values of observables. If one simply postulates the properties to be objective that are uniquely defined by preparation then all difficulties disappear. As for classical properties, the wrong assumption is that there are arbitrarily sharp classical trajectories. It turns out that fuzzy classical trajectories can be obtained from quantum mechanics by taking the limit of high entropy. Finally, standard quantum mechanics implies that any registration on a quantum system is disturbed by all quantum systems of the same kind existing somewhere in the universe. If one works out systematically how quantum mechanics must be corrected so that there is no such disturbance, one finds a new interpretation of von Neumann's "first kind of dynamics", and so a new way to a solution of the quantum measurement problem. The present paper gives a very short review of this work.
Classical solutions in quantum field theories
International Nuclear Information System (INIS)
Quantum field theories are difficult to solve because they are governed by nonlinear operator equations. A one-dimensional example, termed the kink, is presented of a classical solution. Topological and nontopological solitons in more than one spatial dimension are also discussed. Euclidean solutions and barrier penetration are also reviewed, focusing on vacuum decay by tunneling, Yang-Mills Instantons, the physical consequences of vacuum tunneling, and thermal fluctuations and sphalerons. 119 refs., 2 figs
Nucleation for Lennard-Jones Fluid by Density Functional Theory
Institute of Scientific and Technical Information of China (English)
FU Dong
2005-01-01
@@ A non-mean field density functional theory is employed to investigate the vapour-liquid nucleation. The excess Helmholtz free energy functional is formulated in terms of a local density approximation for short ranged repulsion and a density-gradient expansion for long-ranged attractions. An analytical expression for the direct correlation function of a Lennard-Jones fluid is utilized to take into account the effect of long-ranged attractions on intermolecular correlations. With the predicted bulk properties and surface tension as input, the nucleation properties including density profile, work of formation and number of particles at the reduced temperatures T* = 0.694 and 0.741 are inuestigated. The obtained number of particles in the critical nucleus agrees well with the simulation data.
A New Theory of Nucleate Pool Boiling in Arbitrary Gravity
Buyevich, Y. A.; Webbon, Bruce W.
1995-01-01
Heat transfer rates specific to nucleate pool boiling under various conditions are determined by the dynamics of vapour bubbles that are originated and grow at nucleation sites of a superheated surface. A new dynamic theory of these bubbles has been recently developed on the basis of the thermodynamics of irreversible processes. In contrast to other existing models based on empirically postulated equations for bubble growth and motion, this theory does not contain unwarrantable assumptions, and both the equations are rigorously derived within the framework of a unified approach. The conclusions of the theory are drastically different from those of the conventional models. The bubbles are shown to detach themselves under combined action of buoyancy and a surface tension force that is proven to add to buoyancy in bubble detachment, but not the other way round as is commonly presumed. The theory ensures a sound understanding of a number of so far unexplained phenomena, such as effect caused by gravity level and surface tension on the bubble growth rate and dependence of the bubble characteristics at detachment on the liquid thermophysical parameters and relevant temperature differences. The theoretical predictions are shown to be in a satisfactory qualitative and quantitative agreement with observations. When being applied to heat transfer at nucleate pool boiling, this bubble dynamic theory offers an opportunity to considerably improve the main formulae that are generally used to correlate experimental findings and to design boiling heat removal in various industrial applications. Moreover, the theory makes possible to pose and study a great deal of new problems of essential impact in practice. Two such problems are considered in detail. One problem concerns the development of a principally novel physical model for the first crisis of boiling. This model allows for evaluating critical boiling heat fluxes under various conditions, and in particular at different
Introduction to classical and quantum field theory
International Nuclear Information System (INIS)
This is the first introductory textbook on quantum field theory to be written from the point of view of condensed matter physics. As such, it presents the basic concepts and techniques of statistical field theory, clearly explaining how and why they are integrated into modern quantum (and classical) field theory, and includes the latest developments. Written by an expert in the field, with a broad experience in teaching and training, it manages to present such substantial topics as phases and phase transitions or solitons and instantons in an accessible and concise way. Divided into three parts, the first part covers fundamental physics and the mathematics background needed by students in order to enter the field, while the second part introduces more advanced concepts and techniques. Part III discusses applications of quantum field theory to a few basic problems. The emphasis here lies on how modern concepts of quantum field theory are embedded in these approaches, and also on the limitations of standard quantum field theory techniques in facing, 'real' physics problems. Throughout there are numerous end-of-chapter problems, and a free solutions manual is available for lecturers. (orig.)
Differential formalism aspects of the gauge classical theories
International Nuclear Information System (INIS)
The classical aspects of the gauge theories are shown using differential geometry as fundamental tool. Somme comments are done about Maxwell Electro-dynamics, classical Yang-Mills and gravitation theories. (L.C.)
RELEVANCE OF CLASSICALAND NEO-CLASSICAL THEORIES IN PRESENT WORLD
Heena Kashyap
2015-01-01
This paper attempts to explain the impact of various management theories on Modern organisations. Primary purpose of this paper is to explain the relevance of studying Classical and Neo classical theories in the present world. Though these theories don’t consider external environmental changes in Management of Organisation, but they still hold significant place in present scenario. Classical and Neo Classical theories provide foundations for understanding continuous changes in ...
Polynomial Invariant Theory of the Classical Groups
Westrich, Quinton
2011-01-01
The goal of invariant theory is to find all the generators for the algebra of representations of a group that leave the group invariant. Such generators will be called \\emph{basic invariants}. In particular, we set out to find the set of basic invariants for the classical groups GL$(V)$, O$(n)$, and Sp$(n)$ for $n$ even. In the first half of the paper we set up relevant definitions and theorems for our search for the set of basic invariants, starting with linear algebraic groups and then discussing associative algebras. We then state and prove a monumental theorem that will allow us to proceed with hope: it says that the set of basic invariants is finite if $G$ is reductive. Finally we state without proof the First Fundamental Theorems, which aim to list explicitly the relevant sets of basic invariants, for the classical groups above. We end by commenting on some applications of invariant theory, on the history of its development, and stating a useful theorem in the appendix whose proof lies beyond the scope ...
Robust topological degeneracy of classical theories
Vaezi, Mohammad-Sadegh; Ortiz, Gerardo; Nussinov, Zohar
2016-05-01
We challenge the hypothesis that the ground states of a physical system whose degeneracy depends on topology must necessarily realize topological quantum order and display nonlocal entanglement. To this end, we introduce and study a classical rendition of the Toric Code model embedded on Riemann surfaces of different genus numbers. We find that the minimal ground state degeneracy (and those of all levels) depends on the topology of the embedding surface alone. As the ground states of this classical system may be distinguished by local measurements, a characteristic of Landau orders, this example illustrates that topological degeneracy is not a sufficient condition for topological quantum order. This conclusion is generic and, as shown, it applies to many other models. We also demonstrate that certain lattice realizations of these models, and other theories, display a ground state entropy (and those of all levels) that is "holographic", i.e., extensive in the system boundary. We find that clock and U (1 ) gauge theories display topological (in addition to gauge) degeneracies.
Pólya distribution and its asymptotics in nucleation theory
Dubrovskii, V. G.
2014-02-01
A model of condensation-decay rate constants that are linear with respect to the number of monomers in the nucleus is considered. In a particular case of stable growth, this model leads to an exact solution of discrete kinetic equations of the theory of heterogeneous nucleation in the form of the Pólya distribution function. An asymptotic solution in the region of large nucleus sizes that satisfies the normalization condition and provides correct mean nucleus size has been found. It is shown that, in terms of the logarithmic invariant size, the obtained distribution has a universal time-independent form. The obtained solution, being more general than the double-exponent distribution used previously, describes both Gaussian and asymmetric distributions depending on the rate constant of condensation on a bare core. The obtained results are useful for modeling processes in some systems, in particular, the growth of linear chains, two-dimensional clusters, and filamentary nanocrystals.
An approximate classical unimolecular reaction rate theory
Zhao, Meishan; Rice, Stuart A.
1992-05-01
We describe a classical theory of unimolecular reaction rate which is derived from the analysis of Davis and Gray by use of simplifying approximations. These approximations concern the calculation of the locations of, and the fluxes of phase points across, the bottlenecks to fragmentation and to intramolecular energy transfer. The bottleneck to fragment separation is represented as a vibration-rotation state dependent separatrix, which approximation is similar to but extends and improves the approximations for the separatrix introduced by Gray, Rice, and Davis and by Zhao and Rice. The novel feature in our analysis is the representation of the bottlenecks to intramolecular energy transfer as dividing surfaces in phase space; the locations of these dividing surfaces are determined by the same conditions as locate the remnants of robust tori with frequency ratios related to the golden mean (in a two degree of freedom system these are the cantori). The flux of phase points across each dividing surface is calculated with an analytic representation instead of a stroboscopic mapping. The rate of unimolecular reaction is identified with the net rate at which phase points escape from the region of quasiperiodic bounded motion to the region of free fragment motion by consecutively crossing the dividing surfaces for intramolecular energy exchange and the separatrix. This new theory generates predictions of the rates of predissociation of the van der Waals molecules HeI2, NeI2 and ArI2 which are in very good agreement with available experimental data.
Hilbert space theory of classical electrodynamics
Indian Academy of Sciences (India)
RAJAGOPAL A K; GHOSE PARTHA
2016-06-01
Classical electrodynamics is reformulated in terms of wave functions in the classical phase space of electrodynamics, following the Koopman–von Neumann–Sudarshan prescription for classical mechanics on Hilbert spaces sans the superselection rule which prohibits interference effects in classical mechanics. This is accomplished by transforming from a set of commutingobservables in one Hilbert space to another set of commuting observables in a larger Hilbert space. This is necessary to clarify the theoretical basis of the much recent work on quantum-like features exhibited by classical optics. Furthermore, following Bondar et al, {\\it Phys. Rev.} A 88, 052108 (2013), it is pointed out that quantum processes that preserve the positivity or nonpositivity of theWigner function can be implemented by classical optics. This may be useful in interpreting quantum information processing in terms of classical optics.
Confining properties of the classical SU(3) Yang - Mills theory
Dzhunushaliev, V D
1996-01-01
The spherically and cylindrically symmetric solutions of the $SU(3)$ Yang - Mills theory are obtained. The corresponding gauge potential has the confining properties. It is supposed that: a) the spherically symmetric solution is a field distribution of the classical ``quark'' and in this sense it is similar to the Coulomb potential; b) the cylindrically symmetric solution describes a classical field ``string'' (flux tube) between two ``quarks''. It is noticed that these solutions are typically for the classical $SU(3)$ Yang - Mills theory in contradiction to monopole that is an exceptional solution. This allows to conclude that the confining properties of the classical $SU(3)$ Yang - Mills theory are general properties of this theory.
The Possibility of Reconciling Quantum Mechanics with Classical Probability Theory
Slavnov, D. A.
2007-01-01
We describe a scheme for constructing quantum mechanics in which a quantum system is considered as a collection of open classical subsystems. This allows using the formal classical logic and classical probability theory in quantum mechanics. Our approach nevertheless allows completely reproducing the standard mathematical formalism of quantum mechanics and identifying its applicability limits. We especially attend to the quantum state reduction problem.
Introducing quantum effects in classical theories
Fabris, J C; Rodrigues, D C; Daouda, M H
2015-01-01
In this paper, we explore two different ways of implementing quantum effects in a classical structure. The first one is through an external field. The other one is modifying the classical conservation laws. In both cases, the consequences for the description of the evolution of the universe are discussed.
Nucleation theory beyond the deterministic limit. II. The growth stage.
Dubrovskii, V G; Nazarenko, M V
2010-03-21
This work addresses theory of nucleation and condensation based on the continuous Fokker-Plank type kinetic equation for the distribution of supercritical embryos over sizes beyond the deterministic limit. The second part of the work treats the growth stage and the beginning of the Ostwald ripening. We first study in detail the fluctuation-induced spreading of size spectrum at the growth stage. It is shown that the spectrum should be generally obtained by the convolution of the initial distribution with the Gaussian-like Green function with spreading dispersion. The increase in dispersion depends, however, on the growth index m as well as on the space dimension, and the mode of material influx. In particular, we find that the spreading effect on two-dimensional islands growing at a constant material influx is huge at m=1 but almost absent at m=2. Analytical and numerical solutions for the mean size, the dispersion, and the size spectrum are presented in different cases. Finally, the general condition for the stage of Ostwald ripening in an open system with material influx is discussed. PMID:20331306
Gauge-fields and integrated quantum-classical theory
International Nuclear Information System (INIS)
Physical situations in which quantum systems communicate continuously to their classically described environment are not covered by contemporary quantum theory, which requires a temporary separation of quantum degrees of freedom from classical ones. A generalization would be needed to cover these situations. An incomplete proposal is advanced for combining the quantum and classical degrees of freedom into a unified objective description. It is based on the use of certain quantum-classical structures of light that arise from gauge invariance to coordinate the quantum and classical degrees of freedom. Also discussed is the question of where experimenters should look to find phenomena pertaining to the quantum-classical connection. 17 refs
Characterizing protein crystal nucleation
Akella, Sathish V.
We developed an experimental microfluidic based technique to measure the nucleation rates and successfully applied the technique to measure nucleation rates of lysozyme crystals. The technique involves counting the number of samples which do not have crystals as a function of time. Under the assumption that nucleation is a Poisson process, the fraction of samples with no crystals decays exponentially with the decay constant proportional to nucleation rate and volume of the sample. Since nucleation is a random and rare event, one needs to perform measurements on large number of samples to obtain good statistics. Microfluidics offers the solution of producing large number of samples at minimal material consumption. Hence, we developed a microfluidic method and measured nucleation rates of lysozyme crystals in supersaturated protein drops, each with volume of ˜ 1 nL. Classical Nucleation Theory (CNT) describes the kinetics of nucleation and predicts the functional form of nucleation rate in terms of the thermodynamic quantities involved, such as supersaturation, temperature, etc. We analyzed the measured nucleation rates in the context of CNT and obtained the activation energy and the kinetic pre-factor characterizing the nucleation process. One conclusion is that heterogeneous nucleation dominates crystallization. We report preliminary studies on selective enhancement of nucleation in one of the crystal polymorprhs of lysozyme (spherulite) using amorphous mesoporous bioactive gel-glass te{naomi06, naomi08}, CaO.P 2O5.SiO2 (known as bio-glass) with 2-10 nm pore-size diameter distribution. The pores act as heterogeneous nucleation centers and claimed to enhance the nucleation rates by molecular confinement. The measured kinetic profiles of crystal fraction of spherulites indicate that the crystallization of spherulites may be proceeding via secondary nucleation pathways.
Introduction to Classical Density Functional Theory by a Computational Experiment
Jeanmairet, Guillaume; Levy, Nicolas; Levesque, Maximilien; Borgis, Daniel
2014-01-01
We propose an in silico experiment to introduce the classical density functional theory (cDFT). Density functional theories, whether quantum or classical, rely on abstract concepts that are nonintuitive; however, they are at the heart of powerful tools and active fields of research in both physics and chemistry. They led to the 1998 Nobel Prize in…
HCI Theory Classical, Modern, and Contemporary
Rogers, Yvonne
2012-01-01
Theory is the bedrock of many sciences, providing a rigorous method toadvance knowledge through testing and falsifying hypotheses aboutobservable phenomena. To begin with, the nascent field of HCI followedsuit, borrowing theories from cognitive science to test theories aboutuser performance at the interface.But HCI has emerged as an eclectic interdiscipline rather than a welldefinedscience. It now covers all aspects of human life, from birth tobereavement, through all manner of computing, from device ecologiesto nanotechnology. It comes as no surprise that the role of theory in HCIhas also gre
Dense matter theory a simple classical approach
Savic, P
1998-01-01
In the sixties,the first author and R.Kasanin have started developing a mean field theory of dense matter.This paper presents a short review of the basic ideas of the theory,and discusses some examples of its applications,which range from DAC experiments to modelling of planetary interiors.
Functional Approach to Classical Yang-Mills Theories
Carta, P
2002-01-01
Sometime ago it was shown that the operatorial approach to classical mechanics, pioneered in the 30's by Koopman and von Neumann, can have a functional version. In this talk we will extend this functional approach to the case of classical field theories and in particular to the Yang-Mills ones. We shall show that the issues of gauge-fixing and Faddeev-Popov determinant arise also in this classical formalism.
Evaluation of time-dependent void nucleation theory under ion bombardment conditions
International Nuclear Information System (INIS)
The applicability of a steady state and time-dependent homogeneous void nucleation theory to charged-particle irradiation experiments was investigated. The steady-state theory was found to be inappropriate, since significant changes in a metal's microstructure would likely occur before the void nucleation rate could reach steady state. Two types of time dependence were examined, that of the point defect concentrations at the beginning of an irradiation and the longer-term time dependence of void nucleation. It was found that vacancy and interstitial clustering significantly reduce the relaxation time for the point defect concentrations. An efficient form of time-dependent homogeneous nucleation theory was applied to ion bombardment conditions to predict void size distributions
Classical conformality in the Standard Model from Coleman's theory
Kawana, Kiyoharu
2016-01-01
The classical conformality is one of the possible candidates for explaining the gauge hierarchy of the Standard Model. We show that it is naturally obtained from the Coleman's theory on baby universe.
Experimental assessment of unvalidated assumptions in classical plasticity theory.
Energy Technology Data Exchange (ETDEWEB)
Brannon, Rebecca Moss (University of Utah, Salt Lake City, UT); Burghardt, Jeffrey A. (University of Utah, Salt Lake City, UT); Bauer, Stephen J.; Bronowski, David R.
2009-01-01
This report investigates the validity of several key assumptions in classical plasticity theory regarding material response to changes in the loading direction. Three metals, two rock types, and one ceramic were subjected to non-standard loading directions, and the resulting strain response increments were displayed in Gudehus diagrams to illustrate the approximation error of classical plasticity theories. A rigorous mathematical framework for fitting classical theories to the data, thus quantifying the error, is provided. Further data analysis techniques are presented that allow testing for the effect of changes in loading direction without having to use a new sample and for inferring the yield normal and flow directions without having to measure the yield surface. Though the data are inconclusive, there is indication that classical, incrementally linear, plasticity theory may be inadequate over a certain range of loading directions. This range of loading directions also coincides with loading directions that are known to produce a physically inadmissible instability for any nonassociative plasticity model.
Classical gravity coupled to Liouville theory
International Nuclear Information System (INIS)
We consider the two dimensional Jackiw-Teitelboim model of gravity. We first couple the model to the Liouville action and c scalar fields and show, treating the combined system as a non linear sigma model, that the resulting theory can be interpreted as a critical string moving in a target space of dimension D = c + 2. We then analyse perturbatively a generalized model containing a kinetic term and an arbitrary potential for the auxiliary field. We use the background field method and work covariant gauges. We show that the renormalizability of the theory depends on the form of the potential. For a general potential, the theory can be renormalized as a non linear sigma model. In the particular case of a Liouville-like potential, the theory is renormalized in the usual sense. (author). 31 refs
Classical gravity coupled to Liouville theory
International Nuclear Information System (INIS)
We consider the two dimensional Jackiw-Teitelboim model of gravity. We first couple the model to the Liouville action and c scalar fields and show, treating the combined system as a non linear sigma model, that the resulting theory can be interpreted as a critical string moving in a target space of dimension D=c+2. We then analyze the model from a perturbative point of view. We show in particular that the results of conformal field theory are exactly reproduced at the one-loop level. We also show that the theory is one loop finite if the cosmological constant Λ is equal to zero. When Λ is different from zero the one loop divergences are gauge-fixing dependent even on-shell. However, the theory can be renormalized as a non linear sigma model if a kinetic term is included for the auxiliary field. (author). 27 refs
Heterogeneous nucleation of calcium oxalate on native oxide surfaces
International Nuclear Information System (INIS)
The aqueous deposition of calcium oxalate onto colloidal oxides has been studied as a model system for understanding heterogeneous nucleation processes of importance in biomimetic synthesis of ceramic thin films. Calcium oxalate nucleation has been monitored by measuring induction times for nucleation using Constant Composition techniques and by measuring nucleation densities on extended oxide surfaces using an atomic force microscope. Results show that the dependence of calcium oxalate nucleation on solution supersaturation fits the functional form predicted by classical nucleation theories. Anionic surfaces appear to promote nucleation better than cationic surfaces, lowering the effective energy barrier to heterogeneous nucleation
Conformal Invariance in Classical Field Theory
Grigore, D. R.
1993-01-01
A geometric generalization of first-order Lagrangian formalism is used to analyse a conformal field theory for an arbitrary primary field. We require that global conformal transformations are Noetherian symmetries and we prove that the action functional can be taken strictly invariant with respect to these transformations. In other words, there does not exists a "Chern-Simons" type Lagrangian for a conformally invariant Lagrangian theory.
The semi classical laser theory and some applications of laser
International Nuclear Information System (INIS)
The semi classical laser theory is concerned with the interaction between light and matter in such a way that the matter is treated quantum-mechanically whereas light is treated in terms of the classical electromagnetic equations. In this work the Maxwell-Bloch equations are employed to describe the interaction between light and matter. Applications of the theory as well as different types of lasers are reviewed. (Author)
Vibration of Timoshenko Beams Using Non-classical Elasticity Theories
J.V. Araújo dos Santos; J.N. Reddy
2012-01-01
This paper presents a comparison among classical elasticity, nonlocal elasticity, and modified couple stress theories for free vibration analysis of Timoshenko beams. A study of the influence of rotary inertia and nonlocal parameters on fundamental and higher natural frequencies is carried out. The nonlocal natural frequencies are found to be lower than the classical ones, while the natural frequencies estimated by the modified couple stress theory are higher. The modified couple stress theor...
From Classical to Quantum Shannon Theory
Wilde, Mark M
2011-01-01
The aim of this book is to develop "from the ground up" all of the major, exciting, pre- and post-millenium developments in the general area of study known as quantum Shannon theory. As such, we spend a significant amount of time on quantum mechanics for quantum information theory (Part II), we give a careful study of the important unit protocols of teleportation, super-dense coding, and entanglement distribution (Part III), and we develop many of the tools necessary for understanding information transmission or compression (Part IV). Parts V and VI are the culmination of this book, where all of the tools developed come into play for understanding many of the important results in quantum Shannon theory.
[The establishment, contributions, and final results of classical medical theories].
Wang, Tai
2013-01-01
In countries with ancient civilization of both Eastern world and Western world, after the accumulation of clinical experiences of "empirical medicine" to a sufficient amount; in accordance of their primitive philosophical thoughts, classical medical theories were established to play an important role in guiding the clinical practice of "empirical medicine". Because of the similarity of philosophical thoughts all over the ancient world, their medical theories were also very similar to each other. After the scientific evaluation and improvement, Greek classical medical theories were inherited, refined or abandoned, and then eventually finished their historical mission. Chinese classical medical theories also need the similar scientific identification and improvement for flowing into the authorized main stream of modern medical theory systems to continuously apply their guiding roles in clinical practice. Scholars would better consider the developmental principles of cultures and sciences with a historical viewpoint and an open mind to avoid making mistakes from haughty and prejudice. PMID:23596779
Deliquescence and efflorescence of small particles: Unifying perspectives from nucleation theory
Energy Technology Data Exchange (ETDEWEB)
McGraw,R.; Lewis, E.
2009-02-23
We examine size dependent deliquescence/efflorescence phase transformation for particles down to several nanometers in size. A thin layer criterion (TLC) is introduced to define a deliquescence relative humidity (DRH) for small particles. The usual bulk deliquescence conditions are recovered in the limit of large dry particle size. Nano-size particles are shown to deliquesce to metastable states via a nucleation process at relative humidity just below the DRH. The nucleation barrier is located at a critical solution layer thickness and vanishes at the DRH defined by the TLC. Methods from nucleation theory form the basis for the analysis and yield new insights into the theory, facilitate the interpretation of measurements, and point to unification of deliquescence and efflorescence processes for particles in the nano regime. Methods include thermodynamic area constructions, Legendre transforms relating the binary free-energy surfaces for deliquescence and efflorescence processes, and application of nucleation theorems.
Reexamination of Correlations for Nucleate Site Distribution on Boiling Surface by Fractal Theory
Institute of Scientific and Technical Information of China (English)
YangChunxin
1997-01-01
Nucleate site distribution plays an essential role in nucleate boiling process.In this paper,it is pointed out that the size and spatial distributioin density of nucleate sites presented on real boiling surface can be described by the normalized fractal distribution function,and the physical meaning of parameters involved in some experimental correlations proposed by early investigations are identified according to fractal distribution function.It is further suggested that the surface micro geometry characteristics such as the shape of cavities should be described and analyzed qualitatively by using fractal theory.
Classical Coupled Mode Theory of Optomechanical Crystals
Khorasani, Sina
2016-01-01
Acousto-optic interaction in optomechanical crystals allows unidirectional control of elastic waves over optical waves. However, as a result of this nonlinear interaction, infinitely many optical modes are born. This article presents an exact formulaion of coupled mode theory for interaction between elastic Bloch wave waves and photonic Bloch waves moving in a phonotonic waveguide. In general, an optical wavefront is strongly diffracted by an elastic wave in frequency and wavevector, and thus infinite modes with different frequencies and wavevectors appear. We discuss resonance and mode conversion conditions, and present a rigorous method to derive coupling rates and mode profiles. We also find a conservation law which rules over total optical power from interacting individual modes. Modifications of the theory to phonotonic cavities are also discussed. We present application examples including switch, frequency shifter, and reflector.
Computation Of Nucleation Rates For N-Nonane Using The Gradient Theory
Czech Academy of Sciences Publication Activity Database
Labetski, D.G.; Hrubý, Jan; Vinš, Václav; Dongen, M. E. H.
Vienna : Springer Netherlands , 2007, s. 97-101. ISBN 978-1-4020-6474-6. [Nucleation and Atmospheric Aerosols International Conference /17./. Galway (IE), 13.08.2007-17.08.2007] R&D Projects: GA ČR GA101/05/0136 Institutional research plan: CEZ:AV0Z20760514 Keywords : homogeneous nucleation * gradient theory * nonane Subject RIV: BJ - Thermodynamics http://www.springerlink.com/content/r278044g8244v561/
Satin, Seema
2015-01-01
We attempt to introduce an new approach towards study of certain interesting issues in classical gravity. This can be done for few confined, but interesting and meaningful physical situations, which can be modeled by a classical stochastic Einstein equation. The Einstein equation can be looked upon as an equation of motion, while introducing to it a classical stochastic source or classical fluctuations as driving source. This is analogous to the Langevin equation formalism, in Brownian motion studies. A justification for the validity of such an ansatz for classical gravity is given. The regime of validity of such an approach and the consequences and possible outcomes of this formulation are discussed. We also mention, further relevant directions and applications of the same,that act as motivation towards the new proposal. This field of study can be seen to emerge out of well established ideas and results in Brownian motion theory as well as the Stochastic Semiclassical Gravity (which is already an active area...
Bleb Nucleation through Membrane Peeling
Alert, Ricard
2016-01-01
We study the nucleation of blebs, i.e., protrusions arising from a local detachment of the membrane from the cortex of a cell. Based on a simple model of elastic linkers with force-dependent kinetics, we show that bleb nucleation is governed by membrane peeling. By this mechanism, the growth or shrinkage of a detached membrane patch is completely determined by the linker kinetics, regardless of the energetic cost of the detachment. We predict the critical nucleation radius for membrane peeling and the corresponding effective energy barrier. These may be typically smaller than those predicted by classical nucleation theory, implying a much faster nucleation. We also perform simulations of a continuum stochastic model of membrane-cortex adhesion to obtain the statistics of bleb nucleation times as a function of the stress on the membrane. The determinant role of membrane peeling changes our understanding of bleb nucleation and opens new directions in the study of blebs.
Bleb Nucleation through Membrane Peeling
Alert, Ricard; Casademunt, Jaume
2016-02-01
We study the nucleation of blebs, i.e., protrusions arising from a local detachment of the membrane from the cortex of a cell. Based on a simple model of elastic linkers with force-dependent kinetics, we show that bleb nucleation is governed by membrane peeling. By this mechanism, the growth or shrinkage of a detached membrane patch is completely determined by the linker kinetics, regardless of the energetic cost of the detachment. We predict the critical nucleation radius for membrane peeling and the corresponding effective energy barrier. These may be typically smaller than those predicted by classical nucleation theory, implying a much faster nucleation. We also perform simulations of a continuum stochastic model of membrane-cortex adhesion to obtain the statistics of bleb nucleation times as a function of the stress on the membrane. The determinant role of membrane peeling changes our understanding of bleb nucleation and opens new directions in the study of blebs.
Introduction to Classical Density Functional Theory by Computational Experiment
Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel
2014-01-01
We present here an introductory practical course to classical density functional theory (cDFT). Density functional theories, whether quantum or classical, rely largely on nonintuitive abstract concepts and applied mathematics. They are nevertheless a powerful tool and an active field of research in physics and chemistry that led to the 1998 Nobel prize in chemistry. We here illustrate the DFT in its most mathematically simple and yet physically relevant form: the classical density functional theory of an ideal fluid in an external field, as applied to the prediction of the structure of liquid neon at the molecular scale. This introductory course is built around the production of a cDFT code written by students using the Mathematica language. In this way, they are brought to deal with (i) the cDFT theory itself, (ii) some basic concepts around the statistical mechanics of simple fluids, (iii) the underlying mathematical and numerical problem of functional minimization, and (iv) a functional programming languag...
Lectures on Classical and Quantum Theory of Fields
Arodź, Henryk
2010-01-01
This textbook on classical and quantum theory of fields addresses graduate students starting to specialize in theoretical physics. It provides didactic introductions to the main topics in the theory of fields, while taking into account the contemporary view of the subject. The student will find concise explanations of basic notions essential for applications of the theory of fields as well as for frontier research in theoretical physics. One third of the book is devoted to classical fields. Each chapter contains exercises of varying degree of difficulty with hints or solutions, plus summaries and worked examples as useful. The textbook is based on lectures delivered to students of theoretical physics at Jagiellonian University. It aims to deliver a unique combination of classical and quantum field theory in one compact course.
Lectures on classical and quantum theory of fields
International Nuclear Information System (INIS)
This textbook on classical and quantum theory of fields addresses graduate students starting to specialize in theoretical physics. It provides didactic introductions to the main topics in the theory of fields, while taking into account the contemporary view of the subject. The student will find concise explanations of basic notions essential for applications of the theory of fields as well as for frontier research in theoretical physics. One third of the book is devoted to classical fields. Each chapter contains exercises of varying degree of difficulty with hints or solutions, plus summaries and worked examples as useful. The textbook is based on lectures delivered to students of theoretical physics at Jagiellonian University. It aims to deliver a unique combination of classical and quantum field theory in one compact course. (orig.)
The Jackiw-Pi model: Classical theory
International Nuclear Information System (INIS)
Full text: One of the central problems in the framework of gauge field theories is the issue of gauge field mass. Gauge symmetry is not, in principle, conflicting with the presence of a massive gauge boson. In two space-time dimensions, the well-known Schwinger model puts in evidence the presence of a massive photon without the breaking of gauge symmetry. Another evidence for the compatibility between gauge symmetry and massive vector fields comes from the study of three-dimensional gauge theories. A topological mass term referred to as the Chern-Simons Lagrangian, once added to the Yang-Mills term, shifts the photon mass to a non-vanishing value without breaking gauge invariance, however parity symmetry is lost. In 1997, a massive even-parity non- Abelian gauge model in three space-time dimensions has been proposed by Jackiw and Pi, which is studied, at the tree-level, in this work. The propagators are computed and the spectrum consistency is analyzed, besides, the symmetries of the model are collected and established through BRS invariance and Slavnov-Taylor identity. In the Landau gauge, thanks to the antighost equations and the Slavnov-Taylor identity, two rigid symmetries are identified by means of Ward identities. It is presented here a promising path for perturbatively quantization of the Jackiw-Pi model and a hint concerning its possible quantum scale invariance is also pointed out. (author)
Grigorenko, Alexander Ya; Grigorenko, Yaroslav M; Vlaikov, Georgii G
2016-01-01
This volume focuses on the relevant general theory and presents some first applications, namely those based on classical shell theory. After a brief introduction, during which the history and state-of-the-art are discussed, the first chapter presents the mechanics of anisotropic heterogeneous shells, covering all relevant assumptions and the basic relations of 3D elasticity, classical and refined shell models. The second chapter examines the numerical techniques that are used, namely discrete orthogonalization, spline-collocation and Fourier series, while the third highlights applications based on classical theory, in particular, the stress-strain state of shallow shells, non-circular shells, shells of revolution, and free vibrations of conical shells. The book concludes with a summary and an outlook bridging the gap to the second volume.
Classical Solutions in Quantum Field Theory
International Nuclear Information System (INIS)
Quantum field theory has evolved from its early beginnings as a tool for understanding the interaction of light with matter into a rather formidable technical paradigm, one that has successfully provided the mathematical underpinnings of all non-gravitational interactions. Over the eight decades since it was first contemplated the methods have become increasingly more streamlined and sophisticated, yielding new insights into our understanding of the subatomic world and our abilities to make clear and precise predictions. Some of the more elegant methods have to do with non-perturbative and semiclassical approaches to the subject. The chief players here are solitons, instantons, and anomalies. Over the past three decades there has been a steady rise in our understanding of these objects and of our ability to calculate their effects and implications for the rest of quantum field theory. This book is a welcome contribution to this subject. In 12 chapters it provides a clear synthesis of the key developments in these subjects at a level accessible to graduate students that have had an introductory course to quantum field theory. In the author's own words it provides both 'a survey and an overview of this field'. The first half of the book concentrates on solitons-–kinks, vortices, and magnetic monopoles-–and their implications for the subject. The reader is led first through the simplest models in one spatial dimension, into more sophisticated cases that required more advanced topological methods. The author does quite a nice job of introducing the various concepts as required, and beginning students should be able to get a good grasp of the subject directly from the text without having to first go through the primary literature. The middle part of the book deals with the implications of these solitons for both cosmology and for duality. While the cosmological discussion is quite nice, the discussion on BPS solitons, supersymmetry and duality is
Classical theory of nonlinear Compton scattering
International Nuclear Information System (INIS)
The covariant dynamics of a single electron subjected to the electromagnetic field of an intense, ultrashort laser pulse in vacuum is studied theoretically at arbitrary intensities, in the context of the Dirac-Lorentz equation, which has long been suggested as a possible theory including the radiative reaction due to the electron self-interaction. A brief review of the Lorentz-Maxwell electrodynamics including canonical invariants and scattered light spectra will be given, with a special emphasis on frequency modulation effects associated to the nonlinear relativistic Doppler shift induced by radiation pressure on the backscattered radiation. For circular polarization, an exact analytical expression for the full nonlinear spectrum is derived, and is presented. It is found that the scattering of coherent light by an electron describing a well-behaved trajectory can yield chaotic spectra when the laser ponderomotive force strongly modulates the electron's proper time. The Dirac-Lorentz equation is then derived and integrated numerically backward in time to ensure convergence towards the unique acausal solution satisfying the Dirac-Rohrlich asymptotic conditions (no runaway, law of inertia), and its consequences are investigated in terms of nonlinear Compton scattering. The relevance of this work to laser acceleration, as well as ongoing nonlinear Compton scattering experiments at SLAC and to the proposed γ-γ collider will also be discussed
A classical theory of continuous spin and hidden gauge invariance
International Nuclear Information System (INIS)
We present a classical higher derivative point particle theory whose quantization gives Wigner's continuous spin representation of the Poincare group. Although the theory is not reparameterization invariant in the usual sense, it does possess a hidden gauge invariance that provides a non-local representation of the reparameterization group. The Hamiltonian of the theory does not vanish and its value is the continuous spin parameter. The theory presented here represents the simplest example of a wide class of higher derivative theories possessing a hidden gauge invariance
A classical theory of continuous spin and hidden gauge invariance
Energy Technology Data Exchange (ETDEWEB)
Zoller, D.
1991-01-01
We present a classical higher derivative point particle theory whose quantization gives Wigner's continuous spin representation of the Poincare group. Although the theory is not reparameterization invariant in the usual sense, it does possess a hidden gauge invariance that provides a non-local representation of the reparameterization group. The Hamiltonian of the theory does not vanish and its value is the continuous spin parameter. The theory presented here represents the simplest example of a wide class of higher derivative theories possessing a hidden gauge invariance.
A classical theory of continuous spin and hidden gauge invariance
Energy Technology Data Exchange (ETDEWEB)
Zoller, D.
1991-12-31
We present a classical higher derivative point particle theory whose quantization gives Wigner`s continuous spin representation of the Poincare group. Although the theory is not reparameterization invariant in the usual sense, it does possess a hidden gauge invariance that provides a non-local representation of the reparameterization group. The Hamiltonian of the theory does not vanish and its value is the continuous spin parameter. The theory presented here represents the simplest example of a wide class of higher derivative theories possessing a hidden gauge invariance.
Quantum Mind from a Classical Field Theory of the Brain
Zizzi, Paola
2011-01-01
We suggest that, with regard to a theory of quantum mind, brain processes can be described by a classical, dissipative, non-abelian gauge theory. In fact, such a theory has a hidden quantum nature due to its non-abelian character, which is revealed through dissipation, when the theory reduces to a quantum vacuum, where temperatures are of the order of absolute zero, and coherence of quantum states is preserved. We consider in particular the case of pure SU(2) gauge theory with a special anzat...
Quantum fermions and quantum field theory from classical statistics
Wetterich, C.
2012-01-01
An Ising-type classical statistical ensemble can describe the quantum physics of fermions if one chooses a particular law for the time evolution of the probability distribution. It accounts for the time evolution of a quantum field theory for Dirac particles in an external electromagnetic field. This yields in the non-relativistic one-particle limit the Schr\\"odinger equation for a quantum particle in a potential. Interference or tunneling arise from classical probabilities.
Resonances and adiabatic invariance in classical and quantum scattering theory
Jain, S R
2004-01-01
We discover that the energy-integral of time-delay is an adiabatic invariant in quantum scattering theory and corresponds classically to the phase space volume. The integral thus found provides a quantization condition for resonances, explaining a series of results recently found in non-relativistic and relativistic regimes. Further, a connection between statistical quantities like quantal resonance-width and classical friction has been established with a classically deterministic quantity, the stability exponent of an adiabatically perturbed periodic orbit. This relation can be employed to estimate the rate of energy dissipation in finite quantum systems.
Classical theory of atomic collisions - The first hundred years
Grujić, Petar V.
2012-05-01
Classical calculations of the atomic processes started in 1911 with famous Rutherford's evaluation of the differential cross section for α particles scattered on foil atoms [1]. The success of these calculations was soon overshadowed by the rise of Quantum Mechanics in 1925 and its triumphal success in describing processes at the atomic and subatomic levels. It was generally recognized that the classical approach should be inadequate and it was neglected until 1953, when the famous paper by Gregory Wannier appeared, in which the threshold law for the single ionization cross section behaviour by electron impact was derived. All later calculations and experimental studies confirmed the law derived by purely classical theory. The next step was taken by Ian Percival and collaborators in 60s, who developed a general classical three-body computer code, which was used by many researchers in evaluating various atomic processes like ionization, excitation, detachment, dissociation, etc. Another approach was pursued by Michal Gryzinski from Warsaw, who started a far reaching programme for treating atomic particles and processes as purely classical objects [2]. Though often criticized for overestimating the domain of the classical theory, results of his group were able to match many experimental data. Belgrade group was pursuing the classical approach using both analytical and numerical calculations, studying a number of atomic collisions, in particular near-threshold processes. Riga group, lead by Modris Gailitis [3], contributed considerably to the field, as it was done by Valentin Ostrovsky and coworkers from Sanct Petersbourg, who developed powerful analytical methods within purely classical mechanics [4]. We shall make an overview of these approaches and show some of the remarkable results, which were subsequently confirmed by semiclassical and quantum mechanical calculations, as well as by the experimental evidence. Finally we discuss the theoretical and
Introduction to classical and quantum Lagrangian field theory. 9
International Nuclear Information System (INIS)
The basic principles of relativistic Lagrangian field theory are introduced, first in the classical context and later in the quantized form. Various free fields are discussed, their quantization, Lorentz invariance and the important discrete symmetries. Going on to interacting quantum fields, the invariant perturbation theory and Feynman graphs are succinctly discussed. Renormalizability and renormalization methods are covered with emphasis on the method of dimensional regularization. (author).3 refs.; 7 figs
Classical electromagnetic field theory in the presence of magnetic sources
Chen, W J; Naón, C M; Chen, Wen-Jun; Li, Kang
2001-01-01
Using two new well defined 4-dimensional potential vectors, we formulate the classical Maxwell's field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources. We set up a consistent Lagrangian for the theory. Then from the action principle we get both Maxwell's equation and the equation of motion of a dyon moving in the electro-magnetic field.
Classical Electromagnetic Field Theory in the Presence of Magnetic Sources
Institute of Scientific and Technical Information of China (English)
LI Kang(李康); CHEN Wen-Jun(陈文俊); NAON Carlos M.
2003-01-01
Using two new well-defined four-dimensional potential vectors, we formulate the classical Maxwell field theory in a form which has manifest Lorentz covariance and SO(2) duality symmetry in the presence of magnetic sources.We set up a consistent Lagrangian for the theory. Then from the action principle we obtain both Maxwell's equation and the equation of motion of a dyon moving in the electromagnetic field.
Representational Realism, Closed Theories and the Quantum to Classical Limit
de Ronde, Christian
2016-01-01
In this paper we discuss the representational realist stance as a pluralist ontic approach to inter-theoretic relationships. Our stance stresses the fact that physical theories require the necessary consideration of a conceptual level of discourse which determines and configures the specific field of phenomena discussed by each particular theory. We will criticize the orthodox line of research which has grounded the analysis about QM in two (Bohrian) metaphysical presuppositions -accepted in the present as dogmas that all interpretations must follow. We will also examine how the orthodox project of "bridging the gap" between the quantum and the classical domains has constrained the possibilities of research, producing only a limited set of interpretational problems which only focus in the justification of "classical reality" and exclude the possibility of analyzing the possibilities of non-classical conceptual representations of QM. The representational realist stance introduces two new problems, namely, the ...
