Chiral Magnetic Effect and Chiral Phase Transition
FU Wei-Jie; LIU Yu-Xin; WU Yue-Liang
2011-01-01
We study the influence of the chiral phase transition on the chiral magnetic effect.The azimuthal chargeparticle correlations as functions of the temperature are calculated.It is found that there is a pronounced cusp in the correlations as the temperature reaches its critical value for the QCD phase transition.It is predicted that there will be a drastic suppression of the charge-particle correlations as the collision energy in RHIC decreases to below a critical value.We show then the azimuthal charge-particle correlations can be the signal to identify the occurrence of the QCD phase transitions in RHIC energy scan experiments.
Neutrino Oscillation Induced by Chiral Phase Transition
MU Cheng-Fu; SUN Gao-Feng; ZHUANG Peng-Fei
2009-01-01
Electric charge neutrality provides a relationship between chiral dynamics and neutrino propagation in compact stars.Due to the sudden drop of the electron density at the first-order chiral phase transition,the oscillation for low energy neutrinos is significant and can be regarded as a signature of chiral symmetry restoration in the core of compact stars.
Interplay between chiral and deconfinement phase transitions
Mukherjee T.K.
2011-04-01
Full Text Available By using the dressed Polyakov loop or dual chiral condensate as an equivalent order parameter of the deconfinement phase transition, we investigate the relation between the chiral and deconfinement phase transitions at finite temperature and density in the framework of three-flavor Nambu-Jona-Lasinio (NJL model. It is found that in the chiral limit, the critical temperature for chiral phase transition coincides with that of the dressed Polyakov loop in the whole (T,µ plane. In the case of explicit chiral symmetry breaking, it is found that the phase transitions are flavor dependent. For each flavor, the transition temperature for chiral restoration $T^{mathcal{X}}_c$ is smaller than that of the dressed Polyakov loop $T^{mathcal{D}}_c$ in the low baryon density region where the transition is a crossover, and, the two critical temperatures coincide in the high baryon density region where the phase transition is of first order. Therefore, there are two critical end points, i.e, $T^{u,d}_{CEP}$ and $T^{s}_{CEP}$ at finite density. We also explain the feature of $T^{mathcal{X}}_c$ = $T^{mathcal{D}}_c$ in the case of 1st and 2nd order phase transitions, and $T^{mathcal{X}}_c$ < $T^{mathcal{D}}_c$ in the case of crossover, and expect this feature is general and can be extended to full QCD theory.
Interplay between chiral and deconfinement phase transitions
Xu, Fukun; Chen, Huan; Huang, Mei
2011-01-01
By using the dressed Polyakov loop or dual chiral condensate as an equivalent order parameter of the deconfinement phase transition, we investigate the relation between the chiral and deconfinement phase transitions at finite temperature and density in the framework of three-flavor Nambu--Jona-Lasinio (NJL) model. It is found that in the chiral limit, the critical temperature for chiral phase transition coincides with that of the dressed Polyakov loop in the whole $(T,\\mu)$ plane. In the case of explicit chiral symmetry breaking, it is found that the phase transitions are flavor dependent. For each flavor, the transition temperature for chiral restoration $T_c^{\\chi}$ is smaller than that of the dressed Polyakov loop $T_c^{{\\cal D}}$ in the low baryon density region where the transition is a crossover, and, the two critical temperatures coincide in the high baryon density region where the phase transition is of first order. Therefore, there are two critical end points, i.e, $T_{CEP}^{u,d}$ and $T_{CEP}^{s}$ a...
Search for phase transitions changing molecular chirality
Since Pasteur discovered in 1848 that biological molecules possess a rotatory power, the origin of the chiral purity in living organisms has been a constant preoccupation in biology, but the problem is not solved yet. In particular, the appeal to weak interactions, a fundamental physical process which is known to violate parity, has not permitted so far to establish any firm relation between parity nonconservation and the complete dissymmetry between mirror image biological molecules. The main difficulty resides in the weakness of the physical forces, and can be overcome only when some amplification process can be proved to be at work. Recently such a mechanism was proposed, which does not seem to ask for any ad hoc new concept: due to the attractive character of the parity violating force in electro-weak interactions, a phase transition leading eventually to enantiometric purity is predicted. Phase transitions at low temperature have already been detected in biological materials, but no signature concerning the parity aspect was obtained. We undertook this year in Lyon a series of experiments to measure the rotatory power of solutions containing organic dissymmetric molecules, in order to observe if it varies with temperature. Our first measures involved cystine, which possesses a high rotatory power. No variation of this quantity was observed down to .6K. Lower temperatures will be attained in a next step. (author). 4 refs
How tetraquarks can generate a second chiral phase transition
Pisarski, Robert D
2016-01-01
We consider how tetraquarks can affect the chiral phase transition in theories like QCD, with light quarks coupled to three colors. For two flavors the tetraquark field is an isosinglet, and its effect is minimal. For three flavors, however, the tetraquark field transforms in the same representation of the chiral symmetry group as the usual chiral order parameter, and so for very light quarks there may be two chiral phase transitions, which are both of first order. In QCD, results from the lattice indicate that any transition from the tetraquark condensate is a smooth crossover. In the plane of temperature and quark chemical potential, though, a crossover line for the tetraquark condensate is naturally related to the transition line for color superconductivity. For four flavors we suggest that a triquark field, antisymmetric in both flavor and color, combine to form hexaquarks.
Chiral and Deconfining Phase Transitions from Holographic QCD Study
Fang, Zhen; Li, Danning
2015-01-01
A first attempt to accommodate the chiral and deconfining phase transitions of QCD in the bottom-up holographic framework is given. We constrain the relation between dilaton field $\\phi$ and metric warp factor $A_e$ and get several reasonable models in the Einstein-Dilaton system. Using the potential reconstruction approach, we solve the corresponding gravity background. Then we fit the background-related parameters by comparing the equation of state with the two-flavor lattice QCD results. After that we study the temperature dependent behavior of Polyakov loop and chiral condensate under those background solutions. We find that the results are in good agreement with the two-flavor lattice results. All the studies about the equation of state, the Polyakov loop and the chiral condensate signal crossover behavior of the phase transitions, which is consistent with the current understanding on the QCD phase transitions with physical quark mass. Furthermore, the extracted transition temperatures are comparable wit...