On the variational formulation of classical Abelian gauge field theories
International Nuclear Information System (INIS)
It is shown how one can formulate an action principle for classical Abelian gauge theories not by means of gauge potentials and currents but in terms of the gauge invariant field strengths and gauge variant stream potentias. The discussion is on a general formal level in n=s+t space-time dimensions and uses, for brevity, the language of differential forms
Energy Technology Data Exchange (ETDEWEB)
Fradera, J., E-mail: jfradera@ubu.es; Cuesta-López, S., E-mail: scuesta@ubu.es
2013-12-15
Highlights: • The work presented in this manuscript provides a reliable computational tool to quantify the He complex phenomena in a HCLL. • A model based on the self-consistent nucleation theory (SCT) is exposed. It includes radiation induced nucleation modelling and surface tension corrections. • Results informed reinforce the necessity of conducting experiments to determine nucleation conditions and bubble transport parameters in LM breeders. • Our findings and model provide a good qualitative insight into the helium nucleation phenomenon in LM systems for fusion technology and can be used to identify key system parameters. -- Abstract: Helium (He) nucleation in liquid metal breeding blankets of a DT fusion reactor may have a significant impact regarding system design, safety and operation. Large He production rates are expected due to tritium (T) fuel self-sufficiency requirement, as both, He and T, are produced at the same rate. Low He solubility, local high concentrations, radiation damage and fluid discontinuities, among other phenomena, may yield the necessary conditions for He nucleation. Hence, He nucleation may have a significant impact on T inventory and may lower the T breeding ratio. A model based on the self-consistent nucleation theory (SCT) with a surface tension curvature correction model has been implemented in OpenFOAM{sup ®} CFD code. A modification through a single parameter of the necessary nucleation condition is proposed in order to take into account all the nucleation triggering phenomena, specially radiation induced nucleation. Moreover, the kinetic growth model has been adapted so as to allow for the transition from a critical cluster to a macroscopic bubble with a diffusion growth process. Limitations and capabilities of the models are shown by means of zero-dimensional simulations and sensitivity analyses to key parameters under HCLL breeding unit conditions. Results provide a good qualitative insight into the helium
International Nuclear Information System (INIS)
Highlights: • The work presented in this manuscript provides a reliable computational tool to quantify the He complex phenomena in a HCLL. • A model based on the self-consistent nucleation theory (SCT) is exposed. It includes radiation induced nucleation modelling and surface tension corrections. • Results informed reinforce the necessity of conducting experiments to determine nucleation conditions and bubble transport parameters in LM breeders. • Our findings and model provide a good qualitative insight into the helium nucleation phenomenon in LM systems for fusion technology and can be used to identify key system parameters. -- Abstract: Helium (He) nucleation in liquid metal breeding blankets of a DT fusion reactor may have a significant impact regarding system design, safety and operation. Large He production rates are expected due to tritium (T) fuel self-sufficiency requirement, as both, He and T, are produced at the same rate. Low He solubility, local high concentrations, radiation damage and fluid discontinuities, among other phenomena, may yield the necessary conditions for He nucleation. Hence, He nucleation may have a significant impact on T inventory and may lower the T breeding ratio. A model based on the self-consistent nucleation theory (SCT) with a surface tension curvature correction model has been implemented in OpenFOAM® CFD code. A modification through a single parameter of the necessary nucleation condition is proposed in order to take into account all the nucleation triggering phenomena, specially radiation induced nucleation. Moreover, the kinetic growth model has been adapted so as to allow for the transition from a critical cluster to a macroscopic bubble with a diffusion growth process. Limitations and capabilities of the models are shown by means of zero-dimensional simulations and sensitivity analyses to key parameters under HCLL breeding unit conditions. Results provide a good qualitative insight into the helium nucleation
Theory of Optimal Currency Zones: from Classics until Today
Directory of Open Access Journals (Sweden)
Pinchuk Anastasiya K.
2013-12-01
Full Text Available The article analyses evolution of the theory of optimal currency zones (OCZ, starting from its classical provisions until moder developments. Based on the critical analysis of classical criteria of OCZ, the article develops a scheme of selection of the currency mode by the Robert Mundell theory. It considers achievements of the alternative OCZ theory, the main provisions of which are shown schematically in the form of illustrations of evolution of the theory of optimal currency zones. In the result of analysis of classical criteria of optimal currency zones and generalisation of developments of the new OCZ theory, the article develops a universal algorithm of identification of optimal conditions for an efficient currency zone. Using this algorithm allows identification of a system of quantitative indicators of expediency of regional joining the OCZ, on the basis of which one can build an economic model of an optimal currency zone, which reflects the degree of readiness of any country to join or develop the OCZ. Development of this model is necessary for many countries that face the need to select the currency integration. This model is of special importance for Ukraine, for which it is important to select the course of external integration, since various directions of foreign policy significantly influence efficiency of the domestic economic policy in the country.
Momentum Maps and Classical Relativistic Fields; 1, Covariant Field Theory
Gotay, M J; Marsden, J E; Gotay, Mark J.; Isenberg, James; Marsden, Jerrold E.
1998-01-01
This is the first paper of a four part work in which we study the Lagrangian and Hamiltonian structure of classical field theories with constraints. Our goal is to explore some of the connections between initial value constraints and gauge transformations in such theories (either relativistic or not). To do this, in the course of these four papers, we develop and use a number of tools from symplectic and multisymplectic geometry. Of central importance in our analysis is the notion of the ``energy-momentum map'' associated to the gauge group of a given classical field theory. We hope to demonstrate that many different and apparently unrelated facets of field theories can be thereby tied together and understood in an essentially new way. In Part I we develop some of the basic theory of classical fields from a spacetime covariant viewpoint. We begin with a study of the covariant Lagrangian and Hamiltonian formalisms, on jet bundles and multisymplectic manifolds, respectively. Then we discuss symmetries, conserva...
Classical Bianchi Type I Cosmology in K-Essence Theory
2014-01-01
We use one of the simplest forms of the K-essence theory and we apply it to the classical anisotropic Bianchi type I cosmological model, with a barotropic perfect fluid ( p=γρ ) modeling the usual matter content and with cosmological constant Λ . Classical exact solutions for any γ≠1 and Λ=0 are found in closed form, whereas solutions for Λ≠0 are found for particular values in the barotropic parameter. We present the possible isotropization of the cosmological model Bianchi I using the ratio ...
THE NEW CLASSICAL THEORY AND THE REAL BUSINESS CYCLE MODEL
Directory of Open Access Journals (Sweden)
Oana Simona HUDEA (CARAMAN
2014-11-01
Full Text Available The present paper aims at describing some key elements of the new classical theory-related model, namely the Real Business Cycle, mainly describing the economy from the perspective of a perfectly competitive market, characterised by price, wage and interest rate flexibility. The rendered impulse-response functions, that help us in revealing the capacity of the model variables to return to their steady state under the impact of a structural shock, be it technology or monetary policy oriented, give points to the neutrality of the monetary entity decisions, therefore confirming the well-known classical dichotomy existing between the nominal and the real factors of the economy.
Fradera, Jorge
2013-01-01
Helium (He) nucleation in liquid metal breeding blankets of a DT fusion reactor may have a significant impact regarding system design, safety and operation. Large He production rates are expected due to tritium (T) fuel self-sufficiency requirement, as both, He and T, are produced at the same rate. Low He solubility, local high concentrations, radiation damage and fluid discontinuities, among other phenomena, may yield the necessary conditions for He nucleation. Hence, He nucleation may have a significant impact on T inventory and may lower the T breeding ratio. A model based on the self-consistent nucleation theory (SCT) with a surface tension curvature correction model has been implemented in OpenFoam(r) CFD code. A modification through a single parameter of the necessary nucleation condition is proposed in order to take into account all the nucleation triggering phenomena, specially radiation induced nucleation. Moreover, the kinetic growth model has been adapted so as to allow for the transition from a cr...
Classic Grounded Theory to Analyse Secondary Data: Reality and Reflections
Directory of Open Access Journals (Sweden)
Lorraine Andrews
2012-06-01
Full Text Available This paper draws on the experiences of two researchers and discusses how they conducted a secondary data analysis using classic grounded theory. The aim of the primary study was to explore first-time parents’ postnatal educational needs. A subset of the data from the primary study (eight transcripts from interviews with fathers was used for the secondary data analysis. The objectives of the secondary data analysis were to identify the challenges of using classic grounded theory with secondary data and to explore whether the re-analysis of primary data using a different methodology would yield a different outcome. Through the process of re-analysis a tentative theory emerged on ‘developing competency as a father’. Challenges encountered during this re-analysis included the small dataset, the pre-framed data, and limited ability for theoretical sampling. This re-analysis proved to be a very useful learning tool for author 1(LA, who was a novice with classic grounded theory.
Quantum Mind from a Classical Field Theory of the Brain
Zizzi, Paola
2011-01-01
We suggest that, with regard to a theory of quantum mind, brain processes can be described by a classical, dissipative, non-abelian gauge theory. In fact, such a theory has a hidden quantum nature due to its non-abelian character, which is revealed through dissipation, when the theory reduces to a quantum vacuum, where temperatures are of the order of absolute zero, and coherence of quantum states is preserved. We consider in particular the case of pure SU(2) gauge theory with a special anzatz for the gauge field, which breaks Lorentz invariance. In the ansatz, a contraction mapping plays the role of dissipation. In the limit of maximal dissipation, which corresponds to the attractive fixed point of the contraction mapping, the gauge fields reduce, up to constant factors, to the Pauli quantum gates for one-qubit states. Then tubuline-qubits can be processed in the quantum vacuum of the classical field theory of the brain, where decoherence is avoided due to the extremely low temperature. Finally, we interpret...
Podmaniczky, Frigyes; Tóth, Gyula I.; Tegze, György; Gránásy, László
2015-11-01
Crystallization of supersaturated liquids usually starts by epitaxial growth or by heterogeneous nucleation on foreign surfaces. Herein, we review recent advances made in modeling heteroepitaxy and heterogeneous nucleation on flat/modulated surfaces and nanoparticles within the framework of a simple dynamical density functional theory, known as the phase-field crystal model. It will be shown that the contact angle and the nucleation barrier are nonmonotonous functions of the lattice mismatch between the substrate and the crystalline phase. In continuous cooling studies for substrates with lattice mismatch, we recover qualitatively the Matthews-Blakeslee mechanism of stress release via the misfit dislocations. The simulations performed for particle-induced freezing will be confronted with recent analytical results, exploring thus the validity range of the latter. It will be demonstrated that time-dependent studies are essential, as investigations based on equilibrium properties often cannot identify the preferred nucleation pathways. Modeling of these phenomena is essential for designing materials on the basis of controlled nucleation and/or nano-patterning.
Classical field theory on electrodynamics, non-Abelian gauge theories and gravitation
Scheck, Florian
2012-01-01
The book describes Maxwell's equations first in their integral, directly testable form, then moves on to their local formulation. The first two chapters cover all essential properties of Maxwell's equations, including their symmetries and their covariance in a modern notation. Chapter 3 is devoted to Maxwell theory as a classical field theory and to solutions of the wave equation. Chapter 4 deals with important applications of Maxwell theory. It includes topical subjects such as metamaterials with negative refraction index and solutions of Helmholtz' equation in paraxial approximation relevant for the description of laser beams. Chapter 5 describes non-Abelian gauge theories from a classical, geometric point of view, in analogy to Maxwell theory as a prototype, and culminates in an application to the U(2) theory relevant for electroweak interactions. The last chapter 6 gives a concise summary of semi-Riemannian geometry as the framework for the classical field theory of gravitation. The chapter concludes wit...
Zatloukal, Václav
2016-04-01
Classical field theory is considered as a theory of unparametrized surfaces embedded in a configuration space, which accommodates, in a symmetric way, spacetime positions and field values. Dynamics is defined by a (Hamiltonian) constraint between multivector-valued generalized momenta, and points in the configuration space. Starting from a variational principle, we derive local equations of motion, that is, differential equations that determine classical surfaces and momenta. A local Hamilton-Jacobi equation applicable in the field theory then follows readily. The general method is illustrated with three examples: non-relativistic Hamiltonian mechanics, De Donder-Weyl scalar field theory, and string theory.
Quiver Theories for Moduli Spaces of Classical Group Nilpotent Orbits
Hanany, Amihay
2016-01-01
We approach the topic of Classical group nilpotent orbits from the perspective of their moduli spaces, described in terms of Hilbert series and generating functions. We review the established Higgs and Coulomb branch quiver theory constructions for A series nilpotent orbits. We present systematic constructions for BCD series nilpotent orbits on the Higgs branches of quiver theories defined by canonical partitions; this paper collects earlier work into a systematic framework, filling in gaps and providing a complete treatment. We find new Coulomb branch constructions for above minimal nilpotent orbits, including some based upon twisted affine Dynkin diagrams. We also discuss aspects of 3d mirror symmetry between these Higgs and Coulomb branch constructions and explore dualities and other relationships, such as HyperKahler quotients, between quivers. We analyse all Classical group nilpotent orbit moduli spaces up to rank 4 by giving their unrefined Hilbert series and the Highest Weight Generating functions for ...
Quantum to classical transition in quantum field theory
Lombardo, F C
1998-01-01
We study the quatum to classical transition process in the context of quantum field theory. Extending the influence functional formalism of Feynman and Vernon, we study the decoherence process for self-interacting quantum fields in flat space. We also use this formalism for arbitrary geometries to analyze the quantum to classical transition in quantum gravity. After summarizing the main results known for the quantum Brownian motion, we consider a self-interacting field theory in Minkowski spacetime. We compute a coarse grained effective action by integrating out the field modes with wavelength shorter than a critical value. From this effective action we obtain the evolution equation for the reduced density matrix (master equation). We compute the diffusion coefficients for this equation and analyze the decoherence induced on the long-wavelength modes. We generalize the results to the case of a conformally coupled scalar field in de Sitter spacetime. We show that the decoherence is effective as long as the cri...
THE NEW CLASSICAL THEORY AND THE REAL BUSINESS CYCLE MODEL
Oana Simona HUDEA (CARAMAN); Sorin George TOMA; Marin BURCEA
2014-01-01
The present paper aims at describing some key elements of the new classical theory-related model, namely the Real Business Cycle, mainly describing the economy from the perspective of a perfectly competitive market, characterised by price, wage and interest rate flexibility. The rendered impulse-response functions, that help us in revealing the capacity of the model variables to return to their steady state under the impact of a structural shock, be it technology or monetary policy oriented, ...
On Covariant Poisson Brackets in Classical Field Theory
Forger, Michael; Salles, Mário O.
2015-01-01
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem - as testified by the extensive literature on "multisymplectic Poisson brackets", together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls - De Witt bracket and whose construction in a geometrical setting is now well unde...
A magnetic condensate solution of the classical electroweak theory
International Nuclear Information System (INIS)
According to the electroweak theory a large homogeneous magnetic field exceeding m2w/e is unstable. We present a different solution of the classical electroweak field equations which is a condensate of magnetic fluxes induced by an anti-Lenz current of the charged vector bosons. The anti-Lenz mechanism is a consequence of asymptotic freedom. The range of validity of this solution depends on the Weinberg angle θ. (orig.)
A New Fuzzy Set Theory Satisfying All Classical Set Formulas
Institute of Scientific and Technical Information of China (English)
Qing-Shi Gao; Xiao-Yu Gao; Yue Hu
2009-01-01
A new fuzzy set theory, C-fuzzy set theory, is introduced in this paper. It is a particular case of the classical set theory and satisfies all formulas of the classical set theory. To add a limitation to C-fuzzy set system, in which all fuzzy sets must be "non-uniform inclusive" to each other, then it forms a family of sub-systems, the Z-fuzzy set family. It can be proved that the Z0-fuzzy set system, one of Z-fuzzy set systems, is equivalent to Zadeh's fuzzy set system. Analysis shows that 1) Zadeh's fuzzy set system defines the relations A = B and A ∈B between two fuzzy sets A and B as "Vu e U,(u A E (u)=μB(U))" and "Au ∈ U, (μA(U) ≤μB(μ))" respectively is inappropriate, because it makes all fuzzy sets be "non-uniformly inclusive"; 2) it is also inappropriate to define two fuzzy sets' union and intersection operations as the max and rain of their grades of membership, because this prevents fuzzy set's ability to correctly reflect different kinds of fuzzy phenomenon in the natural world. Then it has to work around the problem by invent unnatural functions that are hard to understand, such as augmenting max and min for union and intersection to min{a + b, 1} and max{a + b - 1, 0}, but these functions are incorrect on inclusive case. If both pairs of definitions are used together, not only are they unnatural, but also they are still unable to cover all possible set relationships in the natural world; and 3) it is incorrect to define the set complement as 1 -μA(μ), because it can be proved that set complement cannot exist in Zadeh's fuzzy set, and it causes confusion in logic and thinking. And it is seriously mistaken to believe that logics of fuzzy sets necessarily go against classical and normal thinking, logic, and conception. The C-fuzzy set theory proposed in this paper overcomes all of the above errors and shortcomings, and more reasonably reflects fuzzy phenomenon in the natural world. It satisfies all relations, formulas, and operations of the
Geometric aspects in extended approach of equilibrium classical fluctuation theory
Velazquez, L.
2011-11-01
Previously, an extended approach of equilibrium classical fluctuation theory was developed compatible with the existence of anomalous response functions, e.g. states with negative heat capacities. Now, the geometric aspects associated with this new framework are analyzed. The analysis starts from the so-called reparametrization invariance: a special symmetry of distribution functions dp (I|θ) employed in classical equilibrium statistical mechanics that allows us to express the thermo-statistical relations in the same mathematical appearance in different coordinate representations. The existence of reparametrization invariance can be related to three different geometric frameworks: (1) a non-Riemannian formulation for classical fluctuation theory based on the concept of reparametrization dualities; (2) a Riemannian formulation defined on the manifold {P} of control parameters θ, where the main theorems of inference theory appear as dual counterparts of general fluctuation theorems, and Boltzmann-Gibbs distributions ωBG(I|θ) = exp(-θiIi)/Z(θ) admit a geometric generalization; and finally, (3) a Riemannian formulation defined on the manifold {M}_{\\theta } of macroscopic observables I, which appears as a counterpart approach of inference geometry.
Energy Technology Data Exchange (ETDEWEB)
Olhac, X.; Fillet, C. [CEA Valrho, Dir. de l' Energie Nucleaire, DEN, 30 - Marcoule (France); Phalippou, J. [Montpellier-2 Univ., Lab. des Verres, 34 (France)
1997-07-01
Since the quality of the glass will be affected by its thermal history, an assessment of thermal stability of waste glasses is necessary. A brief review of the classical nucleation theory in glass forming systems is presented. Particular emphasis is given to the driving force and the kinetic barrier which control the beginning of nucleation. The general theory of phase transformation kinetics derived by Kolmogorov-Johnson-Mehl-Avrami is also exposed, including an application of this model to follow the overall crystallization. Special attention is given to devitrification at low temperature. The long time storage of waste glasses at low temperature (below Tg) is next studied with regard to crystallization. Some provisional studies of devitrification rates at low temperature are introduced, based on extrapolation of high temperature measures. Furthermore, in order to understand the mechanisms occurring in the low temperature range, others experiments in concern with specific properties (viscosity, diffusion) are presented. They demonstrate that the occurrence of nucleation and crystal growth at low temperature indicates a decoupling between the kinetic coefficient for transport at the crystal/glass interface and the bulk viscosity. (authors)
Investigation of Vapor-Liquid Nucleation for Associating Fluids by Density Gradient Theory
Institute of Scientific and Technical Information of China (English)
FU Dong; LIU Jianmin
2009-01-01
An equation of state (EOS) applicable to both the uniform and non-uniform associating fluids was established by using the density-gradient expansion, in which the influence parameter κis formulated as a function of tempera-ture. The molecular parameters were regressed by fitting to the experimental data of vapor pressures and liquid den-sities. Within the framework of density gradient theory (DGT), the nucleation rates for water, heavy water, metha-nol, ethanol, 1-propanoi, 1-butanol, 1-pentanol and 1-hexanol were calculated. The results were satisfactory com-pared with the experimental data. Our study shows that DGT preserves all the advantages of density functional the-ory (DFT) in capturing the structure and properties of nucleus but gives much more accurate nucleation rates by adjusting the influence parameter.
Self-consistent nonperturbative theory for classical systems.
Mederos, L; Navascués, G; Velasco, E
2002-01-01
We construct a self-consistent nonperturbative theory for the structure and thermodynamics of a classical system of particles that goes beyond the usual approaches based on perturbation theory. Our theory, which gives accurate predictions for the phase diagram, is based on two ingredients: first, use is made of an exact expression for the free energy of a many-body system in terms of a reference system and a coupling integral connecting the latter to the final system; second, correlation functions may be very accurately approximated using a number of sum rules relating the radial distribution function with thermodynamic quantities. Consistency between the coupling integral expression and the sum rules may be achieved by means of a self-consistent process. PMID:11800760
On some classical problems of descriptive set theory
International Nuclear Information System (INIS)
The centenary of P.S. Novikov's birth provides an inspiring motivation to present, with full proofs and from a modern standpoint, the presumably definitive solutions of some classical problems in descriptive set theory which were formulated by Luzin [Lusin] and, to some extent, even earlier by Hadamard, Borel, and Lebesgue and relate to regularity properties of point sets. The solutions of these problems began in the pioneering works of Aleksandrov [Alexandroff], Suslin [Souslin], and Luzin (1916-17) and evolved in the fundamental studies of Goedel, Novikov, Cohen, and their successors. Main features of this branch of mathematics are that, on the one hand, it is an ordinary mathematical theory studying natural properties of point sets and functions and rather distant from general set theory or intrinsic problems of mathematical logic like consistency or Goedel's theorems, and on the other hand, it has become a subject of applications of the most subtle tools of modern mathematical logic
Common Axioms for Inferring Classical Ensemble Dynamics and Quantum Theory
Parwani, R R
2005-01-01
Within a hamiltonian framework, the same set of physically motivated axioms is used to construct both the classical ensemble Hamilton-Jacobi equation and Schrodingers equation. Crucial roles are played by the assumptions of universality and simplicity (Occam's Razor) which restrict the number and type of of arbitrary constants that appear in the hamiltonian. In this approach, non-relativistic quantum theory is seen as the unique single parameter extension of the classical ensemble dynamics. The method is contrasted with other related constructions in the literature. Possible generalisation to the relativistic case, and some consequences of relaxing the axioms, are also discussed: for example, simple extensions of the linear Schrodinger equation lead to higher-derivative nonlinear corrections that are possibly related to gravity.
The theory of variational hybrid quantum-classical algorithms
McClean, Jarrod R; Babbush, Ryan; Aspuru-Guzik, Alán
2015-01-01
Many quantum algorithms have daunting resource requirements when compared to what is available today. To address this discrepancy, a quantum-classical hybrid optimization scheme known as "the quantum variational eigensolver" was developed with the philosophy that even minimal quantum resources could be made useful when used in conjunction with classical routines. In this work we extend the general theory of this algorithm and suggest algorithmic improvements for practical implementations. Specifically, we develop a variational adiabatic ansatz and explore unitary coupled cluster where we establish a connection from second order unitary coupled cluster to universal gate sets through relaxation of exponential splitting. We introduce the concept of quantum variational error suppression that allows some errors to be suppressed naturally in this algorithm on a pre-threshold quantum device. Additionally, we analyze truncation and correlated sampling in Hamiltonian averaging as ways to reduce the cost of this proced...
BOOK REVIEW: Classical Solutions in Quantum Field Theory Classical Solutions in Quantum Field Theory
Mann, Robert
2013-02-01
Quantum field theory has evolved from its early beginnings as a tool for understanding the interaction of light with matter into a rather formidable technical paradigm, one that has successfully provided the mathematical underpinnings of all non-gravitational interactions. Over the eight decades since it was first contemplated the methods have become increasingly more streamlined and sophisticated, yielding new insights into our understanding of the subatomic world and our abilities to make clear and precise predictions. Some of the more elegant methods have to do with non-perturbative and semiclassical approaches to the subject. The chief players here are solitons, instantons, and anomalies. Over the past three decades there has been a steady rise in our understanding of these objects and of our ability to calculate their effects and implications for the rest of quantum field theory. This book is a welcome contribution to this subject. In 12 chapters it provides a clear synthesis of the key developments in these subjects at a level accessible to graduate students that have had an introductory course to quantum field theory. In the author's own words it provides both 'a survey and an overview of this field'. The first half of the book concentrates on solitons--kinks, vortices, and magnetic monopoles--and their implications for the subject. The reader is led first through the simplest models in one spatial dimension, into more sophisticated cases that required more advanced topological methods. The author does quite a nice job of introducing the various concepts as required, and beginning students should be able to get a good grasp of the subject directly from the text without having to first go through the primary literature. The middle part of the book deals with the implications of these solitons for both cosmology and for duality. While the cosmological discussion is quite nice, the discussion on BPS solitons, supersymmetry and duality is rather condensed. It is
Motion of small bodies in classical field theory
International Nuclear Information System (INIS)
I show how prior work with R. Wald on geodesic motion in general relativity can be generalized to classical field theories of a metric and other tensor fields on four-dimensional spacetime that (1) are second-order and (2) follow from a diffeomorphism-covariant Lagrangian. The approach is to consider a one-parameter-family of solutions to the field equations satisfying certain assumptions designed to reflect the existence of a body whose size, mass, and various charges are simultaneously scaled to zero. (That such solutions exist places a further restriction on the class of theories to which our results apply.) Assumptions are made only on the spacetime region outside of the body, so that the results apply independent of the body's composition (and, e.g., black holes are allowed). The worldline 'left behind' by the shrinking, disappearing body is interpreted as its lowest-order motion. An equation for this worldline follows from the 'Bianchi identity' for the theory, without use of any properties of the field equations beyond their being second-order. The form of the force law for a theory therefore depends only on the ranks of its various tensor fields; the detailed properties of the field equations are relevant only for determining the charges for a particular body (which are the ''monopoles'' of its exterior fields in a suitable limiting sense). I explicitly derive the force law (and mass-evolution law) in the case of scalar and vector fields, and give the recipe in the higher-rank case. Note that the vector force law is quite complicated, simplifying to the Lorentz force law only in the presence of the Maxwell gauge symmetry. Example applications of the results are the motion of 'chameleon' bodies beyond the Newtonian limit, and the motion of bodies in (classical) non-Abelian gauge theory. I also make some comments on the role that scaling plays in the appearance of universality in the motion of bodies.
Local gauge invariant Lagrangeans in classical field theories
International Nuclear Information System (INIS)
We investigate the most general local gauge invariant Lagrangean in the framework of classical field theory. We rederive esentially Utiyama's result with a slight generalization. Our proof makes clear the importance of the so called current conditions, i.e. the requirement that the Noether currents are different from zero. This condition is of importance both in the general motivation for the introduction of the Yang-Mills fields and for the actual proof. Some comments are made about the basic mathematical structure of the problem - the gauge group. (author)
Lie Groupoids in Classical Field Theory I: Noether's Theorem
Costa, Bruno T; Pêgas, Luiz Henrique P
2015-01-01
In the two papers of this series, we initiate the development of a new approach to implementing the concept of symmetry in classical field theory, based on replacing Lie groups/algebras by Lie groupoids/algebroids, which are the appropriate mathematical tools to describe local symmetries when gauge transformations are combined with space-time transformations. Here, we outline the basis of the program and, as a first step, show how to (re)formulate Noether's theorem about the connection between symmetries and conservation laws in this approach.
Topics In False Vacuum Decay (bubble Nucleation, Gauge Dependence, Quantum Field Theory)
Metaxas, D
1998-01-01
I review the formalism for the computation of the rate of false vacuum decay in field theories with a metastable vacuum state. I then proceed to consider the case of field theories where the false vacuum arises as a result of radiative corrections. There the calculation of the rate of false vacuum decay by bubble nucleation depends on the effective potential and the other functions that appear in the derivative expansion of the effective action. Beginning with the Nielsen identity, I derive a series of identities that describe the gauge dependence of these functions...
Inada, Takaaki; Koyama, Toshie; Goto, Fumitoshi; Seto, Takafumi
2011-06-23
Antifreeze protein (AFP) III and poly(vinyl alcohol) (PVA) are known as anti-ice nucleating agents (anti-INAs), which inhibit heterogeneous ice nucleation. However, the effectiveness of these anti-INAs in inhibiting ice nucleation in water-in-oil (W/O) emulsions, in which homogeneous ice nucleation can be experimentally simulated, is unclear. In this study, the ice nucleation temperature in emulsified solutions of AFP III, PVA, and other nonanti-INA polymers was measured, and then the nucleation rate was analyzed based on classical nucleation theory. Results showed that ice nucleation was surface-initiated and, except for PVA solutions, probably caused heterogeneously by the emulsifier, SPAN 65, at the droplet surfaces. In this nucleation mode, AFP III had no significant effect on the ice nucleation rate. In contrast, PVA exhibited ice-nucleating activity only at the droplet surfaces, suggesting that the nucleation is due to the interaction between PVA and SPAN 65. PMID:21619040
Emergence Of A Classical World From Within Quantum Theory
Poulin, D
2005-01-01
The starting point of this dissertation is that a quantum state represents the observer's knowledge about the system of interest. As it has been pointed out several times by the opponents of this epistemic interpretation, it is difficult to reconcile this point of view with our common notion of “physical reality”, which exists independently of our monitoring, and can be discovered without disturbance. Indeed, if quantum theory is correct, it should apply to classical systems—including measurement devices—as well as to any other system. In this dissertation, we will study the quantum mechanisms responsible for our perception of the world and demonstrate how they lead to the emergence of an operational objective reality from within quantum theory: several observers gathering information through these mechanisms will arrive at a common consensus about the properties of the world. The two mechanisms we study in great detail are the redundant proliferation of information in ...
Stochastic theory for classical and quantum mechanical systems
International Nuclear Information System (INIS)
From first principles a theory of stochastic processes in configuration space is formulated. The fundamental equations of the theory are an equation of motion which generalizes Newton's second law and an equation which expresses the condition of conservation of matter. Two types of stochastic motion are possible, both described by the same general equations, but leading in one case to classical Brownian motion behavior and in the other to quantum mechanical behavior. The Schroedinger equation, which is derived with no further assumption, is thus shown to describe a specific stochastic process. It is explicitly shown that only in the quantum mechanical process does the superposition of probability amplitudes give rise to interference phenomena; moreover, the presence of dissipative forces in the Brownian motion equations invalidates the superposition principle. At no point are any special assumptions made concerning the physical nature of the underlying stochastic medium, although some suggestions are discussed in the last section
Marshaling Resources: A Classic Grounded Theory Study of Online Learners
Directory of Open Access Journals (Sweden)
Barbara Yalof
2014-06-01
Full Text Available Classic grounded theory (CGT was used to identify a main concern of online students in higher education. One of the main impediments to studying online is a sense of isolation and lack of access to support systems as students navigate through complex requirements of their online programs. Hypothetical probability statements illustrate the imbalance between heightened needs of virtual learners and perceived inadequate support provided by educational institutions. The core variable, marshaling resources, explains how peer supports sustain motivation toward successful program completion. Understanding the critical contribution virtual interpersonal networks make towards maximizing resources by group problem solving is a significant aspect of this theory. Keywords: Online learning, e-learning, personal learning networks, peer networks
Gauge independence of the bubble nucleation rate in theories with radiative symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Metaxas, D.; Weinberg, E.J. [Department of Physics, Columbia University, New York, New York 10027 (United States)
1996-01-01
In field theories where a metastable false vacuum state arises as a result of radiative corrections, the calculation of the rate of false vacuum decay by bubble nucleation depends on the effective potential and the other functions that appear in the derivative expansion of the effective action. Beginning with the Nielsen identity, we derive a series of identities that govern the gauge dependence of these functions. Using these, we show, to leading nontrivial order, that, even though these functions are individually gauge dependent, one obtains a gauge-independent result for the bubble nucleation rate. Our formal arguments are complemented by explicit calculations for scalar electrodynamics in a class of {ital R}{sub {xi}} gauges. {copyright} {ital 1996 The American Physical Society.}
Gauge independence of the bubble nucleation rate in theories with radiative symmetry breaking
Metaxas, D; Metaxas, Dimitrios; Weinberg, Erick J
1996-01-01
In field theories where a metastable false vacuum state arises as a result of radiative corrections, the calculation of the rate of false vacuum decay by bubble nucleation depends on the effective potential and the other functions that appear in the derivative expansion of the effective action. Beginning with the Nielsen identity, we derive a series of identities that govern the gauge dependence of these functions. Using these, we show, to leading nontrivial order, that even though these functions are individually gauge-dependent, one obtains a gauge-independent result for the bubble nucleation rate. Our formal arguments are complemented by explicit calculations for scalar electrodynamics in a class of R_\\xi gauges.
Binary Nucleation of Water and Sodium Chloride
Energy Technology Data Exchange (ETDEWEB)
Nemec, Thomas [Institute of Thermomechanics ASCR, Prague, Czech Republic; Marsik, Frantisek [Institute of Thermomechanics ASCR, Prague, Czech Republic; Palmer, Donald [ORNL
2005-01-01
Nucleation processes in the binary water-sodium chloride system are investigated in the sense of the classical nucleation theory (CNT). The CNT is modified to be able to handle the electrolytic nature of the system and is employed to investigate the acceleration of the nucleation process due to the presence of sodium chloride in the steam. This phenomenon, frequently observed in the Wilson zone of steam turbines, is called early condensation. Therefore, the nucleation rates of the water-sodium chloride mixture are of key importance in the power cycle industry.
Quasiperiodical orbits in the scalar classical lambdaphi4 field theory
International Nuclear Information System (INIS)
New numerical and theoretical results of resonance kink-antikink (Kanti K) interactions in the classical one-dimentional space Higgs theory are presented. Earlier studies of these interactions revealed nine initial relative velocity-intervals with two-bounce Kanti K-collisions followed by the escape of kinks to infinite separations, the breathing solution was formed outside those intervals. Two-bounce Kanti K-interactions with the number of small oscillations between Kanti K-bounces up to 35 in the initial kink velocity interval 0.18 <= Vsub(infinite) <= 0.26 were found. Several examples for n-bounces Kanti K-interaction (n <= 6) are also found. The observed phenomenon can be explaned by the existence of quasi-two-periodical solutions of the nonlinear wave equation. The simple Hamiltonian with two degrees of freedom is studied. This model supplies quantitative descrtiptions of all numerical results for the field theory considered above. The considered phenomenon may be called ''autoquantization'' of a nonlinear classical scalar selfinteracting field
Emergence of a classical world from within quantum theory
Poulin, David
The starting point of this dissertation is that a quantum state represents the observer's knowledge about the system of interest. As it has been pointed out several times by the opponents of this epistemic interpretation, it is difficult to reconcile this point of view with our common notion of "physical reality", which exists independently of our monitoring, and can be discovered without disturbance. Indeed, if quantum theory is correct, it should apply to classical systems---including measurement devices---as well as to any other system. In this dissertation, we will study the quantum mechanisms responsible for our perception of the world and demonstrate how they lead to the emergence of an operational objective reality from within quantum theory: several observers gathering information through these mechanisms will arrive at a common consensus about the properties of the world. The two mechanisms we study in great detail are the redundant proliferation of information in the environment and the direct measurement of a macroscopic observable. An example of the first mechanism is the photon environment which provides us with our visual data about the world. Several independent observers learning about their surroundings in this indirect fashion will agree on their findings. An example of the second mechanism is our tactile information: when the tip of our finger touches an object, it interacts collectively with a very large number of molecules. Again, under realistic assumptions, this type of information acquisition will lead to a classical perception of the world.
Wu, Ning; Zhang, Dahua
2005-01-01
A systematic method is developed to study classical motion of a mass point in gravitational gauge field. First, the formulation of gauge theory of gravity in arbitrary curvilinear coordinates is given. Then in spherical coordinates system, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the Schwarzschild solution. In gauge theory of gravity, the equation of motion of a classical mass point in gravitational gauge field is given by Ne...
Complex analysis fundamentals of the classical theory of functions
Stalker, John
1998-01-01
This clear, concise introduction to the classical theory of one complex variable is based on the premise that "anything worth doing is worth doing with interesting examples." The content is driven by techniques and examples rather than definitions and theorems. This self-contained monograph is an excellent resource for a self-study guide and should appeal to a broad audience. The only prerequisite is a standard calculus course. The first chapter deals with a beautiful presentation of special functions. . . . The third chapter covers elliptic and modular functions. . . in much more detail, and from a different point of view, than one can find in standard introductory books. . . . For [the] subjects that are omitted, the author has suggested some excellent references for the reader who wants to go through these topics. The book is read easily and with great interest. It can be recommended to both students as a textbook and to mathematicians and physicists as a useful reference. ---Mathematical Reviews Mainly or...
Non-linear coupling of quantum theory and classical gravity
International Nuclear Information System (INIS)
The possibility that the non-linear evolution proposed earlier for a relativistic quantum field theory may be related to its coupling to a classical gravitational field is discussed. Formally, in the Schroedinger picture, it is shown how both the Schroedinger equation and Einstein's equations (with the expectation value of the energy-momentum tensor on the right) can be derived from a variational principle. This yields a non-linear quantum evolution. Other terms can be added to the action integral to incorporate explicit non-linearities of the type discussed previously. The possibility of giving a meaning to the resulting equation in a Heisenberg or interaction-like picture, is briefly discussed. (author)
Deformation Quantization of Principal Fibre Bundles and Classical Gauge Theories
Wei\\ss, Stefan
2010-01-01
In this dissertation the notion of deformation quantization of principal fibre bundles is established and investigated in order to find a geometric formulation of classical gauge theories on noncommutative space-times. As a generalization, the notion of deformation quantization of surjective submersions is also discussed. It is shown that deformation quantizations of surjective submersions and principal fibre bundles always exist and are unique up to equivalence. These statements concerning complex-valued functions are moreover formulated and proved for sections of arbitrary vector bundles over the total space, in particular equivariant vector bundles. The commutants of the deformed right module structures within the differential operators, playing an inportant role with regard to the infinitesimal gauge transformations, are computed explicitly in each case. Depending on the choice of specific covariant derivatives and connections the commutants are isomorphic to the formal power series of the respective vert...
Geometry of Lagrangian first-order classical field theories
International Nuclear Information System (INIS)
We construct a lagrangian geometric formulation for first-order field theories using the canonical structures of first-order jet bundles, which are taken as the phase spaces of the systems in consideration. First of all, we construct all the geometric structures associated with a first-order jet bundle and, using them, we develop the lagrangian formalism, defining the canonical forms associated with a lagrangian density and the density of lagrangian energy, obtaining the Euler-Lagrange equations in two equivalent ways: as the result of a variational problem and developing the jet field formalism (which is a formulation more similar to the case of mechanical systems). A statement and proof of Noether's theorem is also given, using the latter formalism. Finally, some classical examples are briefly studied. (orig.)
Latfield2: A c++ library for classical lattice field theory
David, Daverio; Bevis, Neil
2015-01-01
latfield2 is a C++ library designed to simplify writing parallel codes for solving partial differen- tial equations, developed for application to classical field theories in particle physics and cosmology. It is a significant rewrite of the latfield framework, moving from a slab domain decomposition to a rod decomposition, where the last two dimension of the lattice are scattered into a two dimensional process grid. Parallelism is implemented using the Message Passing Interface (MPI) standard, and hidden in the basic objects of grid-based simulations: Lattice, Site and Field. It comes with an integrated parallel fast Fourier transform, and I/O server class permitting computation to continue during the writing of large files to disk. latfield2 has been used for production runs on tens of thousands of processor elements, and is expected to be scalable to hundreds of thousands.
Geometry of Lagrangian first-order classical field theories
Energy Technology Data Exchange (ETDEWEB)
Echeverria-Enriquez, A. [Univ. Politecnica de Cataluna, Barcelona (Spain). Departamento de Matematica Aplicada y Telematica; Munoz-Lecanda, M.C. [Univ. Politecnica de Cataluna, Barcelona (Spain). Departamento de Matematica Aplicada y Telematica; Roman-Roy, N. [Univ. Politecnica de Cataluna, Barcelona (Spain). Departamento de Matematica Aplicada y Telematica
1996-10-01
We construct a lagrangian geometric formulation for first-order field theories using the canonical structures of first-order jet bundles, which are taken as the phase spaces of the systems in consideration. First of all, we construct all the geometric structures associated with a first-order jet bundle and, using them, we develop the lagrangian formalism, defining the canonical forms associated with a lagrangian density and the density of lagrangian energy, obtaining the Euler-Lagrange equations in two equivalent ways: as the result of a variational problem and developing the jet field formalism (which is a formulation more similar to the case of mechanical systems). A statement and proof of Noether`s theorem is also given, using the latter formalism. Finally, some classical examples are briefly studied. (orig.)
On the Classical String Solutions and String/Field Theory Duality
Aleksandrova, D.; Bozhilov, P.
2003-01-01
We classify almost all classical string configurations, considered in the framework of the semi-classical limit of the string/gauge theory duality. Then, we describe a procedure for obtaining the conserved quantities and the exact classical string solutions in general string theory backgrounds, when the string embedding coordinates depend non-linearly on the worldsheet time parameter.
Semi-classical theory of quiet lasers. I: Principles
Arnaud, J; Philippe, F; Arnaud, Jacques; Chusseau, Laurent; Philippe, Fabrice
2006-01-01
When light originating from a laser diode driven by non-fluctuating electrical currents is incident on a photo-detector, the photo-current does not fluctuate much. Precisely, this means that the variance of the number of photo-electrons counted over a large time interval is much smaller that the average number of photo-electrons. At non-zero Fourier frequency $\\Omega$ the photo-current power spectrum is of the form $\\Omega^2/(1+\\Omega^2)$ and thus vanishes as $\\Omega\\to 0$, a conclusion equivalent to the one given above. The purpose of this paper is to show that results such as the one just cited may be derived from a (semi-classical) theory in which neither the optical field nor the electron wave-function are quantized. We first observe that almost any medium may be described by a circuit and distinguish (possibly non-linear) conservative elements such as pure capacitances, and conductances that represent the atom-field coupling. The theory rests on the non-relativistic approximation. Nyquist noise sources (...
A course in mathematical physics 2 classical field theory
Thirring, Walter
1978-01-01
In the past decade the language and methods ofmodern differential geometry have been increasingly used in theoretical physics. What seemed extravagant when this book first appeared 12 years ago, as lecture notes, is now a commonplace. This fact has strengthened my belief that today students of theoretical physics have to learn that language-and the sooner the better. Afterall, they willbe the professors ofthe twenty-first century and it would be absurd if they were to teach then the mathematics of the nineteenth century. Thus for this new edition I did not change the mathematical language. Apart from correcting some mistakes I have only added a section on gauge theories. In the last decade it has become evident that these theories describe fundamental interactions, and on the classical level their structure is suffi cientlyclear to qualify them for the minimum amount ofknowledge required by a theoretician. It is with much regret that I had to refrain from in corporating the interesting developments in Kal...
Raykov, Tenko; Marcoulides, George A.
2016-01-01
The frequently neglected and often misunderstood relationship between classical test theory and item response theory is discussed for the unidimensional case with binary measures and no guessing. It is pointed out that popular item response models can be directly obtained from classical test theory-based models by accounting for the discrete…
Effects of shear flow on phase nucleation and crystallization
Mura, Federica; Zaccone, Alessio
2016-04-01
Classical nucleation theory offers a good framework for understanding the common features of new phase formation processes in metastable homogeneous media at rest. However, nucleation processes in liquids are ubiquitously affected by hydrodynamic flow, and there is no satisfactory understanding of whether shear promotes or slows down the nucleation process. We developed a classical nucleation theory for sheared systems starting from the molecular level of the Becker-Doering master kinetic equation and we analytically derived a closed-form expression for the nucleation rate. The theory accounts for the effect of flow-mediated transport of molecules to the nucleus of the new phase, as well as for the mechanical deformation imparted to the nucleus by the flow field. The competition between flow-induced molecular transport, which accelerates nucleation, and flow-induced nucleus straining, which lowers the nucleation rate by increasing the nucleation energy barrier, gives rise to a marked nonmonotonic dependence of the nucleation rate on the shear rate. The theory predicts an optimal shear rate at which the nucleation rate is one order of magnitude larger than in the absence of flow.
Merikanto, Joonas; Duplissy, Jonathan; Määttänen, Anni; Henschel, Henning; Donahue, Neil M.; Brus, David; Schobesberger, Siegfried; Kulmala, Markku; Vehkamäki, Hanna
2016-02-01
We derive a version of Classical Nucleation Theory normalized by quantum chemical results on sulfuric acid-water hydration to describe neutral and ion-induced particle formation in the binary sulfuric acid-water system. The theory is extended to treat the kinetic regime where the nucleation free energy barrier vanishes at high sulfuric acid concentrations or low temperatures. In the kinetic regime particle formation rates become proportional to sulfuric acid concentration to second power in the neutral system or first power in the ion-induced system. We derive simple general expressions for the prefactors in kinetic-type and activation-type particle formation calculations applicable also to more complex systems stabilized by other species. The theory predicts that the binary water-sulfuric acid system can produce strong new particle formation in the free troposphere both through barrier crossing and through kinetic pathways. At cold stratospheric and upper free tropospheric temperatures neutral formation dominates the binary particle formation rates. At midtropospheric temperatures the ion-induced pathway becomes the dominant mechanism. However, even the ion-induced binary mechanism does not produce significant particle formation in warm boundary layer conditions, as it requires temperatures below 0°C to take place at atmospheric concentrations. The theory successfully reproduces the characteristics of measured charged and neutral binary particle formation in CERN CLOUD3 and CLOUD5 experiments, as discussed in a companion paper.
Phase-field modeling of submonolayer growth with the modulated nucleation regime
Energy Technology Data Exchange (ETDEWEB)
Dong, X.L.; Xing, H.; Chen, C.L., E-mail: chenchl@nwpu.edu.cn; Wang, J.Y.; Jin, K.X.
2015-10-16
In this letter, we perform the phase-field simulations to investigate nucleation regime of submonolayer growth via a quantified nucleation term. Results show that the nucleation related kinetic coefficients have changed the density of islands and critical sizes to modulate the nucleation regime. The scaling behavior of the island density can be agreed with the classical theory only when effects of modulations have been quantified. We expect to produce the quantitative descriptions of nucleation for submonolayer growth in phase-field models. - Highlights: • The phase-field simulations are systematically compared with the classical nucleation rate theory. • The modulations of nucleation regime by the different kinetic coefficients have been studied. • Appropriate kinetic coefficients contribute to the agreed nucleation regime with the scaling law.
Plimak, L. I.; Ivanov, Misha; Aiello, A.; Stenholm, S.
2015-08-01
Quantum electrodynamics under conditions of distinguishability of interacting matter entities, and of controlled actions and back-actions between them, is considered. Such "mesoscopic quantum electrodynamics" is shown to share its dynamical structure with the classical stochastic electrodynamics. In formal terms, we demonstrate that all general relations of the mesoscopic quantum electrodynamics may be recast in a form lacking Planck's constant. Mesoscopic quantum electrodynamics is therefore subject to "doing quantum electrodynamics while thinking classically," allowing one to substitute essentially classical considerations for quantum ones without any loss in generality. Implications of these results for the quantum measurement theory are discussed.
On Classical de Sitter Vacua in String Theory
Wrase, Timm
2010-01-01
We review the prospect of obtaining tree-level de Sitter (dS) vacua and slow-roll inflation models in string compactifications. Restricting ourselves to the closed string sector and assuming the absence of NSNS-sources, we classify the minimal classical ingredients that evade the simplest no-go theorems against dS vacua and inflation. Spaces with negative integrated curvature together with certain combinations of low-dimensional orientifold planes and low-rank RR-fluxes emerge as the most promising setups of this analysis. We focus on two well-controlled classes that lead to an effective 4D, N=1 supergravity description: Type IIA theory on group or coset manifolds with SU(3)-structure and O6-planes, as well as type IIB compactifications on SU(2)-structure manifolds with O5- and O7-planes. While fully stabilized AdS vacua are generically possible, a number of problems encountered in the search for dS vacua are discussed.
On covariant Poisson brackets in classical field theory
Energy Technology Data Exchange (ETDEWEB)
Forger, Michael [Instituto de Matemática e Estatística, Universidade de São Paulo, Caixa Postal 66281, BR–05315-970 São Paulo, SP (Brazil); Salles, Mário O. [Instituto de Matemática e Estatística, Universidade de São Paulo, Caixa Postal 66281, BR–05315-970 São Paulo, SP (Brazil); Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Campus Universitário – Lagoa Nova, BR–59078-970 Natal, RN (Brazil)
2015-10-15
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on “multisymplectic Poisson brackets,” together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls–De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic “multisymplectic Poisson bracket” already proposed in the 1970s can be derived from the Peierls–De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra.
On covariant Poisson brackets in classical field theory
International Nuclear Information System (INIS)
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on “multisymplectic Poisson brackets,” together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls–De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic “multisymplectic Poisson bracket” already proposed in the 1970s can be derived from the Peierls–De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra
On covariant Poisson brackets in classical field theory
Forger, Michael; Salles, Mário O.
2015-10-01
How to give a natural geometric definition of a covariant Poisson bracket in classical field theory has for a long time been an open problem—as testified by the extensive literature on "multisymplectic Poisson brackets," together with the fact that all these proposals suffer from serious defects. On the other hand, the functional approach does provide a good candidate which has come to be known as the Peierls-De Witt bracket and whose construction in a geometrical setting is now well understood. Here, we show how the basic "multisymplectic Poisson bracket" already proposed in the 1970s can be derived from the Peierls-De Witt bracket, applied to a special class of functionals. This relation allows to trace back most (if not all) of the problems encountered in the past to ambiguities (the relation between differential forms on multiphase space and the functionals they define is not one-to-one) and also to the fact that this class of functionals does not form a Poisson subalgebra.
Rayleigh Scattering Density Measurements, Cluster Theory, and Nucleation Calculations at Mach 10
Balla, R. Jeffrey; Everhart, Joel L.
2012-01-01
In an exploratory investigation, quantitative unclustered laser Rayleigh scattering measurements of density were performed in the air in the NASA Langley Research Center's 31 in. Mach 10 wind tunnel. A review of 20 previous years of data in supersonic and Mach 6 hypersonic flows is presented where clustered signals typically overwhelmed molecular signals. A review of nucleation theory and accompanying nucleation calculations are also provided to interpret the current observed lack of clustering. Data were acquired at a fixed stagnation temperature near 990Kat five stagnation pressures spanning 2.41 to 10.0 MPa (350 to 1454 psi) using a pulsed argon fluoride excimer laser and double-intensified charge-coupled device camera. Data averaged over 371 images and 210 pixels along a 36.7mmline measured freestream densities that agree with computed isentropic-expansion densities to less than 2% and less than 6% at the highest and lowest densities, respectively. Cluster-free Mach 10 results are compared with previous clustered Mach 6 and condensation-free Mach 14 results. Evidence is presented indicating vibrationally excited oxygen and nitrogen molecules are absorbed as the clusters form, release their excess energy, and inhibit or possibly reverse the clustering process. Implications for delaying clustering and condensation onset in hypersonic and hypervelocity facilities are discussed.
Qian, Xiao-Feng; Howell, John C; Eberly, J H
2015-01-01
The growing recognition that entanglement is not exclusively a quantum property, and does not even originate with Schr\\"odinger's famous remark about it [Proc. Camb. Phil. Soc. {\\bf 31}, 555 (1935)], prompts examination of its role in marking the quantum-classical boundary. We have done this by subjecting correlations of classical optical fields to new Bell-analysis experiments, and report here values of the Bell parameter greater than ${\\cal B} = 2.54$. This is many standard deviations outside the limit ${\\cal B} = 2$ established by the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality [Phys. Rev. Lett. {\\bf 23}, 880 (1969)], in agreement with our theoretical classical prediction, and not far from the Tsirelson limit ${\\cal B} = 2.828...$. These results cast a new light on the standard quantum-classical boundary description, and suggest a reinterpretation of it.
International Nuclear Information System (INIS)
The reinterpretation of the BRS equations of Quantum Field Theory as the Maurer Cartan equation of a classical principal fiber bundle leads to a simple gauge invariant classification of the anomalies in Yang Mills theory and gravity
International Nuclear Information System (INIS)
In this paper, a detailed numerical comparison of the high-harmonic generation (HHG) from free electrons in intense laser fields in both classical and semi-classical frameworks has been presented. These two frameworks have been widely used in the literature. It has been found that the HHG spectra display distinct quantitative differences for high-energy electrons. In some special situations, qualitative differences appear. Even if the radiation reaction is included in the electron classical dynamics, no consistent result can be obtained. Hence it should be of critical importance to submit the present HHG theory for high-precision experimental tests, which can help us not only to justify the present theories, but also to check the QED predictions in the high-intensity regime. (paper)
Restrictions imposed on relativistic two-body interactions by classical relativistic field theory
International Nuclear Information System (INIS)
We show that various relativistic potential models (all sharing exact relativistic two-body kinematics and a common nonrelativistic limit) can be distinguished by agreement or disagreement with relativistic corrections produced by classical field theory. We find that the only one of these models whose relativisic corrections duplicate those of classical field theory is the minimal Todorov equation. Conversely, we derive the Todorov equation from the semirelativistic dynamics of classical field theory, thus exposing the classical field-theoretic origins of its characteristic minimal potential structures and dependences on effective one-body variables
A reappraisal of classical archetype theory and its implications for theory and practice.
Merchant, John
2009-06-01
This paper begins with an overview of contemporary approaches to archetype theory and notes the radical nature of certain deductions. Some argue that there is no 'archetype-as-such' as a pre-existing entity at the core of a complex driving its formation whilst the findings of current neuroscience are calling into question one very thing on which the classical theory is built--innatism. Knox's argument for image schemas raises the question as to the extent to which archetypes can be conceived in any preformationist sense. The question is then posed--to what extent can Jung's classical theory of archetypes be read in light of these current models? The case examples Jung uses to evidence the existence of archetypes, his explications of synchronicity and his own Philemon experience are then reappraised. The conclusion is drawn that it is difficult to evidence the existence of autonomous archetypes unrelated to personal affective experience. Not only would this be expected by emergent/developmental models of archetype but it can explain many of Jung's disjunctive statements about archetype constellation; the difficulties in separating personal and collective psychic content and Jung's apparent Lamarckianism. The implications of these models for theory, clinical practice and analyst training are then offered for discussion. PMID:19531124
Traffic breakdown at a signal: classical theory versus the three-phase theory of city traffic
International Nuclear Information System (INIS)
Physical reasons for a crucial difference between the results of a three-phase theory developed recently (Kerner 2011 Phys. Rev. E 84 045102(R); 2013 Europhys. Lett. 102 28010; 2014 Physica A 397 76) and the classical theory are explained. Microscopic characteristics of traffic passing a traffic signal during the green signal phase and their dependence on the duration of the green phase have been found. It turns out that a moving synchronized flow pattern (MSP), which occurs in under-saturated traffic at the signal, causes ‘compression’ of traffic flow: the rate of MSP discharge can be considerably larger than the saturation flow rate of the classical traffic theory of city traffic. This leads to a considerably larger rate of traffic passing the signal in comparison with the saturation flow rate. This effect together with traffic behavior at the upstream queue front explains the metastability of under-saturated traffic with respect to a random time-delayed traffic breakdown. (paper)
Traffic breakdown at a signal: classical theory versus the three-phase theory of city traffic
Kerner, Boris S.; Klenov, Sergey L.; Schreckenberg, Michael
2014-03-01
Physical reasons for a crucial difference between the results of a three-phase theory developed recently (Kerner 2011 Phys. Rev. E 84 045102(R); 2013 Europhys. Lett. 102 28010; 2014 Physica A 397 76) and the classical theory are explained. Microscopic characteristics of traffic passing a traffic signal during the green signal phase and their dependence on the duration of the green phase have been found. It turns out that a moving synchronized flow pattern (MSP), which occurs in under-saturated traffic at the signal, causes ‘compression’ of traffic flow: the rate of MSP discharge can be considerably larger than the saturation flow rate of the classical traffic theory of city traffic. This leads to a considerably larger rate of traffic passing the signal in comparison with the saturation flow rate. This effect together with traffic behavior at the upstream queue front explains the metastability of under-saturated traffic with respect to a random time-delayed traffic breakdown.
Binary nucleation beyond capillarity approximation
Kalikmanov, V.I.
2010-01-01
Large discrepancies between binary classical nucleation theory (BCNT) and experiments result from adsorption effects and inability of BCNT, based on the phenomenological capillarity approximation, to treat small clusters. We propose a model aimed at eliminating both of these deficiencies. Adsorption is taken into account within Gibbsian approximation. Binary clusters are treated by means of statistical-mechanical considerations: tracing out the molecular degrees of freedom of the more volatil...
Classical irregular block, N=2 pure gauge theory and Mathieu equation
Piatek, Marcin
2014-01-01
Combining the semiclassical/Nekrasov-Shatashvili limit of the AGT conjecture and the Bethe/gauge correspondence results in a triple correspondence which identifies classical conformal blocks with twisted superpotentials and then with Yang-Yang functions. In this paper the triple correspondence is studied in the simplest, yet not completely understood case of pure SU(2) super-Yang-Mills gauge theory. A missing element of that correspondence is identified with the classical irregular block. Explicit tests provide a convincing evidence that such a function exists. In particular, it has been shown that the classical irregular block can be recovered from classical blocks on the torus and sphere in suitably defined decoupling limits of classical external conformal weights. These limits are "classical analogues" of known decoupling limits for corresponding quantum blocks. An exact correspondence between the classical irregular block and the SU(2) gauge theory twisted superpotential has been obtained as a result of a...
A critical experimental study of the classical tactile threshold theory
Directory of Open Access Journals (Sweden)
Medina Leonel E
2010-06-01
Full Text Available Abstract Background The tactile sense is being used in a variety of applications involving tactile human-machine interfaces. In a significant number of publications the classical threshold concept plays a central role in modelling and explaining psychophysical experimental results such as in stochastic resonance (SR phenomena. In SR, noise enhances detection of sub-threshold stimuli and the phenomenon is explained stating that the required amplitude to exceed the sensory threshold barrier can be reached by adding noise to a sub-threshold stimulus. We designed an experiment to test the validity of the classical vibrotactile threshold. Using a second choice experiment, we show that individuals can order sensorial events below the level known as the classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance level. Nevertheless, our experimental results are above that chance level contradicting the definition of the classical tactile threshold. Results We performed a three alternative forced choice detection experiment on 6 subjects asking them first and second choices. In each trial, only one of the intervals contained a stimulus and the others contained only noise. According to the classical threshold assumptions, a correct second choice response corresponds to a guess attempt with a statistical frequency of 50%. Results show an average of 67.35% (STD = 1.41% for the second choice response that is not explained by the classical threshold definition. Additionally, for low stimulus amplitudes, second choice correct detection is above chance level for any detectability level. Conclusions Using a second choice experiment, we show that individuals can order sensorial events below the level known as a classical threshold. If the observer's sensorial system is not activated by stimuli below the threshold, then a second choice could not be above the chance
On the concept of Bell’s local causality in local classical and quantum theory
International Nuclear Information System (INIS)
The aim of this paper is to implement Bell’s notion of local causality into a framework, called local physical theory. This framework, based on the axioms of algebraic field theory, is broad enough to integrate both probabilistic and spatiotemporal concepts and also classical and quantum theories. Bell’s original idea of local causality will arise as the classical case of our definition. Classifying local physical theories by whether they obey local primitive causality, a property rendering the dynamics of the theory causal, we then investigate what is needed for a local physical theory to be locally causal. Finally, comparing local causality with the common cause principles and relating both to the Bell inequalities we find a nice parallelism: Bell inequalities cannot be derived neither from local causality nor from a common cause unless the local physical theory is classical or the common cause is commuting, respectively
Liquid Nucleation at Superheated Grain Boundaries
Frolov, T.; Mishin, Y.
2011-04-01
Grain boundaries with relatively low energies can be superheated above the melting temperature and eventually melt by heterogeneous nucleation of liquid droplets. We propose a thermodynamic model of this process based on the sharp-interface approximation with a disjoining potential. The distinct feature of the model is its ability to predict the shape and size of the critical nucleus by using a variational approach. The model reduces to the classical nucleation theory in the limit of large nuclei but is more general and remains valid for small nuclei. Contrary to the classical nucleation theory, the model predicts the existence of a critical temperature of superheating and offers a simple formula for its calculation. The model is tested against molecular dynamic simulations in which liquid nuclei at a superheated boundary were obtained by an adiabatic trapping procedure. The simulation results demonstrate a reassuring consistency with the model.
Quantization, Classical and Quantum Field Theory and Theta - Functions
Tyurin, Andrey N.
2002-01-01
In the abelian case (the subject of several beautiful books) fixing some combinatorial structure (so called theta structure of level k) one obtains a special basis in the space of sections of canonical polarization powers over the jacobians. These sections can be presented as holomorphic functions on the "abelian Schottky space". This fact provides various applications of these concrete analytic formulas to the integrable systems, classical mechanics and PDE's. Our practical goal is to do the...
On inert properties of particles in classical theory
Kosyakov, B. P.
2002-01-01
This is a critical review of inert properties of classical relativistic point objects. The objects are classified as Galilean and non-Galilean. Three types of non-Galilean objects are considered: spinning, rigid, and dressed particles. In the absence of external forces, such particles are capable of executing not only uniform motions along straight lines but also Zitterbewegungs, self-accelerations, self-decelerations, and uniformly accelerated motions. A free non-Galilean object possesses th...
Antigravity and classical solutions of five-dimensional Kaluza-Klein theory
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Pollard, D. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)
1983-02-21
Classical solutions are exhibited of a graviton-graviphoton-graviscalar field theory which are antigravitating in the weak-field approximation. The theory itself is obtained by a Kaluza-Klein type reduction from five to four dimensions. The solutions are dyonic black holes with scalar charge. They share some similarities with the extreme Reissner-Nordstrom black holes of Einstein-Maxwell theory.
Hyperdense coding and superadditivity of classical capacities in hypersphere theories
Massar, Serge; Pironio, Stefano; Pitalúa-García, Damián
2015-01-01
In quantum superdense coding, two parties previously sharing entanglement can communicate a two bit message by sending a single qubit. We study this feature in the broader framework of general probabilistic theories. We consider a particular class of theories in which the local state space of the communicating parties corresponds to Euclidean hyperballs of dimension n (the case n = 3 corresponds to the Bloch ball of quantum theory). We show that a single n-ball can encode at most one bit of i...
Lange, Elizabeth
2015-01-01
This article argues that sociology has been a foundational discipline for the field of adult education, but it has been largely implicit, until recently. This article contextualizes classical theories of sociology within contemporary critiques, reviews the historical roots of sociology and then briefly introduces the classical theories…
Quantum Electrodynamics Basis of Classical-Field High-Harmonic Generation Theory
Institute of Scientific and Technical Information of China (English)
王兵兵; 高靓辉; 傅盘铭; 郭东升; R. R. Freeman
2001-01-01
From the nonperturbative quantum electrodynamics theory, we derive the Landau-Dykhne formula which represents the quantum-mechanical formulation of the three-step model. These studies provide a basis for the classical-field approaches to high-order harmonic generation and justify some assumptions used in classical-field modelling.
The Poisson algebra of classical Hamiltonians in field theory and the problem of its quantization
Stoyanovsky, A.
2010-01-01
We construct the commutative Poisson algebra of classical Hamiltonians in field theory. We pose the problem of quantization of this Poisson algebra. We also make some interesting computations in the known quadratic part of the quantum algebra.
A2: Mathematical relativity and other progress in classical gravity theory - a session report
Chruściel, Piotr T.; Paetz, Tim-Torben
2013-01-01
We report on selected oral contributions to the A2 session "Mathematical relativity and other progress in classical gravity theory" of "The 20th International Conference on General Relativity and Gravitation (GR20)" in Warsaw.
Classical Belief Conditioning and its Generalization to DSm Theory
Czech Academy of Sciences Publication Activity Database
Daniel, Milan
2008-01-01
Roč. 2, č. 4 (2008), s. 267-279. ISSN 1752-8917 R&D Projects: GA AV ČR 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : belief functions * Dempster-Shafer theory * belief conditioning * DSm theory * overlapping elements * hyper-power set * DSm model Subject RIV: BA - General Mathematics http://www.worldacademicunion.com/journal/jus/jusVol02No4paper04.pdf
Institute of Scientific and Technical Information of China (English)
Fu Dong; Liao Tao
2007-01-01
The excess Helmholtz free energy functional for nonpolar chain-like molecules is formulated in terms of a weighted density approximation (WDA) for short-range interactions and a Weaks-Chandler-Andersen (WCA) approximation and a Barker-Henderson (BH) theory for long-range attraction. Within the framework of density functional theory (DFT), vapour-liquid interfacial properties including density profile and surface tension, and vapour-liquid nucleation properties including density profile, work of formation and number of particles are investigated for spherical and chainlike molecules. The obtained vapour-liquid surface tension and the number of particles in critical nucleus for LennardJones (L J) fluids are consistent with the simulation results. The influences of supersaturation, temperature and chain length on vapour-liquid nucleation properties are discussed.
On one classical problem in the radial orbit instability theory
Polyachenko, E. V.; Shukhman, I. G.
2016-02-01
Antonov's classical problem of stability of a collisionless sphere with a purely radial motion of stars is considered as a limit of the problem in which stars move in nearly radial orbits. We provide the proper limiting equations that take into account the singularity in the density distribution at the sphere center and give their solutions. We show that there is instability for even and odd spherical harmonics, with all unstable modes being not slow. The growth rates of aperiodic even modes increase indefinitely when approaching purely radial models. The physics of the radial orbit instability is discussed.
Scattering theory for the quantum envelope of a classical system
International Nuclear Information System (INIS)
Classical dynamics, reformulated in terms of its quantum envelope is studied for the stationary states of the interacting system. The dynamical variable of ''elapsed time'' plays a crucial role in this study. It is shown that the perturbation series for the elapsed time can be summed in various simple cases even when standard perturbation series diverge. For the special class of systems where the interactions fall off sufficiently fast at infinity one could define ''in'' and ''out'' states; and consequently the wave matrices and scattering matrices. The scattering phase shifts bear a simple relation to the time delay in scattering
Classical optics in generalized Maxwell Chern-Simons theory
International Nuclear Information System (INIS)
The authors consider the propagation of electromagnetic waves in a two-dimensional polarizable medium endowed with Chern-Simons terms. The dispersion relation (refractive index) of the waves is computed and the existence of linear birefringence and anomalous dispersion is shown. When absorption is taken into account, the classic signature of a Voigt effect is found. In the case where linearly-polarized, three-dimensional waves pass through a two-dimensional plane, it is shown that there is optical activity, and the analogue of Verdet's constant is computed. 19 refs., 2 figs
On inert properties of particles in classical theory
Kosyakov, B P
2002-01-01
This is a critical review of inert properties of classical relativistic point objects. The objects are classified as Galilean and non-Galilean. Three types of non-Galilean objects are considered: spinning, rigid, and dressed particles. In the absence of external forces, such particles are capable of executing not only uniform motions along straight lines but also Zitterbewegungs, self-accelerations, self-decelerations, and uniformly accelerated motions. A free non-Galilean object possesses the four-velocity and the four-momentum which are in general not collinear, therefore, its inert properties are specified by two, rather than one, invariant quantities. It is shown that a spinning particle need not be a non-Galilean object. The necessity of a rigid mechanics for the construction of a consistent classical electrodynamics in spacetimes of dimension D+1 is justified for D+1>4. The problem of how much the form of fundamental laws of physics orders four dimensions of our world is revised together with its soluti...
A course in mathematical physics 1 and 2 classical dynamical systems and classical field theory
Thirring, Walter
1992-01-01
The last decade has seen a considerable renaissance in the realm of classical dynamical systems, and many things that may have appeared mathematically overly sophisticated at the time of the first appearance of this textbook have since become the everyday tools of working physicists. This new edition is intended to take this development into account. I have also tried to make the book more readable and to eradicate errors. Since the first edition already contained plenty of material for a one semester course, new material was added only when some of the original could be dropped or simplified. Even so, it was necessary to expand the chap ter with the proof of the K-A-M Theorem to make allowances for the cur rent trend in physics. This involved not only the use of more refined mathe matical tools, but also a reevaluation of the word "fundamental. " What was earlier dismissed as a grubby calculation is now seen as the consequence of a deep principle. Even Kepler's laws, which determine the radii of the ...
New views on classical and quantum Brans-Dicke theory
Fabris, Júlio C; Rodrigues, Davi C; Almeida, Carla R; Piattella, Oliver F
2016-01-01
The Brans-Dicke action is one of the most natural extensions of the Einstein-Hilbert action. It is based on the introduction of a fundamental scalar field that effectively incorporates a dynamics to the gravitational coupling $G$. In spite of the diverse motivations and the rich phenomenology that comes from its solutions, Solar System tests impose strong constraints on the Brans-Dicke theory, rendering it indistinguishable from General Relativity. In the present text, new perspectives for the Brans-Dicke theory are presented, based on the possibility that the scalar field presented in the BD theory can be external, as well as on the applications to black hole physics and the primordial universe.
Quantization of light energy directly from classical electromagnetic theory in vacuum
Institute of Scientific and Technical Information of China (English)
She Wei-Long
2005-01-01
It is currently believed that light quantum or the quantization of light energy is beyond classical physics, and the picture of wave-particle duality, which was criticized by Einstein but has attracted a number of experimental researches, is necessary for the description of light. It is shown in this paper, however, that the quantization of light energy in vacuum, which is the same as that in quantum electrodynamics, can be derived directly from the classical electromagnetic theory through the consideration of statistics based on classical physics. Therefore, the quantization of energy is an intrinsic property of light as a classical electromagnetic wave and has no need of being related to particles.
3D gravity with dust: classical and quantum theory
Husain, Viqar
2015-01-01
We study the Einstein gravity and dust system in three spacetime dimensions as an example of a non-perturbative quantum gravity model with local degrees of freedom. We derive the Hamiltonian theory in the dust time gauge and show that it has a rich class of exact solutions. These include the Ba\\~nados-Teitelboim-Zanelli black hole, static solutions with naked singularities and travelling wave solutions with dynamical horizons. We give a complete quantization of the wave sector of the theory, including a definition of a self-adjoint spacetime metric operator. This operator is used to demonstrate the quantization of deficit angle and the fluctuation of dynamical horizons.
Classical Belief Conditioning and its Generalization to DSm Theory
Czech Academy of Sciences Publication Activity Database
Daniel, Milan
San Luis Obispo : California Polytechnic State University, 2007 - (Lee, T.; Liu, Y.; Zhao, X.), s. 596-603 ISSN 1539-2023. - (Series of Information & Management Sciences. 6). [International Conference on Information and Management Sciences /6./. Lhasa (CN), 01.06.2007-06.06.2007] R&D Projects: GA AV ČR 1ET100300419 Institutional research plan: CEZ:AV0Z10300504 Keywords : belief functions * Dempster-Shafer theory * belief conditioning * DSm theory * overlapping elements * hyper-power set * DSm model Subject RIV: BA - General Mathematics
Topics in the theory of quantum and classical networks
Almaas, Eivind
We study both quantum and classical networks. The quantum networks consist of 1D and 2D arrays of Josephson junctions coupled to a resonant cavity. We derive dynamical equations for these arrays by applying the Heisenberg equations of motion to a model Hamiltonian. By means of a canonical transformation, we also show that, in the absence of an applied current and dissipation, our model reduces to one used to describe coupled qubits, and that the cavity-junction coupling corresponds to a capacitive coupling between the array and the cavity mode. From extensive numerical solutions of the model in both 1D and 2D, we find that the array locks into a coherent, periodic state above a critical number of active junctions, that the current-voltage characteristics of the array have self-induced resonant steps (SIRS's), that when N a active junctions are synchronized on a SIRS, the energy emitted into the resonant cavity is quadratic in Na, and that when a fixed number of junctions is biased on a SIRS, the energy is linear in the input power. All these results are in agreement with recent experiments. We conclude that most of the experimental data can be understood from classical equations of motion. Our study of classical networks is divided into two parts. In the first, we study the structural properties of 'small-world' networks (SWN)---networks that display properties of both regular and random graphs. We generalize the model for generating such networks that was first introduced by Watts and Strogatz. For this model, we study the distribution function for minimal paths, derive its general form and also discuss its scaling properties. Using this distribution function, we derive exact expressions for several network properties, like the average minimal distance, ℓ¯ and its variance, sigma2. These exact relations are independent of the 'degree distribution', i.e. the distribution of nearest-neighbor connections. In the second, we study how the structure of the network
k-Cosymplectic Classical Field Theories: Tulczyjew and Skinner–Rusk Formulations
International Nuclear Information System (INIS)
The k-cosymplectic Lagrangian and Hamiltonian formalisms of first-order classical field theories are reviewed and completed. In particular, they are stated for singular and almost-regular systems. Subsequently, several alternative formulations for k-cosymplectic first-order field theories are developed: First, generalizing the construction of Tulczyjew for mechanics, we give a new interpretation of the classical field equations. Second, the Lagrangian and Hamiltonian formalisms are unified by giving an extension of the Skinner–Rusk formulation on classical mechanics.
Haataja, Mikko; Gránásy, László; Löwen, Hartmut
2010-08-01
, about a half of which are related to the theoretical materials science community and the other half came from the soft-matter community. We begin by discussing papers related to PFC. Diverse subjects related to the phase-field crystal model include exciting topics such as predicting/controlling the equilibrium phase behavior [19, 18, 17] and kinetics of epitaxial island formation on nano-membranes [20]. Moreover, phase-field crystal modeling has proved to be very successful in simulating homogeneous and heterogeneous crystal nucleation and growth, and several aspects of these phenomena are discussed in this issue [18, 21]. Finally, it is shown how to incorporate additional orientational degrees of freedom within the PFC approach to model liquid crystals [22]. On the DFT side, the other papers in this special issue deal with problems associated with advanced DFT techniques and applications. The existence of a structural instability in sub-critical crystalline fluctuations in a supercooled liquid within a square-gradient theory is discussed in [23]. Fundamental measure theory for hard-body systems is improved by discussing a correction term in detail, as discussed in [24]. A mean-field-like density functional for charges is applied to the effective interaction between charged colloids obtained within a cell model [25]. The remaining articles provide fundamental insight into how to supplement DDFT-type methods with hydrodynamics [26, 27], highlight the role of the projection operator technique in deriving dynamical density functional theories [28], and demonstrate how perturbation methods can be employed to compute the properties of solid-liquid interfaces [29]. This particular collection of papers demonstrates rather convincingly the significant potential that classical density functional techniques possess in modeling complex systems built of either soft or hard matter (or combinations thereof). While the PFC approach offers a simple and appealing means to simulate
Foundations of the classical theory of partial differential equations
Egorov, Yu V
1998-01-01
From the reviews of the first printing, published as volume 30 of the Encyclopaedia of Mathematical Sciences: "... I think the volume is a great success and an excellent preparation for future volumes in the series. ... the introductory style of Egorov and Shubin is .. attractive. ... a welcome addition to the literature and I am looking forward to the appearance of more volumes of the Encyclopedia in the near future. ..." The Mathematical Intelligencer, 1993 "... According to the authors ... the work was written for nonspecialists and physicists but in my opinion almost every specialist will find something new ... in the text. The style is clear, the notations are chosen luckily. The most characteristic feature of the work is the accurate emphasis on the fundamental notions ..." Acta Scientiarum Mathematicarum, 1993 "... On the whole, a thorough overview on the classical aspects of the topic may be gained from that volume." Monatshefte für Mathematik, 1993 "... It is comparable in scope with the great Coura...
Classical theory of thermal radiation from a solid.
Guo, Wei
2016-06-01
In this work, a solid at a finite temperature is modeled as an ensemble of identical atoms, each of which moves around a lattice site inside an isotropic harmonic potential. The motion of one such atom is studied first. It is found that the atom moves like a time-dependent current density and, thus, can emit electromagnetic radiation. Since all the atoms are identical, they can radiate, too. The resultant radiation from the atoms is the familiar thermal radiation from the solid. After its general expression is obtained, the intensity of the thermal radiation is discussed for its properties, and specifically calculated in the low-temperature limit. Both atomic motion and radiation are formulated in the classical domain. PMID:27409442
Classical instanton and wormhole solutions of Type IIB string theory
Kim, Jin Young; Lee, H. W.; Myung, Y. S.
1996-01-01
We study $p=-1$ D-brane in type IIB superstring theory. In addition to RR instanton, we obtain the RR charged wormhole solution in the Einstein frame. This corresponds to the ten-dimensional singular wormhole solution with infinite euclidean action.
Collaboration in classical political economy and noncooperative game theory.
McCain, Roger A
2014-06-01
This commentary suggests (1) that there are precedents for Smaldino's "collaboration" in the history of economic thought before 1900 and (2) that the distinction of collaboration from what is thought of as cooperation in game theory is less clear than Smaldino suggests. PMID:24970411
Regulating photon mass in classical 5D gauge theory
International Nuclear Information System (INIS)
Full Text:Off-shell electrodynamics, the local gauge theory associated with a covariant symplectic mechanics developed by Stueckelberg, describes instantaneous interactions between spacetime events, mediated by five massive gauge fields. Event evolution in this formalism is parameterized by an independent, monotonically increasing, Poincare-invariant parameter, and not by the proper time of the motion, and so one is led to a dynamical theory in which mass conservation is demoted from the status of an a priori constraint to that of a Noether current conserved for a certain class or interactions. While the total mass-energy of particles and fields is conserved, particles and photons may, in general, exchange mass. In the equilibrium limit, photons are pushed onto the Maxwell zero-mass shell, but during interaction, photons may acquire any mass, even pushing particle trajectories far into the spacelike region. We discuss a higher derivative correction to the photon kinetic term, which regulates the photon mass while preserving gauge invariance and Poincare covariance of the original theory. We discuss an information-theoretic interpretation of this mechanism, and demonstrate that the resulting quantum field theory is made super-renormalizable
Fradera, Jorge; Cuesta-López, Santiago
2013-01-01
Helium (He) nucleation in liquid metal breeding blankets of a DT fusion reactor may have a significant impact regarding system design, safety and operation. Large He production rates are expected due to tritium (T) fuel self-sufficiency requirement, as both, He and T, are produced at the same rate. Low He solubility, local high concentrations, radiation damage and fluid discontinuities, among other phenomena, may yield the necessary conditions for He nucleation. Hence, He nucleation may have ...
Universality principle and the development of classical density functional theory
Institute of Scientific and Technical Information of China (English)
周世琦; 张晓琪
2002-01-01
The universality principle of the free energy density functional and the ‘test particle' trick by Percus are combined to construct the approximate free energy density functional or its functional derivative. Information about the bulk fluid ralial distribution function is integrated into the density functional approximation directly for the first time in the present methodology. The physical foundation of the present methodology also applies to the quantum density functional theory.
Effect of oxygen partial pressure on the nucleation kinetics of orthorhombic YBCO
International Nuclear Information System (INIS)
Effect of oxygen partial pressure on the nucleation kinetics of orthorhombic YBCO from tetragonal phase has been studied using classical nucleation theory. The free energy of formation of orthorhombic YBCO has been evaluated as a function of oxygen partial pressure. (Abstract Copyright [2002], Wiley Periodicals, Inc.)
Opportunizing: A classic grounded theory study on business and management
Directory of Open Access Journals (Sweden)
Ólavur Christiansen
2006-11-01
Full Text Available Opportunizing emerged as the core variable of this classic GT study on business and management. Opportunizing is the recurrent main concern that businesses have to continually resolve, and it explains how companies recurrently create, identify, seize or exploit situations to maintain their growth or survival. Opportunizing is the recurrent creation and re-creation of opportunities in business. Opportunizing is basically what business managers do and do all the time. The problematic nature of opportunizing is resolved by a core social process ofopportunizing and its attached sub-processes that account for change over time and for the variations of the problematic nature of its resolution.Opportunizing has five main facets. These are conditional befriending (confidence building & modifying behavior,prospecting (e.g. information gaining, weighing up (information appraisal & decision-making, moment capturing (quick intervention for seizing strategic opportunities, andconfiguration matching (adjusting the business organization to abet the other activities of opportunizing.On a more abstract level, opportunizing has three more organizational facets: the physically boundary-less, the valuehierarchical, and the physically bounded. The first of these called perpetual opportunizing. This emerges from the conjunction of conditional befriending and prospecting. The second facet is called triggering opportunizing. It arises from the coming together of weighing up and moment capturing. The final facet is called spasmodic opportunizing. This happens when moment capturing and configuration matching unite.
Semi-classical theory of fluctuations in nuclear matter
International Nuclear Information System (INIS)
At intermediate energies the heavy ion collisions can be studied within the framework of a semi-classical approach based on the Vlasov-Uehling-Uhlenbeck (VUU) equation. Such an approach reduces the N-body problem to its description in terms of the one-body distribution function and constitutes the basis of several successful simulation models. Our aim in this work is to extend these average approaches to treat fluctuations. Within the framework of a linear approximation, we derived a Fokker-Planck transport equation in the one-body phase space. When it is reduced to its first moments, one recovers the VUU equation for the average dynamics together with the time evolution equation for the correlations. The collective transport coefficients are then obtained by projection on the one-body collective space. Independently, using a projection method introduced by Van Kampen, based on the constants of motion, we deduce the stationary expressions for the covariance matrix in phase space. We extract then, the equilibrium dispersions of one-body observables in a homogeneous case and in a spherical symmetric one. These results are compared with two types of simulation models in a relaxation time approximation. In the first one which is of Lagrangian type, the collective transport coefficients are directly extracted from the simulation and consequently the numerical fluctuations are washed out. The second model, due to its Eulerian character, allows us to make a microscopical comparison. (author)
Reese, Lynda M.
This study extended prior Law School Admission Council (LSAC) research related to the item response theory (IRT) local item independence assumption into the realm of classical test theory. Initially, results from the Law School Admission Test (LSAT) and two other tests were investigated to determine the approximate state of local item independence…
A modification of Amiet's classical trailing edge noise theory for strictly two dimensional flows
Sandberg, Richard D.; Sandham, Neil D.
2007-01-01
The aim of this report is to derive theoretical expressions for the far-field pressure generated by disturbances convecting over a trailing edge. First, a general calculation of the far-field pressure is discussed. Then the classical theory of Amiet (1976b) is reviewed, listing the most relevant assumptions. Amiet's theory is then revised for two-dimensional flows.
Matrix Analogues to Some Classical Problems in Number Theory
Niwa, Masahiko
1996-01-01
The aim of this paper is to give a few results on some problems in the matrix ring Mn(R) over a commutative ring R analogous to some classical problems in number theory, which are handled in L. N. Vaserstein[4]. As for Matrix Goldbach Problem we can easily give an affirmative solution in Mn(R)(any n≧2), contrary to the difficulty of the original conjecture. As for Matrix Fermat Problem we will explain the connection of this problem with elements of finite order of the group GLn(R) of uni...
Perturbative quantization of Yang-Mills theory with classical double as gauge algebra
International Nuclear Information System (INIS)
Perturbative quantization of Yang-Mills theory with a gauge algebra given by the classical double of a semisimple Lie algebra is considered. The classical double of a real Lie algebra is a nonsemisimple real Lie algebra that admits a nonpositive definite invariant metric, the indefiniteness of the metric suggesting an apparent lack of unitarity. It is shown that the theory is UV divergent at one loop and that there are no radiative corrections at higher loops. One-loop UV divergences are removed through renormalization of the coupling constant, thus introducing a renormalization scale. The terms in the classical action that would spoil unitarity are proved to be cohomologically trivial with respect to the Slavnov-Taylor operator that controls gauge invariance for the quantum theory. Hence they do not contribute gauge invariant radiative corrections to the quantum effective action and the theory is unitary. (orig.)
Perturbative quantization of Yang-Mills theory with classical double as gauge algebra
Ruiz Ruiz, F.
2016-02-01
Perturbative quantization of Yang-Mills theory with a gauge algebra given by the classical double of a semisimple Lie algebra is considered. The classical double of a real Lie algebra is a nonsemisimple real Lie algebra that admits a nonpositive definite invariant metric, the indefiniteness of the metric suggesting an apparent lack of unitarity. It is shown that the theory is UV divergent at one loop and that there are no radiative corrections at higher loops. One-loop UV divergences are removed through renormalization of the coupling constant, thus introducing a renormalization scale. The terms in the classical action that would spoil unitarity are proved to be cohomologically trivial with respect to the Slavnov-Taylor operator that controls gauge invariance for the quantum theory. Hence they do not contribute gauge invariant radiative corrections to the quantum effective action and the theory is unitary.
Perturbative quantization of Yang-Mills theory with classical double as gauge algebra
Energy Technology Data Exchange (ETDEWEB)
Ruiz Ruiz, F. [Universidad Complutense de Madrid, Departamento de Fisica Teorica I, Madrid (Spain)
2016-02-15
Perturbative quantization of Yang-Mills theory with a gauge algebra given by the classical double of a semisimple Lie algebra is considered. The classical double of a real Lie algebra is a nonsemisimple real Lie algebra that admits a nonpositive definite invariant metric, the indefiniteness of the metric suggesting an apparent lack of unitarity. It is shown that the theory is UV divergent at one loop and that there are no radiative corrections at higher loops. One-loop UV divergences are removed through renormalization of the coupling constant, thus introducing a renormalization scale. The terms in the classical action that would spoil unitarity are proved to be cohomologically trivial with respect to the Slavnov-Taylor operator that controls gauge invariance for the quantum theory. Hence they do not contribute gauge invariant radiative corrections to the quantum effective action and the theory is unitary. (orig.)
Ternary nucleation of H2SO4, NH3 and H2O
Kulmala, M.; Korhonen, P.; Laaksonen, A.; Viisanen, Y.; McGraw, R; Seinfeld, J. H.
2000-01-01
A classical theory of the ternary homogeneous nucleation of sulfuric acid—ammonia—water is presented. For NH3 mixing ratios exceeding 1 ppt, the presence of ammonia enhances the binary (sulfuric acid—water) nucleation rate by several orders of magnitude. However, the limiting component for ternary nucleation—as for binary nucleation—is sulfuric acid. The sulfuric acid concentration needed for significant ternary nucleation is several orders of magnitude below that required in binary case....
Modelling microscopic clusters of sulphuric acid and water relevant to atmospheric nucleation
Stinson, J
2015-01-01
Classical nucleation theory has been a useful tool for predicting the phenomena of nucleation for the past seventy years. However the model has several limitations, which in some examples give rise to predicted rates that are several orders of magnitude in error. One such example is that of sulphuric acid and water nucleation which has long been framed as an important source of cloud condensation nuclei and therefore has implications for the climate, both locally and globally. In addition str...
Pseudo-one-dimensional nucleation in dilute polymer solutions
Zhang, Lingyun; Schmit, Jeremy D.
2016-06-01
Pathogenic protein fibrils have been shown in vitro to have nucleation-dependent kinetics despite the fact that one-dimensional structures do not have the size-dependent surface energy responsible for the lag time in classical theory. We present a theory showing that the conformational entropy of the peptide chains creates a free-energy barrier that is analogous to the translational entropy barrier in higher dimensions. We find that the dynamics of polymer rearrangement make it very unlikely for nucleation to succeed along the lowest free-energy trajectory, meaning that most of the nucleation flux avoids the free-energy saddle point. We use these results to construct a three-dimensional model for amyloid nucleation that accounts for conformational entropy, backbone H bonds, and side-chain interactions to compute nucleation rates as a function of concentration.