Chirality Quantum Phase Transition in Noncommutative Dirac Oscillator
The charged Dirac oscillator on a noncommutative plane coupling to a uniform perpendicular magnetic held is studied in this paper. We map the noncommutative plane to a commutative one by means of Bopp shift and study this problem on the commutative plane. We find that this model can be mapped onto a quantum optics model which contains Anti—Jaynes—Cummings (AJC) or Jaynes—Cummings (JC) interactions when a dimensionless parameter ζ (which is the function of the intensity of the magnetic held) takes values in different regimes. Furthermore, this model behaves as experiencing a chirality quantum phase transition when the dimensionless parameter ζ approaches the critical point. Several evidences of the chirality quantum phase transition are presented. We also study the non-relativistic limit of this model and find that a similar chirality quantum phase transition takes place in its non-relativistic limit. (physics of elementary particles and fields)
On SU(3) effective models and chiral phase-transition
Tawfik, Abdel Nasser
2015-01-01
The sensitivity of Polyakov Nambu-Jona-Lasinio (PNJL) model as an effective theory of quark dynamics to chiral symmetry has been utilized in studying the QCD phase-diagram. Also, Poyakov linear sigma-model (PLSM), in which information about the confining glue sector of the theory was included through Polyakov-loop potential. Furthermore, from quasi-particle model (QPM), the gluonic sector of QPM is integrated to LSM in order to reproduce recent lattice calculations. We review PLSM, QLSM, PNJL and HRG with respect to their descriptions for the chiral phase-transition. We analyse chiral order-parameter M(T), normalized net-strange condensate Delta_{q,s}(T) and chiral phase-diagram and compare the results with lattice QCD. We conclude that PLSM works perfectly in reproducing M(T) and Delta_{q,s}(T). HRG model reproduces Delta_{q,s}(T), while PNJL and QLSM seem to fail. These differences are present in QCD chiral phase-diagram. PLSM chiral boundary is located in upper band of lattice QCD calculations and agree we...
On the chiral phase transition in the linear sigma model
The Cornwall- Jackiw-Tomboulis (CJT) effective action for composite operators at finite temperature is used to investigate the chiral phase transition within the framework of the linear sigma model as the low-energy effective model of quantum chromodynamics (QCD). A new renormalization prescription for the CJT effective action in the Hartree-Fock (HF) approximation is proposed. A numerical study, which incorporates both thermal and quantum effect, shows that in this approximation the phase transition is of first order. However, taking into account the higher-loop diagrams contribution the order of phase transition is unchanged. (author)
Chiral Phase Transition at Finite Isospin Density in Linear Sigma Model
SHU Song; LI Jia-Rong
2005-01-01
Using the linear sigma model, we have introduced the pion isospin chemical potential. The chiral phase transition is studied at finite temperatures and finite isospin densities. We have studied the μ - T phase diagram for the chiral phase transition and found the transition cannot happen below a certain low temperature because of the BoseEinstein condensation in this system. Above that temperature, the chiral phase transition is studied by the isotherms of pressure versus density. We indicate that the transition, in the chiral limit, is a first-order transition from a low-density phase to a high-density phase like a gas-liquid phase transition.
Chiral and deconfining phase transitions from holographic QCD study
Fang, Zhen; He, Song; Li, Danning
2016-06-01
A preliminary quantitative study to match the lattice QCD simulation on the chiral and deconfining phase transitions of QCD in the bottom-up holographic framework is given. We constrain the relation between dilaton field ϕ and metric warp factor Ae and get several reasonable models in the Einstein-Dilaton system. Using the potential reconstruction approach, we solve the corresponding gravity background. Then we fit the background-related parameters by comparing the equation of state with the two-flavor lattice QCD results. After that we study the temperature dependent behavior of Polyakov loop and chiral condensate under those background solutions. We find that the results are in good agreement with the two-flavor lattice results. All the studies about the equation of state, the Polyakov loop and the chiral condensate signal crossover behavior of the phase transitions, which are consistent with the current understanding on the QCD phase transitions with physical quark mass. Furthermore, the extracted transition temperatures are comparable with the two-flavor lattice QCD results.
Net baryon number probability distribution near the chiral phase transition
Morita, Kenji; Skokov, Vladimir; Friman, Bengt; Redlich, Krzysztof
2014-01-01
We discuss the properties of the net baryon number probability distribution near the chiral phase transition to explore the effect of critical fluctuations. Our studies are performed within Landau theory, where the coefficients of the polynomial potential are parametrized, so as to reproduce the mean-field (MF), the Z(2) , and the O(4) scaling behaviors of the cumulants of the net baryon number. We show that in the critical region the structure of the probability distribution changes, dependi...
Non-equilibrium physics at a holographic chiral phase transition
Evans, Nick; Kim, Keun-young [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Kavli Institute for Theoretical Physics China, Beijing (China); Kalaydzhyan, Tigran; Kirsch, Ingo [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2010-11-15
The D3/D7 system holographically describes an N=2 gauge theory which spontaneously breaks a chiral symmetry by the formation of a quark condensate in the presence of a magnetic field. At finite temperature it displays a first order phase transition. We study out of equilibrium dynamics associated with this transition by placing probe D7 branes in a geometry describing a boost-invariant expanding or contracting plasma. We use an adiabatic approximation to track the evolution of the quark condensate in a heated system and reproduce the phase structure expected from equilibrium dynamics. We then study solutions of the full partial differential equation that describes the evolution of out of equilibrium configurations to provide a complete description of the phase transition including describing aspects of bubble formation. (orig.)
Non-equilibrium physics at a holographic chiral phase transition
The D3/D7 system holographically describes an N=2 gauge theory which spontaneously breaks a chiral symmetry by the formation of a quark condensate in the presence of a magnetic field. At finite temperature it displays a first order phase transition. We study out of equilibrium dynamics associated with this transition by placing probe D7 branes in a geometry describing a boost-invariant expanding or contracting plasma. We use an adiabatic approximation to track the evolution of the quark condensate in a heated system and reproduce the phase structure expected from equilibrium dynamics. We then study solutions of the full partial differential equation that describes the evolution of out of equilibrium configurations to provide a complete description of the phase transition including describing aspects of bubble formation. (orig.)