On the Foundational Equations of the Classical Theory of Electrodynamics
Mansuripur, Masud
2014-01-01
A close examination of the Maxwell-Lorentz theory of electrodynamics reveals that polarization and magnetization of material media need not be treated as local averages over small volumes - volumes that nevertheless contain a large number of electric and/or magnetic dipoles. Indeed, Maxwell's macroscopic equations are exact and self-consistent mathematical relations between electromagnetic fields and their sources, which consist of free charge, free current, polarization, and magnetization. When necessary, the discrete nature of the constituents of matter and the granularity of material media can be handled with the aid of special functions, such as Dirac's delta-function. The energy of the electromagnetic field and the exchange of this energy with material media are treated with a single postulate that establishes the Poynting vector S = ExH as the rate of flow of electromagnetic energy under all circumstances. Similarly, the linear and angular momentum densities of the fields are simple functions of the Poy...
On a Gauge Invariant Quantum Formulation for Non-gauge Classical Theory
I.L. Buchbinder; Pershin, V. D.; Toder, G. B.
1996-01-01
We propose a method of constructing a gauge invariant canonical formulation for non-gauge classical theory which depends on a set of parameters. Requirement of closure for algebra of operators generating quantum gauge transformations leads to restrictions on parameters of the theory. This approach is then applied for illustration to bosonic string theory coupled to background tachyonic field. It is shown that within the proposed canonical formulation the known mass-shell condition for tachyon...
Methods of geometric function theory in classical and modern problems for polynomials
International Nuclear Information System (INIS)
This paper gives a survey of classical and modern theorems on polynomials, proved using methods of geometric function theory. Most of the paper is devoted to results of the author and his students, established by applying majorization principles for holomorphic functions, the theory of univalent functions, the theory of capacities, and symmetrization. Auxiliary results and the proofs of some of the theorems are presented. Bibliography: 124 titles.
Antigravity and classical solutions of five-dimensional Kaluza-Klein theory
International Nuclear Information System (INIS)
Classical solutions are exhibited of a graviton-graviphoton-graviscalar field theory which are antigravitating in the weak-field approximation. The theory itself is obtained by a Kaluza-Klein type reduction from five to four dimensions. The solutions are dyonic black holes with scalar charge. They share some similarities with the extreme Reissner-Nordstrom black holes of Einstein-Maxwell theory. (author)
Impurity mediated nucleation in hexadecane-in-water emulsions
Herhold, Amy; Ertas, Deniz; Levine, Alex J.; King Jr, H. E.
1998-01-01
We report detailed nucleation studies on the liquid-to-solid transition of hexadecane using nearly monodisperse hexadecane-in-water emulsions. A careful consideration of the kinetics of isothermal and nonisothermal freezing show deviations from predictions of classical nucleation theory, if one assumes that the emulsion droplet population is homogeneous. Similar deviations have been observed previously. As an explanation, we propose a novel argument based on the dynamic generation of droplet ...
International Nuclear Information System (INIS)
The one loop effective action in quantum field theory can be expressed as a quantum mechanical path integral over world lines, with internal symmetries represented by Grassmanian variables. In this paper, we develop a real time, many body, world line formalism for the one loop effective action. In particular, we study hot QCD and obtain the classical transport equations which, as Litim and Manuel have shown, reduce in the appropriate limit to the non-Abelian Boltzmann-Langevin equation first obtained by Boedeker. In the Vlasov limit, the classical kinetic equations are those that correspond to the hard thermal loop effective action. We also discuss the imaginary time world line formalism for a hot φ4 theory, and elucidate its relation to classical transport theory. (c) 2000 The American Physical Society
Jalilian-Marian, J; Venugopalan, R; Wirstam, J; Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju; Wirstam, Jens
2000-01-01
The one loop effective action in quantum field theory can be expressed as a quantum mechanical path integral over world lines, with internal symmetries represented by Grassmanian variables. In this paper, we develop a real time, many body, world line formalism for the one loop effective action. In particular, we study hot QCD and obtain the classical transport equations which, as Litim and Manuel have shown, reduce in the appropriate limit to the non-Abelian Boltzmann-Langevin equation first obtained by Bödeker. In the Vlasov limit, the classical kinetic equations are those that correspond to the hard thermal loop effective action. We also discuss the imaginary time world line formalism for a hot $\\phi^4$ theory, and elucidate its relation to classical transport theory.
Treatise on classical elasticity theory and related problems
Teodorescu, Petre P
2013-01-01
Deformable solids have a particularly complex character; mathematical modeling is not always simple and often leads to inextricable difficulties of computation. One of the simplest mathematical models and, at the same time, the most used model, is that of the elastic body – especially the linear one. But, notwithstanding its simplicity, even this model of a real body may lead to great difficulties of computation. The practical importance of a work about the theory of elasticity, which is also an introduction to the mechanics of deformable solids, consists of the use of scientific methods of computation in a domain in which simplified methods are still used. This treatise takes into account the consideration made above, with special attention to the theoretical study of the state of strain and stress of a deformable solid. The book draws on the known specialized literature, as well as the original results of the author and his 50+ years experience as Professor of Mechanics and Elasticity at the University o...
Momentum relation and classical limit in the future-not-included complex action theory
Nagao, Keiichi
2013-01-01
Studying the time development of the expectation value in the future-not-included complex action theory we point out that the momentum relation (relation analogous to $p=\\frac{\\partial L}{\\partial \\dot{q}}$), which was derived via Feynman path integral and was shown to be right in the future-included theory in our previous papers, is not valid in the future-not-included theory. We provide the correct momentum relation in the future-not-included theory, and argue that the future-not-included classical theory is described by a certain real action. In addition we provide another way to understand the time development of the future-not-included theory by utilizing the future-included theory. Furthermore, applying the method used in our previous paper to the future-not-included theory properly by introducing a formal Lagrangian, we derive the correct momentum relation in the future-not-included theory.
A generalization of a classical model in contract theory: The agent behavior
Gutiérrez, Francisco; Moreno, Stefany
2011-01-01
We present a first approximation of agent behaviour in a generalized model in contract theory. This model relaxes some of the the assumptions of one of the classical models allowing to include a broader range of agents. We introduce the motivation for the agent and reinterpret the classical definition of risk perception. Besides, we analyze different scenarios for the relation between the effort exerted by the agent and the probability that he gets an especfic result.
Development of a unified viscoplasticity constitutive model based on classical plasticity theory
Institute of Scientific and Technical Information of China (English)
GUAN Ping; LIU ChangChun; L(U) HeXiang
2009-01-01
The traditional unified viscoplasticity constitutive model can be only applied to metal materials. The study of the unified constitutive theory for metal materials has discovered the correlation between the classical plasticity theory and the unified viscoplasticity constitutive model, thus leading to the con-cepts of the classic plastic potential and yield surface in the unified constitutive model. Moreover, this research has given the continuous expression of the classical plastic multiplier and presented the corresponding constructive method, which extends its physical significance and lays down a good foundation for the application of the unified constitutive theory to the material analysis in more fields.This paper also introduces the unified constitutive model for metal materials and geo-materials. The numerical simulation indicates that the construction should be both reasonable and practical.
Development of a unified viscoplasticity constitutive model based on classical plasticity theory
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The traditional unified viscoplasticity constitutive model can be only applied to metal materials.The study of the unified constitutive theory for metal materials has discovered the correlation between the classical plasticity theory and the unified viscoplasticity constitutive model,thus leading to the con-cepts of the classic plastic potential and yield surface in the unified constitutive model.Moreover,this research has given the continuous expression of the classical plastic multiplier and presented the corresponding constructive method,which extends its physical significance and lays down a good foundation for the application of the unified constitutive theory to the material analysis in more fields.This paper also introduces the unified constitutive model for metal materials and geo-materials.The numerical simulation indicates that the construction should be both reasonable and practical.
Classical and quantum contents of solvable game theory on Hilbert space
International Nuclear Information System (INIS)
A simple and general formulation of the quantum game theory is presented, accommodating all possible strategies in the Hilbert space for the first time. The theory is solvable for the two strategy quantum game, which is shown to be equivalent to a family of classical games supplemented by quantum interference. Our formulation gives a clear perspective to understand why and how quantum strategies outmaneuver classical strategies. It also reveals novel aspects of quantum games such as the stone-scissor-paper phase sub-game and the fluctuation-induced moderation
Theory for nucleation at an interface and magnetization reversal of a two-layer nanowire
Loxley, P.N.; Stamps, R. L.
2006-01-01
Nucleation at the interface between two adjoining regions with dissimilar physical properties is investigated using a model for magnetization reversal of a two-layer ferromagnetic nanowire. Each layer of the nanowire is considered to have a different degree of magnetic anisotropy, representing a hard magnetic layer exchange-coupled to a softer layer. A magnetic field applied along the easy axis causes the softer layer to reverse, forming a domain wall close to the interface. For small applied...
Neo-classical theory of competition or Adam Smith's hand as mathematized ideology
McCauley, Joseph L.
2001-10-01
Orthodox economic theory (utility maximization, rational agents, efficient markets in equilibrium) is based on arbitrarily postulated, nonempiric notions. The disagreement between economic reality and a key feature of neo-classical economic theory was criticized empirically by Osborne. I show that the orthodox theory is internally self-inconsistent for the very reason suggested by Osborne: lack of invertibility of demand and supply as functions of price to obtain price as functions of supply and demand. The reason for the noninvertibililty arises from nonintegrable excess demand dynamics, a feature of their theory completely ignored by economists.
a Classical Isodual Theory of Antimatter and its Prediction of Antigravity
Santilli, Ruggero Maria
An inspection of the contemporary physics literature reveals that, while matter is treated at all levels of study, from Newtonian mechanics to quantum field theory, antimatter is solely treated at the level of second quantization. For the purpose of initiating the restoration of full equivalence in the treatment of matter and antimatter in due time, and as the classical foundations of an axiomatically consistent inclusion of gravitation in unified gauge theories recently appeared elsewhere, in this paper we present a classical representation of antimatter which begins at the primitive Newtonian level with corresponding formulations at all subsequent levels. By recalling that charge conjugation of particles into antiparticles is antiautomorphic, the proposed theory of antimatter is based on a new map, called isoduality, which is also antiautomorphic (and more generally, antiisomorphic), yet it is applicable beginning at the classical level and then persists at the quantum level where it becomes equivalent to charge conjugation. We therefore present, apparently for the first time, the classical isodual theory of antimatter, we identify the physical foundations of the theory as being the novel isodual Galilean, special and general relativities, and we show the compatibility of the theory with all available classical experimental data on antimatter. We identify the classical foundations of the prediction of antigravity for antimatter in the field of matter (or vice-versa) without any claim on its validity, and defer its resolution to specifically identified experiments. We identify the novel, classical, isodual electromagnetic waves which are predicted to be emitted by antimatter, the so-called space-time machine based on a novel non-Newtonian geometric propulsion, and other implications of the theory. We also introduce, apparently for the first time, the isodual space and time inversions and show that they are nontrivially different than the conventional ones, thus
Guillemin, Ernst A
2013-01-01
An eminent electrical engineer and authority on linear system theory presents this advanced treatise, which approaches the subject from the viewpoint of classical dynamics and covers Fourier methods. This volume will assist upper-level undergraduates and graduate students in moving from introductory courses toward an understanding of advanced network synthesis. 1963 edition.
Estimation of the nucleation rate by differential scanning calorimetry
Kelton, Kenneth F.
1992-01-01
A realistic computer model is presented for calculating the time-dependent volume fraction transformed during the devitrification of glasses, assuming the classical theory of nucleation and continuous growth. Time- and cluster-dependent nucleation rates are calculated by modeling directly the evolving cluster distribution. Statistical overlap in the volume fraction transformed is taken into account using the standard Johnson-Mehl-Avrami formalism. Devitrification behavior under isothermal and nonisothermal conditions is described. The model is used to demonstrate that the recent suggestion by Ray and Day (1990) that nonisothermal DSC studies can be used to determine the temperature for the peak nucleation rate, is qualitatively correct for lithium disilicate, the glass investigated.
Al-Safi, Sabri W.; Short, Anthony J.
2013-01-01
Many-party correlations between measurement outcomes in general probabilistic theories are given by conditional probability distributions obeying the non-signalling condition. We show that any such distribution can be obtained from classical or quantum theory, by relaxing positivity constraints on either the mixed state shared by the parties, or the local functions which generate measurement outcomes. Our results apply to generic non-signalling correlations, but in particular they yield two d...
Finite-Block-Length Analysis in Classical and Quantum Information Theory
Hayashi, Masahito
2016-01-01
This is a review article of finite-block-length analysis in classical and quantum information theory for non-specialist. Transmitting an information is a fundamental technology. However, there are several demands for this transmission. The research area to study such problems is called information theory. In the information transmission, the information is transmitted via a physical media. Hence, the analysis of this problem might depends on the property of the physical media. Indeed, while i...
Generalization of the Activated Complex Theory of Reaction Rates. II. Classical Mechanical Treatment
Marcus, R. A.
1964-01-01
In its usual classical form activated complex theory assumes a particular expression for the kinetic energy of the reacting system -- one associated with a rectilinear motion along the reaction coordinate. The derivation of the rate expression given in the present paper is based on the general kinetic energy expression.
Uniting the Spheres: Modern Feminist Theory and Classic Texts in AP English
Drew, Simao J. A.; Bosnic, Brenda G.
2008-01-01
High school teachers Simao J. A. Drew and Brenda G. Bosnic help familiarize students with gender role analysis and feminist theory. Students examine classic literature and contemporary texts, considering characters' historical, literary, and social contexts while expanding their understanding of how patterns of identity and gender norms exist and…
Atmospheric nucleation: highlights of the EUCAARI project and future directions
Directory of Open Access Journals (Sweden)
V.-M. Kerminen
2010-11-01
Full Text Available Within the project EUCAARI (European Integrated project on Aerosol Cloud Climate and Air Quality interactions, atmospheric nucleation was studied by (i developing and testing new air ion and cluster spectrometers, (ii conducting homogeneous nucleation experiments for sulphate and organic systems in the laboratory, (iii investigating atmospheric nucleation mechanism under field conditions, and (iv applying new theoretical and modelling tools for data interpretation and development of parameterisations. The current paper provides a synthesis of the obtained results and identifies the remaining major knowledge gaps related to atmospheric nucleation. The most important technical achievement of the project was the development of new instruments for measuring sub-3 nm particle populations, along with the extensive application of these instruments in both the laboratory and the field. All the results obtained during EUCAARI indicate that sulphuric acid plays a central role in atmospheric nucleation. However, also vapours other than sulphuric acid are needed to explain the nucleation and the subsequent growth processes, at least in continental boundary layers. Candidate vapours in this respect are some organic compounds, ammonia, and especially amines. Both our field and laboratory data demonstrate that the nucleation rate scales to the first or second power of the nucleating vapour concentration(s. This agrees with the few earlier field observations, but is in stark contrast with classical thermodynamic nucleation theories. The average formation rates of 2-nm particles were found to vary by almost two orders of magnitude between the different EUCAARI sites, whereas the formation rates of charged 2-nm particles varied very little between the sites. Overall, our observations are indicative of frequent, yet moderate, ion-induced nucleation usually outweighed by much stronger neutral nucleation events in the continental lower troposphere. The most concrete
The Simulation of High Pressure Nucleation Experiments in Diffusion Cloud Chamber
Fisenko, Sergey P
2007-01-01
For high- pressure nucleation experiments in upward diffusion cloud chamber, there is the great deviation of predictions of classical nucleation theory from experimental results; the discrepancy is more than 10 orders of magnitude of nucleation rate. Experimental data for 1-propanol vapor are under investigation in this paper. It was shown that mathematical model of a single droplet growth and motion semi- quantitatively explained all experimentally discovered regularities. For explanations low nucleation rate versus high supersaturation, the coalescence mechanism in gaseous phase has been proposed. As result of coalescence the vast majority of newly formed clusters evaporate and restore vapor density and temperature profile in DCC. The observed picture with low nucleation rate is result of diffusion interaction between small clusters and droplets in nucleation zone for high- pressure nucleation experiments.
The Master Ward Identity and generalized Schwinger-Dyson Equation in classical field theory
International Nuclear Information System (INIS)
In the framework of perturbative quantum field theory a new, universal renormalization condition (called Master Ward Identity) was recently proposed by one of us (M.D.) in a joint paper with F.-M. Boas. The main aim of the present paper is to get a better understanding of the Master Ward Identity by analyzing its meaning in classical field theory. It turns out that it is the most general identity for classical local fields which follows from the field equations. It is equivalent to a generalization of the Schwinger-Dyson Equation and is closely related to the Quantum Action Principle of Lowenstein and Lam. The validity of the Master Ward Identity makes possible a local construction of quantum gauge theories. (orig.)
A New Conformal Theory of Semi-Classical Quantum General Relativity
Directory of Open Access Journals (Sweden)
Suhendro I.
2007-10-01
Full Text Available We consider a new four-dimensional formulation of semi-classical quantum general relativity in which the classical space-time manifold, whose intrinsic geometric properties give rise to the effects of gravitation, is allowed to evolve microscopically by means of a conformal function which is assumed to depend on some quantum mechanical wave function. As a result, the theory presented here produces a unified field theory of gravitation and (microscopic electromagnetism in a somewhat simple, effective manner. In the process, it is seen that electromagnetism is actually an emergent quantum field originating in some kind of stochastic smooth extension (evolution of the gravitational field in the general theory of relativity.
An analogue of the Heisenberg uncertainty relation in prequantum classical field theory
International Nuclear Information System (INIS)
Prequantum classical statistical field theory (PCSFT) is a model that provides the possibility of representing averages of quantum observables, including correlations of observables on subsystems of a composite system, as averages with respect to fluctuations of classical random fields. PCSFT is a classical model of wave type. For example, 'electron' is described by electronic field. In contrast to quantum mechanics (QM), this field is a real physical field and not a field of probabilities. An important point is that the prequantum field of , for example, an electron contains the irreducible contribution of the background field vacuum fluctuations. In principle, the traditional QM-formalism can be considered as a special regularization procedure: subtraction of averages with respect to vacuum fluctuations. In this paper, we derive a classical analogue of the Heisenberg-Robertson inequality for dispersions of functionals of classical (prequantum) fields. The PCSFT Robertson-like inequality provides a restriction on the product of classical dispersions. However, this restriction is not so rigid as in QM.
Sokolov, Igor V
2015-01-01
A theory of Symplectic Manifold with Contact Degeneracies (SMCD) was developed in [Zot'ev,2007]. The symplectic geometry uses an anti-symmetric tensor (closed differential form) such as a field tensor used in the classical field theory. The SMCD theory studies degeneracies of such form. In [Zot'ev,2011] the SMCD theory was applied to study a front of an electromagnetic pulsed field propagating into a region with no field. Here, the result of [Zot'ev,2011] is compared with the problem solution obtained using the well-known method presented in Witham, G.B., Linear and nonlinear waves, 1974. It is shown that the SMCD theory prediction is not supported by the result obtained with the Witham method.
Zarei, Mohammad Hossein
2016-01-01
Although creating a unified theory in Elementary Particles Physics is still an open problem, there are a lot of attempts for unifying other fields of physics. Following such unifications, we regard a two dimensional (2D) classical $\\Phi^{4}$ field theory model to study several field theories with different symmetries in various dimensions. While the completeness of this model has been already proved by a mapping between statistical mechanics and quantum information theory, here, we take into account a fundamental systematic approach with purely mathematical basis to re-derive such completeness in a general manner. Due to simplicity and generality, we believe that our method leads to a general approach which can be understood by other physical communities as well as quantum information theorists. Furthermore, our proof of the completeness is not only a proof-of-principle, but also an interesting algorithmic proof. We consider a discrete version of a general field theory as an arbitrary polynomial function of f...
Shiramomo, T.; Gao, B.; Mercier, F.; Nishizawa, S.; Nakano, S.; Kakimoto, K.
2014-01-01
The effect of nitrogen and aluminum as doped impurities on the stability of SiC polytypes (C- or Si-face 4H and 6H substrates) formed by physical vapor transport (PVT) was investigated. The stability of the polytypes was analyzed using classical thermodynamic nucleation theory with numerical results obtained from a global model including heat, mass and species transfer in a PVT furnace. The results reveal that the formation of 4H-SiC was more stable than that of 6H-SiC when a grown crystal was doped with nitrogen using C-face 4H- and 6H-SiC as seed crystals. In contrast, formation of 6H-SiC was favored over 4H-SiC when Si-face 4H- and 6H-SiC seed crystals were used. Meanwhile, the formation of 4H-SiC was more stable than that of 6H-SiC when aluminum was the dopant and C- and Si-faces of 6H-SiC were used as seed crystals. Formation of 6H-SiC occurred over that of 4H-SiC in the cases of C- and Si-faces of 4H-SiC as seed crystals.
International Nuclear Information System (INIS)
We have computed the surface self-diffusion constants on four different crystal faces [fcc(111), fcc(100), bcc(110), and bcc(211)] using classical transition state theory methods. These results can be compared directly with previous classical-trajectory results which used the same Lennard-Jones 6-12 potential and template model; the agreement is good, though dynamical effects are evident for the fcc(111) and bcc(110) surfaces. Implications are discussed for low-temperature diffusion studies, which are inaccessible to direct molecular dynamics, and the use of ab initio potentials rather than approximate pairwise potentials
Molecular dynamics simulations of bubble nucleation in dark matter detectors
Denzel, Philipp; Angélil, Raymond
2016-01-01
Bubble chambers and droplet detectors used in dosimetry and dark matter particle search experiments use a superheated metastable liquid in which nuclear recoils trigger bubble nucleation. This process is described by the classical heat spike model of F. Seitz [Phys. Fluids (1958-1988) 1, 2 (1958)], which uses classical nucleation theory to estimate the amount and the localization of the deposited energy required for bubble formation. Here we report on direct molecular dynamics simulations of heat-spike-induced bubble formation. They allow us to test the nanoscale process described in the classical heat spike model. 40 simulations were performed, each containing about 20 million atoms, which interact by a truncated force-shifted Lennard-Jones potential. We find that the energy per length unit needed for bubble nucleation agrees quite well with theoretical predictions, but the allowed spike length and the required total energy are about twice as large as predicted. This could be explained by the rapid energy di...
Directory of Open Access Journals (Sweden)
Eun Young Lim
2004-01-01
Full Text Available The results of the 64th and 65th Korean Medical Licensing Examination were analyzed according to the classical test theory and item response theory in order to know the possibility of applying item response theory to item analys and to suggest its applicability to computerized adaptive test. The correlation coefficiency of difficulty index, discriminating index and ability parameter between two kinds of analysis were got using computer programs such as Analyst 4.0, Bilog and Xcalibre. Correlation coefficiencies of difficulty index were equal to or more than 0.75; those of discriminating index were between - 0.023 and 0.753; those of ability parameter were equal to or more than 0.90. Those results suggested that the item analysis according to item response theory showed the comparable results with that according to classical test theory except discriminating index. Since the ability parameter is most widely used in the criteria-reference test, the high correlation between ability parameter and total score can provide the validity of computerized adaptive test utilizing item response theory.
International Nuclear Information System (INIS)
A second order classical perturbation theory is developed to calculate the sticking probability of a particle scattered from an uncorrugated thermal surface. An analytic expression for the temperature dependent energy loss of the particle to the surface is derived by employing a one-dimensional generalized Langevin equation. The surface temperature reduces the energy loss, since the thermal surface transfers energy to the particle. Using a Gaussian energy loss kernel and the multiple collision theory of Fan and Manson [J. Chem. Phys. 130, 064703 (2009)], enables the determination of the fraction of particles trapped on the surface after subsequent momentum reversals of the colliding particle. This then leads to an estimate of the trapping probability. The theory is tested for the model scattering of Ar on a LiF(100) surface. Comparison with numerical simulations shows excellent agreement of the analytical theory with simulations, provided that the energy loss is determined by the second order perturbation theory
Nucleation and structural growth of cluster crystals
Leitold, Christian
2016-01-01
We study the nucleation of crystalline cluster phases in the generalized exponential model with exponent n=4. Due to the finite value of this pair potential for zero separation, at high densities the system forms cluster crystals with multiply occupied lattice sites. Here, we investigate the microscopic mechanisms that lead to the formation of cluster crystals from a supercooled liquid in the low-temperature region of the phase diagram. Using molecular dynamics and umbrella sampling, we calculate the free energy as a function of the size of the largest crystalline nucleus in the system, and compare our results with predictions from classical nucleation theory. Employing bond-order parameters based on a Voronoi tessellation to distinguish different crystal structures, we analyze the average composition of crystalline nuclei. We find that even for conditions where a multiply-occupied fcc crystal is the thermodynamically stable phase, the nucleation into bcc cluster crystals is strongly preferred. Furthermore, w...
The Classical Theory of Light Colors: a Paradigm for Description of Particle Interactions
Mazilu, Nicolae; Agop, Maricel; Gatu, Irina; Iacob, Dan Dezideriu; Butuc, Irina; Ghizdovat, Vlad
2016-06-01
The color is an interaction property: of the interaction of light with matter. Classically speaking it is therefore akin to the forces. But while forces engendered the mechanical view of the world, the colors generated the optical view. One of the modern concepts of interaction between the fundamental particles of matter - the quantum chromodynamics - aims to fill the gap between mechanics and optics, in a specific description of strong interactions. We show here that this modern description of the particle interactions has ties with both the classical and quantum theories of light, regardless of the connection between forces and colors. In a word, the light is a universal model in the description of matter. The description involves classical Yang-Mills fields related to color.
International Nuclear Information System (INIS)
We derive the fundamental equations of an optimal control theory for systems containing both quantum electrons and classical ions. The system is modeled with Ehrenfest dynamics, a non-adiabatic variant of molecular dynamics. The general formulation, that needs the fully correlated many-electron wavefunction, can be simplified by making use of time-dependent density-functional theory. In this case, the optimal control equations require some modifications that we will provide. The abstract general formulation is complemented with the simple example of the H2+ molecule in the presence of a laser field. (paper)
International Nuclear Information System (INIS)
Highlights: • Simulations of point defects in alpha-Zr using ab initio and forcefield methods. • Anisotropic strain dependent diffusion for interstitials and vacancies. • Explanation of pre-breakaway irradiation growth. • Interstitial nanoclusters cause expansion in 〈a〉, vacancy clusters contract 〈c〉. • H atoms diffuse isotropically, attracted to vacancy defects. - Abstract: Diffusion of point defects, nucleation of dislocation loops, and the associated dimensional changes of pure and H-loaded hcp-Zr have been investigated by a combination of ab initio calculations and classical simulations. Vacancy diffusion is computed to be anisotropic with Dvac,basal = 8.6 × 10−6 e−Q/(RT) (m2/s) and Dvac,axial = 9.9 × 10−6 e−Q/(RT) (m2/s), Q = 69 and 72 kJ/mol for basal and axial diffusion, respectively. At 550 K vacancy diffusion is about twice as fast in the basal plane as in a direction parallel to the c-axis. Diffusion of self-interstitials is found to be considerably faster and anisotropic involving collective atomic motions. At 550 K diffusion occurs predominantly in the a-directions, but this anisotropy diminishes with increasing temperature. Furthermore, the diffusion anisotropy is very dependent on the local strain (c/a ratio). Interstitial H atoms are found to diffuse isotropically with DH = 1.1 × 10−7 e−42/(RT) (m2/s). These results are consistent with experimental data and other theoretical studies. Molecular dynamics simulations at 550 K with periodic injection of vacancies and self-interstitial atoms reveal the formation of small nanoclusters, which are sufficient to cause a net expansion of the lattice in the a-directions driven by clusters of self-interstitials and a smaller contraction in the c-direction involving nanoclusters of vacancies. This is consistent with and can explain experimental data of irradiation growth. Energy minimizations show that vacancy c-loops can collapse into stacking-fault pyramids and, somewhat
Energy Technology Data Exchange (ETDEWEB)
Christensen, M., E-mail: mchristensen@materialsdesign.com [Materials Design, Inc., 6 First National Place, Angel Fire, NM 87710 (United States); Wolf, W.; Freeman, C.; Wimmer, E. [Materials Design, Inc., 6 First National Place, Angel Fire, NM 87710 (United States); Adamson, R.B. [Zircology Plus, 36848 Montecito Dr, Fremont, CA 94536 (United States); Hallstadius, L. [Westinghouse Electric Sweden AB, SE-721 63 Västerås (Sweden); Cantonwine, P.E. [Global Nuclear Fuel – Americas, P.O. Box 780, M/C F12, Wilmington, NC 28402 (United States); Mader, E.V. [Electric Power Research Institute (EPRI), 3420 Hillview Ave, Palo Alto, CA 94303 (United States)
2015-05-15
Highlights: • Simulations of point defects in alpha-Zr using ab initio and forcefield methods. • Anisotropic strain dependent diffusion for interstitials and vacancies. • Explanation of pre-breakaway irradiation growth. • Interstitial nanoclusters cause expansion in 〈a〉, vacancy clusters contract 〈c〉. • H atoms diffuse isotropically, attracted to vacancy defects. - Abstract: Diffusion of point defects, nucleation of dislocation loops, and the associated dimensional changes of pure and H-loaded hcp-Zr have been investigated by a combination of ab initio calculations and classical simulations. Vacancy diffusion is computed to be anisotropic with D{sub vac,basal} = 8.6 × 10{sup −6} e{sup −Q/(RT)} (m{sup 2}/s) and D{sub vac,axial} = 9.9 × 10{sup −6} e{sup −Q/(RT)} (m{sup 2}/s), Q = 69 and 72 kJ/mol for basal and axial diffusion, respectively. At 550 K vacancy diffusion is about twice as fast in the basal plane as in a direction parallel to the c-axis. Diffusion of self-interstitials is found to be considerably faster and anisotropic involving collective atomic motions. At 550 K diffusion occurs predominantly in the a-directions, but this anisotropy diminishes with increasing temperature. Furthermore, the diffusion anisotropy is very dependent on the local strain (c/a ratio). Interstitial H atoms are found to diffuse isotropically with D{sub H} = 1.1 × 10{sup −7} e{sup −42/(RT)} (m{sup 2}/s). These results are consistent with experimental data and other theoretical studies. Molecular dynamics simulations at 550 K with periodic injection of vacancies and self-interstitial atoms reveal the formation of small nanoclusters, which are sufficient to cause a net expansion of the lattice in the a-directions driven by clusters of self-interstitials and a smaller contraction in the c-direction involving nanoclusters of vacancies. This is consistent with and can explain experimental data of irradiation growth. Energy minimizations show that vacancy
Czech Academy of Sciences Publication Activity Database
Planková, B.; Hrubý, Jan; Vinš, Václav
Liberec: Technical University of Liberec, 2013 - (Dančová, P.; Novotný, P.). (EPJ Web of Conferences. 45). ISBN 978-80-7372-912-7. ISSN 2100-014X. [Experimental Fluid Mechanics 2012 /7./. Hradec Králové (CZ), 20.11.2012-23.11.2012] R&D Projects: GA AV ČR IAA200760905; GA ČR(CZ) GPP101/11/P046; GA ČR GA101/09/1633; GA MŠk LA09011 Institutional support: RVO:61388998 Keywords : gradient theory * n- alkanes * nucleation * PC-SAFT equation of state Subject RIV: BJ - Thermodynamics http://dx.doi.org/10.1051/epjconf/20134501076
International Nuclear Information System (INIS)
By introducing the concepts of 'superclassicality' and 'relational causality', it is shown here that the velocity field emerging from an n-slit system can be calculated as an average classical velocity field with suitable weightings per channel. No deviation from classical probability theory is necessary in order to arrive at the resulting probability distributions. In addition, we can directly show that when translating the thus obtained expression for said velocity field into a more familiar quantum language, one immediately derives the basic postulate of the de Broglie-Bohm theory, i.e. the guidance equation, and, as a corollary, the exact expression for the quantum mechanical probability density current. Some other direct consequences of this result will be discussed, such as an explanation of Born's rule and Sorkin's first and higher order sum rules, respectively.
[Athens and Mycenea. On the integration of classical and recent psychoanalytic theory].
Whitebook, J
1995-03-01
The relation between zeitgeist and psychoanalytic theory formation can be illustrated with reference to the transition from neurosis to psychosis. The author regards Freud as an oedipal thinker in two respects, first as the psychologist who "discovered" the father complex, and secondly as a scholar in the positivist tradition of the nineteenth century with its claims to be able to distinguish clearly between subject and object, hallucination and perception. The pre-oedipal, narcissistic disturbances described and discussed since the beginning of the First World War allow the conclusion that this period saw the onset of a zeitgeist increasingly prepared to countenance archaic dimensions of the psyche and an intermingling of subject and object. In the author's view, the difficulty of reconciling classical and post-classical psychoanalytic theory lies in the fact that this involves completely re-thinking our ideas on the bourgeois individual and challenging the concepts we have of such things as objectivity, normality, autonomy and individuation. PMID:7708949
International Nuclear Information System (INIS)
The nucleation of the Cu3Si phase was studied on sputter-deposited Cu/Si/Cu trilayered specimens both in curved and planar geometry. Two experimental methods, atom probe tomography and secondary neutral mass spectrometry, independently confirmed that the Cu on Si interface is significantly broader than the Si on Cu (5.3 vs. 2.4 nm from the atom probe measurements). It is demonstrated that the enhanced mixing on the top interface leads to a reduced nucleation barrier for the silicide phase. The presence of a nucleation barrier for a sharp interface, but no barrier for a broad interface, is reproduced using the polymorphic mode of nucleation. Classical nucleation theory or the transverse nucleation mode failed to explain this behavior
Uporov, Igor V.; Forlemu, Neville Y.; Rahul Nori; Tsvetan Aleksandrov; Sango, Boris A.; Yvonne E. Bongfen Mbote; Sandeep Pothuganti; Thomasson, Kathryn A.
2015-01-01
The dipole interaction model is a classical electromagnetic theory for calculating circular dichroism (CD) resulting from the π-π* transitions of amides. The theoretical model, pioneered by J. Applequist, is assembled into a package, DInaMo, written in Fortran allowing for treatment of proteins. DInaMo reads Protein Data Bank formatted files of structures generated by molecular mechanics or reconstructed secondary structures. Crystal structures cannot be used directly with DInaMo; they either...
A classically stable state in a broken SU(2) gauge theory
International Nuclear Information System (INIS)
The probable existence of a classically stable state is demonstrated in the case of a broken SU(2) gauge theory with a doublet Higgs field and no fermions. The state is quantum mechanically unstable and its energy is less than 4π/e2m(subv)x0.755 where m(subv) is a vector boson mass and e is the coupling constant. (Auth.)
Kuwahara, Y; Nakamura, Y; Yamanaka, Y
2013-01-01
The $2 \\times 2$-matrix structure of Green's functions is a common feature for the real-time formalisms of quantum field theory under thermal situations, such as the closed time path formalism and Thermo Field Dynamics (TFD). It has been believed to originate from quantum nature. Recently, Galley has proposed the Hamilton's principle with initial data for nonconservative classical systems, doubling each degree of freedom [Phys. Rev. Lett. 110, 174301 (2013)]. We show that the Galley's Hamilto...
International Nuclear Information System (INIS)
A physical interpretation of translation-invariant polarons and bipolarons is presented, some results of their existence are discussed. Consideration is given to the problem of quantization in the vicinity of the classical solution in the quantum field theory. The lowest variational estimate is obtained for the bipolaron energy E(η) with E(0) = -0.440636α2, where α is a constant of electron-phonon coupling, η is a parameter of ion binding
Relativistic semi-classical theory of atom ionization in ultra-intense laser
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A relativistic semi-classical theory (RSCT) of H-atom ionizationin ultra-intense laser (UIL) is proposed. A relativistic analytical expression for ionization probability of H-atom in its ground state is given. This expression, compared with non-relativistic expression, clearly shows the effects of the magnet vector in the laser, the non-dipole approximation and the relativistic mass-energy relation on the ionization processes. At the same time, we show that under some conditions the relativistic expression reduces to the non-relativistic expression of non-dipole approximation. At last, some possible applications of the relativistic theory are briefly stated.
Charged free fermions, vertex operators and the classical theory of conjugate nets
Energy Technology Data Exchange (ETDEWEB)
Doliwa, Adam [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome (Italy); Instytut Fizyki Teoretycznej, Uniwersytet Warszawski, Warsaw (Poland); Manas, Manuel [Departamento de Matematica Aplicada y Estadistica, EUIT Aeronautica, Universidad Politecnica de Madrid, Madrid (Spain); Departamento de Fisica Teorica, Universidad Complutense, Madrid (Spain); Martinez Alonso, Luis; Medina, Elena [Departamento de Matematicas, Universidad de Cadiz, Cadiz (Spain); Santini, Paolo Maria [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, Rome (Italy); Dipartimento di Fisica, Universita di Catania, Catania (Italy)
1999-02-19
We show that the quantum field theoretical formulation of the {tau}-function theory has a geometrical interpretation within the classical transformation theory of conjugate nets. In particular, we prove that (i) the partial charge transformations preserving the neutral sector are Laplace transformations, (ii) the basic vertex operators are Levy and adjoint Levy transformations and (iii) the diagonal soliton vertex operators generate fundamental transformations. We also show that the bilinear identity for the multicomponent Kadomtsev-Petviashvili hierarchy becomes, through a generalized Miwa map, a bilinear identity for the multidimensional quadrilateral lattice equations. (author)
Kuwahara, Y.; Nakamura, Y.; Yamanaka, Y.
2013-12-01
The 2×2-matrix structure of Green's functions is a common feature for the real-time formalisms of quantum field theory under thermal situations, such as the closed time path formalism and Thermo Field Dynamics (TFD). It has been believed to originate from quantum nature. Recently, Galley has proposed the Hamilton's principle with initial data for nonconservative classical systems, doubling each degree of freedom [1]. We show that the Galley's Hamilton formalism can be extended to quantum field and that the resulting theory is naturally identical with nonequilibrium TFD.
Energy Technology Data Exchange (ETDEWEB)
Kuwahara, Y., E-mail: a.kuwahara1224@asagi.waseda.jp; Nakamura, Y., E-mail: nakamura@aoni.waseda.jp; Yamanaka, Y., E-mail: yamanaka@waseda.jp
2013-12-09
The 2×2-matrix structure of Green's functions is a common feature for the real-time formalisms of quantum field theory under thermal situations, such as the closed time path formalism and Thermo Field Dynamics (TFD). It has been believed to originate from quantum nature. Recently, Galley has proposed the Hamilton's principle with initial data for nonconservative classical systems, doubling each degree of freedom. We show that the Galley's Hamilton formalism can be extended to quantum field and that the resulting theory is naturally identical with nonequilibrium TFD.
Charged free fermions, vertex operators and the classical theory of conjugate nets
International Nuclear Information System (INIS)
We show that the quantum field theoretical formulation of the τ-function theory has a geometrical interpretation within the classical transformation theory of conjugate nets. In particular, we prove that (i) the partial charge transformations preserving the neutral sector are Laplace transformations, (ii) the basic vertex operators are Levy and adjoint Levy transformations and (iii) the diagonal soliton vertex operators generate fundamental transformations. We also show that the bilinear identity for the multicomponent Kadomtsev-Petviashvili hierarchy becomes, through a generalized Miwa map, a bilinear identity for the multidimensional quadrilateral lattice equations. (author)
Homotopy Theory of Probability Spaces I: Classical independence and homotopy Lie algebras
Park, Jae-Suk
2015-01-01
This is the first installment of a series of papers whose aim is to lay a foundation for homotopy probability theory by establishing its basic principles and practices. The notion of a homotopy probability space is an enrichment of the notion of an algebraic probability space with ideas from algebraic homotopy theory. This enrichment uses a characterization of the laws of random variables in a probability space in terms of symmetries of the expectation. The laws of random variables are reinterpreted as invariants of the homotopy types of infinity morphisms between certain homotopy algebras. The relevant category of homotopy algebras is determined by the appropriate notion of independence for the underlying probability theory. This theory will be both a natural generalization and an effective computational tool for the study of classical algebraic probability spaces, while keeping the same central limit. This article is focused on the commutative case, where the laws of random variables are also described in t...
Energy Technology Data Exchange (ETDEWEB)
Zhou, Yun, E-mail: zhou.yun.x@gmail.com; Pollak, Eli, E-mail: eli.pollak@weizmann.ac.il [Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot (Israel); Miret-Artés, Salvador, E-mail: s.miret@iff.csic.es [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain)
2014-01-14
A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to “soft” corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.
A High Order Theory for Linear Thermoelastic Shells: Comparison with Classical Theories
Directory of Open Access Journals (Sweden)
V. V. Zozulya
2013-01-01
Full Text Available A high order theory for linear thermoelasticity and heat conductivity of shells has been developed. The proposed theory is based on expansion of the 3-D equations of theory of thermoelasticity and heat conductivity into Fourier series in terms of Legendre polynomials. The first physical quantities that describe thermodynamic state have been expanded into Fourier series in terms of Legendre polynomials with respect to a thickness coordinate. Thereby all equations of elasticity and heat conductivity including generalized Hooke's and Fourier's laws have been transformed to the corresponding equations for coefficients of the polynomial expansion. Then in the same way as in the 3D theories system of differential equations in terms of displacements and boundary conditions for Fourier coefficients has been obtained. First approximation theory is considered in more detail. The obtained equations for the first approximation theory are compared with the corresponding equations for Timoshenko's and Kirchhoff-Love's theories. Special case of plates and cylindrical shell is also considered, and corresponding equations in displacements are presented.
Is That a Real Theory or Did You Just Make It Up? Teaching Classic Grounded Theory
Directory of Open Access Journals (Sweden)
Odis E. Simmons, Ph.D.
2010-06-01
Full Text Available The title of this paper was derived from an incident I observed some years ago while accompanying a highly talented musician-songwriter friend to a performance. During a break, an audience member approached him to compliment the last song he had performed. He had written both the music and the lyrics to the song, one of many he had written. The audience member queried, “Is that a real song, or did you just make it up?” A touch amused, and not knowing whether he should be flattered or insulted, he politely replied, “It is a real song and I made it up.”This episode puts in mind a similar attitude in the social sciences that Glaser and Strauss (1967 noted, in which a small number of ’theoretical capitalists’ originate what are considered to be “real” theories and others are relegated to the role of “proletariat” testers. The means by which these theorists derived their theories remained largely mysterious. Unleashing proletariat testers was one of the chief rationales behind Glaser and Strauss’ development of grounded theory. It brought a democratic option into the social sciences that enabled anyone who learned the methodology to generate theory. The democratic ethos of the methodology may also have inadvertently unleashed an abundance of aspiring remodelers of the methodology, who unfortunately have eroded its primary purpose—to generate theories that are fully grounded in data rather than speculation or ideology.