QCD phase transition with chiral quarks and physical quark masses.
Bhattacharya, Tanmoy; Buchoff, Michael I; Christ, Norman H; Ding, H-T; Gupta, Rajan; Jung, Chulwoo; Karsch, F; Lin, Zhongjie; Mawhinney, R D; McGlynn, Greg; Mukherjee, Swagato; Murphy, David; Petreczky, P; Renfrew, Dwight; Schroeder, Chris; Soltz, R A; Vranas, P M; Yin, Hantao
2014-08-22
We report on the first lattice calculation of the QCD phase transition using chiral fermions with physical quark masses. This calculation uses 2+1 quark flavors, spatial volumes between (4 fm)(3) and (11 fm)(3) and temperatures between 139 and 196 MeV. Each temperature is calculated at a single lattice spacing corresponding to a temporal Euclidean extent of N(t) = 8. The disconnected chiral susceptibility, χ(disc) shows a pronounced peak whose position and height depend sensitively on the quark mass. We find no metastability near the peak and a peak height which does not change when a 5 fm spatial extent is increased to 10 fm. Each result is strong evidence that the QCD "phase transition" is not first order but a continuous crossover for m(π) = 135 MeV. The peak location determines a pseudocritical temperature T(c) = 155(1)(8) MeV, in agreement with earlier staggered fermion results. However, the peak height is 50% greater than that suggested by previous staggered results. Chiral SU(2)(L) × SU(2)(R) symmetry is fully restored above 164 MeV, but anomalous U(1)(A) symmetry breaking is nonzero above T(c) and vanishes as T is increased to 196 MeV. PMID:25192088
The QCD phase transition with physical-mass, chiral quarks
Bhattacharya, Tanmoy; Christ, Norman H; Ding, H -T; Gupta, Rajan; Jung, Chulwoo; Karsch, F; Lin, Zhongjie; Mawhinney, R D; McGlynn, Greg; Mukherjee, Swagato; Murphy, David; Petreczky, P; Schroeder, Chris; Soltz, R A; Vranas, P M; Yin, Hantao
2014-01-01
We report on the first lattice calculation of the QCD phase transition using chiral fermions at physical values of the quark masses. This calculation uses 2+1 quark flavors, spatial volumes between (4 fm$)^3$ and (11 fm$)^3$ and temperatures between 139 and 196 MeV . Each temperature was calculated using a single lattice spacing corresponding to a temporal Euclidean extent of $N_t=8$. The disconnected chiral susceptibility, $\\chi_{\\rm disc}$ shows a pronounced peak whose position and height depend sensitively on the quark mass. We find no metastability in the region of the peak and a peak height which does not change when a 5 fm spatial extent is increased to 10 fm. Each result is strong evidence that the QCD ``phase transition'' is not first order but a continuous cross-over for $m_\\pi=135$ MeV. The peak location determines a pseudo-critical temperature $T_c = 155(1)(8)$ MeV. Chiral $SU(2)_L\\times SU(2)_R$ symmetry is fully restored above 164 MeV, but anomalous $U(1)_A$ symmetry breaking is non-zero above $T...
Enhanced global symmetries and the chiral phase transition
We examine the possibility that the physical spectrum of a vectorlike gauge field theory exhibits an enhanced global symmetry near a chiral phase transition. A transition from the Goldstone phase to the symmetric phase is expected as the number of fermions Nf is increased to some critical value. Various investigations have suggested that a parity-doubled spectrum develops as the critical value is approached. Using an effective Lagrangian as a guide, we note that parity doubling is associated with the appearance of an enhanced global symmetry in the spectrum of the theory. The enhanced symmetry would develop as the spectrum splits into two sectors, with the first exhibiting the usual pattern of a spontaneously broken chiral symmetry, and the second exhibiting an additional, unbroken symmetry and parity doubling. The first sector includes the Goldstone bosons and other states such as massive scalar partners. The second includes a parity-degenerate vector and axial vector along with other possible parity partners. We note that if such a near-critical theory describes symmetry breaking in the electroweak theory, the additional symmetry suppresses the contribution of the parity-doubled sector to the S parameter. (c) 1999 The American Physical Society
Meson phenomenology and phase transitions in nonlocal chiral quark models
Carlomagno, J. P.; Gomez Dumm, D.; Pagura, V.; Scoccola, N. N.
2015-07-01
We study the features of nonlocal chiral quark models that include wave function renormalization. Model parameters are determined from meson phenomenology, considering different nonlocal form factor shapes. In this context we analyze the characteristics of the deconfinement and chiral restoration transitions at finite temperature and chemical potential, introducing the couplings of fermions to the Polyakov loop for different Polyakov potentials. The results for various thermodynamical quantities are compared with data obtained from lattice QCD calculations.
Yu, Lang; Huang, Mei
2015-01-01
We study the chiral phase transition in the presence of the chiral chemical potential $\\mu_5$ using the two-flavor Nambu--Jona-Lasinio model. In particular, we analyze the reason why one can obtain two opposite behaviors of the chiral critical temperature as a function of $\\mu_5$ in the framework of different regularization schemes. We compare the modifications of the chiral condensate and the critical temperature due to $\\mu_5$ in different regularization schemes, analytically and numerically. Finally, we find that, for the conventional hard-cutoff regularization scheme, the increasing dependence of the critical temperature on the chiral chemical potential is an artifact, which is caused by the fact that it does not include complete contribution from the thermal fluctuations. When the thermal contribution is fully taken into account, the chiral critical temperature should decrease with $\\mu_5$.
The chiral phase transition for QCD with sextet quarks
Sinclair, D K
2011-01-01
QCD with 2 massless colour-sextet quarks is studied as a model of Walking Technicolor. We simulate lattice QCD with 2 light color-sextet staggered quarks at finite temperature, and use the dependence of the coupling at the chiral transition on the temporal extent, $N_t$, of the lattice in lattice units to study the running of the bare lattice coupling with lattice spacing. Our goal is to determine whether this theory is QCD-like and `walks', or if it is conformal. If it is QCD-like, the coupling at the chiral transition should tend to zero as $N_t \\rightarrow \\infty$ in a manner controlled by asymptotic freedom, i.e. by the perturbative $\\beta$-function. On the other hand, if this theory is conformal, this coupling will approach a non-zero limit in the $N_t \\rightarrow \\infty$ limit. We are extending our simulations on an $N_t=8$ lattice to determine the position of the chiral transition with greater accuracy, and are performing simulations on an $N_t=12$ lattice.