Force-Field Functor Theory: Classical Force-Fields which Reproduce Equilibrium Quantum Distributions
Directory of Open Access Journals (Sweden)
Ryan eBabbush
2013-10-01
Full Text Available Feynman and Hibbs were the first to variationally determine an effective potential whose associated classical canonical ensemble approximates the exact quantum partition function. We examine the existence of a map between the local potential and an effective classical potential which matches the exact quantum equilibrium density and partition function. The usefulness of such a mapping rests in its ability to readily improve Born-Oppenheimer potentials for use with classical sampling. We show that such a map is unique and must exist. To explore the feasibility of using this result to improve classical molecular mechanics, we numerically produce a map from a library of randomly generated one-dimensional potential/effective potential pairs then evaluate its performance on independent test problems. We also apply the map to simulate liquid para-hydrogen, finding that the resulting radial pair distribution functions agree well with path integral Monte Carlo simulations. The surprising accessibility and transferability of the technique suggest a quantitative route to adapting Born-Oppenheimer potentials, with a motivation similar in spirit to the powerful ideas and approximations of density functional theory.
Múnera, Héctor A.
2016-07-01
It is postulated that there exists a fundamental energy-like fluid, which occupies the flat three-dimensional Euclidean space that contains our universe, and obeys the two basic laws of classical physics: conservation of linear momentum, and conservation of total energy; the fluid is described by the classical wave equation (CWE), which was Schrödinger's first candidate to develop his quantum theory. Novel solutions for the CWE discovered twenty years ago are nonharmonic, inherently quantized, and universal in the sense of scale invariance, thus leading to quantization at all scales of the universe, from galactic clusters to the sub-quark world, and yielding a unified Lorentz-invariant quantum theory ab initio. Quingal solutions are isomorphic under both neo-Galilean and Lorentz transformations, and exhibit nother remarkable property: intrinsic unstability for large values of ℓ (a quantum number), thus limiting the size of each system at a given scale. Unstability and scale-invariance together lead to nested structures observed in our solar system; unstability may explain the small number of rows in the chemical periodic table, and nuclear unstability of nuclides beyond lead and bismuth. Quingal functions lend mathematical basis for Boscovich's unified force (which is compatible with many pieces of evidence collected over the past century), and also yield a simple geometrical solution for the classical three-body problem, which is a useful model for electronic orbits in simple diatomic molecules. A testable prediction for the helicoidal-type force is suggested.
Bruneton, Jean-Philippe
2006-01-01
Field theories whose full action is Lorentz invariant (or diffeomorphism invariant) can exhibit superluminal behaviors through the breaking of local Lorentz invariance. Quantum induced superluminal velocities are well-known examples of this effect. The issue of the causal behavior of such propagations is somewhat controversial in the literature and we intend to clarify it. We provide a careful analysis of the meaning of causality in classical relativistic field theories, and we stress the rol...
Gleiser, M; Gleiser, Marcelo; Howell, Rafael
2004-01-01
We investigate the role played by fast quenching on the decay of metastable (or false vacuum) states. Instead of the exponentially-slow decay rate per unit volume, $\\Gamma_{\\rm HN} \\sim \\exp[-E_b/k_BT]$ ($E_b$ is the free energy of the critical bubble), predicted by Homogeneous Nucleation theory, we show that under fast enough quenching the decay rate is, in fact, a power law $\\Gamma_{\\rm RN} \\sim [E_b/k_BT]^{-B}$, where $B$ is weakly sensitive to the temperature. We argue that the fast quench generates large-amplitude fluctuations about the metastable state which promote its rapid decay via parametric resonance. Possible decay mechanisms and their dependence on $E_b$ are proposed and illustrated in a (2+1)-dimensional scalar field model with an asymmetric double-well potential.
Bubble nucleation in polymer–CO2 mixtures.
Xu, Xiaofei; Cristancho, Diego E; Costeux, Stéphane; Wang, Zhen-Gang
2013-10-28
We combine density-functional theory with the string method to calculate the minimum free energy path of bubble nucleation in two polymer–CO2 mixture systems, poly(methyl methacrylate) (PMMA)–CO2 and polystyrene (PS)–CO2. Nucleation is initiated by saturating the polymer liquid with high pressure CO2 and subsequently reducing the pressure to ambient condition. Below a critical temperature (Tc), we find that there is a discontinuous drop in the nucleation barrier as a function of increased initial CO2 pressure (P0), as a result of an underlying metastable transition from a CO2-rich-vapor phase to a CO2-rich-liquid phase. The nucleation barrier is generally higher for PS–CO2 than for PMMA–CO2 under the same temperature and pressure conditions, and both higher temperature and higher initial pressure are required to lower the nucleation barrier for PS–CO2 to experimentally relevant ranges. Classical nucleation theory completely fails to capture the structural features of the bubble nucleus and severely underestimates the nucleation barrier. PMID:26029777
Motion in classical field theories and the foundations of the self-force problem
Harte, Abraham I
2014-01-01
This article serves as a pedagogical introduction to the problem of motion in classical field theories. The primary focus is on self-interaction: How does an object's own field affect its motion? General laws governing the self-force and self-torque are derived using simple, non-perturbative arguments. The relevant concepts are developed gradually by considering motion in a series of increasingly complicated theories. Newtonian gravity is discussed first, then Klein-Gordon theory, electromagnetism, and finally general relativity. Linear and angular momenta as well as centers of mass are defined in each of these cases. Multipole expansions for the force and torque are then derived to all orders for arbitrarily self-interacting extended objects. These expansions are found to be structurally identical to the laws of motion satisfied by extended test bodies, except that all relevant fields are replaced by effective versions which exclude the self-fields in a particular sense. Regularization methods traditionally ...
Indian Academy of Sciences (India)
D P Paul; R Jayavel; C Subramanian; P Ramasamy
2000-04-01
Investigations on nucleation thermodynamical parameters are very essential for the successful growth of good quality single crystals from high temperature solution. A theoretical estimation of the nucleation thermodynamical parameters like interfacial energy between the solid Nd123 and its flux BaO–CuO, metastable zone-width, Gibbs free energy, critical energy barrier for nucleation and critical nucleation radius have been calculated from the knowledge of solubility data and by applying the classical nucleation theory. Results are discussed to understand the growth kinetics of Nd123 crystals.
Direct Simulations of Homogeneous Bubble Nucleation: Agreement with CNT and no Local Hot Spots
Diemand, Jürg; Tanaka, Kyoko K; Tanaka, Hidekazu
2014-01-01
We present results from direct, large-scale molecular dynamics (MD) simulations of homogeneous bubble (liquid-to-vapor) nucleation. The simulations contain half a billion Lennard-Jones (LJ) atoms and cover up to 56 million time-steps. The unprecedented size of the simulated volumes allows us to resolve the nucleation and growth of many bubbles per run in simple direct micro-canonical (NVE) simulations while the ambient pressure and temperature remain almost perfectly constant. We find bubble nucleation rates which are lower than in most of the previous, smaller simulations. It is widely believed that classical nucleation theory (CNT) generally underestimates bubble nucleation rates by very large factors. However, our measured rates are within two orders of magnitude of CNT predictions - only at very low temperatures does CNT underestimate the nucleation rate significantly. Introducing a small, positive Tolman length leads to very good agreement at all temperatures, as found in our recent vapor-to-liquid nucle...
Khrennikov, Andrei
2016-01-01
The scientific methodology based on two descriptive levels, ontic (reality as it is ) and epistemic (observational), is briefly presented. Following Schr\\"odinger, we point to the possible gap between these two descriptions. Our main aim is to show that, although ontic entities may be inaccessible for observations, they can be useful for clarification of the physical nature of operational epistemic entities. We illustrate this thesis by the concrete example: starting with the concrete ontic model preceding quantum mechanics (the latter is treated as an epistemic model), namely, prequantum classical statistical field theory (PCSFT), we propose the natural physical interpretation for the basic quantum mechanical entity - the quantum state ("wave function"). The correspondence PCSFT to QM is not straightforward, it couples the covariance operators of classical (prequantum) random fields with the quantum density operators. We use this correspondence to clarify the physical meaning of the pure quantum state and th...
Thermal flucatuations in a classical theory with shape degrees of freedom for heavy ion collisions
Samaddar, S. K.; Sperber, D.; Zielińska-Pfabe, M.; Sobel, M. I.; Garpman, S. I.
1981-02-01
We use a classical dynamical theory with shape degrees of freedom to describe deep inelastic scattering of heavy ions, and include thermal fluctuations by means of the Fokker-Planck equation. The degrees of freedom allow for neck formation, mass transfer, and stretching of the two-nucleus system. Inertias are calculated for these degrees of freedom, and dissipative and conservative forces are used. Fluctuations are calculated by considering the second moments of the distribution and determining a temperature from the excitation energy at each time. We calculate distributions in final energy, angle, charge, and mass, including some double differential cross sections. Results are in good agreement with data. NUCLEAR REACTIONS Classical dynamical model, shape degrees of freedom, Fokker-Planck equation, thermal fluctuations; angular, energy, mass, and charge distributions are calculated for the reactions 209Bi + 84Kr, 209Bi + 136Xe, and 197Au + 63Cu.
The Postmodern Turn: Shall Classic Grounded Theory Take That Detour? A Review Essay
Directory of Open Access Journals (Sweden)
Vivian B. Martin, PhD
2006-06-01
Full Text Available Adherents to classic grounded theory have gotten used to spotting the pretenders working under the grounded theory banner. Some of these faux-GT researchers have worked in a fog, misunderstanding fundamentals of the method; these are the studies that leave us shaking our heads and wondering about the doctoral committee and peer reviewers who did not bother to find out more about the method they were evaluating. More infuriating are the authors who are claiming to improve on grounded theory, to reground it, to quote one notable British author who, lack of handson grounded theory experience aside, manages a booklength critique of the method. Two recent books in the“remaking grounded theory” genre are from sociologists with some years of grounded theory projects behind them. Adele E. Clarke, author of Situational Analysis, was a student and colleague of Anselm L. Strauss at the University of California San Francisco. Kathy Charmaz, author of Constructing Grounded Theory, is among the few grounded theorists who studied with Barney G. Glaser and Strauss at UCSF.
Failure of classical traffic flow theories: Stochastic highway capacity and automatic driving
Kerner, Boris S
2016-01-01
In a mini-review [Physica A {\\bf 392} (2013) 5261--5282] it has been shown that classical traffic flow theories and models failed to explain empirical traffic breakdown -- a phase transition from metastable free flow to synchronized flow at highway bottlenecks. The main objective of this mini-review is to study the consequence of this failure of classical traffic-flow theories for an analysis of empirical stochastic highway capacity as well as for the effect of automatic driving vehicles and cooperative driving on traffic flow. To reach this goal, we show a deep connection between the understanding of empirical stochastic highway capacity and a reliable analysis of automatic driving vehicles in traffic flow. With the use of simulations in the framework of three-phase traffic theory, a probabilistic analysis of the effect of automatic driving vehicles on a mixture traffic flow consisting of a random distribution of automatic driving and manual driving vehicles has been made. We have found that the parameters o...
Failure of classical traffic flow theories: Stochastic highway capacity and automatic driving
Kerner, Boris S.
2016-05-01
In a mini-review Kerner (2013) it has been shown that classical traffic flow theories and models failed to explain empirical traffic breakdown - a phase transition from metastable free flow to synchronized flow at highway bottlenecks. The main objective of this mini-review is to study the consequence of this failure of classical traffic-flow theories for an analysis of empirical stochastic highway capacity as well as for the effect of automatic driving vehicles and cooperative driving on traffic flow. To reach this goal, we show a deep connection between the understanding of empirical stochastic highway capacity and a reliable analysis of automatic driving vehicles in traffic flow. With the use of simulations in the framework of three-phase traffic theory, a probabilistic analysis of the effect of automatic driving vehicles on a mixture traffic flow consisting of a random distribution of automatic driving and manual driving vehicles has been made. We have found that the parameters of automatic driving vehicles can either decrease or increase the probability of the breakdown. The increase in the probability of traffic breakdown, i.e., the deterioration of the performance of the traffic system can occur already at a small percentage (about 5%) of automatic driving vehicles. The increase in the probability of traffic breakdown through automatic driving vehicles can be realized, even if any platoon of automatic driving vehicles satisfies condition for string stability.
Two-Component Theory of Classical Proca Fields in Curved Spacetimes with Torsionless Affinities
Santos Júnior, S. I.; Cardoso, J. G.
2016-04-01
The world formulation of the full theory of classical Proca fields in generally relativistic spacetimes is reviewed. Subsequently the entire set of field equations is transcribed in a straightforward way into the framework of one of the Infeld-van der Waerden formalisms. Some well-known calculational techniques are then utilized for deriving the wave equations that control the propagation of the fields allowed for. It appears that no interaction couplings between such fields and electromagnetic curvatures are ultimately carried by the wave equations at issue. What results is, in effect, that the only interactions which occur in the theoretical context under consideration involve strictly Proca fields and wave functions for gravitons.
AMMARI, Zied; Falconi, Marco
2016-01-01
In the mid Sixties Edward Nelson proved the existence of a consistent quantum field theory that describes the Yukawa-like interaction of a non-relativistic nucleon field with a relativistic meson field. Since then it is thought, despite the renormalization procedure involved in the construction, that the quantum dynamics should be governed in the classical limit by a Schr\\"odinger-Klein-Gordon system with Yukawa coupling. In the present paper we prove this fact in the form of a Bohr correspon...
Redundancy of constraints in the classical and quantum theories of gravitation.
Moncrief, V.
1972-01-01
It is shown that in Dirac's version of the quantum theory of gravitation, the Hamiltonian constraints are greatly redundant. If the Hamiltonian constraint condition is satisfied at one point on the underlying, closed three-dimensional manifold, then it is automatically satisfied at every point, provided only that the momentum constraints are everywhere satisfied. This permits one to replace the usual infinity of Hamiltonian constraints by a single condition which may be taken in the form of an integral over the manifold. Analogous theorems are given for the classical Einstein Hamilton-Jacobi equations.
Eu, Byung Chan
2010-01-01
In the kinetic theory of dense fluids the many-particle collision bracket integral is given in terms of a classical collision operator defined in the phase space. To find an algorithm to compute the collision bracket integrals, we revisit the eigenvalue problem of the Liouville operator and re-examine the method previously reported[Chem. Phys. 20, 93(1977)]. Then we apply the notion and concept of the eigenfunctions of the Liouville operator and knowledge acquired in the study of the eigenfun...
The classically perfect fixed point action for SU(3) gauge theory
DeGrand, T; Hasenfratz, A.; Hasenfratz, P.; Niedermayer, F.
1995-01-01
In this paper (the first of a series) we describe the construction of fixed point actions for lattice $SU(3)$ pure gauge theory. Fixed point actions have scale invariant instanton solutions and the spectrum of their quadratic part is exact (they are classical perfect actions). We argue that the fixed point action is even 1--loop quantum perfect, i.e. in its physical predictions there are no $g^2 a^n$ cut--off effects for any $n$. We discuss the construction of fixed point operators and presen...
The Energy-Momentum Tensor(s) in Classical Gauge Theories
Blaschke, Daniel N; Gieres, Francois; Reboud, Meril; Schweda, Manfred
2016-01-01
We give an introduction to, and review of, the energy-momentum tensors in classical gauge field theories in Minkowski space, and to some extent also in curved space-time. For the canonical energy-momentum tensor of non-Abelian gauge fields and of matter fields coupled to such fields, we present a new and simple improvement procedure based on gauge invariance for constructing a gauge invariant, symmetric energy-momentum tensor. The relationship with the Einstein-Hilbert tensor following from t...
He, Jing-Lin
2009-05-01
There are so many discussions on the body physiognomy in Huangdineijing (Huangdi's Inner Classic) that include not only the description of both difference of body physiognomy and its reasons, but also the discussions on physiological and pathological characteristics of different body physiognomy traits. Different physiological and pathological characteristics lead to different applicable therapeutic methods, so that Huangdineijing discusses the applicable therapeutic methods to different body physiognomy characteristics, especially elaborating on the difference between applicable acupuncture manipulation to those characteristics. Contents such as the above form the embryonic form of the theory of body physiognomy in Traditional Chinese Medicine (TCM). PMID:19930931
The Energy-Momentum Tensor(s) in Classical Gauge Theories
Blaschke, Daniel N; Reboud, Meril; Schweda, Manfred
2016-01-01
We give an introduction to, and review of, the energy-momentum tensors in classical gauge field theories in Minkowski space, and to some extent also in curved space-time. For the canonical energy-momentum tensor of non-Abelian gauge fields and of matter fields coupled to such fields, we present a new and simple improvement procedure based on gauge invariance for constructing a gauge invariant, symmetric energy-momentum tensor. The relationship with the Einstein-Hilbert tensor following from the coupling to a gravitational field is also discussed.
Correlation effects in the theory of combined Doppler and pressure broadening. I - Classical theory
Ward, J.; Cooper, J.; Smith, E. W.
1974-01-01
An investigation is conducted of the combined effects of radiator-perturber collisions and radiator translational motion in the context of foreign gas broadening of optical transitions in neutral radiators. Questions concerning the speed-dependent collision frequency are considered and aspects of general theory are explored, taking into account the correlation function, the ensemble average, and the kinetic equation formalism. An elementary solution is discussed along with a one-perturber approximation, inverse power law model calculations, and a comparison with the Voigt profile.
International Nuclear Information System (INIS)
For a quantum field coupled to a classical background gsub(μnu)-field we propose a recursive technique which relates the diagonal matrix element to its value at t=-infinity. We then employ the lowest non-trivial order to renormalize the semi-classical theory of gravity. The existence of two important classes of solutions of the linearized theory is briefly discussed. (author)
Axiomatics of classical electrodynamics and its relation to gauge field theory
Gronwald, F; Nitsch, J; Gronwald, Frank; Hehl, Friedrich W.
2005-01-01
We give a concise axiomatic introduction into the fundamental structure of classical electrodynamics: It is based on electric charge conservation, the Lorentz force, magnetic flux conservation, and the existence of local and linear constitutive relations. The {\\it inhomogeneous} Maxwell equations, expressed in terms of $D^i$ and $H_i$, turn out to be a consequence of electric charge conservation, whereas the {\\it homogeneous} Maxwell equations, expressed in terms of $E_i$ and $B^i$, are derived from magnetic flux conservation and special relativity theory. The excitations $D^i$ and $H_i$, by means of constitutive relations, are linked to the field strengths $E_i$ and $B^i$. Eventually, we point out how this axiomatic approach is related to the framework of gauge field theory.
Vacuum-to-vacuum transition probability and the classic radiation theory
International Nuclear Information System (INIS)
Using the fact that the vacuum-to-vacuum transition probability for the interaction of the Maxwell field Aμ(x) with a given current Jμ(x) represents the probability of no photons emitted by the current of a Poisson distribution, the average number of photons emitted of given energies for the underlying distribution is readily derived. From this the classical power of radiation of Schwinger of a relativistic charged particle follows. - Highlights: • Quantum viewpoint of radiation theory based on the vacuum-to-transition probabilities. • Mathematical method in handling radiation for extended and point sources. • Radiated energy and power for arbitrary source distribution obtained from the above. • Explicit power of radiation for point relativistic sources from the general theory
Mahajan, Gaurang
2007-01-01
The quantum theory of a harmonic oscillator with a time dependent frequency arises in several important physical problems, especially in the study of quantum field theory in an external background. While the mathematics of this system is straightforward, several conceptual issues arise in such a study. We present a general formalism to address some of the conceptual issues like the emergence of classicality, definition of particle content, back reaction etc. In particular, we parametrize the wave function in terms of a complex number (which we call excitation parameter) and express all physically relevant quantities in terms it. Many of the notions -- like those of particle number density, effective Lagrangian etc., which are usually defined using asymptotic in-out states -- are generalized as time-dependent concepts and we show that these generalized definitions lead to useful and reasonable results. Having developed the general formalism we apply it to several examples. Exact analytic expressions are found ...
Turesson, Martin; Szparaga, Ryan; Ma, Ke; Woodward, Clifford E; Forsman, Jan
2014-05-14
A new classical density functional approach is developed to accurately treat a coarse-grained model of room temperature aromatic ionic liquids. Our major innovation is the introduction of charge-charge correlations, which are treated in a simple phenomenological way. We test this theory on a generic coarse-grained model for aromatic RTILs with oligomeric forms for both cations and anions, approximating 1-alkyl-3-methyl imidazoliums and BF₄⁻, respectively. We find that predictions by the new density functional theory for fluid structures at charged surfaces are very accurate, as compared with molecular dynamics simulations, across a range of surface charge densities and lengths of the alkyl chain. Predictions of interactions between charged surfaces are also presented. PMID:24718295
A semi-classical theory of multi-step nuclear reaction processes
International Nuclear Information System (INIS)
The master equation theory of precompound and compound nuclear reaction has been generalized to the inclusion of the conservation of angular momentum and parity. This improved semi-classical theory has been extended for application as an evaluation tool of the calculations of nucleon induced reaction cross sections and double differential cross sections. For structural materials at incident neutron energies below 20 MeV, it is demonstrated that the constructed model contains the Hauser-Feshbach, Weisskopf-Ewing as well as the exciton models as limiting cases. The unified treatment of pre-equilibrium processes includes a number of interesting features, such as the exciton state densities with the exact Pauli exclusion correction which are renormalized to the back-shifted Fermi-gas formula; the introduction of formation factors of composite particle in calculations of pick-up type composite particle emission and the double differential cross sections for all kinds of particles in terms of the leading particle model
Giordano, Peter J
2014-06-01
An important objective of personality psychology is to provide compelling descriptions and explanations of intraindividual personality dynamics that capture the unique qualities of persons. Among contemporary Western personality theories, the Five-Factor Model enjoys prominence in describing individual differences in personality traits. It falls short, however, in its ability to work with intraindividual personality function. This article argues that classical Confucianism, originating 2500 years ago in mainland China, offers Western personality psychologists important theoretical resources for capturing the complex and dynamic processes inherent in human personality. The Confucian perspective emphasizes a behaviorally anchored, continuous, stochastic, process-oriented understanding of the self as relationally constructed and proposes an elegant description of the relational virtuosity of exemplary persons. The article concludes with five characteristics of a Confucian inspired model of personality and questions the viability of a universal theory of personality. PMID:24101234
Directory of Open Access Journals (Sweden)
Jesús García-de-Madariaga
2011-10-01
Full Text Available There has been a lot of discussion about corporate social responsibility (CSR during these last decades. Neoclassical authors support the idea that CSR is not compatible with the objective of profit maximization, and defenders of CSR argue that, in these times of globalization and network economies, the idea of a company managed just to meet shareholders’ interests does not support itself. However, beyond this discussion, how can CSR affect firms’ market value? If we found a positive relationship between these variables, we could conclude that the two theories are reconcilable and the objective of profit maximization, perhaps, should satisfy not only shareholders’ interests, but also stakeholders’. We review previous literature and propose a model to analyze how CSR affects firms’ market value.
In Situ Investigations into CaCO3 Nucleation
Nielsen, Michael Harold
Classical theories of nucleation were developed over a hundred years ago starting with Gibbs. However, much remains unknown about the process of phase transition in aqueous electrolyte solutions due to the lack of experimental tools able to probe dynamic processes at the time and length scales of the phase transformation. In the calcium carbonate system, recent discovery of an amorphous phase, as well as the suggested existence of potential precursor states such as so-called 'pre-nucleation clusters' or dense liquid droplets, has called into question the utility of the classical framework in making accurate predictions of nucleation. Added to these questions are those regarding the effects that chemical templates have on nucleating calcium carbonate. Many organisms use complex organic matrices to form architecturally complex functional structures out of sea water at ambient temperatures. By contrast, laboratory methods to materials synthesis often require extreme conditions yet maintain at best a low level of control over the development of the resulting material. With the goal of tightly controlling formation of functional materials, scientists have looked to such biomineral systems for inspiration. Self-assembled monolayers (SAMs) of functionalized alkanethiols have been found to act as idealized chemical templates for calcium carbonate nucleation, controlling the nucleating plane of the calcite phase for many surface functionalities. Yet there remain many open questions as to the fundamental mechanisms by which these templates achieve this control. In this dissertation many investigations of calcium carbonate nucleation are discussed, which examine the nucleation pathways of calcium carbonate and mechanisms of control by which alkanethiol surfaces direct the oriented formation of calcite. Traditional in situ microscopy techniques are used to make nucleation rate measurements of templated calcite nucleation on alkanethiol SAMs to test the applicability of the
Wigner's dynamical transition state theory in phase space: classical and quantum
International Nuclear Information System (INIS)
We develop Wigner's approach to a dynamical transition state theory in phase space in both the classical and quantum mechanical settings. The key to our development is the construction of a normal form for describing the dynamics in the neighbourhood of a specific type of saddle point that governs the evolution from reactants to products in high dimensional systems. In the classical case this is the standard Poincaré–Birkhoff normal form. In the quantum case we develop a normal form based on the Weyl calculus and an explicit algorithm for computing this quantum normal form. The classical normal form allows us to discover and compute the phase space structures that govern classical reaction dynamics. From this knowledge we are able to provide a direct construction of an energy dependent dividing surface in phase space having the properties that trajectories do not locally 're-cross' the surface and the directional flux across the surface is minimal. Using this, we are able to give a formula for the directional flux through the dividing surface that goes beyond the harmonic approximation. We relate this construction to the flux–flux autocorrelation function which is a standard ingredient in the expression for the reaction rate in the chemistry community. We also give a classical mechanical interpretation of the activated complex as a normally hyperbolic invariant manifold (NHIM), and further describe the structure of the NHIM. The quantum normal form provides us with an efficient algorithm to compute quantum reaction rates and we relate this algorithm to the quantum version of the flux–flux autocorrelation function formalism. The significance of the classical phase space structures for the quantum mechanics of reactions is elucidated by studying the phase space distribution of scattering states. The quantum normal form also provides an efficient way of computing Gamov–Siegert resonances. We relate these resonances to the lifetimes of the quantum activated
Plimak, L. I.; Ivanov, Misha; Aiello, A.; Stenholm, S.
2015-01-01
Quantum electrodynamics under conditions of distinguishability of interacting matter entities, and of controlled actions and back-actions between them, is considered. Such "mesoscopic quantum electrodynamics" is shown to share its dynamical structure with the classical stochastic electrodynamics. In formal terms, we demonstrate that all general relations of the mesoscopic quantum electrodynamics may be recast in a form lacking Planck's constant. Mesoscopic quantum electrodynamics is therefore...
Relativistic and nonrelativistic classical field theory on fivedimensional space-time
International Nuclear Information System (INIS)
This paper is a sequel to earlier ones in which, on the one hand, classical field theories were described on a curved Newtonian space-time, and on the other hand, the Newtonian gravitation theory was formulated on a fivedimensional space-time with a metric of signature and a covariantly constant vector field. Here we show that Lagrangians for matter fields are easily formulated on this extended space-time from simple invariance arguments and that stress-energy tensors can be derived from them in the usual manner so that four-dimensional space-time expressions are obtained that are consistent in the relativistic as well as in the Newtonian case. In the former the theory is equivalent to General Relativity. When the magnitude of the distinguished vector field vanishes equations for the (covariant) Newtonian limit follow. We demonstrate this here explicity in the case of the Klein-Gordon/Schroedinger and the Dirac field and its covariant nonrelativistic analogue, the Levy-Leblond field. Especially in the latter example the covariant Newtonian theory simplifies dramatically in this fivedimensional form
Oriols, X.
2016-03-01
Exact predictions for most quantum systems are computationally inaccessible. This is the so-called many body problem, which is present in most common interpretations of quantum mechanics. Therefore, predictions of natural quantum phenomena have to rely on some approximations (assumptions or simplifications). In the literature, there are different types of approximations, ranging from those whose justification is basically based on theoretical developments to those whose justification lies on the agreement with experiments. This last type of approximations can convert a quantum theory into an “unfalsifiable” quantum theory, true by construction. On the practical side, converting some part of a quantum theory into an “unfalsifiable” one ensures a successful modeling (i.e. compatible with experiments) for quantum engineering applications. An example of including irreversibility and dissipation in the Bohmian modeling of open systems is presented. On the ontological level, however, the present-day foundational problems related to controversial quantum phenomena have to avoid (if possible) being contaminated by the unfalsifiability originated from the many body problem. An original attempt to show how the Bohmian theory itself (minimizing the role of many body approximations) explains the transitions from a microscopic quantum system towards a macroscopic classical one is presented.
The nucleation kinetics of ammonium metavanadate precipitated by ammonium chloride
Du, Guangchao; Sun, Zhaohui; Xian, Yong; Jing, Han; Chen, Haijun; Yin, Danfeng
2016-05-01
The nucleation kinetics of ammonium metavanadate (NH4VO3) was investigated under conditions of the simulated process for precipitation of NH4VO3 from the vanadium-containing solution. Induction periods for the nucleation of NH4VO3 were experimentally determined as a function of supersaturation at temperatures from 30 to 45 °C. Using the classical nucleation theory, the interfacial tension between NH4VO3 and supersaturated solution, the nucleation rate and critical radius of nucleus for the homogeneous nucleation of NH4VO3 were estimated. With temperature increasing, the calculated interfacial tension gradually decreased from 29.78 mJ/m2 at 30 °C to 23.66 mJ/m2 at 45 °C. The nucleation rate was found to proportionally increase but the critical radius of nucleus exponentially decreased, with increase in supersaturation ratio at a constant temperature. The activation energy for NH4VO3 nucleation was obtained from the relationship between temperature and induction period, ranging from 79.17 kJ/mol at S=25 to 115.50 kJ/mol at S=15. FT-IR and Raman spectrum indicated that the crystals obtained in the precipitation process were NH4VO3.
Dumas, H Scott
2014-01-01
This is a semi-popular mathematics book aimed at a broad readership of mathematically literate scientists, especially mathematicians and physicists who are not experts in classical mechanics or KAM theory, and scientific-minded readers. Parts of the book should also appeal to less mathematically trained readers with an interest in the history or philosophy of science. The scope of the book is broad: it not only describes KAM theory in some detail, but also presents its historical context (thus showing why it was a 'breakthrough'). Also discussed are applications of KAM theory (especially to celestial mechanics and statistical mechanics) and the parts of mathematics and physics in which KAM theory resides (dynamical systems, classical mechanics, and Hamiltonian perturbation theory). Although a number of sources on KAM theory are now available for experts, this book attempts to fill a long-standing gap at a more descriptive level. It stands out very clearly from existing publications on KAM theory because it ...
International Nuclear Information System (INIS)
The system of stiff nonlinear differential equations describing the kinetics of vacancy voids and interstitial dislocation loops nucleation and growth in pure metal (nickel) is solved with the high mobilities of divacances and diinterstitials taken into account. The calculated time dependences of void nucleation rate are presented and discussed, the dependences of other values calculated are briefly described. It is shown that the account of di-defects mobility results in significant increase of void nucleation rate. However, the rates obtained are not high enough to meet the void concentrations usually observed at highest temperatures of void formations. 13 refs.; 1 fig.; 1 tab
Experimental investigation of the role of ions in aerosol nucleation
DEFF Research Database (Denmark)
Enghoff, Martin Andreas Bødker
The role of ions in producing aerosols in Earth’s atmosphere is an area of very active research. Atmospheric and experimental observations have shown that the nucleation of aerosol particles can occur under conditions that cannot be explained by classical nucleation theory. Several ideas have been...... work demonstrated that ions, produced by cosmic rays in the atmosphere, are likely to play an important role in the production of new aerosol particles. The mechanism whereby energetic cosmic rays can promote the production of cloud condensation nuclei at low altitudes constitutes a link between cosmic...
Notes on Collective Field Theory of Large N Vector Models as Classical Mechanics on the Siegel Disc
Agarwal, A
2004-01-01
We use deformation quantization to construct the large N limits of Bosonic vector models as classical dynamical systems on the Siegel disc and study the relation of this formulation to standard results of collective field theory. Special emphasis is paid to relating the collective potential of the large N theory to a particular cocycle of the symplectic group.
Directory of Open Access Journals (Sweden)
N.K.Chhapkhane
2013-07-01
Full Text Available The laminate is a two or more lamina bonded together to act as an integral structural element. The laminae are combined to create a laminate. Classical lamination theory consists of a collection of mechanics of materials type of stress and deformation hypothesis. By use of classical lamination theory we can consistently proceed directly from the basic building block, the lamina, to the end result, a structural laminate. The classical lamination theory is very important in analysis of laminate because it will predict the stresses, strains, forces and moments relationships with reasonable accuracy. The composite materials are widely used in military aircraft, civil aircraft, space and automobile applications. ANSYS 11software is used for analysis of composite laminate. First order shear stress deformation theory is used for the analysis of laminate in finite element technique.
Barnum, Howard
2009-01-01
We review some of our recent results (with collaborators) on information processing in an ordered linear spaces framework for probabilistic theories. These include demonstrations that many "inherently quantum" phenomena are in reality quite general characteristics of non-classical theories, quantum or otherwise. As an example, a set of states in such a theory is broadcastable if, and only if, it is contained in a simplex whose vertices are cloneable, and therefore distinguishable by a single measurement. As another example, information that can be obtained about a system in this framework without causing disturbance to the system state, must be inherently classical. We also review results on teleportation protocols in the framework, and the fact that any non-classical theory without entanglement allows exponentially secure bit commitment in this framework. Finally, we sketch some ways of formulating our framework in terms of categories, and in this light consider the relation of our work to that of Abramsky, ...
Self psychology as a shift away from the paranoid strain in classical analytic theory.
Terman, David M
2014-12-01
Classical psychoanalytic theory has a paranoid strain. There is, in effect, an "evil other"--the id--within each individual that must be tamed in development and confronted and worked through as resistance in treatment. This last has historically endgendered an adversarial relationship between patient and analyst. This paranoid strain came from a paranoid element in Freud's personality that affected his worldview, his relationships, and his theory. Self psychology offers a different view of development and conflict. It stresses the child's need for responsiveness from and admiration of caretakers in order to develop a well-functioning self. Though severe behavioral and character problems may result from faults in the process of self-construction, the essential need is not instinctual discharge but connection. Hence the long-assumed opposition between individual needs and social institutions or between patient and analyst is no longer inevitable or universal. Rather, an understanding of the primary need for connection creates both a different interpretive stance and a more cooperative ambience. These changes in theory and technique are traced to Kohut's personal struggles to emancipate himself from his paranoid mother. PMID:25339303
Classical and quantum theories of proton disorder in hexagonal water ice
Benton, Owen; Sikora, Olga; Shannon, Nic
2016-03-01
It has been known since the pioneering work of Bernal, Fowler, and Pauling that common, hexagonal (Ih) water ice is the archetype of a frustrated material: a proton-bonded network in which protons satisfy strong local constraints (the "ice rules") but do not order. While this proton disorder is well established, there is now a growing body of evidence that quantum effects may also have a role to play in the physics of ice at low temperatures. In this paper, we use a combination of numerical and analytic techniques to explore the nature of proton correlations in both classical and quantum models of ice Ih. In the case of classical ice Ih, we find that the ice rules have two, distinct, consequences for scattering experiments: singular "pinch points," reflecting a zero-divergence condition on the uniform polarization of the crystal, and broad, asymmetric features, coming from its staggered polarization. In the case of the quantum model, we find that the collective quantum tunneling of groups of protons can convert states obeying the ice rules into a quantum liquid, whose excitations are birefringent, emergent photons. We make explicit predictions for scattering experiments on both classical and quantum ice Ih, and show how the quantum theory can explain the "wings" of incoherent inelastic scattering observed in recent neutron scattering experiments [Bove et al., Phys. Rev. Lett. 103, 165901 (2009), 10.1103/PhysRevLett.103.165901]. These results raise the intriguing possibility that the protons in ice Ih could form a quantum liquid at low temperatures, in which protons are not merely disordered, but continually fluctuate between different configurations obeying the ice rules.
Numerical study of chiral plasma instability within the classical statistical field theory approach
Buividovich, P. V.; Ulybyshev, M. V.
2016-07-01
We report on a numerical study of real-time dynamics of electromagnetically interacting chirally imbalanced lattice Dirac fermions within the classical statistical field theory approach. Namely, we perform exact simulations of the real-time quantum evolution of fermionic fields coupled to classical electromagnetic fields, which are in turn coupled to the vacuum expectation value of the fermionic electric current. We use Wilson-Dirac Hamiltonian for fermions, and noncompact action for the gauge field. In general, we observe that the backreaction of fermions on the electromagnetic field prevents the system from acquiring chirality imbalance. In the case of chirality pumping in parallel electric and magnetic fields, the electric field is screened by the produced on-shell fermions and the accumulation of chirality is hence stopped. In the case of evolution with initially present chirality imbalance, axial charge tends to transform to helicity of the electromagnetic field. By performing simulations on large lattices we show that in most cases this decay process is accompanied by the inverse cascade phenomenon, which transfers energy from short-wavelength to long-wavelength electromagnetic fields. In some simulations, however, we observe a very clear signature of inverse cascade for the helical magnetic fields that is not accompanied by the axial charge decay. This suggests that the relation between the inverse cascade and axial charge decay is not as straightforward as predicted by the simplest form of anomalous Maxwell equations.
Steady-state molecular dynamics simulation of vapor to liquid nucleation with Mc Donald's demon
International Nuclear Information System (INIS)
Grand canonical MD with McDonald's demon is discussed in the present contribution and applied for sampling both nucleation kinetics and steady-state properties of a supersaturated vapor. The idea behind the new approach is to simulate the production of clusters up to a given size for a specified supersaturation. The classical nucleation theory is found to overestimate the free energy of cluster formation and deviate by two orders of magnitude from the nucleation rate below the triple point at high supersaturations.
Kinetic theory of the shear viscosity of a strongly coupled classical one-component plasma
International Nuclear Information System (INIS)
We present an approximation to the linearized collision operator or memory function of the exact kinetic equation obeyed by the correlation function of the phase-space density of a classical one-component plasma. This approximate collision operator generalizes the well known Balescu-Guernsey-Lenard (BGL) operator to finite wavelengths, finite frequencies, and finite coupling constants. It, moreover, satisfies the necessary symmetry relations, leads to appropriate conservation laws, and fulfills its first sum rule exactly. Next we use this operator to compute the shear viscosity eta for a series of coupling constants spanning the whole fluid phase. For weak coupling we make contact with the BGL theory, while for strong coupling we confirm, at least qualitatively, the results of Vieillefosse and Hansen, who predicted a minimum in eta as a function of temperature. We also demonstrate the important role played by the sum rules in the quantitative evaluation of a transport coefficient such as eta
Classical solutions in quantum field theory solitons and instantons in high energy physics
Weinberg, Erick J
2012-01-01
Classical solutions play an important role in quantum field theory, high energy physics and cosmology. Real-time soliton solutions give rise to particles, such as magnetic monopoles, and extended structures, such as domain walls and cosmic strings, that have implications for early universe cosmology. Imaginary-time Euclidean instantons are responsible for important nonperturbative effects, while Euclidean bounce solutions govern transitions between metastable states. Written for advanced graduate students and researchers in elementary particle physics, cosmology and related fields, this book brings the reader up to the level of current research in the field. The first half of the book discusses the most important classes of solitons: kinks, vortices and magnetic monopoles. The cosmological and observational constraints on these are covered, as are more formal aspects, including BPS solitons and their connection with supersymmetry. The second half is devoted to Euclidean solutions, with particular emphasis on ...
Chandrasekhar limit: an elementary approach based on classical physics and quantum theory
Pinochet, Jorge; Van Sint Jan, Michael
2016-05-01
In a brief article published in 1931, Subrahmanyan Chandrasekhar made public an important astronomical discovery. In his article, the then young Indian astrophysicist introduced what is now known as the Chandrasekhar limit. This limit establishes the maximum mass of a stellar remnant beyond which the repulsion force between electrons due to the exclusion principle can no longer stop the gravitational collapse. In the present article, we create an elemental approximation to the Chandrasekhar limit, accessible to non-graduate science and engineering students. The article focuses especially on clarifying the origins of Chandrasekhar’s discovery and the underlying physical concepts. Throughout the article, only basic algebra is used as well as some general notions of classical physics and quantum theory.
Jeanmairet, Guillaume; Levesque, Maximilien; Rotenberg, Benjamin; Borgis, Daniel
2014-01-01
We report here how the hydration of complex surfaces can be efficiently studied thanks to recent advances in classical molecular density functional theory. This is illustrated on the example of the pyrophylite clay. After presenting the most recent advances, we show that the strength of this implicit method is that (i) it is in quantitative or semi-quantitative agreement with reference all-atoms simulations (molecular dynamics here) for both the solvation structure and energetics, and that (ii) the computational cost is two to three orders of magnitude less than in explicit methods. The method remains imperfect, in that it locally overestimates the polarization of water close to hydrophylic sites of the clay. The high numerical efficiency of the method is illustrated and exploited to carry a systematic study of the electrostatic and van der Waals components of the surface-solvant interactions within the most popular force field for clays, CLAYFF. Hydration structure and energetics are found to weakly depend u...
Classical and quantum theory of the massive spin-two field
Koenigstein, Adrian; Giacosa, Francesco; Rischke, Dirk H.
2016-05-01
In this paper, we review classical and quantum field theory of massive non-interacting spin-two fields. We derive the equations of motion and Fierz-Pauli constraints via three different methods: the eigenvalue equations for the Casimir invariants of the Poincaré group, a Lagrangian approach, and a covariant Hamilton formalism. We also present the conserved quantities, the solution of the equations of motion in terms of polarization tensors, and the tree-level propagator. We then discuss canonical quantization by postulating commutation relations for creation and annihilation operators. We express the energy, momentum, and spin operators in terms of the former. As an application, quark-antiquark currents for tensor mesons are presented. In particular, the current for tensor mesons with quantum numbers JPC =2-+ is, to our knowledge, given here for the first time.
Classical and quantum theory of the massive spin-two field
Koenigstein, Adrian; Rischke, Dirk H
2015-01-01
In this paper, we review classical and quantum field theory of massive non-interacting spin-two fields. We derive the equations of motion and Fierz-Pauli constraints via three different methods: the eigenvalue equations for the Casimir invariants of the Poincar\\'{e} group, a Lagrangian approach, and a covariant Hamilton formalism. We also present the conserved quantities, the solution of the equations of motion in terms of polarization tensors, and the tree-level propagator. We then discuss canonical quantization by postulating commutation relations for creation and annihilation operators. We express the energy, momentum, and spin operators in terms of the former. As an application, quark-antiquark currents for tensor mesons are presented. In particular, the current for tensor mesons with quantum numbers $J^{PC}=2^{-+}$ is, to our knowledge, given here for the first time.
Gauge bridges in classical field theory; Eichbruecken in der klassischen Feldtheorie
Energy Technology Data Exchange (ETDEWEB)
Jakobs, S.
2009-03-15
In this thesis Poisson structures of two classical gauge field theories (Maxwell-Klein-Gordon- and Maxwell-Dirac-system) are constructed using the parametrix construction of Green's functions. Parametrices for the Maxwell-Klein-Gordon- and Maxwell-Dirac-system are constructed in Minkowski space and this construction is later generalized to curved space times for the Maxwell-Klein-Gordon-system. With these Green's functions Poisson brackets will be defined as Peierls brackets. Finally non-local, gauge invariant observables, the so-called 'gauge bridges'are constructed. Gauge bridges are the matrix elements of holonomy operators. It is shown, that these emerge from Poisson brackets of local, gauge invariant observables. (orig.)
Sharkness, Jessica; DeAngelo, Linda
2011-01-01
This study compares the psychometric utility of Classical Test Theory (CTT) and Item Response Theory (IRT) for scale construction with data from higher education student surveys. Using 2008 Your First College Year (YFCY) survey data from the Cooperative Institutional Research Program at the Higher Education Research Institute at UCLA, two scales…
Sosso, Gabriele C; Chen, Ji; Cox, Stephen J; Fitzner, Martin; Pedevilla, Philipp; Zen, Andrea; Michaelides, Angelos
2016-06-22
The nucleation of crystals in liquids is one of nature's most ubiquitous phenomena, playing an important role in areas such as climate change and the production of drugs. As the early stages of nucleation involve exceedingly small time and length scales, atomistic computer simulations can provide unique insights into the microscopic aspects of crystallization. In this review, we take stock of the numerous molecular dynamics simulations that, in the past few decades, have unraveled crucial aspects of crystal nucleation in liquids. We put into context the theoretical framework of classical nucleation theory and the state-of-the-art computational methods by reviewing simulations of such processes as ice nucleation and the crystallization of molecules in solutions. We shall see that molecular dynamics simulations have provided key insights into diverse nucleation scenarios, ranging from colloidal particles to natural gas hydrates, and that, as a result, the general applicability of classical nucleation theory has been repeatedly called into question. We have attempted to identify the most pressing open questions in the field. We believe that, by improving (i) existing interatomic potentials and (ii) currently available enhanced sampling methods, the community can move toward accurate investigations of realistic systems of practical interest, thus bringing simulations a step closer to experiments. PMID:27228560
International Nuclear Information System (INIS)
Highlights: • We proposed a general data reduction scheme that combines scanning AC and DC calorimetry results for the study of reaction kinetics. • Calorimetry measurements at cooling rates ranging from 30 K/s to 20,000 K/s were achieved. • Upon initial melting, the Bi thin-film sample breaks up into thousands of isolated islands, and highly repeatable nucleation behavior is observed. • The nucleation rate of melted Bi is calculated, which can be well described by classical nucleation theory over a wide range of cooling rates. - Abstract: We study the nucleation behavior of undercooled liquid Bi at cooling rates ranging from 101 to 104 K/s using a combination of scanning DC and AC nano-calorimetry techniques. Upon initial melting, the Bi thin-film sample breaks up into silicon nitride-coated isolated islands. The number of islands in a typical sample is sufficiently large that highly repeatable nucleation behavior is observed, despite the stochastic nature of the nucleation process. We establish a data reduction technique to evaluate the nucleation rate from DC and AC calorimetry results. The results show that the driving force for the nucleation of melted Bi is well described by classical nucleation theory over a wide range of cooling rates. The proposed technique provides a unique and efficient way to examine nucleation kinetics with cooling rates over several orders of magnitude. The technique is quite general and can be used to evaluate reaction kinetics in other materials
Hagen, D. E.; Anderson, R. J.; Kassner, J. L., Jr.
1981-01-01
Experimental data on ice nucleation, presented in an earlier paper, are analyzed to yield information about the homogeneous nucleation rate of ice from supercooled liquid and the heights of energy barriers to that nucleation. The experiment consisted of using an expansion cloud chamber to nucleate from the vapor a cloud of supercooled pure water drops and the observation of the fraction of drops which subsequently froze. The analysis employed standard classical homogeneous nucleation theory. The data are used to extract the first experimental measurement (albeit indirect) of the activation energy for the transfer of a water molecule across the liquid-ice interface at temperatures near -40 C. The results provide further evidence that the local liquid structure becomes more icelike as the temperature is lowered.
Field theory and weak Euler-Lagrange equation for classical particle-field systems
Qin, Hong; Davidson, Ronald C
2015-01-01
It is commonly believed as a fundamental principle that energy-momentum conservation of a physical system is the result of space-time symmetry. However, for classical particle-field systems, e.g., charged particles interacting through self-consistent electromagnetic or electrostatic fields, such a connection has only been cautiously suggested. It has not been formally established. The difficulty is due to the fact that the dynamics of particles and the electromagnetic fields reside on different manifolds. We show how to overcome this difficulty and establish the connection by generalizing the Euler-Lagrange equation, the central component of a field theory, to a so-called weak form. The weak Euler-Lagrange equation induces a new type of flux, called the weak Euler-Lagrange current, which enters conservation laws. Using field theory together with the weak Euler-Lagrange equation developed here, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived from the underly...
Charmaine Scrimnger-Christian; S. Wedzerai Musvoto
2011-01-01
The purpose of this study is to discuss a possible way forward in accounting measurement. It also highlights the importance of understanding the lack of appreciation given by the accounting researchers to the distinction between representation measurement theory and the axioms of quantity on which the classical theory of measurement is based. For long, research in measurement theory has classified representational measurement as nothing but applications of the axioms of quantity. It was belie...
Current-carrying plasma and the magnetic field ambiguity in classical MHD theory
International Nuclear Information System (INIS)
An ambiguity in the classical theoretical framework used for computing magnetohydrostatic equilibrium is pointed out and analyzed. This inconsistency implies that some proposed solutions of the magnetohydrodynamic (MHD) equations may not represent actual magnetic fields of plasma currents in the geometry considered. The root of the inconsistency is that the magnetostatic field equation and the magnetohydrostatic equations are not invariant under the same transformations. There are two types of problems where inconsistencies have arisen in the literature: (a) unphysical magnetic fields are postulated inside a plasma current; and (b) vacuum magnetic fields are postulated that are not gradient fields. In both cases, magnetic fields are obtained which cannot be created in the laboratory. This inconsistency is traced back to a mishandling of the mathematical structure of the magnetic field equation. The magnetic field rvec B is a vector potential for the current density distribution rvec j, just as rvec A is a vector potential for rvec B. Nevertheless, whereas a gauge transformation on rvec A is unobservable (gauge invariant), the analogous gauge transformation in the rvec B vector (gradient field transformation) is indeed observable and changes the Lorentz force. Following Alfven, the authors characterize plasmas mathematically through the field lines of the current density distribution vector. Classical MHD theory, by contrast, is concerned strictly with magnetic field lines. They show here how this magnetic field approach can lead to inconsistencies when applied to plasmas. A resolution of entrenched ambiguities is made possible by using the current fiber description to derive a corrected Grad-Shafranov plasma equilibrium equation
Structure Theory for Extended Kepler-Coulomb 3D Classical Superintegrable Systems
Directory of Open Access Journals (Sweden)
Ernie G. Kalnins
2012-06-01
Full Text Available The classical Kepler-Coulomb system in 3 dimensions is well known to be 2nd order superintegrable, with a symmetry algebra that closes polynomially under Poisson brackets. This polynomial closure is typical for 2nd order superintegrable systems in 2D and for 2nd order systems in 3D with nondegenerate (4-parameter potentials. However the degenerate 3-parameter potential for the 3D extended Kepler-Coulomb system (also 2nd order superintegrable is an exception, as its quadratic symmetry algebra doesn't close polynomially. The 3D 4-parameter potential for the extended Kepler-Coulomb system is not even 2nd order superintegrable. However, Verrier and Evans (2008 showed it was 4th order superintegrable, and Tanoudis and Daskaloyannis (2011 showed that in the quantum case, if a second 4th order symmetry is added to the generators, the double commutators in the symmetry algebra close polynomially. Here, based on the Tremblay, Turbiner and Winternitz construction, we consider an infinite class of classical extended Kepler-Coulomb 3- and 4-parameter systems indexed by a pair of rational numbers (k_1,k_2 and reducing to the usual systems when k_1=k_2=1. We show these systems to be superintegrable of arbitrarily high order and work out explicitly the structure of the symmetry algebras determined by the 5 basis generators we have constructed. We demonstrate that the symmetry algebras close rationally; only for systems admitting extra discrete symmetries is polynomial closure achieved. Underlying the structure theory is the existence of raising and lowering constants of the motion, not themselves polynomials in the momenta, that can be employed to construct the polynomial symmetries and their structure relations.
Heterogeneous nucleation on surfaces of the ellipsoid of rotation
Li, Xiang-Ming; Liu, Qing-Hui
2016-08-01
This paper focusses on the heterogeneous nucleation on the surface with the non-constant curvature. The formation of a spherical nucleus on the ellipsoid of rotation is considered. Following the classical nucleation theory, the work of formation of a critical nucleus on the ellipsoid of rotation has been given, and the effects of geometry sizes and the material properties of the ellipsoid of rotation on the work of formation of a critical nucleus have been obtained. When the geometry size of the substrate is about value of the critical nucleus radius, there may exist twice nucleation on the ellipsoid of rotation for the case of the smaller value of λ and ϕ rotational ellipsoid is more easy than on the spherical surface, while nucleation on the prolate ellipsoid of rotation is more difficult than on the spherical surface. Furthermore, if the particles of the ellipsoid are added into the parent phase as nucleation agents or catalysts, for some geometry sizes, they would not have the effects on the heterogeneous nucleation.
Crystal nucleation in the hard-sphere system revisited: a critical test of theoretical approaches.
Tóth, Gyula I; Gránásy, László
2009-04-16
The hard-sphere system is the best known fluid that crystallizes: the solid-liquid interfacial free energy, the equations of state, and the height of the nucleation barrier are known accurately, offering a unique possibility for a quantitative validation of nucleation theories. A recent significant downward revision of the interfacial free energy from approximately 0.61kT/sigma(2) to (0.56 +/- 0.02)kT/sigma(2) [Davidchack, R.; Morris, J. R.; Laird, B. B. J. Chem. Phys. 2006, 125, 094710] necessitates a re-evaluation of theoretical approaches to crystal nucleation. This has been carried out for the droplet model of the classical nucleation theory (CNT), the self-consistent classical theory (SCCT), a phenomenological diffuse interface theory (DIT), and single- and two-field variants of the phase field theory that rely on either the usual double-well and interpolation functions (PFT/S1 and PFT/S2, respectively) or on a Ginzburg-Landau expanded free energy that reflects the crystal symmetries (PFT/GL1 and PFT/GL2). We find that the PFT/GL1, PFT/GL2, and DIT models predict fairly accurately the height of the nucleation barrier known from Monte Carlo simulations in the volume fraction range of 0.52 SCCT, PFT/S1, and PFT/S2 models underestimate it significantly. PMID:19320450
Directory of Open Access Journals (Sweden)
Jason Herb
2011-02-01
Full Text Available The impact of organic species which are present in the Earth’s atmosphere on the burst of new particles is critically important for the understanding of the molecular nature of atmospheric nucleation phenomena. Amines have recently been proposed as possible stabilizers of binary pre-nucleation clusters. In order to advance the understanding of atmospheric nucleation phenomena, a quantum-chemical study of hydrogen-bonded complexes of binary sulfuric acid-water clusters with methyl-, dimethyl- and trimethylamines representing common atmospheric organic species, vegetation products and laboratory impurities has been carried out. The thermochemical stability of the sulfuric acid-amines-water complexes was found to be higher than that of the sulfuric acid-ammonia-water complexes, in qualitative agreement with the previous studies. However, the enhancement in stability due to amines appears to not be large enough to overcome the difference in typical atmospheric concentrations of ammonia and amines. Further research is needed in order to address the existing uncertainties and to reach a final conclusion about the importance of amines for the atmospheric nucleation.
Institute of Scientific and Technical Information of China (English)
Chen Wen-Xue; Zhang Shu-Lian; Zhang Peng; Zeng Zhao-Li
2012-01-01
In this paper,we propose a semi-classical theory to successfully explain the polarization flipping in a single frequency laser. An experimental setup is built to verify this theory. The observed experimental phenomena are consistent with the theoretical analysis.We perform phase retardation measurements of birefringent components using this experimental system.The results show that the measurement repeatability is 0.12° and the measurement accuracy is 0.22°.
International Nuclear Information System (INIS)
In this paper, we propose a semi-classical theory to successfully explain the polarization flipping in a single frequency laser. An experimental setup is built to verify this theory. The observed experimental phenomena are consistent with the theoretical analysis. We perform phase retardation measurements of birefringent components using this experimental system. The results show that the measurement repeatability is 0.12° and the measurement accuracy is 0.22°
Cremaschini, Claudio; 10.1140/epjp/i2011-11063-3
2012-01-01
A notorious difficulty in the covariant dynamics of classical charged particles subject to non-local electromagnetic (EM) interactions arising in the EM radiation-reaction (RR) phenomena is due to the definition of the related non-local Lagrangian and Hamiltonian systems. The lack of a standard Lagrangian/Hamiltonian formulation in the customary asymptotic approximation for the RR equation may inhibit the construction of consistent kinetic and fluid theories. In this paper the issue is investigated in the framework of Special Relativity. It is shown that, for finite-size spherically-symmetric classical charged particles, non-perturbative Lagrangian and Hamiltonian formulations in standard form can be obtained, which describe particle dynamics in the presence of the exact EM RR self-force. As a remarkable consequence, based on axiomatic formulation of classical statistical mechanics, the covariant kinetic theory for systems of charged particles subject to the EM RR self-force is formulated in Hamiltonian form....
International Nuclear Information System (INIS)
A systematic method is developed to study the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton's second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.
Polar-solvation classical density-functional theory for electrolyte aqueous solutions near a wall
Warshavsky, Vadim; Marucho, Marcelo
2016-04-01
A precise description of the structural and dielectric properties of liquid water is critical to understanding the physicochemical properties of solutes in electrolyte solutions. In this article, a mixture of ionic and dipolar hard spheres is considered to account for water crowding and polarization effects on ionic electrical double layers near a uniformly charged hard wall. As a unique feature, solvent hard spheres carrying a dipole at their centers were used to model water molecules at experimentally known concentration, molecule size, and dipolar moment. The equilibrium ionic and dipole density profiles of this electrolyte aqueous model were calculated using a polar-solvation classical density-functional theory (PSCDFT). These profiles were used to calculate the charge density distribution, water polarization, dielectric permittivity function, and mean electric potential profiles as well as differential capacitance, excess adsorptions, and wall-fluid surface tension. These results were compared with those corresponding to the pure dipolar model and unpolar primitive solvent model of electrolyte aqueous solutions to understand the role that water crowding and polarization effects play on the structural and thermodynamic properties of these systems. Overall, PSCDFT predictions are in agreement with available experimental data.
Carreón-Calderón, Bernardo
2012-10-14
Stability analysis is generally used to verify that the solution to phase equilibrium calculations corresponds to a stable state (minimum of the free energy). In this work, tangent plane distance analysis for stability of macroscopic mixtures is also used for analyzing the nucleation process, reconciling thus this analysis with classical nucleation theories. In the context of the revised nucleation theory, the driving force and the nucleation work are expressed as a function of the Lagrange multiplier corresponding to the mole fraction constraint from the minimization problem of stability analysis. Using a van der Waals fluid applied to a ternary mixture, Lagrange multiplier properties are illustrated. In particular, it is shown how the Lagrange multiplier value is equal to one on the binodal and spinodal curves at the same time as the driving force of nucleation vanishes on these curves. Finally, it is shown that, on the spinodal curve, the nucleation work from the revised and generalized nucleation theories are characterized by two different local minima from stability analysis, irrespective of any interfacial tension models. PMID:23061836
Anderson, Edward
2013-01-01
I already showed that Kendall's shape geometry work was the geometrical description of Barbour's relational mechanics' reduced configuration spaces (alias shape spaces). I now describe the extent to which Kendall's subsequent statistical application to such as the `standing stones problem' realizes further ideas along the lines of Barbour-type timeless records theories, albeit just at the classical level.
Anderson, Edward
2013-01-01
I previously showed that Kendall's work on shape geometry is in fact also the geometrical description of Barbour's relational mechanics' reduced configuration spaces (alias shape spaces). I now describe the extent to which Kendall's subsequent statistical application to e.g. the `standing stones problem' realizes further ideas along the lines of Barbour-type timeless records theories, albeit just at the classical level.
International Nuclear Information System (INIS)
Field theories with Lorentz (or diffeomorphism invariant) action can exhibit superluminal behavior through the breaking of local Lorentz invariance. Quantum induced superluminal velocities are well-known examples of this effect. The issue of the causal behavior of such propagation is somewhat controversial in the literature and we intend to clarify it. We provide a careful analysis of the meaning of causality in classical relativistic field theories and stress the role played by the Cauchy problem and the notion of chronology. We show that, in general, superluminal behavior threatens causality only if one assumes that a prior chronology in spacetime exists. In the case where superluminal propagation occurs, however, there are at least two nonconformally related metrics in spacetime and thus two available notions of chronology. These two chronologies are on equal footing, and it would thus be misleading to choose ab initio one of them to define causality. Rather, we provide a formulation of causality in which no prior chronology is assumed. We argue that this is the only way to deal with the issue of causality in the case where some degrees of freedom propagate faster than others. In that framework, then, it is shown that superluminal propagation is not necessarily noncausal, the final answer depending on the existence of an initial data formulation. This also depends on global properties of spacetime that we discuss in detail. As an illustration of these conceptual issues, we consider two field theories, namely, k-essence scalar fields and bimetric theories of gravity, and we derive the conditions imposed by causality. We discuss various applications such as the dark energy problem, modified-Newtonian-dynamics-like theories of gravity, and varying speed of light theories
Nonperturbative effects on nucleation
Gleiser, Marcello; Gleiser, Marcelo; Heckler, Andrew F
1996-01-01
A nonperturbative correction to the thermal nucleation rate of critical bubbles in a first order phase transition is estimated. The correction originates from large-amplitude fluctuations which may be present before the transition occurs. Using a simple model of a scalar field in a double-well potential, we present a method to obtain a corrected potential which incorporates the free-energy density available from large-amplitude fluctuations, which is not included in the usual perturbative calculation. For weaker phase transitions, the nucleation rate can be much larger than the rate calculated via perturbation theory. As an application of our method, we show how nonperturbative corrections can both qualitatively and quantitatively explain anomalously high nucleation rates observed in 2-d numerical simulations.
Multicomponent nonisothermal nucleation. 1. Kinetic equation
Kurasov, Victor
1999-01-01
The first part of the theory for the multicomponent nonisothermal nucleation is presented. On the base of analysis of the elementary acts of interation between an embryo and environment the kinetic equation is derived. This equation will be solved later and gives the nucleation rate for nonisothermal nucleation in the system with many condensating components. The orders of operators in this equation are estimated.
Thermodynamic Derivation of the Activation Energy for Ice Nucleation
Barahona, D.
2015-01-01
Cirrus clouds play a key role in the radiative and hydrological balance of the upper troposphere. Their correct representation in atmospheric models requires an understanding of the microscopic processes leading to ice nucleation. A key parameter in the theoretical description of ice nucleation is the activation energy, which controls the flux of water molecules from the bulk of the liquid to the solid during the early stages of ice formation. In most studies it is estimated by direct association with the bulk properties of water, typically viscosity and self-diffusivity. As the environment in the ice-liquid interface may differ from that of the bulk, this approach may introduce bias in calculated nucleation rates. In this work a theoretical model is proposed to describe the transfer of water molecules across the ice-liquid interface. Within this framework the activation energy naturally emerges from the combination of the energy required to break hydrogen bonds in the liquid, i.e., the bulk diffusion process, and the work dissipated from the molecular rearrangement of water molecules within the ice-liquid interface. The new expression is introduced into a generalized form of classical nucleation theory. Even though no nucleation rate measurements are used to fit any of the parameters of the theory the predicted nucleation rate is in good agreement with experimental results, even at temperature as low as 190 K, where it tends to be underestimated by most models. It is shown that the activation energy has a strong dependency on temperature and a weak dependency on water activity. Such dependencies are masked by thermodynamic effects at temperatures typical of homogeneous freezing of cloud droplets; however, they may affect the formation of ice in haze aerosol particles. The new model provides an independent estimation of the activation energy and the homogeneous ice nucleation rate, and it may help to improve the interpretation of experimental results and the
Nucleation in a Sheared Liquid Binary Mixture.
Min, Kyung-Yang
inverse of the initial supercooling revealed a curvature for small values of supercooling, implying a breakdown of the classical nucleation theory (3). (Abstract shortened by UMI.).
Sihvola, Ari
2005-03-01
' multipole theory. But then the focus is shifted to observables associated with the reflection of waves from a surface. And there the classical analysis fails. This gives the motivation for the following chapters where the transformed multipole theory is represented. As expected, the correct multipole balance restores the physicality of the results in the reflection problem. One of the healthy reminders for an electrical engineer-scientist reading the book is the fact that E and B are the primary electric and magnetic fields. The other two field quantities, D and H, are the response fields (which, by the way, are also shown to be origin-dependent and poorly\\endcolumn defined in the framework of classical multipole theory). In defence, however, for these poor latter quantities one can mention the many advantages of the engineering-type constitutive relations where D and B are expressed as responses to E and H. An example is the beautiful symmetry and complete analogy between the electric and magnetic quantities (voltage becomes current and vice versa in the duality transformation) which helps us write down solutions to electromagnetic problems from other known cases. From a pragmatic point of view we would also favour the use of quantities like Poynting vector and energy density (which require the H field). Another discussion-provoking question to the authors of the book might be whether their new multipole balance could be broken in the analysis of artificial materials. New nanotechnological discoveries and devices make it look like engineers can do anything. Perhaps in the design of complex media and metamaterials, a hot topic in todayÂ's materials science, such macroscopic responses can be tailored where a certain high-order multipole contribution dominates over other, more basic ones. Multiple Theory in Electromagnetism is suitable for a broad spectrum of readers: solid-state physicists, molecular chemists, theoretical and experimental optics scientists, radiophysics
Multipole Theory in Electromagnetism: Classical, Quantum and Symmetry Aspects, with Applications
Energy Technology Data Exchange (ETDEWEB)
Sihvola, Ari [Helsinki University of Technology (Finland)
2005-03-11
everything seems to work well with the 'old' multipole theory. But then the focus is shifted to observables associated with the reflection of waves from a surface. And there the classical analysis fails. This gives the motivation for the following chapters where the transformed multipole theory is represented. As expected, the correct multipole balance restores the physicality of the results in the reflection problem. One of the healthy reminders for an electrical engineer-scientist reading the book is the fact that E and B are the primary electric and magnetic fields. The other two field quantities, D and H, are the response fields (which, by the way, are also shown to be origin-dependent and poorly defined in the framework of classical multipole theory). In defence, however, for these poor latter quantities one can mention the many advantages of the engineering-type constitutive relations where D and B are expressed as responses to E and H. An example is the beautiful symmetry and complete analogy between the electric and magnetic quantities (voltage becomes current and vice versa in the duality transformation) which helps us write down solutions to electromagnetic problems from other known cases. From a pragmatic point of view we would also favour the use of quantities like Poynting vector and energy density (which require the H field). Another discussion-provoking question to the authors of the book might be whether their new multipole balance could be broken in the analysis of artificial materials. New nanotechnological discoveries and devices make it look like engineers can do anything. Perhaps in the design of complex media and metamaterials, a hot topic in today?s materials science, such macroscopic responses can be tailored where a certain high-order multipole contribution dominates over other, more basic ones. Multiple Theory in Electromagnetism is suitable for a broad spectrum of readers: solid-state physicists, molecular chemists, theoretical and
Multipole Theory in Electromagnetism: Classical, Quantum and Symmetry Aspects, with Applications
International Nuclear Information System (INIS)
' multipole theory. But then the focus is shifted to observables associated with the reflection of waves from a surface. And there the classical analysis fails. This gives the motivation for the following chapters where the transformed multipole theory is represented. As expected, the correct multipole balance restores the physicality of the results in the reflection problem. One of the healthy reminders for an electrical engineer-scientist reading the book is the fact that E and B are the primary electric and magnetic fields. The other two field quantities, D and H, are the response fields (which, by the way, are also shown to be origin-dependent and poorly defined in the framework of classical multipole theory). In defence, however, for these poor latter quantities one can mention the many advantages of the engineering-type constitutive relations where D and B are expressed as responses to E and H. An example is the beautiful symmetry and complete analogy between the electric and magnetic quantities (voltage becomes current and vice versa in the duality transformation) which helps us write down solutions to electromagnetic problems from other known cases. From a pragmatic point of view we would also favour the use of quantities like Poynting vector and energy density (which require the H field). Another discussion-provoking question to the authors of the book might be whether their new multipole balance could be broken in the analysis of artificial materials. New nanotechnological discoveries and devices make it look like engineers can do anything. Perhaps in the design of complex media and metamaterials, a hot topic in today?s materials science, such macroscopic responses can be tailored where a certain high-order multipole contribution dominates over other, more basic ones. Multiple Theory in Electromagnetism is suitable for a broad spectrum of readers: solid-state physicists, molecular chemists, theoretical and experimental optics scientists, radiophysics experts
Directory of Open Access Journals (Sweden)
B. Verheggen
2006-01-01
Full Text Available Classical nucleation theory is unable to explain the ubiquity of nucleation events observed in the atmosphere. This shows a need for an empirical determination of the nucleation rate. Here we present a novel inverse modeling procedure to determine particle nucleation and growth rates based on consecutive measurements of the aerosol size distribution. The particle growth rate is determined by regression analysis of the measured change in the aerosol size distribution over time, taking into account the effects of processes such as coagulation, deposition and/or dilution. This allows the growth rate to be determined with a higher time-resolution than can be deduced from inspecting contour plots ('banana-plots''. Knowing the growth rate as a function of time enables the evaluation of the time of nucleation of measured particles of a certain size. The nucleation rate is then obtained by integrating the particle losses from time of measurement to time of nucleation. The regression analysis can also be used to determine or verify the optimum value of other parameters of interest, such as the wall loss or coagulation rate constants. As an example, the method is applied to smog chamber measurements. This program offers a powerful interpretive tool to study empirical aerosol population dynamics in general, and nucleation and growth in particular.
International Nuclear Information System (INIS)
A method for numerically simulating quantum systems is proposed and applied to the two-dimensional electron fluid at T = 0. This method maps quantum systems onto classical ones in the spirit of the classical-map hypernetted-chain theory and performs simulations on the latter. The results of the simulations are free from the assumption of the hypernetted-chain approximation and the neglect of the bridge diagrams. A merit of this method is the applicability to systems with geometrical complexity and finite sizes including the cases at finite temperatures. Monte Carlo and molecular dynamics simulations are performed corresponding to two previous proposals for the 'quantum' temperature and an improvement in the description of the diffraction effect. It is shown that one of these two proposals with the improved diffraction effect gives significantly better agreement with quantum Monte Carlo results reported previously for the range of 5≤rs≤40. These results may serve as the basis for the application of this method to finite non-periodic systems like quantum dots and systems at finite temperatures.
Brown, W Byers
2011-01-01
C.T.R.Wilson showed that when supersaturated water vapour was exposed to ultraviolet radiation from sunlight or other sources in the presence of oxygen it immediately condensed to form an aerosol. This phenomenon was eventually explained as due to the formation of a charge-transfer complex H2O+O2-, whose existence was confirmed theoretically and subsequently established experimentally. It is proposed that the correlation recently discovered between the stream-flow of the Parana and three other rivers in South America and the solar sunspot cycle is due to the photo-nucleation mechanism investigated by Wilson.
"今枝, 国之助"; "イマエダ, クニノスケ"; Kuninosuke", "Imaeda
1985-01-01
"Quaternionic formulation of classical electrodynamics by using ""biq""(real part of a complex-quaternions) has been presented. Also, the solutions of Maxwell's equations have been given using regular functions of a biq variable."
Open and Closed String field theory interpreted in classical Algebraic Topology
Sullivan, Dennis
2003-01-01
There is an interpretation of open string field theory in algebraic topology. An interpretation of closed string field theory can be deduced from this open string theory to obtain as well the interpretation of open and closed string field theory combined.
Kerner, Boris S
2016-01-01
We show that the minimization of travel times in a network as generally accepted in classical traffic and transportation theories deteriorates the traffic system through a considerable increase in the probability of traffic breakdown in the network. We introduce a network characteristic {\\it minimum network capacity} that shows that rather than the minimization of travel times in the network, the minimization of the probability of traffic breakdown in the network maximizes the network throughput at which free flow persists in the whole network.
Jaco Gericke
2014-01-01
Contemporary analyses of אלהים as generic concept tend to be based on psychological theories of concepts. This article, by contrast, attempts to show what a philosophical analysis of the concept of generic אלהים in the Hebrew Bible is concerned with when approached from the perspective of the classical or definitionist view of conceptual structure. However, rather than offering a conceptual analysis of generic אלהים in any given context, the discussion features a general meta-conceptual overv...
Monnet, Grégoire O.
2015-01-01
Approved for public release; distribution is unlimited Since 1991, a long list of scholars has sought to write off Clausewitz as outdated and no longer worth study. In light of the past fifteen years and the absence of a strategic victory in the wars in Iraq and Afghanistan, however, Clausewitz’s early retirement is misguided, to say the least. Are the classical theories of Clausewitz on the nature of war—particularly concerning small wars and insurgencies—relevant to contemporary conflict...
Alonso Izquierdo, Alberto; González León, Miguel Ángel; Torre Mayado, Marina de la; Mateos Guilarte, Juan
2004-01-01
[EN ] Superpotentials in {\\cal N}=2 supersymmetric classical mechanics are no more than the Hamilton characteristic function of the Hamilton–Jacobi theory for the associated purely bosonic dynamical system. Modulo a global sign, there are several superpotentials ruling Hamilton–Jacobi separable supersymmetric systems, with a number of degrees of freedom greater than 1. Here, we explore how supersymmetry and separability are entangled in the quantum version of this kind of system. We also show...
Heterogeneous nucleation of ice from supercooled NaCl solution confined in porous cement paste
Zeng, Qiang; Li, Kefei; Fen-Chong, Teddy
2015-01-01
Clarifying the nucleation process of chloride-based deicing salt solution (e.g., NaCl solution) confined in cement-based porous materials remains an important issue to understand its detrimental effects on material substrates. In this study, the pore structures of hardened cement pastes were characterized by mercury-intrusion and nitrogen-sorption porosimetry. The ice nucleation temperature of NaCl solution of different concentrations confined in the hardened cement pastes was measured and analyzed by classical heterogeneous nucleation theory. The kinetic factor, contact-angle factor including the contact angle between ice and the substrate were evaluated. The results revealed that the contact angle between ice and the substrate showed the minimum value when adding 3% NaCl into water. The heterogeneous ice nucleation rates were found to be proportional to the water activity shifts.
Homogeneous bubble nucleation in binary systems of liquid solvent and dissolved gas
Němec, Tomáš
2016-03-01
A formulation of the classical nucleation theory (CNT) is developed for bubble nucleation in a binary system composed of a liquid solvent and a dissolved gas. The theoretical predictions are compared to the experimental nucleation data of four binary mixtures, i.e. diethylether - nitrogen, propane - carbon dioxide, isobutane - carbon dioxide, and R22 (chlorodifluoromethane) - carbon dioxide. The presented CNT formulation is found to improve the precision of the simpler theoretical method of Ward et al. [J. Basic Eng. 92 (10), 71-80, 1970] based on the weak-solution approximation. By analyzing the available experimental nucleation data, an inconsistency in the data reported by Mori et al. [Int. J. Heat Mass Transfer, 19 (10), 1153-1159, 1976] for propane - carbon dioxide and R22 - carbon dioxide is identified.
International Nuclear Information System (INIS)
We show that the partition function of many classical models with continuous degrees of freedom, e.g. Abelian lattice gauge theories and statistical mechanical models, can be written as the partition function of an (enlarged) four-dimensional lattice gauge theory (LGT) with gauge group U(1). This result is very general in that it includes models in different dimensions with different symmetries. In particular, we show that a U(1) LGT defined in a curved spacetime can be mapped to a U(1) LGT with a flat background metric. The result is achieved by expressing the U(1) LGT partition function as an inner product between two quantum states
A Time-Dependent Classical Solution of C=1 String Field Theory and Non-Perturbative Effects
Dhar, A; Wadia, S R; Dhar, Avinash; Mandal, Gautam; Wadia, Spenta R.
1993-01-01
We describe a real-time classical solution of $c=1$ string field theory written in terms of the phase space density, $u(p,q,t)$, of the equivalent fermion theory. The solution corresponds to tunnelling of a single fermion above the filled fermi sea and leads to amplitudes that go as $\\exp(- C/ \\gst)$. We discuss how one can use this technique to describe non-perturbative effects in the Marinari-Parisi model. We also discuss implications of this type of solution for the two-dimensional black hole.
A New Semi-Symmetric Uniﬁed Field Theory of the Classical Fields of Gravity and Electromagnetism
Directory of Open Access Journals (Sweden)
Suhendro I.
2007-10-01
Full Text Available We attempt to present a classical theoretical framework in which the gravitational and electromagnetic fields are unified as intrinsic geometric objects in the space-time manifold. For this purpose, we first present the preliminary geometric considerations dealing with the metric differential geometry of Cartan connections. The unified field theory is then developed as an extension of the general theory of relativity based on a semi- symmetric Cartan connection which is meant to be as close as possible structurally to the symmetric connection of the Einstein-Riemann space-time.
Hong, Ban Zhen; Keong, Lau Kok; Shariff, Azmi Mohd
2016-05-01
The employment of different mathematical models to address specifically for the bubble nucleation rates of water vapour and dissolved air molecules is essential as the physics for them to form bubble nuclei is different. The available methods to calculate bubble nucleation rate in binary mixture such as density functional theory are complicated to be coupled along with computational fluid dynamics (CFD) approach. In addition, effect of dissolved gas concentration was neglected in most study for the prediction of bubble nucleation rates. The most probable bubble nucleation rate for the water vapour and dissolved air mixture in a 2D quasi-stable flow across a cavitating nozzle in current work was estimated via the statistical mean of all possible bubble nucleation rates of the mixture (different mole fractions of water vapour and dissolved air) and the corresponding number of molecules in critical cluster. Theoretically, the bubble nucleation rate is greatly dependent on components' mole fraction in a critical cluster. Hence, the dissolved gas concentration effect was included in current work. Besides, the possible bubble nucleation rates were predicted based on the calculated number of molecules required to form a critical cluster. The estimation of components' mole fraction in critical cluster for water vapour and dissolved air mixture was obtained by coupling the enhanced classical nucleation theory and CFD approach. In addition, the distribution of bubble nuclei of water vapour and dissolved air mixture could be predicted via the utilisation of population balance model.
Shchekin, Alexander K; Shabaev, Ilya V; Hellmuth, Olaf
2013-02-01
Thermodynamic and kinetic peculiarities of nucleation, deliquescence and efflorescence transitions in the ensemble of droplets formed on soluble condensation nuclei from a solvent vapor have been considered. The interplay of the effects of solubility and the size of condensation nuclei has been analyzed. Activation barriers for the deliquescence and phase transitions and for the reverse efflorescence transition have been determined as functions of the relative humidity of the vapor-gas atmosphere, initial size, and solubility of condensation nuclei. It has been demonstrated that, upon variations in the relative humidity of the atmosphere, the crossover in thermodynamically stable and unstable variables of the droplet state takes place. The physical meaning of stable and unstable variables has been clarified. The kinetic equations for establishing equilibrium and steady distributions of binary droplets have been solved. The specific times for relaxation, deliquescence and efflorescence transitions have been calculated. PMID:23406138
Camilleri, Kristian
2015-01-01
Niels Bohr's doctrine of the primacy of "classical concepts" is arguably his most criticized and misunderstood view. We present a new, careful historical analysis that makes clear that Bohr's doctrine was primarily an epistemological thesis, derived from his understanding of the functional role of experiment. A hitherto largely overlooked disagreement between Bohr and Heisenberg about the movability of the "cut" between measuring apparatus and observed quantum system supports the view that, for Bohr, such a cut did not originate in dynamical (ontological) considerations, but rather in functional (epistemological) considerations. As such, both the motivation and the target of Bohr's doctrine of classical concepts are of a fundamentally different nature than what is understood as the dynamical problem of the quantum-to-classical transition. Our analysis suggests that, contrary to claims often found in the literature, Bohr's doctrine is not, and cannot be, at odds with proposed solutions to the dynamical problem...
The Hamilton--Jacobi Theory and the Analogy between Classical and Quantum Mechanics
G. Marmo(Università di Napoli and INFN, Napoli, Italy); Morandi, G.; Mukunda, N.
2009-01-01
We review here some conventional as well as less conventional aspects of the time-independent and time-dependent Hamilton-Jacobi (HJ) theory and of its connections with Quantum Mechanics. Less conventional aspects involve the HJ theory on the tangent bundle of a configuration manifold, the quantum HJ theory, HJ problems for general differential operators and the HJ problem for Lie groups.
International Nuclear Information System (INIS)
For an arbitrary potential V with classical trajectories x-vector=g-vector(t) we construct localized oscillating three-dimensional wave lumps ψ(x-vector,t,g-vector) representing a single quantum particle. The crest of the envelope of the ripple follows the classical orbit g-vector(t) slightly modified due to potential V and ψ(x-vector,t;g-vector) satisfies the Schroedinger equation. The field energy, momentum and angular momentum calculated as integrals over all space are equal to particle energy, momentum and angular momentum. The relation to coherent states and to Schroedinger waves are also discussed. (author). 6 refs
Semi-classical theory for quantum quenches in the O(3) non-linear sigma model
International Nuclear Information System (INIS)
We use the semi-classical approach to study the non-equilibrium dynamics of the O(3) non-linear sigma model. For a class of quenches defined in the text, we obtain the order-parameter dynamical correlator in the thermodynamic limit. In particular we predict quench-dependent relaxation times and correlation lengths. The approach developed for the O(3) non-linear sigma model can also be applied to the transverse field Ising chain, where the semi-classical results can be directly compared to both the exact and the numerical ones, revealing the limits of the method. (paper)
Quantum limits on optical phase estimation accuracy from classical rate-distortion theory
Energy Technology Data Exchange (ETDEWEB)
Nair, Ranjith [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3 (Singapore)
2014-12-04
The classical information-theoretic lower bound on the distortion of a random variable upon transmission through a noisy channel is applied to quantum-optical phase estimation. An approach for obtaining Bayesian lower bounds on the phase estimation accuracy is described that employs estimates of the classical capacity of the relevant quantum-optical channels. The Heisenberg limit for lossless phase estimation is derived for arbitrary probe state and prior distributions of the phase, and shot-noise scaling of the phase accuracy is established in the presence of nonzero loss for a parallel entanglement-assisted strategy with a single probe mode.
Non-Noetherian symmetries for oscillators in classical mechanics and in field theory
Hojman, Sergio A.; Delajara, Jamie; Pena, Leda
1995-01-01
Infinitely many new conservation laws both for free fields as well as for test fields evolving on a given gravitational background are presented. The conserved currents are constructed using the field theoretical counterpart of a recently discovered non-Noetherian symmetry which gives rise to a new way of solving the classical small oscillations problem. Several examples are discussed.
Subscores Based on Classical Test Theory: To Report or Not to Report
Sinharay, Sandip; Haberman, Shelby; Puhan, Gautam
2007-01-01
There is an increasing interest in reporting subscores, both at examinee level and at aggregate levels. However, it is important to ensure reasonable subscore performance in terms of high reliability and validity to minimize incorrect instructional and remediation decisions. This article employs a statistical measure based on classical test theory…
Institute of Scientific and Technical Information of China (English)
WU Ning; ZHANG Da-Hua
2007-01-01
A systematic method is developed to study the classical motion of a mass point in gravitational gauge field.First,by using Mathematica,a spherical symmetric solution of the field equation of gravitational gauge field is obtained,which is just the traditional Schwarzschild solution.Combining the principle of gauge covariance and Newton's second law of motion,the equation of motion of a mass point in gravitational field is deduced.Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field,we can discuss classical tests of gauge theory of gravity,including the deflection of light by the sun,the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun.It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.
Directory of Open Access Journals (Sweden)
Vera Barton-Caro Ph.D.,
2015-12-01
Full Text Available The purpose of this classic grounded theory study was to explain the complex decision making process of heart failure (HF patients considering primary prevention implantable cardioverter defibrillator (ICD therapy. Sudden cardiac death (SCD is the leading cause of death for people with HF as well as the primary cause of death in the United States (US. ICDs represent the standard of care as the only effective therapy for primary prevention of SCD. However, a significant proportion of qualifying HF patients declines this invasive, yet life-saving device. The grounded theory is of Embodied revelation. The threat of SCD for ICD candidates consists of four stages: living in conscious denial, heightening of awareness, sanctioning ICD therapy, and living in new assurance. The first stage ends abruptly with the critical juncture of grasping the threat of SCD. This grounded theory has implications for research, nursing and medical practice, as well as bioethical considerations.
Classical and quantum dynamics of a gravitational theory with absolute teleparallelism
International Nuclear Information System (INIS)
The dynamics of an alternative theory of gravitation with absolute teleparallelism is sustied. In the Cauchy problem of this theory four constraint relations are obtained, as in general relativity, because of the existence of the manifold mapping group. Propagation equations for the dynamical variables are also derived by applying Dirac's Hamiltonian methods. In addition, an algebra of generators related to the global Lorentz group and the correspondence principle leading to a quantum version of the theory are also discussed. (author)
Homogeneous SPC/E water nucleation in large molecular dynamics simulations
Angelil, R; Tanaka, K; Tanaka, H
2015-01-01
We perform direct large molecular dynamics simulations of homogeneous SPC/E water nucleation, using up to $\\sim 4\\cdot 10^6$ molecules. Our large system sizes allow us to measure extremely low and accurate nucleation rates, down to $\\sim 10^{19}\\,\\textrm{cm}^{-3}\\textrm{s}^{-1}$, helping close the gap between experimentally measured rates $\\sim 10^{17}\\,\\textrm{cm}^{-3}\\textrm{s}^{-1}$. We are also able to precisely measure size distributions, sticking efficiencies, cluster temperatures, and cluster internal densities. We introduce a new functional form to implement the Yasuoka-Matsumoto nucleation rate measurement technique (threshold method). Comparison to nucleation models shows that classical nucleation theory over-estimates nucleation rates by a few orders of magnitude. The semi-phenomenological nucleation model does better, under-predicting rates by at worst, a factor of 24. Unlike what has been observed in Lennard-Jones simulations, post-critical clusters have temperatures consistent with the run avera...
Theory of hybrid systems; 1, The operator formulation of classical mechanics and semiclassical limit
Prvanovic, S
2001-01-01
The algebra of polynomials in operators that represent generalized coordinate and momentum and depend on the Planck constant is defined. The Planck constant is treated as the parameter taking values between zero and some nonvanishing $h_0$. For the second of these two extreme values, introduced operatorial algebra becomes equivalent to the algebra of observables of quantum mechanical system defined in the standard manner by operators in the Hilbert space. For the vanishing Planck constant, the generalized algebra gives the operator formulation of classical mechanics since it is equivalent to the algebra of variables of classical mechanical system defined, as usually, by functions over the phase space. In this way, the semiclassical limit of kinematical part of quantum mechanics is established through the generalized operatorial framework.