Probing the chiral phase transition of Nf=2 clover fermions with valence overlap fermions
Overlap fermions are a powerful tool for investigating the chiral and topological structure of the vacuum and the thermal states of QCD. We study various chiral and topological aspects of the finite temperature phase transition of Nf=2 flavours of O(a) improved Wilson fermions, using valence overlap fermions as a probe. Particular emphasis is placed upon the analysis of the spectral density and the localisation properties of the eigenmodes as well as on the local structure of topological charge fluctuations in the vicinity of the chiral phase transition. The calculations are done on 163 x 8 lattices generated by the DIK collaboration. (orig.)
Chiral phase transition in the soft-wall model of AdS/QCD
Chelabi, Kaddour; Fang, Zhen; Huang, Mei; Li, Danning; Wu, Yue-Liang
2016-04-01
We investigate the chiral phase transition in the soft-wall model of AdS/QCD at zero chemical potential for two-flavor and three-flavor cases, respectively. We show that there is no spontaneous chiral symmetry breaking in the original soft-wall model. After detailed analysis, we find that in order to realize chiral symmetry breaking and restoration, both profiles for the scalar potential and the dilaton field are essential. The scalar potential determines the possible solution structure of the chiral condensate, except the mass term, it takes another quartic term for the two-flavor case, and for the three-flavor case, one has to take into account an extra cubic term due to the t'Hooft determinant interaction. The profile of the dilaton field reflects the gluodynamics, which is negative at a certain ultraviolet scale and approaches positive quadratic behavior at far infrared region. With this set-up, the spontaneous chiral symmetry breaking in the vacuum and its restoration at finite temperature can be realized perfectly. In the two-flavor case, it gives a second order chiral phase transition in the chiral limit, while the transition turns to be a crossover for any finite quark mass. In the case of three-flavor, the phase transition becomes a first order one in the chiral limit, while above sufficient large quark mass it turns to be a crossover again. This scenario agrees exactly with the current understanding on chiral phase transition from lattice QCD and other effective model studies.
Chiral and deconfinement phase transition in the Hamiltonian approach to QCD in Coulomb gauge
Reinhardt, H
2016-01-01
The chiral and deconfinement phase transitions are investigated within the variational Hamiltonian approach to QCD in Coulomb gauge. The temperature $\\beta^{-1}$ is introduced by compactifying a spatial dimension. Thereby the whole temperature dependence is encoded in the vacuum state on the spatial manifold $\\mathbb{R}^2 \\times S^1(\\beta)$. The chiral quark condensate and the dual quark condensate (dressed Polyakov loop) are calculated as function of the temperature. From their inflection points the pseudo-critical temperatures for the chiral and deconfinement crossover transitions are determined. Using the zero-temperature quark and gluon propagators obtained within the variational approach as input, we find 226 MeV and 262 MeV, respectively, for the chiral and deconfinement transition.
UA(1) breaking and phase transition in chiral random matrix model
Sano, T; Ohtani, M
2009-01-01
We propose a chiral random matrix model which properly incorporates the flavor-number dependence of the phase transition owing to the \\UA(1) anomaly term. At finite temperature, the model shows the second-order phase transition with mean-field critical exponents for two massless flavors, while in the case of three massless flavors the transition turns out to be of the first order. The topological susceptibility satisfies the anomalous \\UA(1) Ward identity and decreases gradually with the temperature increased.
Effects of gauge boson mass on chiral and deconfinement phase transitions in QED$_{3}$
Yin, Pei-Lin; Feng, Hong-Tao; Zong, Hong-Shi
2016-01-01
Based on the experimental observation that there is a coexisting region between the antiferromagnetic (AF) and $\\textit{d}$-wave superconducting ($\\textit{d}$SC) phases, the influences of gauge boson mass $m_{a}$ on chiral symmetry restoration and deconfinement phase transitions in QED$_{3}$ are investigated simultaneously within a unified framework, i.e., Dyson-Schwinger equations. The results show that the chiral symmetry restoration phase transition in the presence of the gauge boson mass $m_{a}$ is a typical second-order phase transition; the chiral symmetry restoration and deconfinement phase transitions are coincident; the critical number of fermion flavors $N^{c}_{f}$ decreases as the gauge boson mass $m_{a}$ increases and there exists a boundary that separates the $N^{c}_{f}$-$m_{a}$ plane into chiral symmetry breaking/confinement region for ($N_{f}^{c}$, $m_{a}$) below the boundary and chiral symmetry restoration/deconfinement region for ($N_{f}^{c}$, $m_{a}$) above it.
Amplification of Quantum Meson Modes in the Late Time of the Chiral Phase Transition
Watanabe, K
2007-01-01
We investigate the time evolution of the quantum meson modes in the late time of chiral phase transition. In particular, it is shown that there exists a possible solution to the equation of motion for the quantum meson modes, which reveals a parametric resonance and/or resonance through forced oscillation induced by the small oscillation of the chiral condensate. After that, we demonstrate the unstable regions for the quantum meson modes in both the cases of a uniform and spatially expanding system.
The chicken or the egg; or Who ordered the chiral phase transition?
Kogan, I I; Tekin, B; Kogan, Ian I.; Kovner, Alex; Tekin, Bayram
2001-01-01
We draw an analogy between the deconfining transition in the 2+1 dimensional Georgi-Glashow model and the chiral phase transition in 3+1 dimensional QCD. Based on the detailed analysis of the former (hep-th/0010201) we suggest that the chiral symmetry restoration in QCD at high temperature is driven by the thermal ensemble of baryons and antibaryons. The chiral symmetry is restored when roughly half of the volume is occupied by the baryons. Surprisingly enough, even though baryons are rather heavy, a crude estimate for the critical temperature gives $T_c=180$ Mev. In this scenario the binding of the instantons is not the cause but rather a consequence of the chiral symmetry restoration.
Chiral Phase Transition and Meson Melting from AdS/QCD
Bartz, Sean P
2016-01-01
We investigate the in-medium behavior of mesons at finite temperature and baryon chemical potential within a soft-wall model of AdS/QCD. We use a quartic scalar potential to obtain the correct form of chiral symmetry breaking. At zero quark mass the chiral phase transition is second-order, becoming a crossover at physical quark mass. At zero baryon chemical potential, we find a chiral transition temperature of 155 MeV in the chiral limit and a pseudo-transition temperature of 151 MeV at physical quark mass, consistent with lattice results. In the low-temperature limit, the second-order transition occurs at a baryon chemical potential of 566 MeV while the rapid crossover occurs at 559 MeV. A new parameterization of the dilaton profile results in improved meson spectra. Meson melting occurs at a lower temperature and chemical potential than the chiral phase transition, so the vector-axial vector mass splitting remains constant until the bound states melt.
Zhang, Zhao
2010-01-01
The combined effect of the repulsive vector interaction and the positive electric chemical potential on the chiral phase transition is investigated by considering neutral color superconductivity. Under the charge-neutrality constraint, the chiral condensate, diquark condensate and quark number densities are obtained in two-plus-one-flavor Nambu-Jona-Lasinio model with the so called Kobayashi-Maskawa-'t Hooft term. We demonstrate that multiple chiral critical-point structures always exist in the Nambu-Jona-Lasinio model within the self-consistent mean-field approximation, and that the number of chiral critical points can vary from zero to four, which is dependent on the magnitudes of vector interaction and the diquark coupling.
The $N_f= 2$ chiral phase transition from imaginary chemical potential with Wilson Fermions
Philipsen, Owe
2015-01-01
The order of the thermal transition in the chiral limit of QCD with two dynamical flavours of quarks is a long-standing issue. Still, it is not definitely known whether the transition is of first or second order in the continuum limit. Which of the two scenarios is realized has important implications for the QCD phase diagram and the existence of a critical endpoint at finite densities. Settling this issue by simulating at successively decreased pion mass was not conclusive yet. Recently, an alternative approach was proposed, extrapolating the first order phase transition found at imaginary chemical potential to zero chemical potential with known exponents, which are induced by the Roberge-Weiss symmetry. For staggered fermions on $N_t=4$ lattices, this results in a first order transition in the chiral limit. Here we report of $N_t=4$ simulations with Wilson fermions, where the first order region is found to be large.
The Chirality Of Life: From Phase Transitions To Astrobiology
Gleiser, Marcelo
2008-01-01
The search for life elsewhere in the universe is a pivotal question in modern science. However, to address whether life is common in the universe we must first understand the likelihood of abiogenesis by studying the origin of life on Earth. A key missing piece is the origin of biomolecular homochirality: permeating almost every life-form on Earth is the presence of exclusively levorotary amino acids and dextrorotary sugars. In this work we discuss recent results suggesting that life's homochirality resulted from sequential chiral symmetry breaking triggered by environmental events in a mechanism referred to as punctuated chirality. Applying these arguments to other potentially life-bearing platforms has significant implications for the search for extraterrestrial life: we predict that a statistically representative sampling of extraterrestrial stereochemistry will be racemic on average.
Chiral phase transition and Schwinger mechanism in a pure electric field
Cao, Gaoqing
2016-01-01
We systematically study the chiral symmetry breaking and restoration in the presence of a pure electric field in the Nambu--Jona-Lasinio (NJL) model at finite temperature and baryon chemical potential. In addition, we also study the effect of the chiral phase transition on the charged pair production due to the Schwinger mechanism. For these purposes, a general formalism for parallel electric and magnetic fields is developed at finite temperature and chemical potential for the first time. In the pure electric field limit $B\\rightarrow0$, we compute the order parameter, the transverse-to-longitudinal ratio of the Goldstone mode velocities, and the Schwinger pair production rate as functions of the electric field. The inverse catalysis effect of the electric field to chiral symmetry breaking is recovered. And the Goldstone mode is find to disperse anisotropically such that the transverse velocity is always smaller than the longitudinal one, especially at nonzero temperature and baryon chemical potential. As exp...
Chiral phase transition in a lattice fermion-gauge-scalar model with U(1) gauge symmetry
The chiral phase transition induced by a charged scalar field is investigated numerically in a lattice fermion-gauge-scalar model with U(1) gauge symmetry, proposed recently as a model for dynamical fermion mass generation. For very strong gauge coupling the transition is of second order and its scaling properties are very similar to those of the Nambu-Jona-Lasinio model. However, in the vicinity of the tricritical point at somewhat weaker coupling, where the transition changes the order, the scaling behavior is different. Therefore it is worthwhile to investigate the continuum limit of the model at this point. (orig.)
The chiral phase transition in two-flavor QCD from imaginary chemical potential
Bonati, Claudio; D'Elia, Massimo; Philipsen, Owe; Sanfilippo, Francesco
2014-01-01
We investigate the order of the finite temperature chiral symmetry restoration transition for QCD with two massless fermions, by using a novel method, based on simulating imaginary values of the quark chemical potential $\\mu=i\\mu_i,\\mu_i\\in\\mathbb{R}$. Our method exploits the fact that, for low enough quark mass $m$ and large enough chemical potential $\\mu_i$, the chiral transition is decidedly first order, then turning into crossover at a critical mass $m_c(\\mu)$. It is thus possible to determine the critical line in the $m - \\mu^2$ plane, which can be safely extrapolated to the chiral limit by taking advantage of the known tricritical indices governing its shape. We test this method with standard staggered fermions and the result of our simulations is that $m_c(\\mu=0)$ is positive, so that the phase transition at zero density is definitely first order in the chiral limit, on our coarse $N_t=4$ lattices with $a\\simeq 0.3\\,\\mathrm{fm}$.
Nf=2 QCD chiral phase transition with Wilson fermions at zero and imaginary chemical potential
Philipsen, Owe; Pinke, Christopher
2016-06-01
The order of the thermal phase transition in the chiral limit of quantum chromodynamics (QCD) with two dynamical flavors of quarks is a long-standing issue and still not known in the continuum limit. Whether the transition is first or second order has important implications for the QCD phase diagram and the existence of a critical end point at finite densities. We follow a recently proposed approach to explicitly determine the region of first order chiral transitions at imaginary chemical potential, where it is large enough to be simulated, and extrapolate it to zero chemical potential with known critical exponents. Using unimproved Wilson fermions on coarse Nt=4 lattices, the first order region turns out to be so large that no extrapolation is necessary. The critical pion mass mπc≈560 MeV is by nearly a factor 10 larger than the corresponding one using staggered fermions. Our results are in line with investigations of three-flavor QCD using improved Wilson fermions and indicate that the systematic error on the two-flavor chiral transition is still of order 100%.