A concise course on the theory of classical liquids basics and selected topics
Santos, Andrés
2016-01-01
This short primer offers non-specialist readers a concise, yet comprehensive introduction to the field of classical fluids – providing both fundamental information and a number of selected topics to bridge the gap between the basics and ongoing research. In particular, hard-sphere systems represent a favorite playground in statistical mechanics, both in and out of equilibrium, as they represent the simplest models of many-body systems of interacting particles, and at higher temperature and densities they have proven to be very useful as reference systems for real fluids. Moreover, their usefulness in the realm of soft condensed matter has become increasingly recognized – for instance, the effective interaction among (sterically stabilized) colloidal particles can be tuned to almost perfectly match the hard-sphere model. These lecture notes present a brief, self-contained overview of equilibrium statistical mechanics of classical fluids, with special applications to both the structural and thermodynamic pr...
THE CLASSICAL BALLET METHODOLOGY AND THEIR POSSIBLE DIALOGUE WITH LABANIANAS THEORIES
Lanusse Sousa Jaime
2015-01-01
Establish a dialogue between a codified technique with other body techniques becomes a challenge when it comes to a tradition. Moths new avenues for the ballet teaching may move several problems found with respect to a hierarchy of knowledge. Ballet with its tradition and its stroked paths can be reorganized to build thinking and conscious bodies? The traditional classical technique transits other body language? Often there are more complex issues to think today in teaching and learning balle...
A Hamiltonian theory of adaptive resolution simulations of classical and quantum models of nuclei
Kreis, Karsten; Donadio, Davide; Kremer, Kurt; Potestio, Raffaello
2015-03-01
Quantum delocalization of atomic nuclei strongly affects the physical properties of low temperature systems, such as superfluid helium. However, also at room temperature nuclear quantum effects can play an important role for molecules composed by light atoms. An accurate modeling of these effects is possible making use of the Path Integral formulation of Quantum Mechanics. In simulations, this numerically expensive description can be restricted to a small region of space, while modeling the remaining atoms as classical particles. In this way the computational resources required can be significantly reduced. In the present talk we demonstrate the derivation of a Hamiltonian formulation for a bottom-up, theoretically solid coupling between a classical model and a Path Integral description of the same system. The coupling between the two models is established with the so-called Hamiltonian Adaptive Resolution Scheme, resulting in a fully adaptive setup in which molecules can freely diffuse across the classical and the Path Integral regions by smoothly switching their description on the fly. Finally, we show the validation of the approach by means of adaptive resolution simulations of low temperature parahydrogen. Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany.
Marsalek, Ondrej; Markland, Thomas E.
2016-02-01
Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost.
Marsalek, Ondrej; Markland, Thomas E
2016-02-01
Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost. PMID:26851913
International Nuclear Information System (INIS)
Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost
Energy Technology Data Exchange (ETDEWEB)
Marsalek, Ondrej; Markland, Thomas E., E-mail: tmarkland@stanford.edu [Department of Chemistry, Stanford University, Stanford, California 94305 (United States)
2016-02-07
Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ring polymer contraction scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive protonated and deprotonated water dimer systems. We find that the vast majority of the nuclear quantum effects are accurately captured using contraction to just the ring polymer centroid, which requires the same number of density functional theory calculations as a classical simulation. Combined with a multiple time step scheme using the same reference system, which allows the time step to be increased, this approach is as fast as a typical classical ab initio molecular dynamics simulation and 35× faster than a full path integral calculation, while still exactly including the quantum sampling of nuclei. This development thus offers a route to routinely include nuclear quantum effects in ab initio molecular dynamics simulations at negligible computational cost.
Veenendaal, van E.; Hoof, van P.J.C.M.; Suchtelen, van J.; Enckevort, van W.J.P.; Bennema, P.
1998-01-01
Kinetic roughening is not a phase transition and, as such, it lacks an exact definition. Many criteria are used to mark the onset of kinetic roughening. Criteria stemming from the classical two-dimensional nucleation theory are widely used. On the other hand, experimentalists observe a transition fr
Selected topics in the classical theory of functions of a complex variable
Heins, Maurice
2014-01-01
Elegant and concise, this text is geared toward advanced undergraduate students acquainted with the theory of functions of a complex variable. The treatment presents such students with a number of important topics from the theory of analytic functions that may be addressed without erecting an elaborate superstructure. These include some of the theory's most celebrated results, which seldom find their way into a first course. After a series of preliminaries, the text discusses properties of meromorphic functions, the Picard theorem, and harmonic and subharmonic functions. Subsequent topics incl
Masliukivska, A.
2013-01-01
The paper studies the evolution of the appearance of the term “innovation” and its classical definition. The study exposes the main provisions of innovation theory of Joseph Schumpeter and their modern understanding.
Directory of Open Access Journals (Sweden)
A. Masliukivska
2013-03-01
Full Text Available The paper studies the evolution of the appearance of the term “innovation” and its classical definition. The study exposes the main provisions of innovation theory of Joseph Schumpeter and their modern understanding.
Classical Electron Model with Negative Energy Density in Einstein-Cartan Theory of Gravitation
Ray, Saibal; Bhadra, Sumana
2002-01-01
Experimental result regarding the maximum limit of the radius of the electron \\sim 10^{-16} cm and a few of the theoretical works suggest that the gravitational mass which is a priori a positive quantity in Newtonian mechanics may become negative in general theory of relativity. It is argued that such a negative gravitational mass and hence negative energy density also can be obtained with a better physical interpretation in the framework of Einstein-Cartan theory.
Popa, Alexandru
2013-01-01
Quantum and Classical Connections in Modeling Atomic, Molecular and Electrodynamic Systems is intended for scientists and graduate students interested in the foundations of quantum mechanics and applied scientists interested in accurate atomic and molecular models. This is a reference to those working in the new field of relativistic optics, in topics related to relativistic interactions between very intense laser beams and particles, and is based on 30 years of research. The novelty of this work consists of accurate connections between the properties of quantum equations and correspon
THE CLASSICAL BALLET METHODOLOGY AND THEIR POSSIBLE DIALOGUE WITH LABANIANAS THEORIES
Directory of Open Access Journals (Sweden)
Lanusse Sousa Jaime
2015-12-01
Full Text Available Establish a dialogue between a codified technique with other body techniques becomes a challenge when it comes to a tradition. Moths new avenues for the ballet teaching may move several problems found with respect to a hierarchy of knowledge. Ballet with its tradition and its stroked paths can be reorganized to build thinking and conscious bodies? The traditional classical technique transits other body language? Often there are more complex issues to think today in teaching and learning ballet . These issues translate my need to research and experiment with new ways to teach this technique.
Field theory and weak Euler-Lagrange equation for classical particle-field systems
Energy Technology Data Exchange (ETDEWEB)
Qin, Hong [PPPL; Burby, Joshua W [PPPL; Davidson, Ronald C [PPPL
2014-10-01
It is commonly believed that energy-momentum conservation is the result of space-time symmetry. However, for classical particle-field systems, e.g., Klimontovich-Maxwell and Klimontovich- Poisson systems, such a connection hasn't been formally established. The difficulty is due to the fact that particles and the electromagnetic fields reside on different manifolds. To establish the connection, the standard Euler-Lagrange equation needs to be generalized to a weak form. Using this technique, energy-momentum conservation laws that are difficult to find otherwise can be systematically derived.
Narayan, K. Lakshmi; Kelton, K. F.; Ray, C. S.
1996-01-01
Heterogeneous nucleation and its effects on the crystallization of lithium disilicate glass containing small amounts of Pt are investigated. Measurements of the nucleation frequencies and induction times with and without Pt are shown to be consistent with predictions based on the classical nucleation theory. A realistic computer model for the transformation is presented. Computed differential thermal analysis data (such as crystallization rates as a function of time and temperature) are shown to be in good agreement with experimental results. This modeling provides a new, more quantitative method for analyzing calorimetric data.
International Nuclear Information System (INIS)
Bohmian mechanics is a quantum theory about particles in motion (i.e. about particle trajectories) that is empirically equivalent to orthodox quantum mechanics. Since also Newtonian mechanics is about particle trajectories, in Bohmian mechanics the question of the classical limit is as simple as it can possibly be: When do Bohmian trajectories look like Newtonian trajectories? As a first step towards an answer to this question we show, that the Bohmian trajectories belonging to a particular class of semiclassical wave packets become classical in an appropriate scaling limit. Furthermore, also the Bohmian trajectories of particles scattered on a short range potential become free in the classical sense: For large times their velocities tend to constants. We use this result to deduce the scattering cross section (the probability of detecting particles in a given solid angle) from first principles. In particular we show that, in the case of many particles, the collapse of the wave function due to the detection of one particle does not alter the remaining particles' detection statistics. (orig.)
Marsalek, Ondrej
2015-01-01
Path integral molecular dynamics simulations, combined with an ab initio evaluation of interactions using electronic structure theory, incorporate the quantum mechanical nature of both the electrons and nuclei, which are essential to accurately describe systems containing light nuclei. However, path integral simulations have traditionally required a computational cost around two orders of magnitude greater than treating the nuclei classically, making them prohibitively costly for most applications. Here we show that the cost of path integral simulations can be dramatically reduced by extending our ring polymer contraction approach to ab initio molecular dynamics simulations. By using density functional tight binding as a reference system, we show that our ab initio ring polymer contraction (AI-RPC) scheme gives rapid and systematic convergence to the full path integral density functional theory result. We demonstrate the efficiency of this approach in ab initio simulations of liquid water and the reactive pro...
Babikov, Dmitri; Semenov, Alexander
2016-01-28
A mixed quantum/classical approach to inelastic scattering (MQCT) is developed in which the relative motion of two collision partners is treated classically, and the rotational and vibrational motion of each molecule is treated quantum mechanically. The cases of molecule + atom and molecule + molecule are considered including diatomics, symmetric-top rotors, and asymmetric-top rotor molecules. Phase information is taken into consideration, permitting calculations of elastic and inelastic, total and differential cross sections for excitation and quenching. The method is numerically efficient and intrinsically parallel. The scaling law of MQCT is favorable, which enables calculations at high collision energies and for complicated molecules. Benchmark studies are carried out for several quite different molecular systems (N2 + Na, H2 + He, CO + He, CH3 + He, H2O + He, HCOOCH3 + He, and H2 + N2) in a broad range of collision energies, which demonstrates that MQCT is a viable approach to inelastic scattering. At higher collision energies it can confidently replace the computationally expensive full-quantum calculations. At low collision energies and for low-mass systems results of MQCT are less accurate but are still reasonable. A proposal is made for blending MQCT calculations at higher energies with full-quantum calculations at low energies. PMID:26618533
International Nuclear Information System (INIS)
The rule of additivity was first proposed by Scheil and Steinberg for predicting the incubation time for nucleation of solid phases during continuous-cooling phase transformations, and has since been widely used for both the nucleation incubation and the entire process of phase transformation. While having been successfully used to calculate the transformed volume fraction during continuous cooling in many steel alloy systems, there is experimental evidence that shows rule of additivity to be invalid for describing the incubation time for nucleation. Attempts to prove the validity of the rule of additivity for the incubation time have not met with much success, and much confusion still exists about its applicability to the incubation time. This article investigates the additivity of the consumption of the incubation time for nucleation during continuous cooling through an analysis based upon classical nucleation theory. It is rigorously demonstrated that the rule of additivity is invalid for the incubation time for nucleation. However, in practice, the relative error caused by using the rule of additivity could be very small in many cases due to the resolution limit of current experimental techniques. The present theory provides an explanation for the failure of the rule of additivity in predicting the incubation time for nucleation during continuous cooling. copyright 1997 American Institute of Physics
Mechanics and analysis of beams, columns and cables. A modern introduction to the classic theories
DEFF Research Database (Denmark)
Krenk, Steen
The book illustrates the use of simple mathematical analysis techniques within the area of basic structural mechanics, in particular the elementary theories of beams, columns and cables. The focus is on: i) Identification of the physical background of the theories and their particular mathematical...... properties. ii) Demonstration of mathematical techniques for analysis of simple problems in structural mechanics, and identification of the relevant parameters and properties of the solution. iii) Derivation of the solutions to a number of basic problems of structural mechanics in a form suitable for later...
Institute of Scientific and Technical Information of China (English)
李世荣; 万泽青; 张静华
2014-01-01
The free vibration of functionally graded material (FGM) beams is studied based on both the classical and the first-order shear deformation beam theories. The equations of motion for the FGM beams are derived by considering the shear deforma-tion and the axial, transversal, rotational, and axial-rotational coupling inertia forces on the assumption that the material properties vary arbitrarily in the thickness direction. By using the numerical shooting method to solve the eigenvalue problem of the coupled ordinary differential equations with different boundary conditions, the natural frequen-cies of the FGM Timoshenko beams are obtained numerically. In a special case of the classical beam theory, a proportional transformation between the natural frequencies of the FGM and the reference homogenous beams is obtained by using the mathematical similarity between the mathematical formulations. This formula provides a simple and useful approach to evaluate the natural frequencies of the FGM beams without dealing with the tension-bending coupling problem. Approximately, this analogous transition can also be extended to predict the frequencies of the FGM Timoshenko beams. The numerical results obtained by the shooting method and those obtained by the analogous transformation are presented to show the effects of the material gradient, the slenderness ratio, and the boundary conditions on the natural frequencies in detail.
The effects of fluid turbulence on metal vapor nucleation
Liu, Jun; Garrick, Sean
2010-11-01
The rising need for clean, renewable energy sources has led to recent studies on hydrogen production via hydrolysis of zinc nanoparticles. Aerosol or gas-phase processes are favored in many industrial applications due to its advantage in controlling particle size distribution and the resultant chemical conversion. The rising need for clean, renewable energy sources has led to recent studies on hydrogen production via hydrolysis of zinc nanoparticles. Aerosol or gas-phase processes are favored in many industrial applications due to its advantage in controlling particle size distribution and the resultant chemical conversion. In this work we study the formation of metal particles in a shear flows. Direct numerical simulation of homogeneous metal vapor nucleation in laminar and turbulent flows are performed for a variety of metals. The flows consist of hot metal vapor issuing into cooler inert gas. As the metal vapor cools, nanoparticles form and are transported throughout the flow-field. Homogeneous nucleation is simulated using classical nucleation theory and two approaches to representing the surface tension. The effects of three-dimensional turbulent mixing are also analyzed. The results suggest that fluid, thermal and species mixing greatly affects the nucleation dynamics. We report on the effects of vapor concentration level, fluid mixing, and particle surface tension on the conversion from metal vapor to metal nanoparticles.
Directory of Open Access Journals (Sweden)
S. Dobbie
2010-01-01
Full Text Available A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It was observed that the spread in the onset relative humidities with respect to ice (RHi for Saharan dust particles varied from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although the spread in the onset RHi for the three Saharan dust samples were in agreement, the active fractions and nucleation time-lags calculated at various temperature and RHi conditions were found to differ. This could be due to the subtle variation in the elemental composition of the dust samples, and surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities on the nucleability parameter, contact angle that is widely used in ice cloud modeling. These calculations show that the surface irregularities can reduce the contact angle by approximately 10 degrees.
What can we learn from the classical theory of Yang-Mills and Dirac fields
International Nuclear Information System (INIS)
Minimally coupled classical Yang-Mills and Dirac fields in the Minkowski space-time and in spatially bounded domains are investigated. The extended phase space, defined as the space of the Cauchy data admitting solutions of the evolution equations, is identified. The structure of the gauge symmetry group, defined as the group of all gauge transformations acting in the extended phase space is analysed. In the Minkowski space-time the Lie algebra of infinitesimal gauge symmetries has an ideal giving rise to the constraints. The quotient algebra, isomorphic to the structure algebra, labels the conserved colour charges. In the case of spatially bounded domains, each set of the boundary data gives rise to an extended phase space in which the evolution is Hamiltonian. The problem of a physical interpretation of the boundary data is discussed. (author)
On the limits of quantum theory: Contextuality and the quantum–classical cut
International Nuclear Information System (INIS)
This paper is based on four assumptions: 1. Physical reality is made of linearly behaving components combined in non-linear ways. 2. Higher level behaviour emerges from this lower level structure. 3. The way the lower level elements behaves depends on the context in which they are embedded. 4. Quantum theory applies to the lower level entities. An implication is that higher level effective laws, based on the outcomes of non-linear combinations of lower level linear interactions, will generically not be unitary; hence the applicability of quantum theory at higher levels is strictly limited. This leads to the view that both state vector preparation and the quantum measurement process are crucially based on top-down causal effects, and helps provide criteria for the Heisenberg cut that challenge some views on Schrödinger’s cat. - Highlights: ► Gives a framework for looking at emergence based on quantum theory. ► Considers how the linearity of quantum theory relates to complex systems. ► Emphasizes the interaction of bottom-up and top-down causation. ► Uses this to discuss the classical–quantum cut. ► Applies this to Schrödinger’s cat.
Hamiltonian approach to GR - Part 1: covariant theory of classical gravity
Cremaschini, Claudio
2016-01-01
A challenging issue in General Relativity concerns the determination of the manifestly-covariant continuum Hamiltonian structure underlying the Einstein field equations and the related formulation of the corresponding covariant Hamilton-Jacobi theory. The task is achieved by adopting a synchronous variational principle requiring distinction between the prescribed deterministic metric tensor $\\hat{g}(r)\\equiv \\left\\{ \\hat{g}_{\\mu \
N=4 super-Yang-Mills in LHC superspace. Part I: Classical and quantum theory
Chicherin, Dmitry
2016-01-01
We present a formulation of the maximally supersymmetric N=4 gauge theory in Lorentz harmonic chiral (LHC) superspace. It is closely related to the twistor formulation of the theory but employs the simpler notion of Lorentz harmonic variables. They parametrize a two-sphere and allow us to handle efficiently infinite towers of higher-spin auxiliary fields defined on ordinary space-time. In this approach the chiral half of N=4 supersymmetry is manifest. The other half is realized non-linearly and the algebra closes on shell. We give a straightforward derivation of the Feynman rules in coordinate space. We show that the LHC formulation of the N=4 super-Yang-Mills theory is remarkably similar to the harmonic superspace formulation of the N=2 gauge and hypermultiplet matter theories. In the twin paper \\cite{twin} we apply the LHC formalism to the study of the non-chiral multipoint correlation functions of the N=4 stress-tensor supermultiplet.
FEATURES OF INVESTMENT PROCESS UNDERSTANDING BY A. SMITH AS THE FOUNDER OF CLASSICAL THEORY
Directory of Open Access Journals (Sweden)
T. Ovcharenko
2013-03-01
Full Text Available The paper examines the essence and the nature of the concept of “investment”. The main conceptual elements of a scientific theory of Adam Smith are defined. The features of the investment process by Adam Smith as the driving mechanism for social and economic development of a society are revealed.
Comparison of 3D Classical Trajectory and Transition-State Theory Reaction Cross Sections
Koeppl, G. W.; Karplus, Martin
1970-10-01
Although there is excellent agreement for a system such as H+H{sub 2} --> H{sub 2}+H, in which both the potential and the particle masses are symmetric, significant deviations occur for more asymmetric reactions. A detailed analysis show that the calculated differences are from the violation of two assumptions of transition-state theory.
Philosophical Roots of Classical Grounded Theory: Its Foundations in Symbolic Interactionism
Aldiabat, Khaldoun M.; Le Navenec, Carole-Lynne
2011-01-01
Although many researchers have discussed the historical relationship between the Grounded Theory methodology and Symbolic Interactionism, they have not clearly articulated the congruency of their salient concepts and assumptions. The purpose of this paper is to provide a thorough discussion of this congruency. A hypothetical example about smoking…
Classical and quantum dynamics of two-dimensional nonlinear field theories: a review
International Nuclear Information System (INIS)
Progress in understanding and solving a large class of two-dimensional nonlinear quantum field theories is reviewed. The discovery and development of the inverse scattering method for solving partial differential equations, and development of new perturbative methods are discussed. The generalized Bethe-ansatz method and its application to exactly diagonalize a fermionic problem are covered. 52 references
Nucleation kinetics of paracetamol-ethanol solutions from metastable zone widths
Mitchell, Niall A.; Frawley, Patrick J.
2010-09-01
A study of the nucleation kinetics for a cooling crystallisation of paracetamol-ethanol solutions in a batch reactor is described in this paper. Metastable zone width (MSZW) experiments were conducted in order to estimate the nucleation kinetics of the system. Measured MSZWs can be affected by numerous process parameters, such as cooling rate, concentration, agitation rate, and working volume. Two theoretical approaches were employed to estimate the nucleation kinetics, the classical mass based approach of Nývlt, and a more recent approach by Kubota, which also considers number density. Both approaches were found to produce similar estimates for the nucleation rates of the paracetamol-ethanol solutions as a function of supersaturation for an assumed nucleus size of 10 μm. The theory of Kubota was found to predict satisfactory estimates for the induction time of the nucleation process from MSZW data. The induction time was observed to be independent of the solution temperature as suggested by Kubota's theory. This is a novel finding and serves to validate the induction time theory of Kubota. In this investigation, MSZWs were observed to decrease with increased levels of agitation and found to be independent of working volume.
Directory of Open Access Journals (Sweden)
Vinš Václav
2013-04-01
Full Text Available In this work, we used the density gradient theory (DGT combined with the cubic equation of state (EoS by Peng and Robinson (PR and the perturbed chain (PC modification of the SAFT EoS developed by Gross and Sadowski [1]. The PR EoS is based on very simplified physical foundations, it has significant limitations in the accuracy of the predicted thermodynamic properties. On the other hand, the PC-SAFT EoS combines different intermolecular forces, e.g., hydrogen bonding, covalent bonding, Coulombic forces which makes it more accurate in predicting of the physical variables. We continued in our previous works [2,3] by solving the boundary value problem which arose by mathematical solution of the DGT formulation and including the boundary conditions. Achieving the numerical solution was rather tricky; this study describes some of the crucial developments that helped us to overcome the partial problems. The most troublesome were computations for low temperatures where we achieved great improvements compared to [3]. We applied the GT for the n-alkanes: nheptane, n-octane, n-nonane, and n-decane because of the availability of the experimental data. Comparing them with our numerical results, we observed great differences between the theories; the best results gave the combination of the GT and the PC-SAFT. However, a certain temperature drift was observed that is not satisfactorily explained by the present theories.
Energy Technology Data Exchange (ETDEWEB)
Benhassine, B. [Nantes Univ., 44 (France)
1994-01-14
At intermediate energies the heavy ion collisions can be studied within the framework of a semi-classical approach based on the Vlasov-Uehling-Uhlenbeck (VUU) equation. Such an approach reduces the N-body problem to its description in terms of the one-body distribution function and constitutes the basis of several successful simulation models. Our aim in this work is to extend these average approaches to treat fluctuations. Within the framework of a linear approximation, we derived a Fokker-Planck transport equation in the one-body phase space. When it is reduced to its first moments, one recovers the VUU equation for the average dynamics together with the time evolution equation for the correlations. The collective transport coefficients are then obtained by projection on the one-body collective space. Independently, using a projection method introduced by Van Kampen, based on the constants of motion, we deduce the stationary expressions for the covariance matrix in phase space. We extract then, the equilibrium dispersions of one-body observables in a homogeneous case and in a spherical symmetric one. These results are compared with two types of simulation models in a relaxation time approximation. In the first one which is of Lagrangian type, the collective transport coefficients are directly extracted from the simulation and consequently the numerical fluctuations are washed out. The second model, due to its Eulerian character, allows us to make a microscopical comparison. (author) 58 refs.
New techniques for classic and quantum investigations on supersymmetry and supergravity theories
International Nuclear Information System (INIS)
Aspects on supersymmetry and supergravity are studied. The superfield Feynman rules are obtained, where global supersymmetry is spontaneously broken by F-terms. The complete superspace dependence of superpropagators is factored out, which are used to discuss corrections for the effective action and the non-renormalization theorems. The external gauge superfield coupling, taking in account the finite matter contributions to the gauging mass and the Fayet-Illiopoulos term, is discussed. By considering, the arbitrary globally supersymmetric Abelian gauge theory, the most general shifts on the matter and gauge superfields are carried out. The superpropagators are derived and used to discuss the structure of the terms generated into the effective action. An algorithm to obtain the minimal set of auxiliary field for the femionic of supergravity theories. Explicit examples are shown as illustrations and the N=1, N=10, studied in detail. (M.C.K.)
Young, Matthew B
2016-01-01
We introduce a new class of representations of the cohomological Hall algebras of Kontsevich and Soibelman which we call cohomological Hall modules, or CoHM for short. These representations are constructed from self-dual representations of a quiver with contravariant involution $\\sigma$ and provide a mathematical model for the space of BPS states in orientifold string theory. We use the CoHM to define a generalization of cohomological Donaldson-Thomas theory of quivers which allows the quiver representations to have orthogonal and symplectic structure groups. The associated invariants are called orientifold Donaldson-Thomas invariants. We prove the integrality conjecture for orientifold Donaldson-Thomas invariants of $\\sigma$-symmetric quivers. We also formulate precise conjectures regarding the geometric meaning of these invariants and the freeness of the CoHM of a $\\sigma$-symmetric quiver. We prove the freeness conjecture for disjoint union quivers, loop quivers and the affine Dynkin quiver of type $\\widet...
Vasques, Richard
2013-01-01
This paper extends a recently introduced theory describing particle transport for random statistically homogeneous systems in which the distribution function p(s) for chord lengths between scattering centers is non-exponential. Here, we relax the previous assumption that p(s) does not depend on the direction of flight \\Omega; this leads to an extended generalized linear Boltzmann equation that includes angular-dependent cross sections, and to an extended generalized diffusion equation that accounts for anisotropic behavior resulting from the statistics of the system.
Equations of motion in Double Field Theory: from classical particles to quantum cosmology
Kan, Nahomi; Shiraishi, Kiyoshi
2012-01-01
The equation of motion for a point particle in the background field of double field theory is considered. We find that the motion is described by a geodesic flow in the doubled geometry. Inspired by analysis on the particle motion, we propose a modified model of quantum string cosmology, which includes two scale factors. The report is based on Phys. Rev. D84 (2011) 124049 [arXiv:1108.5795].
Cisne, John L.; Ziomkowski, Robert M.; Schwager, Steven J.
2010-01-01
Philologists reconstructing ancient texts from variously miscopied manuscripts anticipated information theorists by centuries in conceptualizing information in terms of probability. An example is the editorial principle difficilior lectio potior (DLP): in choosing between otherwise acceptable alternative wordings in different manuscripts, “the more difficult reading [is] preferable.” As philologists at least as early as Erasmus observed (and as information theory's version of the second law o...
Sidles, J A; Dougherty, W M; Chao Shang Huang
2000-01-01
A general theory of thermal magnetic fluctuations near conductive materials is developed; such fluctuations are the magnetic analog of Johnson noise. For realistic experiments in quantum computing and magnetic resonance force microscopy, the predicted relaxation can be rapid enough that substantial experimental care should be taken to minimize it. The same Hamiltonian matrix elements that govern fluctuation and dissipation are shown to also govern entanglement and renormalization, and a specific example of a fluctuation-dissipation-entanglement theorem is constructed.
Information-theory-based solution of the inverse problem in classical statistical mechanics
D'Alessandro, Marco; Cilloco, Francesco
2010-01-01
We present a procedure for the determination of the interaction potential from the knowledge of the radial pair distribution function. The method, realized inside an inverse Monte Carlo simulation scheme, is based on the application of the Maximum Entropy Principle of information theory and the interaction potential emerges as the asymptotic expression of the transition probability. Results obtained for high density monoatomic fluids are very satisfactory and provide an accurate extraction of...
Institute of Scientific and Technical Information of China (English)
李小华; 黄锦凡
2003-01-01
Molecular dynamics computer simulation based on the Born-Mayer-Huggins potential function has been carried out to study the effects of duster size and temperature on the nucleation rate of sodium chloride dusters in the temperature range of 580 K to 630 K. Clusters with 256 and 500 NaCl molecules have been studied and the results have been compared with those obtained from 108 molecule dusters. The melting point (MP) of the clusters were observed to increase with the size of the clusters and can be well described by a linear equation MP =1107(37)-1229(23)N-1/3(N is the number of molecules in the duster).The nucleation rate was found to decrease with increasing the duster size or temperature. Various nucleation theories have been used to interpret the nucleation rates obtained from this molecular dynamics simulation. It is possible to use a constant diffuse interface thickness to interpret the nucleation rate from the diffuse interface theory in the temperature range of this study. However, the interfacinl free energy estimated from classical nucleation theory and diffuse interface theory increases too fast with increasing the temperature while that from Gran-Gunton theory does not change with changing temperatures.The sizes of critical nuclei estimated from all the theories are smaller than those estimated from our simulations.
Li, J. H.; Albu, M.; Ludwig, T. H.; Hofer, F.; Arnberg, L.; Schumacher, P.
2016-03-01
Entrained droplet technique and DSC analyses were employed to investigate the influence of trace elements of Sr, Eu and P on the heterogeneous nucleation of entrained eutectic Si in high purity melt spun Al-5wt.% Si alloys. Sr and Eu addition was found to exert negative effects on the nucleation process, while an increased undercooling was observed. This can be attributed to the formation of phosphide compounds having a lower free energy and hence may preferentially form compared to AlP. Only a trace P addition was found to have a profound effect on the nucleation process. The nucleation kinetics is discussed on the basis of the classical nucleation theory and the free growth model, respectively. The estimated AlP patch size was found to be sufficient for the free growth of Si to occur within the droplets, which strongly indicates that the nucleation of Si on an AlP patch or AlP particle is a limiting step for free growth. The maximum nucleation site density within one droplet is directly related to the size distribution of AlP particles or AlP patches for Si nucleation, but is independent of the cooling rates. Although the nucleation conditions were optimized in entrained droplet experiments, the observed mechanisms are also valid at moderate cooling conditions, such as in shape casting.
Molecular dynamics simulations of bubble nucleation in dark matter detectors.
Denzel, Philipp; Diemand, Jürg; Angélil, Raymond
2016-01-01
Bubble chambers and droplet detectors used in dosimetry and dark matter particle search experiments use a superheated metastable liquid in which nuclear recoils trigger bubble nucleation. This process is described by the classical heat spike model of F. Seitz [Phys. Fluids (1958-1988) 1, 2 (1958)PFLDAS0031-917110.1063/1.1724333], which uses classical nucleation theory to estimate the amount and the localization of the deposited energy required for bubble formation. Here we report on direct molecular dynamics simulations of heat-spike-induced bubble formation. They allow us to test the nanoscale process described in the classical heat spike model. 40 simulations were performed, each containing about 20 million atoms, which interact by a truncated force-shifted Lennard-Jones potential. We find that the energy per length unit needed for bubble nucleation agrees quite well with theoretical predictions, but the allowed spike length and the required total energy are about twice as large as predicted. This could be explained by the rapid energy diffusion measured in the simulation: contrary to the assumption in the classical model, we observe significantly faster heat diffusion than the bubble formation time scale. Finally we examine α-particle tracks, which are much longer than those of neutrons and potential dark matter particles. Empirically, α events were recently found to result in louder acoustic signals than neutron events. This distinction is crucial for the background rejection in dark matter searches. We show that a large number of individual bubbles can form along an α track, which explains the observed larger acoustic amplitudes. PMID:26871185
Dahms, Rainer N.
2016-04-01
A generalized framework for multi-component liquid injections is presented to understand and predict the breakdown of classic two-phase theory and spray atomization at engine-relevant conditions. The analysis focuses on the thermodynamic structure and the immiscibility state of representative gas-liquid interfaces. The most modern form of Helmholtz energy mixture state equation is utilized which exhibits a unique and physically consistent behavior over the entire two-phase regime of fluid densities. It is combined with generalized models for non-linear gradient theory and for liquid injections to quantify multi-component two-phase interface structures in global thermal equilibrium. Then, the Helmholtz free energy is minimized which determines the interfacial species distribution as a consequence. This minimal free energy state is demonstrated to validate the underlying assumptions of classic two-phase theory and spray atomization. However, under certain engine-relevant conditions for which corroborating experimental data are presented, this requirement for interfacial thermal equilibrium becomes unsustainable. A rigorously derived probability density function quantifies the ability of the interface to develop internal spatial temperature gradients in the presence of significant temperature differences between injected liquid and ambient gas. Then, the interface can no longer be viewed as an isolated system at minimal free energy. Instead, the interfacial dynamics become intimately connected to those of the separated homogeneous phases. Hence, the interface transitions toward a state in local equilibrium whereupon it becomes a dense-fluid mixing layer. A new conceptual view of a transitional liquid injection process emerges from a transition time scale analysis. Close to the nozzle exit, the two-phase interface still remains largely intact and more classic two-phase processes prevail as a consequence. Further downstream, however, the transition to dense-fluid mixing
Wiesendanger, C.
2011-01-01
Viewing gravitational energy-momentum $p_G^\\mu$ as equal by observation, but different in essence from inertial energy-momentum $p_I^\\mu$ naturally leads to the gauge theory of volume-preserving diffeormorphisms of an inner Minkowski space ${\\bf M}^{\\sl 4}$. To extract its physical content the full gauge group is reduced to its Poincar\\'e subgroup. The respective Poincar\\'e gauge fields, field strengths and Poincar\\'e-covariant field equations are obtained and point-particle source currents a...
Classical self-dual strings in d=6, (2,0) theory from afar
Gustavsson, Andreas(Physics Department, University of Seoul, Seoul, 130-743, Korea)
2002-01-01
We show how one can get solitonic strings in a six-dimensional (2,0) supersymmetric theory by incorporating a nonlinear interaction term. We derive a zero force condition between parallel strings, and compute a metric on a moduli space which is $R^4$ when the strings are far apart. When compactifying the strings on a two-torus we show that, in the limit of vanishing two-torus, one regains the moduli space of two widely separated dyons of equal magnetic charges in four dimensions.
Interpreting nowhere dense graph classes as a classical notion of model theory
Adler, H; Adler, I
2014-01-01
A class of graphs is nowhere dense if for every integer r there is a finite upper bound on the size of complete graphs that occur as r-minors. We observe that this recent tameness notion from (algorithmic) graph theory is essentially the earlier stability theoretic notion of superflatness. For subgraph-closed classes of graphs we prove equivalence to stability and to not having the independence property. Expressed in terms of PAC learning, the concept classes definable in first-order logic in...
Directory of Open Access Journals (Sweden)
J.-P. Chen
2008-12-01
Full Text Available The rate of ice nucleation in clouds is not easily determined and large discrepancies exist between model predictions and actual ice crystal concentration measured in clouds. In an effort to improve the parameterization of ice nucleating in cloud models, we investigate the rate of heterogeneous ice nucleation under specific ambient conditions by knowing the sizes as well as two thermodynamic parameters of the ice nuclei – contact angle and activation energy. Laboratory data of freezing and deposition nucleation modes were analyzed to derive inversely the two thermodynamic parameters for a variety of ice nuclei, including mineral dusts, bacteria, pollens, and soot particles. The analysis considered the Zeldovich factor for the adjustment of ice germ formation, as well as the solute and curvature effects on surface tension; the latter effects have strong influence on the contact angle. Contact angle turns out to be a more important factor than the activation energy in discriminating the nucleation capabilities of various ice nuclei species. By extracting these thermodynamic parameters, laboratory results can be converted into a formulation that follows classical nucleation theory, which then has the flexibility of incorporating factors such as the solute effect and curvature effect that were not considered in the experiments. Due to various uncertainties, contact angle and activation energy derived in this study should be regarded as "apparent" thermodynamics parameters.
Investigating heterogeneous nucleation in peritectic materials via the phase-field method
International Nuclear Information System (INIS)
Here we propose a phase-field approach to investigate the influence of convection on peritectic growth as well as the heterogeneous nucleation kinetics of peritectic systems. For this purpose we derive a phase-field model for peritectic growth taking into account fluid flow in the melt, which is convergent to the underlying sharp interface problem in the thin interface limit (Karma and Rappel 1996 Phys. Rev. E 53 R3017). Moreover, we employ our new phase-field model to study the heterogeneous nucleation kinetics of peritectic material systems. Our approach is based on a similar approach towards homogeneous nucleation in Granasy et al (2003 Interface and Transport Dynamics (Springer Lecture Notes in Computational Science and Engineering vol 32) ed Emmerich et al (Berlin: Springer) p 190). We applied our model successfully to extend the nucleation rate predicted by classical nucleation theory for an additional morphological term relevant for peritectic growth. Further applications to understand the mechanisms and consequences of heterogeneous nucleation kinetics in more detail are discussed
Decoherence and the Appearance of a Classical World in Quantum Theory
International Nuclear Information System (INIS)
In the last decade decoherence has become a very popular topic mainly due to the progress in experimental techniques which allow monitoring of the process of decoherence for single microscopic or mesoscopic systems. The other motivation is the rapid development of quantum information and quantum computation theory where decoherence is the main obstacle in the implementation of bold theoretical ideas. All that makes the second improved and extended edition of this book very timely. Despite the enormous efforts of many authors decoherence with its consequences still remains a rather controversial subject. It touches on, namely, the notoriously confusing issues of quantum measurement theory and interpretation of quantum mechanics. The existence of different points of view is reflected by the structure and content of the book. The first three authors (Joos, Zeh and Kiefer) accept the standard formalism of quantum mechanics but seem to reject orthodox Copenhagen interpretation, Giulini and Kupsch stick to both while Stamatescu discusses models which go beyond the standard quantum theory. Fortunately, most of the presented results are independent of the interpretation and the mathematical formalism is common for the (meta)physically different approaches. After a short introduction by Joos followed by a more detailed review of the basic concepts by Zeh, chapter 3 (the longest chapter) by Joos is devoted to the environmental decoherence. Here the author considers mostly rather 'down to earth' and well-motivated mechanisms of decoherence through collisions with atoms or molecules and the processes of emission, absorption and scattering of photons. The issues of decoherence induced superselection rules and localization of objects including the possible explanation of the molecular structure are discussed in details. Many other topics are also reviewed in this chapter, e.g., the so-called Zeno effect, relationships between quantum chaos and decoherence, the role of
The Super-Natural Supersymmetry and Its Classic Example: M-Theory Inspired NMSSM
Li, Tianjun; Wang, Xiao-Chuan
2015-01-01
We briefly review the super-natural supersymmetry (SUSY), which provides a most promising solution to the SUSY electroweak fine-tuning problem. In particular, we address its subtle issues as well. Unlike the Minimal Supersymmetric Standard model (MSSM), the Next to MSSM (NMSSM) can be scale invariant and has no mass parameter in its Lagrangian before SUSY and gauge symmetry breakings. Therefore, the NMSSM is a perfect framework for super-natural SUSY. To give the SUSY breaking soft mass to the singlet, we consider the moduli and dilaton dominant SUSY breaking scenarios in M-theory on $S^1/Z_2$. In these scenarios, SUSY is broken by one and only one $F$-term of moduli or dilaton, and the SUSY breaking soft terms can be determined via the K\\"ahler potential and superpotential from Calabi-Yau compactification of M-theory on $S^1/Z_2$. Thus, as predicted by super-natural SUSY, the SUSY electroweak fine-tuning measure is of unity order. In the moduli dominant SUSY breaking scenario, the right-handed sleptons are r...
Wrochna, Michał
2014-01-01
We investigate linearized gauge theories on globally hyperbolic spacetimes in the BRST formalism. A consistent definition of the classical phase space and of its Cauchy surface analogue is proposed. We prove it is isomorphic to the phase space in the subsidiary condition approach of Hack and Schenkel in the case of Maxwell, Yang-Mills, and Rarita-Schwinger fields. Defining Hadamard states in the BRST formalism in a standard way, their existence in the Maxwell and Yang-Mills case is concluded from known results in the subsidiary condition (or Gupta-Bleuler) formalism. Within our framework, we also formulate criteria for non-degeneracy of the phase space in terms of BRST cohomology and discuss special cases. These include an example in the Yang-Mills case, where degeneracy is not related to a non-trivial topology of the Cauchy surface.
Revisiting Classical Theories on Quality Management%质量管理经典理论再启示
Institute of Scientific and Technical Information of China (English)
牟慈
2015-01-01
质量是企业的立身之本。重温质量管理经典理论，为增强企业整体质量管理意识，创新管理理念，提升全员质量管理水平夯实理论基础，让中国石化“质量永远领先一步”。%Quality is fundamental to the development of companies. Revisiting classical theories on quality management can facilitate a more solid theoretical basis for the company’s efforts to improve its overall quality management awareness, innovate management philosophies and elevate total quality management level, thereby always keeping SINOPEC“a step ahead in quality”.
Core structure of a screw dislocation in Ti from density functional theory and classical potentials
International Nuclear Information System (INIS)
Previous density functional theory (DFT) studies of the 1/3 〈12¯10〉 screw dislocation in titanium have shown metastable core structures depending on the initial position of the dislocation line. We investigate this problem by modeling a screw dislocation with two initial positions using both DFT and a modified embedded atom (MEAM) potential for Ti with flexible boundary conditions. Both DFT and MEAM produce initial-position-dependent core structures. The MEAM potential stacking fault energies and core structures are in good agreement with DFT. MEAM potential computes the core energies and shows the behavior of both cores under applied strain. We found that the higher-energy core always reconstructs into the lower-energy one independent of the applied strain direction. Transformation from low- to high-energy core was not observed. Therefore, at T = 0 K, only the low-energy core is stable under applied strain.
On the limits of quantum theory: contextuality and the quantum-classical cut
Ellis, George F R
2011-01-01
This paper is based on four assumptions: 1. Physical reality is made of linearly behaving components combined in non-linear ways. 2. Higher level behaviour emerges from this lower level structure. 3. The way the lower level elements behaves depends on the context in which they are imbedded. 4. Quantum theory applies to the lower level entities. An implication is that higher level effective laws, based in the outcomes of non-linear combinations of lower level linear interactions, will generically not be unitary. This leads to the view that both state vector preparation and the quantum measurement process are crucially based in top-down causal effects, supports the contention that the flow of time is real, and helps provide criteria for the Heisenberg cut that challenge some views on Schroedinger's cat and the existence of the wave function of the universe.
Dynamical systems with classical spin in the Einstein-Maxwell-Cartan theory
International Nuclear Information System (INIS)
By using variational precedures, spinning charged particles and fluids, with magnetic dipole moment, are analysed. Electromagnetic and gravitational interactions are also dynamically considered. A relativistic formalism which describes the space-time as a Riemann-Cartan manifold caraccterized by curvature and torsion tensors was adopted. The specific features of the Einstein-Maxell-Cartan theory have been analised in detail for the considered models. Also the holonomy of the local Lorentz Frames and constraints has been studied, and as a consequence it has been possible to generate new equations of motion for particles with spin. It has also been possible to derive the complete differential system which includes the fluid, the electromagnetic, the curvature and the torsion fields. (author)
Supernatural supersymmetry and its classic example: M-theory inspired NMSSM
Li, Tianjun; Raza, Shabbar; Wang, Xiao-Chuan
2016-06-01
We briefly review the supernatural supersymmetry (SUSY), which provides a most promising solution to the SUSY electroweak fine-tuning problem. In particular, we address its subtle issues as well. Unlike the minimal supersymmetric standard model (MSSM), the next to MSSM (NMSSM) can be scale invariant and has no mass parameter in its Lagrangian before SUSY and gauge symmetry breakings. Therefore, the NMSSM is a perfect framework for supernatural SUSY. To give the SUSY breaking soft mass to the singlet, we consider the moduli and dilaton dominant SUSY breaking scenarios in M-theory on S1/Z2. In these scenarios, SUSY is broken by one and only one F term of moduli or dilaton, and the SUSY breaking soft terms can be determined via the Kähler potential and superpotential from Calabi-Yau compactification of M-theory on S1/Z2. Thus, as predicted by supernatural SUSY, the SUSY electroweak fine-tuning measure is of unity order. In the moduli dominant SUSY breaking scenario, the right-handed sleptons are relatively light around 1 TeV, stau can even be as light as 580 GeV and degenerate with the lightest neutralino, chargino masses are larger than 1 TeV, the light stop masses are around 2 TeV or larger, the first two-generation squark masses are about 3 TeV or larger, and gluinos are heavier tha.n squarks. In the dilaton dominant SUSY breaking scenario, the qualitative picture remains the same but we have heavier spectra as compared to the moduli dominant SUSY breaking scenario. In addition to it, we have Higgs H2/A1-resonance solutions for dark matter (DM). In both scenarios, the minimal value of DM relic density is about 0.2. To obtain the observed DM relic density, we can consider the dilution effect from supercritical string cosmology or introduce the axino as the lightest supersymmetric particle.