Chiral Phase Transition in the Soft-Wall Model of AdS/QCD
Chelabi, Kaddour; Huang, Mei; Li, Danning; Wu, Yue-Liang
2015-01-01
We investigate the chiral phase transition in the soft-wall model of AdS/QCD at zero chemical potential for two-flavor and three-flavor cases, respectively. We show that there is no spontaneous chiral symmetry breaking in the original soft-wall model. After detailed analysis, we find that in order to realize chiral symmetry breaking and restoration, both profiles for the scalar potential and the dilaton field are essential. The scalar potential determines the possible solution structure of the chiral condensate, except the mass term, it takes another quartic term for the two-flavor case, and for the three-flavor case, one has to take into account an extra cubic term due to the t'Hooft determinant interaction. The profile of the dilaton field reflects the gluodynamics, which is negative at a certain ultraviolet scale and approaches positive quadratic behavior at far infrared region. With this set-up, the spontaneous chiral symmetry breaking in the vacuum and its restoration at finite temperature can be realize...
A large N phase transition in the continuum two dimensional SU(N) X SU(N) principal chiral model
R. Narayanan; Neuberger, H.; Vicari, E.
2008-01-01
It is established by numerical means that the continuum large N principal chiral model in two dimensions has a phase transition in a smoothed two point function at a critical distance of the order of the correlation length.
Chiral phase transition scenarios from the vector meson extended Polyakov quark meson model
Kovács, Péter
2015-01-01
Chiral phase transition is investigated in an $SU(3)_L \\times SU(3)_R$ symmetric vector meson extended linear sigma model with additional constituent quarks and Polyakov loops (extended Polyakov quark meson model). The parameterization of the Lagrangian is done at zero temperature in a hybrid approach, where the mesons are treated at tree-level, while the constituent quarks at 1-loop level. The temperature and baryochemical potential dependence of the two assumed scalar condensates are calculated from the hybrid 1-loop level equations of states. The order of the phase transition along the $T=0$ and $\\mu_B=0$ axes are determined for various parameterization scenarios. We find that in order to have a first order phase transition at $T=0$ as a function of $\\mu_B$ a light isoscalar particle is needed.
Ghazaryan, Areg; Chakraborty, Tapash
2015-12-01
We have studied the influence of electron-electron interaction on the fractal butterfly spectrum of Dirac fermions in biased bilayer graphene in the fractional quantum Hall effect (FQHE) regime. We demonstrate that the butterfly spectrum exhibits remarkable phase transitions between the FQHE gap and the butterfly gap for chiral electrons in bilayer graphene, when the periodic potential strength or the bias voltage is varied. We also find that, in addition to those phase transitions, by varying the bias voltage one can effectively control the periodic potential strength experienced by the electrons. The electron-electron interaction causes the butterfly spectrum to exhibit new gaps inside the Bloch sub-bands not found in the single-particle case. We expect that both the observed phase transition and other new features in the butterfly spectrum of interacting Dirac fermions will be of great interest to researchers from diverse fields.
Influence of the Polyakov loop on the chiral phase transition in the two flavor chiral quark model
Markó, G.; Szép, Zs.
2010-09-01
The SU(2)L×SU(2)R chiral quark model consisting of the (σ,π→) meson multiplet and the constituent quarks propagating on the homogeneous background of a temporal gauge field is solved at finite temperature and quark baryon chemical potential μq using an expansion in the number of flavors Nf, both in the chiral limit and for the physical value of the pion mass. Keeping the fermion propagator at its tree level, several approximations to the pion propagator are investigated. These approximations correspond to different partial resummations of the perturbative series. Comparing their solution with a diagrammatically formulated resummation relying on a strict large-Nf expansion of the perturbative series, one concludes that only when the local part of the approximated pion propagator resums infinitely many orders in 1/Nf of fermionic contributions a sufficiently rapid crossover transition at μq=0 is achieved allowing for the existence of a tricritical point or a critical end point in the μq-T phase diagram. The renormalization and the possibility of determining the counterterms in the resummation provided by a strict large-Nf expansion are investigated.
Eser, Jürgen; Rischke, Dirk H
2015-01-01
The transition in quantum chromodynamics (QCD) from hadronic matter to the quark-gluon plasma (QGP) at high temperatures and/or net-baryon densities is associated with the restoration of chiral symmetry and can be investigated in the laboratory via heavy-ion collisions. We study this chiral transition within the functional renormalization group (FRG) approach applied to the two-flavor version of the extended Linear Sigma Model (eLSM). The eLSM is an effective model for the strong interaction and features besides scalar and pseudoscalar degrees of freedom also vector and axial- vector mesons. We discuss the impact of the quark masses and the axial anomaly on the order of the chiral transition. We also confirm the degeneracy of the masses of chiral partners above the transition temperature. We find that the mass of the $a_1$ meson ($\\rho$ meson) decreases (increases) towards the chiral transition.
Eser, Jürgen; Grahl, Mara; Rischke, Dirk H.
2015-11-01
The transition in quantum chromodynamics from hadronic matter to the quark-gluon plasma at high temperatures and/or net-baryon densities is associated with the restoration of chiral symmetry and can be investigated in the laboratory via heavy-ion collisions. We study this chiral transition within the functional renormalization group approach applied to the two-flavor version of the extended linear sigma model (eLSM). The eLSM is an effective model for the strong interaction and features besides scalar and pseudoscalar degrees of freedom also vector and axial-vector mesons. We discuss the impact of the quark masses and the axial anomaly on the order of the chiral transition. We also confirm the degeneracy of the masses of chiral partners above the transition temperature. We find that the mass of the a1 meson (ρ meson) decreases (increases) towards the chiral transition.
Progress in vacuum susceptibilities and their applications to the chiral phase transition of QCD
The QCD vacuum condensates and various vacuum susceptibilities are all important parameters which characterize the nonperturbative properties of the QCD vacuum. In the QCD sum rules external field formula, various QCD vacuum susceptibilities play important roles in determining the properties of hadrons. In this paper, we review the recent progress in studies of vacuum susceptibilities together with their applications to the chiral phase transition of QCD. The results of the tensor, the vector, the axial–vector, the scalar, and the pseudo-scalar vacuum susceptibilities are shown in detail in the framework of Dyson–Schwinger equations
Effects of (axialvector mesons on the chiral phase transition: initial results
Kovács P.
2014-01-01
Full Text Available We investigate the effects of (axialvector mesons on the chiral phase transition in the framework of an SU(3, (axialvector meson extended linear sigma model with additional constituent quarks and Polyakov loops. We determine the parameters of the Lagrangian at zero temperature in a hybrid approach, where we treat the mesons at tree-level, while the constituent quarks at 1-loop level. We assume two nonzero scalar condensates and together with the Polyakov-loop variables we determine their temperature dependence according to the 1-loop level field equations.
Chiral phase transition at finite temperature and conformal dynamics in large Nf QCD
Miura, Kohtaroh
2011-01-01
We investigate the chiral phase transition at finite temperature (T) in colour SU(Nc=3) Quantum Chromodynamics (QCD) with six species of fermions (Nf=6) in the fundamental representation by using lattice QCD with improved staggered fermions. By considering lattices with several temporal extensions Nt, we observe asymptotic scaling for Nt > 4. We then extract the dimensionless ratio Tc/Lambda_L (Lambda_L = Lattice Lambda-parameter) for Nf = 6 and Nf = 8, the latter relying on our earlier results. Further, we collect the critical couplings beta^c for the chiral phase transition at Nf = 0 (quenched), and Nf = 4 at a fixed Nt = 6. The results are consistent with enhanced fermionic screening at larger Nf. The Tc/Lambda_L depends very mildly on Nf in the Nf = 0 - 4 region, starts increasing at Nf = 6, and becomes significantly larger at Nf = 8, close to the edge of the conformal window. We discuss interpretations of these results as well as their possible interrelation with preconformal dynamics in the light of a f...
Dynamics of the chiral transition
Measurements of disoriented chiral condensates (DCC) in heavy ion collisions at RHIC can yield fundamental information on the nature of the QCD phase transition. I review theoretical efforts to understand DCC formation and present work in progress on possible experimental ramifications
Fluctuations and the Phase Transition in a Chiral Model with Polyakov Loops
Sasaki, C.; Friman, B.; Redlich, K.
2007-01-01
We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation, where both chiral symmetry and confinement are taken into account. We focus on the phase structure of the model and study the chiral and Polyakov loop susceptibilities.
Chiral phase transition and meson spectrum in improved soft-wall AdS/QCD
Fang, Zhen; Zhang, Lin
2016-01-01
We investigate in detail the chiral thermal transition of QCD in an improved soft-wall AdS/QCD model with a simply modified 5D conformal mass of the bulk scalar field. We also present a calculation in this model for the light meson spectra and other low-energy characteristic quantities including the pion form factor, the pi-rho coupling constant and the decay constants of pi, rho, a_1, which are shown to result in a good agreement with experimental data except for the pion decay constant. The thermal behavior of chiral condensate is studied. It is found that such a simply improved soft-wall model incorporates the crossover behavior of chiral thermal transition indicated by lattice simulations. The expected chiral transition temperature can be obtained.
Chiral phase transition in the vector meson extended linear sigma model
Kovács, Péter; Wolf, György
2015-01-01
In the framework of an SU(3) (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops, we investigate the effects of (axial)vector mesons on the chiral phase transition. The parameters of the Lagrangian are set at zero temperature and we use a hybrid approach where in the effective potential the constituent quarks are treated at one-loop level and all the mesons at tree-level. We have four order parameters, two scalar condensates and two Polyakov loop variables and their temperature and baryochemical potential dependence are determined from the corresponding field equations. We also investigate the changes of the tree-level scalar meson masses in the hot and dense medium.
Ichihara, Terukazu; Ohnishi, Akira
2015-01-01
We investigate the net-baryon number fluctuations across the chiral phase transition at finite density in the strong coupling and chiral limit. Mesonic field fluctuations are taken into account by using the auxiliary field Monte-Carlo method. We find that the higher-order cumulant ratios, $S\\sigma$ and $\\kappa\\sigma^2$, show oscillatory behavior around the phase boundary at $\\mu/T\\gtrsim 0.2$, and there exists the region where the higher-order cumulant ratios are negative. The negative region of $\\kappa\\sigma^2$ is found to shrink with increasing lattice size. This behavior agrees with the expectations from the scaling analysis.
Global Currents, Phase Transitions, and Chiral Symmetry Breaking in Large N_c Gauge Theory
Albash, T; Johnson, C V; Kundu, A; Albash, Tameem; Filev, Veselin; Johnson, Clifford V.; Kundu, Arnab
2006-01-01
We study the finite temperature dynamics of SU(N_c) gauge theory for large N_c, with fundamental quark flavours in a quenched approximation, in the presence of a fixed charge under a global current. We observe several notable phenomena. There is a first order phase transition where the quark condensate jumps discontinuously at finite quark mass, generalizing similar transitions seen at zero charge. We find a non-zero condensate at zero quark mass above a critical value of the charge, corresponding to an analogue of spontaneous chiral symmetry breaking at finite number density. We find that the spectrum of mesons contains the expected associated Goldstone (``pion'') degrees of freedom with a mass dependence on the quark mass that is consistent with the Gell-Mann-Oakes-Renner relation. Our tool in these studies is holography, the string dual of the gauge theory being the geometry of $N_c$ spinning D3-branes at finite temperature, probed by a D7-brane.