Chan, Ho Yin; Lubchenko, Vassiliy
2015-09-28
We set up the problem of finding the transition state for phase nucleation in multi-component fluid mixtures, within the Landau-Ginzburg density functional. We establish an expression for the coordinate-dependent local pressure that applies to mixtures, arbitrary geometries, and certain non-equilibrium configurations. The expression allows one to explicitly evaluate the pressure in spherical geometry, à la van der Waals. Pascal's law is recovered within the Landau-Ginzburg density functional theory, formally analogously to how conservation of energy is recovered in the Lagrangian formulation of mechanics. We establish proper boundary conditions for certain singular functional forms of the bulk free energy density that allow one to obtain droplet solutions with thick walls in essentially closed form. The hydrodynamic modes responsible for mixing near the interface are explicitly identified in the treatment; the composition at the interface is found to depend only weakly on the droplet size. Next we develop a Landau-Ginzburg treatment of the effects of amphiphiles on the surface tension; the amphiphilic action is seen as a violation of Pascal's law. We explicitly obtain the binding potential for the detergent at the interface and the dependence of the down-renormalization of the surface tension on the activity of the detergent. Finally, we argue that the renormalization of the activation barrier for escape from long-lived structures in glassy liquids can be viewed as an action of uniformly seeded, randomly oriented amphiphilic molecules on the interface separating two dissimilar aperiodic structures. This renormalization is also considered as a "wetting" of the interface. The resulting conclusions are consistent with the random first order transition theory. PMID:26429019
Direct Calculation of Ice Homogeneous Nucleation Rate for a Molecular Model of Water
Haji-Akbari, Amir
2015-01-01
Ice formation is ubiquitous in nature, with important consequences in a variety of systems and environments, including biological cells [1], soil [2], aircraft [3], transportation infrastructure [4] and atmospheric clouds [5,6]. However, its intrinsic kinetics and microscopic mechanism are difficult to discern with current experiments. Molecular simulations of ice nucleation are also challenging, and direct rate calculations have only been performed for coarse-grained models of water [7-9]. For the more realistic molecular models, only indirect estimates have been obtained, e.g.~by assuming the validity of classical nucleation theory [10]. Here, we use a path sampling approach to perform the first direct rate calculation of homogeneous nucleation of ice in a molecular model of water. We use TIP4P/Ice [11], the most accurate among the existing molecular models for studying ice polymorphs. By using a novel topological order parameter for distinguishing different polymorphs, we are able to identify a freezing me...
Directory of Open Access Journals (Sweden)
John L Cisne
Full Text Available Philologists reconstructing ancient texts from variously miscopied manuscripts anticipated information theorists by centuries in conceptualizing information in terms of probability. An example is the editorial principle difficilior lectio potior (DLP: in choosing between otherwise acceptable alternative wordings in different manuscripts, "the more difficult reading [is] preferable." As philologists at least as early as Erasmus observed (and as information theory's version of the second law of thermodynamics would predict, scribal errors tend to replace less frequent and hence entropically more information-rich wordings with more frequent ones. Without measurements, it has been unclear how effectively DLP has been used in the reconstruction of texts, and how effectively it could be used. We analyze a case history of acknowledged editorial excellence that mimics an experiment: the reconstruction of Lucretius's De Rerum Natura, beginning with Lachmann's landmark 1850 edition based on the two oldest manuscripts then known. Treating words as characters in a code, and taking the occurrence frequencies of words from a current, more broadly based edition, we calculate the difference in entropy information between Lachmann's 756 pairs of grammatically acceptable alternatives. His choices average 0.26+/-0.20 bits higher in entropy information (95% confidence interval, P = 0.005, as against the single bit that determines the outcome of a coin toss, and the average 2.16+/-0.10 bits (95% of (predominantly meaningless entropy information if the rarer word had always been chosen. As a channel width, 0.26+/-0.20 bits/word corresponds to a 0.790.79(+0.09 (-0.15 likelihood of the rarer word being the one accepted in the reference edition, which is consistent with the observed 547/756 = 0.72+/-0.03 (95%. Statistically informed application of DLP can recover substantial amounts of semantically meaningful entropy information from noise; hence the extension copiosior
Henderson, R. L.
1974-01-01
The partial structure factors of classical simple liquid mixtures near phase separation are dicussed. The theory is developed for particles interacting through pair potentials, and is thus appropriate both to insulating fluids, and also to metallic systems if these may be described by an effective ion-ion pair interaction. The motivation arose from consideration of metallic liquid mixtures, in which resistive anomalies have been observed near phase separation. A mean field theory correction appropriate to 3 pair potential for the effects of correlated motions in the reference fluid is studied. The work is cast in terms of functions which are closely related to the direct correlation functions of Ornstein and Zernike. The results are qualitatively in accord with physical expectations. Quantitative agreement with experiment seems to turn on the selection of the hard core reference potential in terms of the metallic effective pair potential. It is suggested that the present effective pair potentials are perhaps not properly used to calculate the metallic structure factors at long wavelength.
Relativistic semi-classical theory of atom ionization in ultra-intense laser
Institute of Scientific and Technical Information of China (English)
CHEN; Baozhen
2001-01-01
［1］Schoch, A., Seitliche Versetzung eines total reflektierten strahles bei Utraschallwellen, Acustica, 1952, 2: 17.［2］Neubauer, W. G., Ultrasonic reflection of a bounded beam at Rayleigh and critical angles for a plane liquid-solid interface, J. Appl. Phys., 1973, 44: 48.［3］Ngoc, T. D. K., Mayer, W. G., Numerical integration method for reflected beam profiles near Rayleigh angle, J. Acoust. Soc. Am., 1980, 67, 1149.［4］Nagy, P. B., Cho, K., Focal shift of convergent ultrasonic beams reflected from a liquid-solid interface, J. Acoust. Soc. Am., 1987, 81(4): 835.［5］Bertoni, H. L., Hsue, C. W., Tamir, T., Non-specular reflection of convergent beams from liquid-solid interface, Traitement du Signal, 1985, 2: 201.［6］Zhu Guozhen, Liu Liang, Fu Deyong, Reflected beam displacements of a slightly divergent ultrasonic Gaussian beam on a water-glass interface near Rayleigh angle incidence, Chinese Physics Letters, 1999, 16(11): 819.［7］Bertoni, H. L., Tamir, T., Unified theory of Rayleigh-angle phenomena for acoustic beams onto liquid-solid interface, Appl. Phys., 1973, 2: 157.［8］Zeroug, S., Felsen, L. B., Nonspecular reflection of two- and three-dimensional acoustic beams from fluid-immersed plane-layered elastic structures, J. Acoust. Soc. Am., 1994, 95: 3075.［9］Chimenti, D. E., Zeroug, S. et al., Interaction of acoustic beams with fluid-loaded elastic structures, J. Acoust. Soc. Am., 1994, 95(1): 45.［10］Breazeale, M. A. L., Adler, L., Scott, G. W., Interaction of ultrasonic waves incident at the Rayleigh angle onto a liquid-solid interface, J. Appl. Phys., 1977, 48(2): 530.［11］Ngoc, T. D. K., Mayer, W. G., General description of ultrasonic nonspecular reflection and transmission effects for layered media, IEEE Trans. Sonics Ultrason., 1980, SU-27: 229.［12］Martin, F. D., Breazeale, M. A., J. Acoust. Soc. Am., 1971, 49: 1668.［13］Gunarathne, G. P. P., Szilard, J., A new stroboscope for Schlieren and photoelastic visualization
Kooi, BJ
2004-01-01
Monte Carlo (MC) simulations of isothermal phase transformations were performed based on a temperature- and time-dependent nucleation rate and a temperature-dependent and time-independent anisotropic growth rate (linear growth). One- or two-dimensional anisotropic growth in two-dimensional space is considered and nucleation occurs randomly throughout space. The MC simulations show that parallel growth of anisotropically growing transformation products with identical convex shape can be descri...
The Impact of Technology and Distance Education: A Classical Learning Theory Viewpoint
Directory of Open Access Journals (Sweden)
Herb Thompson
1999-01-01
Full Text Available For the past two years the author has been teaching economics (History of Economic Thought and Economic Development at the tertiary level via the Internet and computer-mediation. This is done primarily for students who are unable or who do not wish to attend classes on campus, but desire an education as good, if not better, as the campus based enterprise. This paper provides a reflective analysis of the theoretical content of that practice. Teaching online is a vastly different enterprise than face-to-face exercises, thereby demanding a revaluation of ones pedagogical theory and praxis. In The German Ideology, Marx and Engels articulated their claim that historically dominant classes embody their ideas in essential forms, representing them as universally valid. It is within this framework that we begin to examine what it means to "know" in economics. How knowledge is legitimated in universities continues to be under-theorised, particularly with regard to electronic transmission. The mechanism of transmission of particular concern here is that which is computer-mediated. Landow represents hypertext as the latest flowering in a long march of democratic processes originating in the displacement of Platonic authority by the lesser authority of the written word. It is argued here that the determinism of the "progressive narrative" within and around the "hypertext revolution" deserves careful scrutiny, particularly in its application to pedagogy. Pedagogical artefacts, such as computers, mediate the transmission of ideas. The question "how does this happen?" relates to the complexity of theorizing the relationship between the educational process and the social relations of capitalist social formations. Over two decades ago, Bowles and Gintis attempted a Marxist understanding of the nature of this relationship. In their conception, pedagogical mechanisms were seen to operate in a fairly deterministic way to mirror and model the norms and values
International Nuclear Information System (INIS)
A review of tachyons, with particular attention to their classical theory, is presented. The extension of Special Relativity to tachyons in two dimensional is first presented, an elegant model-theory which allows a better understanding also of ordinary physics. Then, the results are extended to the four-dimensional case (particular on tachyon mechanics) that can be derived without assuming the existence of Super-luminal reference-frames. Localizability and the unexpected apparent shape of tachyonic objects are discussed, and it is shown (on the basis of tachyon kinematics) how to solve the common causal paradoxes. In connection with General Relativity, particularly the problem of the apparent superluminal expansions in astrophysics is reviewed. The problem (still open) of the extension of relativitic theories to tachyons in four dimensions is tackled, and the electromagnetic theory of tachyons, a topic that can be relevant also for the experimental side, is reviewed. (Author)
Nucleation and dissociation of nano-particles in gas phase
International Nuclear Information System (INIS)
This work deals with the study of nano-particles formation in gas phase and their dissociation pathways after an optical excitation. The clusters formation decomposes in two steps: a seed is formed (nucleation phase) and sticks atoms during its propagation in a sodium atomic vapor (growth phase). Those two steps have been observed separately for homogeneous Nan and heterogeneous NanX particles (X = (NaOH)2 or (Na2O)2). The growth mechanism is well interpreted by a Monte Carlo simulation taking into account an accretion mechanism with hard-sphere cross section. The homogeneous nucleation mechanism has been highlighted by a direct comparison with the Classical Nucleation Theory predictions. The clusters fragmentation of ionic Na+(NaOH)p et Na+(NaF)p particles is studied in the second part. The way clusters fragment with size when they are excited optically is compared with theoretical previsions: this highlights the existence of an energetic barrier for special size of clusters. Finally, the fragmentation of doubly charged Na+ Na+ (NaOH)p clusters shows a competition between the fission into two single charged fragments and the unimolecular evaporation of a neutral fragment. (author)
Modelling polytypism in III-V nanowires: role of group V and nucleation patterns during the growth
Grecenkov, J.; Dubrovskii, V. G.
2015-11-01
This theoretical work deals with polytypism in nanowires by utilizing nucleation theory and by modifying standard expression for nucleation rate. Polycentric and monocentric nucleation cases are also considered. Results show good agreement with experimental data.
Härtel, Andreas; Samin, Sela; van Roij, René
2016-06-01
The ongoing scientific interest in the properties and structure of electric double layers (EDLs) stems from their pivotal role in (super)capacitive energy storage, energy harvesting, and water treatment technologies. Classical density functional theory (DFT) is a promising framework for the study of the in- and out-of-plane structural properties of double layers. Supported by molecular dynamics simulations, we demonstrate the adequate performance of DFT for analyzing charge layering in the EDL perpendicular to the electrodes. We discuss charge storage and capacitance of the EDL and the impact of screening due to dielectric solvents. We further calculate, for the first time, the in-plane structure of the EDL within the framework of DFT. While our out-of-plane results already hint at structural in-plane transitions inside the EDL, which have been observed recently in simulations and experiments, our DFT approach performs poorly in predicting in-plane structure in comparison to simulations. However, our findings isolate fundamental issues in the theoretical description of the EDL within the primitive model and point towards limitations in the performance of DFT in describing the out-of-plane structure of the EDL at high concentrations and potentials.
Härtel, Andreas; Samin, Sela; van Roij, René
2016-06-22
The ongoing scientific interest in the properties and structure of electric double layers (EDLs) stems from their pivotal role in (super)capacitive energy storage, energy harvesting, and water treatment technologies. Classical density functional theory (DFT) is a promising framework for the study of the in- and out-of-plane structural properties of double layers. Supported by molecular dynamics simulations, we demonstrate the adequate performance of DFT for analyzing charge layering in the EDL perpendicular to the electrodes. We discuss charge storage and capacitance of the EDL and the impact of screening due to dielectric solvents. We further calculate, for the first time, the in-plane structure of the EDL within the framework of DFT. While our out-of-plane results already hint at structural in-plane transitions inside the EDL, which have been observed recently in simulations and experiments, our DFT approach performs poorly in predicting in-plane structure in comparison to simulations. However, our findings isolate fundamental issues in the theoretical description of the EDL within the primitive model and point towards limitations in the performance of DFT in describing the out-of-plane structure of the EDL at high concentrations and potentials. PMID:27116552
International Nuclear Information System (INIS)
The Helmholtz-Poincare Wave Equation (H-PWE) arises in many areas of classical wave scattering theory. In particular it can be found for the cases of acoustical scattering from submerged bounded objects and electromagnetic scattering from objects. The extended boundary integral equations (EBIE) method is derived from considering both the exterior and interior solutions of the H-PWE's. This coupled set of expressions has the advantage of not only offering a prescription for obtaining a solution for the exterior scattering problem, but it also obviates the problem of irregular values corresponding to fictitious interior eigenvalues. Once the coupled equations are derived, they can by obtained in matrix form be expanding all relevant terms in partial wave expansions, including a biorthogonal expansion of the Green function. However some freedom of choice in the choice of the surface expansion is available since the unknown surface quantities may be expanded in a variety of ways to long as closure is obtained. Out of many possible choices, we develop an optimal method to obtain such expansions which is based on the optimum eigenfunctions related to the surface of the object. In effect, we convert part of the problem (that associated with the Fredholms integral equation of the first kind) an eigenvalue problem of a related Hermition operator. The methodology will be explained in detail and examples will be presented
Energy Technology Data Exchange (ETDEWEB)
Bottcher, C.; Strayer, M.R. [Oak Ridge National Lab., TN (United States); Werby, M.F. [Naval Research Lab. Detachment, Stennis Space Center, MS (United States)
1993-10-01
The Helmholtz-Poincare Wave Equation (H-PWE) arises in many areas of classical wave scattering theory. In particular it can be found for the cases of acoustical scattering from submerged bounded objects and electromagnetic scattering from objects. The extended boundary integral equations (EBIE) method is derived from considering both the exterior and interior solutions of the H-PWE`s. This coupled set of expressions has the advantage of not only offering a prescription for obtaining a solution for the exterior scattering problem, but it also obviates the problem of irregular values corresponding to fictitious interior eigenvalues. Once the coupled equations are derived, they can by obtained in matrix form be expanding all relevant terms in partial wave expansions, including a biorthogonal expansion of the Green function. However some freedom of choice in the choice of the surface expansion is available since the unknown surface quantities may be expanded in a variety of ways to long as closure is obtained. Out of many possible choices, we develop an optimal method to obtain such expansions which is based on the optimum eigenfunctions related to the surface of the object. In effect, we convert part of the problem (that associated with the Fredholms integral equation of the first kind) an eigenvalue problem of a related Hermition operator. The methodology will be explained in detail and examples will be presented.
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A self-consistent approximation scheme is formulated for the calculation of the dynamical linear polarizability of classical electron monolayers. The derivation is carried out in two stages. In the first stage, the authors formulate a simple response function relation linking linear and quadratic polarizabilities; the dynamical coupling function is expressed entirely in terms of the latter. The basic elements in the derivation are the first BBGKY kinetic equation (prepared in the velocity average approximation) and the non-linear fluctuation-dissipation theorem. The new response function relation is exact at zero frequency and exactly satisfies the third frequency moment sum rule. In the second stage, self-consistency is guaranteed by approximating the quadratic polarizability in terms of linear ones. The theory is examined in the weak coupling limit where it is found that a dominant γ-independent non-RPA contribution to the damping is missing. The structure of the missing term is identified at arbitrary coupling strengths. Work is in progress to see how it can be incorporated into the approximation scheme. (author)
International Nuclear Information System (INIS)
We compare behaviour of quasi-two-dimensional aluminium crack tips undergoing mode I loading using orbital-free density functional theory (OFDFT) and the classical embedded atom method (EAM). Low-index crack orientations are compared in the context of the Griffith, Rice and Tadmor–Hai continuum criteria, using values from Kohn–Sham DFT (KSDFT). All orientations are predicted to be ductile, and twinning is expected to occur only in certain orientations of low-dimensional or low-temperature Al. OFDFT and the EAM predict similar values to KSDFT for the relevant properties. In simulations of two crack orientations, the critical stress intensity factor in EAM simulations is close to continuum predictions while crack tips modelled by OFDFT do not exhibit plasticity until loaded at least 13% over the continuum prediction. The EAM and OFDFT give qualitatively similar results for a crack orientation that emits edge dislocations. For a twinning orientation, OFDFT simulations emit partial dislocations in the same order, even with different pseudopotentials. However, EAM simulations predict that a partial is emitted along a different slip plane from OFDFT. Differences between EAM and OFDFT simulations suggest that methods that give accurate stacking fault energies, elastic constants and surface energies may not necessarily reproduce all important physical processes at crack tips
Nucleation of voids - the impurity effect
International Nuclear Information System (INIS)
Nucleation of voids under irradiation in multicomponent alloys remains an unsolved theoretical problem. Of particular interest are the effects of nonequilibrium solute segregation phenomena on the critical nucleus and the nucleation rate. The resolution of the multicomponent nucleation in a dissipative system also has broader implication to the field of irreversible thermodynamics. The present paper describes a recent study of solute segregation effects in void nucleation. We begin with a thermodynamic model for a nonequilibrium void with interfacial segregation. The thermodynamic model is coupled with kinetic considerations of solute/solvent diffusion under a bias, which is itself related to segregation by the coating effect, to assess the stability of void embryos. To determine nucleation rate, we develop a novel technique by extending the most probable path method in statistical mechanics for nonequilibrium steady state to simulate large fluctuation with nonlinear dissipation. The path of nucleation is determined by solving an analogous problem on particle trajectory in classical dynamics. The results of both the stability analysis and the fluctuation analysis establish the paramount significance of the impurity effect via the mechanism of nonequilibrium segregation. We conclude that over-segregation is probably the most general cause for the apparently low nucleation barriers that are responsible for nearly ubiquitous occurrence of void swelling in common metals
Energy Technology Data Exchange (ETDEWEB)
Feiden, P
2007-09-15
This work deals with the study of nano-particles formation in gas phase and their dissociation pathways after an optical excitation. The clusters formation decomposes in two steps: a seed is formed (nucleation phase) and sticks atoms during its propagation in a sodium atomic vapor (growth phase). Those two steps have been observed separately for homogeneous Na{sub n} and heterogeneous Na{sub n}X particles (X = (NaOH){sub 2} or (Na{sub 2}O){sub 2}). The growth mechanism is well interpreted by a Monte Carlo simulation taking into account an accretion mechanism with hard-sphere cross section. The homogeneous nucleation mechanism has been highlighted by a direct comparison with the Classical Nucleation Theory predictions. The clusters fragmentation of ionic Na{sup +}(NaOH){sub p} et Na{sup +}(NaF){sub p} particles is studied in the second part. The way clusters fragment with size when they are excited optically is compared with theoretical previsions: this highlights the existence of an energetic barrier for special size of clusters. Finally, the fragmentation of doubly charged Na{sup +} Na{sup +} (NaOH){sub p} clusters shows a competition between the fission into two single charged fragments and the unimolecular evaporation of a neutral fragment. (author)
Directory of Open Access Journals (Sweden)
O. Möhler
2006-01-01
Full Text Available Activation energies ΔGact for the nucleation of nitric acid dihydrate (NAD in supercooled binary HNO3/H2O solution droplets were calculated from volume-based nucleation rate measurements using the AIDA (Aerosol, Interactions, and Dynamics in the Atmosphere aerosol chamber of Forschungszentrum Karlsruhe. The experimental conditions covered temperatures T between 192 and 197 K, NAD saturation ratios SNAD between 7 and 10, and nitric acid molar fractions of the nucleating sub-micron sized droplets between 0.26 and 0.28. Based on classical nucleation theory, a new parameterisation for ΔGact=A×(T ln SNAD−2+B is fitted to the experimental data with A=2.5×106 kcal K2 mol−1 and B=11.2−0.1(T−192 kcal mol−1. A and B were chosen to also achieve good agreement with literature data of ΔGact. The parameter A implies, for the temperature and composition range of our analysis, a mean interface tension σsl=51 cal mol−1 cm−2 between the growing NAD germ and the supercooled solution. A slight temperature dependence of the diffusion activation energy is represented by the parameter B. Investigations with a detailed microphysical process model showed that literature formulations of volume-based (Salcedo et al., 2001 and surface-based (Tabazadeh et al., 2002 nucleation rates significantly overestimate NAD formation rates when applied to the conditions of our experiments.
Steady-state molecular dynamics simulation of vapour to liquid nucleation with McDonald's daemon
Horsch, Martin; Vrabec, Jadran
2009-01-01
The most interesting step of condensation is the cluster formation up to the critical size. In a closed system, this is an instationary process, as the vapour is depleted by the emerging liquid phase. This imposes a limitation on direct molecular dynamics (MD) simulation of nucleation by affecting the properties of the vapour to a significant extent so that the nucleation rate varies over simulation time. Grand canonical MD with McDonald's daemon is discussed in the present contribution and applied for sampling both nucleation kinetics and steady-state properties of a supersaturated vapour. The idea behind that approach is to simulate the production of clusters up to a given size for a specified supersaturation. In that way, nucleation is studied by a steady-state simulation. A series of simulations is conducted for the truncated and shifted Lennard-Jones fluid which accurately describes the fluid phase coexistence of noble gases and methane. The classical nucleation theory is found to overestimate the free e...
Nucleation and growth of geological faults
Stoyan, D.; Gloaguen, R.
2011-08-01
We present a new model of fault nucleation and growth based on the Weibull theory, already widely used in fracture research engineering. We propose that, according to a birth-and-growth process, germs (nuclei) are born at random instants at random spatial locations and then grow with time. This leads to a satisfactory formulation of fault length distribution, different from classical statistical laws. Especially, this formulation reconciles previous analyses of fault datasets displaying power-law and/or exponential behaviors. The Weibull parameters can be statistically estimated in a simple way. We show that the model can be successfully fitted to natural data in Kenya and Ethiopia. In contrast to existing descriptive models developed for geological fault systems, such as fractal approaches, the Weibull theory allows to characterize the strength of the material, i.e. its resistance to deformation. Since this model is very general, we expect that it can be applied in many situations, and for simulations of geological fracture processes. The model is independent of deformation intensity and type and therefore allows a better constraint of the seismic risk in threatened regions.
Revision of nucleated boiling mechanisms
International Nuclear Information System (INIS)
The boiling occurrence plays an important role in the power reactors energy transfer. But still, there is not a final theory on the boiling mechanisms. This paper presents a critical analysis of the most important nucleated boiling models that appear in literature. The conflicting points are identified and experiments are proposed to clear them up. Some of these experiments have been performed at the Thermohydraulics laboratory (Bariloche Atomic Center). (Author)
Cavitation in a metallic liquid: Homogeneous nucleation and growth of nanovoids
Energy Technology Data Exchange (ETDEWEB)
Cai, Y. [Department of Modern Mechanics, CAS Key Laboratory of Materials Behavior and Design, University of Science and Technology of China, Hefei, Anhui 230027 (China); The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 (China); Wu, H. A., E-mail: wuha@ustc.edu.cn [Department of Modern Mechanics, CAS Key Laboratory of Materials Behavior and Design, University of Science and Technology of China, Hefei, Anhui 230027 (China); Luo, S. N., E-mail: sluo@pims.ac.cn [The Peac Institute of Multiscale Sciences, Chengdu, Sichuan 610207 (China)
2014-06-07
Large-scale molecular dynamics (MD) simulations are performed to investigate homogeneous nucleation and growth of nanovoids during cavitation in liquid Cu. We characterize in detail the atomistic cavitation processes by following the temporal evolution of cavities or voids, analyze the nucleation behavior with the mean first-passage time (MFPT) and survival probability (SP) methods, and discuss the results against classical nucleation theory (CNT), the Tolman equation for surface energy, independent calculation of surface tension via integrating the stress profiles, the Johnson-Mehl-Avrami (JMA) growth law, and the power law for nucleus size distributions. Cavitation in this representative metallic liquid is a high energy barrier Poisson processes, and the steady-state nucleation rates obtained from statistical runs with the MFPT and SP methods are in agreement. The MFPT method also yields the critical nucleus size and the Zeldovich factor. Fitting with the Tolman's equation to the MD simulations yields the surface energy of a planar interface (∼0.9 J m{sup −2}) and the Tolman length (0.4–0.5 Å), and those values are in accord with those from integrating the stress profiles of a planar interface. Independent CNT predictions of the nucleation rate (10{sup 33−34} s{sup −1} m{sup −3}) and critical size (3–4 Å in radius) are in agreement with the MFPT and SP results. The JMA law can reasonably describe the nucleation and growth process. The size distribution of subcritical nuclei appears to follow a power law with an exponent decreasing with increasing tension owing to coupled nucleation and growth, and that of the supercritical nuclei becomes flattened during further stress relaxation due to void coalescence.
Cavitation in a metallic liquid: homogeneous nucleation and growth of nanovoids.
Cai, Y; Wu, H A; Luo, S N
2014-06-01
Large-scale molecular dynamics (MD) simulations are performed to investigate homogeneous nucleation and growth of nanovoids during cavitation in liquid Cu. We characterize in detail the atomistic cavitation processes by following the temporal evolution of cavities or voids, analyze the nucleation behavior with the mean first-passage time (MFPT) and survival probability (SP) methods, and discuss the results against classical nucleation theory (CNT), the Tolman equation for surface energy, independent calculation of surface tension via integrating the stress profiles, the Johnson-Mehl-Avrami (JMA) growth law, and the power law for nucleus size distributions. Cavitation in this representative metallic liquid is a high energy barrier Poisson processes, and the steady-state nucleation rates obtained from statistical runs with the MFPT and SP methods are in agreement. The MFPT method also yields the critical nucleus size and the Zeldovich factor. Fitting with the Tolman's equation to the MD simulations yields the surface energy of a planar interface (~0.9 J m⁻²) and the Tolman length (0.4-0.5 Å), and those values are in accord with those from integrating the stress profiles of a planar interface. Independent CNT predictions of the nucleation rate (10(33 - 34) s(-1) m(-3)) and critical size (3-4 Å in radius) are in agreement with the MFPT and SP results. The JMA law can reasonably describe the nucleation and growth process. The size distribution of subcritical nuclei appears to follow a power law with an exponent decreasing with increasing tension owing to coupled nucleation and growth, and that of the supercritical nuclei becomes flattened during further stress relaxation due to void coalescence. PMID:24908018
Kooi, BJ
2004-01-01
Monte Carlo (MC) simulations of isothermal phase transformations were performed based on a temperature- and time-dependent nucleation rate and a temperature-dependent and time-independent anisotropic growth rate (linear growth). One- or two-dimensional anisotropic growth in two-dimensional space is
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We present a mixed time-dependent density-functional theory (TDDFT)/classical trajectory surface hopping (SH) study of the photochemical ring opening in oxirane. Previous preparatory work limited to the symmetric CC ring-opening pathways of oxirane concluded that the Tamm-Dancoff approximation (TDA) is important for improving the performance of TDDFT away from the equilibrium geometry. This observation is supported by the present TDDFT TDA/SH calculations which successfully confirm the main experimentally derived Gomer-Noyes mechanism for the photochemical CO ring opening of oxirane and, in addition, provide important state-specific information not easily accessible from experiments. In particular, we find that, while one of the lowest two excited states is photochemically relatively inert, excitation into the other excited state leads predominantly to rapid ring opening, cyclic-C2H4O→CH2CH2O. This is followed by hopping to the electronic ground state where hot (4000 K) dynamics leads to further reactions, namely, CH2CH2O→CH3CHO→CH3+CHO and CH4+CO. We note that, in the dynamics, we are not limited to following minimum energy pathways and several surface hops may actually be needed before products are finally reached. The performance of different functionals is then assessed by comparison of TDDFT and diffusion Monte Carlo potential energy curves along a typical TDDFT TDA/SH reaction path. Finally, although true (S0,S1) conical intersections are expected to be absent in adiabatic TDDFT, we show that the TDDFT TDA is able to approximate a conical intersection in this system.
Tapavicza, Enrico; Tavernelli, Ivano; Rothlisberger, Ursula; Filippi, Claudia; Casida, Mark E.
2008-09-01
We present a mixed time-dependent density-functional theory (TDDFT)/classical trajectory surface hopping (SH) study of the photochemical ring opening in oxirane. Previous preparatory work limited to the symmetric CC ring-opening pathways of oxirane concluded that the Tamm-Dancoff approximation (TDA) is important for improving the performance of TDDFT away from the equilibrium geometry. This observation is supported by the present TDDFT TDA/SH calculations which successfully confirm the main experimentally derived Gomer-Noyes mechanism for the photochemical CO ring opening of oxirane and, in addition, provide important state-specific information not easily accessible from experiments. In particular, we find that, while one of the lowest two excited states is photochemically relatively inert, excitation into the other excited state leads predominantly to rapid ring opening, cyclic-C2H4O→C•H2CH2O•. This is followed by hopping to the electronic ground state where hot (4000K) dynamics leads to further reactions, namely, C•H2CH2O•→CH3CHO→C•H3+C•HO and CH4+CO. We note that, in the dynamics, we are not limited to following minimum energy pathways and several surface hops may actually be needed before products are finally reached. The performance of different functionals is then assessed by comparison of TDDFT and diffusion Monte Carlo potential energy curves along a typical TDDFT TDA/SH reaction path. Finally, although true (S0,S1) conical intersections are expected to be absent in adiabatic TDDFT, we show that the TDDFT TDA is able to approximate a conical intersection in this system.
Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt
International Nuclear Information System (INIS)
The homogeneous nucleation of crystals of the ionic liquid [dmim+][Cl−] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589–2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 1010 cm−3 s−1 was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores
Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt
Energy Technology Data Exchange (ETDEWEB)
He, Xiaoxia; Shen, Yan [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Hung, Francisco R., E-mail: frhung@lsu.edu [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Santiso, Erik E. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
2015-09-28
The homogeneous nucleation of crystals of the ionic liquid [dmim{sup +}][Cl{sup −}] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589–2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 10{sup 10} cm{sup −3} s{sup −1} was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores.
Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt.
He, Xiaoxia; Shen, Yan; Hung, Francisco R; Santiso, Erik E
2015-09-28
The homogeneous nucleation of crystals of the ionic liquid [dmim(+)][Cl(-)] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589-2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 10(10) cm(-3) s(-1) was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores. PMID:26429023
Institute of Scientific and Technical Information of China (English)
汪大白
2001-01-01
ZHU Xi's theory of and his deeds in commenting on Classic Poetry through Classic Poetry is a negation and criticism on the idea of illustrating Classic Poetry with history expressed in “the Preface to Classic Poetry" and the Confucianists' concept of illustrating Classic Poetry with “the Preface to Classic Poetry". It also shows a deep understanding on the literature nature of Classic Poetry and the rules in composing poems. To carry out the principle of commenting on classic Poetry through Classic Poetry and to implement a great reform on traditional studies on classic Poetry is a great mission for scholars in Song Dynasty from the need of historical development and the time. Being a famous literaturist as well as a master in the studies on Classic Poetry and integrating literature of past dynasties with the studies on “Classic Poetry" of past dynasties are the main condition and the objective foundation for ZHU Xi to implement his reform on the studies on classic Poetry.%朱熹首倡并躬行的“以《诗》言《诗》”说是对《诗序》“以史证《诗》”以及后儒“以《序》解《诗》”的否定与批判，同时又体现了对《诗经》文学本质与诗歌创作规律的深刻认识。贯彻“以《诗》言《诗》”的原则，实现传统《诗经》学的重大变革，是历史的发展与时代的需求赋予宋代学者的重大使命；而文学名家与经学大师的一身兼任，历代文学与历代经学的双轨集成，是朱熹实现《诗经》学变革的主体条件与客观基础。
Directory of Open Access Journals (Sweden)
Trentini Clarissa M
2008-01-01
Full Text Available Abstract Background Aging has determined a demographic shift in the world, which is considered a major societal achievement, and a challenge. Aging is primarily a subjective experience, shaped by factors such as gender and culture. There is a lack of instruments to assess attitudes to aging adequately. In addition, there is no instrument developed or validated in developing region contexts, so that the particularities of ageing in these areas are not included in the measures available. This paper aims to develop and validate a reliable attitude to aging instrument by combining classical psychometric approach and Rasch analysis. Methods Pilot study and field trial are described in details. Statistical analysis included classic psychometric theory (EFA and CFA and Rasch measurement model. The latter was applied to examine unidimensionality, response scale and item fit. Results Sample was composed of 424 Brazilian old adults, which was compared to an international sample (n = 5238. The final instrument shows excellent psychometric performance (discriminant validity, confirmatory factor analysis and Rasch fit statistics. Rasch analysis indicated that modifications in the response scale and item deletions improved the initial solution derived from the classic approach. Conclusion The combination of classic and modern psychometric theories in a complementary way is fruitful for development and validation of instruments. The construction of a reliable Brazilian Attitudes to Aging Questionnaire is important for assessing cultural specificities of aging in a transcultural perspective and can be applied in international cross-cultural investigations running less risk of cultural bias.
Wan, Chonghua; Li, Hezhan; Fan, Xuejin; Yang, Ruixue; Pan, Jiahua; Chen, Wenru; Zhao, Rong
2014-01-01
Background Quality of life (QOL) for patients with coronary heart disease (CHD) is now concerned worldwide with the specific instruments being seldom and no one developed by the modular approach. Objectives This paper is aimed to develop the CHD scale of the system of Quality of Life Instruments for Chronic Diseases (QLICD-CHD) by the modular approach and validate it by both classical test theory and Generalizability Theory. Methods The QLICD-CHD was developed based on programmed decision pro...
International Nuclear Information System (INIS)
It is shown that the rational power law potentials in the two-body radial Schrodinger equations admit a systematic treatment available from the classical theory of ordinary linear differential equations of the second order. The resulting potentials come into families evolved from equations having a fixed number of elementary regular singularities. As a consequence, relations are found and discussed among the several potentials in a family. (Author)
Clerc, Daryl G
2016-07-21
An ab initio approach was used to study the molecular-level interactions that connect gene-mutation to changes in an organism׳s phenotype. The study provides new insights into the evolutionary process and presents a simplification whereby changes in phenotypic properties may be studied in terms of the binding affinities of the chemical interactions affected by mutation, rather than by correlation to the genes. The study also reports the role that nonlinear effects play in the progression of organs, and how those effects relate to the classical theory of evolution. Results indicate that the classical theory of evolution occurs as a special case within the ab initio model - a case having two attributes. The first attribute: proteins and promoter regions are not shared among organs. The second attribute: continuous limiting behavior exists in the physical properties of organs as well as in the binding affinity of the associated chemical interactions, with respect to displacements in the chemical properties of proteins and promoter regions induced by mutation. Outside of the special case, second-order coupling contributions are significant and nonlinear effects play an important role, a result corroborated by analyses of published activity levels in binding and transactivation assays. Further, gradations in the state of perfection of an organ may be small or large depending on the type of mutation, and not necessarily closely-separated as maintained by the classical theory. Results also indicate that organs progress with varying degrees of interdependence, the likelihood of successful mutation decreases with increasing complexity of the affected chemical system, and differences between the ab initio model and the classical theory increase with increasing complexity of the organism. PMID:27029513
Blázquez, J.S.; Conde, C. F.; Conde, A.
2014-01-01
The classical theory of Johnson–Mehl–Avrami–Kolmogorov (JMAK) is widely used to describe the kinetics of crystallization even when the premises required for its application are not strictly fulfilled. In this paper we propose a procedure to obtain the JMAK parameters of the independent transformations that simultaneously occur during a crystallization process (e.g. leading to the formation of several crystalline phases). The predictions of the analysis have been used to describe the crystalli...
Lischner, Johannes; Arias, T. A.
2008-01-01
The Gordian knot of density-functional theories for classical molecular liquids remains finding an accurate free-energy functional in terms of the densities of the atomic sites of the molecules. Following Kohn and Sham, we show how to solve this problem by considering noninteracting molecules in a set of effective potentials. This shift in perspective leads to an accurate and computationally tractable description in terms of simple three-dimensional functions. We also treat both the linear- a...
International Nuclear Information System (INIS)
It is shown that the rational power law potentials in the two-body radial Schoedinger equation admit a systematic treatment available from the classical theory of ordinary linear differential equations of the second order. The admissible potentials come into families evolved from equations having a fixed number of elementary singularities. As a consequence, relations are found and discussed among the several potentials in a family. (Author)
Ferguson, Brian S.
2013-01-01
Chapter 2 is one of the most important chapters in the General Theory. Not only does it set out Keynes’ disagreements with key elements of the classical model, it lays out his own model of the working of the labour market, which underlies the analysis in the remainder of the General Theory. The issue of how labour’s response to a change in its real wage differs depending on whether the change is driven by a change in the nominal wage or in the price of consumer goods plays a key part in the w...
Semenov, Alexander; Babikov, Dmitri
2015-12-17
The mixed quantum classical theory, MQCT, for inelastic scattering of two molecules is developed, in which the internal (rotational, vibrational) motion of both collision partners is treated with quantum mechanics, and the molecule-molecule scattering (translational motion) is described by classical trajectories. The resultant MQCT formalism includes a system of coupled differential equations for quantum probability amplitudes, and the classical equations of motion in the mean-field potential. Numerical tests of this theory are carried out for several most important rotational state-to-state transitions in the N2 + H2 system, in a broad range of collision energies. Besides scattering resonances (at low collision energies) excellent agreement with full-quantum results is obtained, including the excitation thresholds, the maxima of cross sections, and even some smaller features, such as slight oscillations of energy dependencies. Most importantly, at higher energies the results of MQCT are nearly identical to the full quantum results, which makes this approach a good alternative to the full-quantum calculations that become computationally expensive at higher collision energies and for heavier collision partners. Extensions of this theory to include vibrational transitions or general asymmetric-top rotor (polyatomic) molecules are relatively straightforward. PMID:26323089
How does degree heterogeneity affect nucleation on complex networks?
International Nuclear Information System (INIS)
Nucleation is an initiating process of a stable phase from a metastable phase in a first-order phase transition. Taking the Ising model as a paradigm, we investigate the dynamics of nucleation on complex networks and focus on the role played by the heterogeneity of degree distribution on nucleation rate. Using Monte Carlo simulation combined with forward flux sampling, we find that for a weak external field the nucleation rate decreases monotonically as degree heterogeneity increases. Interestingly, for a relatively strong external field the nucleation rate exhibits a nonmonotonic dependence on degree heterogeneity, in which there exists a maximal nucleation rate at an intermediate level of degree heterogeneity. Furthermore, we develop a heterogeneous mean-field theory for evaluating the free-energy barrier of nucleation. The theoretical estimations are qualitatively consistent with the simulation results. Our study suggests that degree heterogeneity plays a nontrivial role in the dynamics of phase transitions in networked Ising systems. (paper)
Alpert, Peter A.; Knopf, Daniel A.
2016-02-01
Immersion freezing is an important ice nucleation pathway involved in the formation of cirrus and mixed-phase clouds. Laboratory immersion freezing experiments are necessary to determine the range in temperature, T, and relative humidity, RH, at which ice nucleation occurs and to quantify the associated nucleation kinetics. Typically, isothermal (applying a constant temperature) and cooling-rate-dependent immersion freezing experiments are conducted. In these experiments it is usually assumed that the droplets containing ice nucleating particles (INPs) all have the same INP surface area (ISA); however, the validity of this assumption or the impact it may have on analysis and interpretation of the experimental data is rarely questioned. Descriptions of ice active sites and variability of contact angles have been successfully formulated to describe ice nucleation experimental data in previous research; however, we consider the ability of a stochastic freezing model founded on classical nucleation theory to reproduce previous results and to explain experimental uncertainties and data scatter. A stochastic immersion freezing model based on first principles of statistics is presented, which accounts for variable ISA per droplet and uses parameters including the total number of droplets, Ntot, and the heterogeneous ice nucleation rate coefficient, Jhet(T). This model is applied to address if (i) a time and ISA-dependent stochastic immersion freezing process can explain laboratory immersion freezing data for different experimental methods and (ii) the assumption that all droplets contain identical ISA is a valid conjecture with subsequent consequences for analysis and interpretation of immersion freezing. The simple stochastic model can reproduce the observed time and surface area dependence in immersion freezing experiments for a variety of methods such as: droplets on a cold-stage exposed to air or surrounded by an oil matrix, wind and acoustically levitated droplets
Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Zou, Xu-Bo; Guo, Guang-Can
2012-01-01
We experimentally generate a non-classical correlated two-color photon pair at 780 and 1529.4 nm in a ladder-type configuration using a hot 85Rb atomic vapor with the production rate of ~107/s. The non-classical correlation between these two photons is demonstrated by strong violation of Cauchy-Schwarz inequality by the factor R=48+-12. Besides, we experimentally investigate the relations between the correlation and some important experimental parameters such as the single-photon detuning, th...