Chiral phase transitions in the linear sigma model in the Tsallis nonextensive statistics
Ishihara, Masamichi
2016-01-01
We studied chiral phase transitions in the Tsallis nonextensive statistics which has two parameters, the temperature $T$ and entropic parameter $q$. The linear sigma model was used in this study. The critical temperature, condensate, masses, and energy density were calculated under the massless free particle approximation. The critical temperature decreases as $q$ increases. The condensate at $q>1$ is smaller than that at $q=1$. The sigma mass at $q>1$ is heavier than the mass at $q=1$ at high temperature, while the sigma mass at $q>1$ is lighter than the mass at $q=1$ at low temperature. The pion mass at $q>1$ is heavier than the mass at $q=1$. The energy density increases remarkably as $q$ increases. The $q$ dependence in the case of the $q$-expectation value is weaker than that in the case of the conventional expectation value with a Tsallis distribution. The parameter $q$ should be smaller than $4/3$ from energetic point of view. The validity of the Tsallis statistics can be determined by the difference i...
Umeda, T; Kanaya, K; Maezawa, Y; Nakagawa, Y; Ohno, H; Saito, H; Yoshida, S
2013-01-01
We study scaling behavior of a chiral order parameter in the low density region, performing a simulation of two-flavor QCD with improved Wilson quarks. The scaling behavior of the chiral order parameter defined by a Ward-Takahashi identity agrees with the scaling function of the three-dimensional O(4) spin model at zero chemical potential. We extend the scaling study to finite density QCD. Applying the reweighting method and calculating derivatives of the chiral order parameter with respect to the chemical potential, the scaling properties of the chiral phase transition are discussed in the low density region. We moreover calculate the curvature of the phase boundary of the chiral phase transition in the temperature and chemical potential plane assuming the O(4) scaling relation.
The effect of the Polyakov loop on the chiral phase transition
Szép Zs.
2011-04-01
Full Text Available The Polyakov loop is included in the S U(2L × S U(2R chiral quark-meson model by considering the propagation of the constituent quarks, coupled to the (σ, π meson multiplet, on the homogeneous background of a temporal gauge field, diagonal in color space. The model is solved at finite temperature and quark baryon chemical potential both in the chiral limit and for the physical value of the pion mass by using an expansion in the number of flavors Nf. Keeping the fermion propagator at its tree-level, a resummation on the pion propagator is constructed which resums infinitely many orders in 1/Nf, where O(1/Nf represents the order at which the fermions start to contribute in the pion propagator. The influence of the Polyakov loop on the tricritical or the critical point in the µq – T phase diagram is studied for various forms of the Polyakov loop potential.
The effect of the Polyakov loop on the chiral phase transition
Markó, G.; Szép, Zs.
2011-04-01
The Polyakov loop is included in the S U(2)L × S U(2)R chiral quark-meson model by considering the propagation of the constituent quarks, coupled to the (σ, π) meson multiplet, on the homogeneous background of a temporal gauge field, diagonal in color space. The model is solved at finite temperature and quark baryon chemical potential both in the chiral limit and for the physical value of the pion mass by using an expansion in the number of flavors Nf. Keeping the fermion propagator at its tree-level, a resummation on the pion propagator is constructed which resums infinitely many orders in 1/Nf, where O(1/Nf) represents the order at which the fermions start to contribute in the pion propagator. The influence of the Polyakov loop on the tricritical or the critical point in the µq - T phase diagram is studied for various forms of the Polyakov loop potential.
Ruggieri, M
2016-01-01
In this article we study spontaneous chiral symmetry breaking for quark matter in the background of an electric-magnetic flux tube with static, homogeneous and parallel electric field $\\bm E$ and magnetic field $\\bm B$. We use a Nambu-Jona-Lasinio model with a local kernel interaction to compute the relevant quantities to describe chiral symmetry breaking at finite temperature for a wide range of $E$ and $B$. We study the effect of the flux tube background on inverse catalysis of chiral symmetry breaking for $E$ and $B$ of the same order of magnitude. We then focus on the effect of equilibration of chiral density, $n_5$, produced dynamically by axial anomaly on the critical temperature. The equilibration of $n_5$, a consequence of chirality flipping processes in the thermal bath, allows for the introduction of the chiral chemical potential, $\\mu_5$, which is computed self-consistently as a function of temperature and field strength by coupling the number equation to the gap equation. We find that even if chir...
The chiral phase transition for lattice QCD with 2 colour-sextet quarks
Kogut, J B
2015-01-01
QCD with 2 flavours of massless colour-sextet quarks is studied as a possible walking-Technicolor candidate. We simulate the lattice version of this model at finite temperatures near to the chiral-symmetry restoration transition, to determine whether it is indeed a walking theory (QCD-like with a running coupling which evolves slowly over an appreciable range of length scales) or if it has an infrared fixed point, making it a conformal field theory. The lattice spacing at this transition is decreased towards zero by increasing the number $N_t$ of lattice sites in the temporal direction. Our simulations are performed at $N_t=4,6,8,12$, on lattices with spatial extent much larger than the temporal extent. A range of small fermion masses is chosen to make predictions for the chiral (zero mass) limit. We find that the bare lattice coupling does decrease as the lattice spacing is decreased. However, it decreases more slowly than would be predicted by asymptotic freedom. We discuss whether this means that the coupl...
Anomalous dimension, chiral phase transition and inverse magnetic catalysis in soft-wall AdS/QCD
Fang, Zhen
2016-07-01
A modified soft-wall AdS/QCD model with a z-dependent bulk scalar mass is proposed. We argue for the necessity of a modified bulk scalar mass from the quark mass anomalous dimension and carefully constrain the form of bulk mass by the corresponding UV and IR asymptotics. After fixing the form of bulk scalar mass, we calculate the mass spectra of (axial-)vector and pseudoscalar mesons, which have a good agreement with the experimental data. The behavior of chiral phase transition is also investigated, and the results are consistent with the standard scenario and lattice simulations. Finally, the issue of chiral magnetic effects is addressed. We find that the inverse magnetic catalysis emerges naturally from the modified soft-wall model, which is consistent with the recent lattice simulations.
The chiral phase transition for lattice QCD with 2 color-sextet quarks
Kogut, J. B.; Sinclair, D. K.
2015-09-01
QCD with 2 flavors of massless color-sextet quarks is studied as a possible walking-Technicolor candidate. We simulate the lattice version of this model at finite temperatures near to the chiral-symmetry restoration transition, to determine whether it is indeed a walking theory (QCD-like with a running coupling which evolves slowly over an appreciable range of length scales) or if it has an infrared fixed point, making it a conformal field theory. The lattice spacing at this transition is decreased towards zero by increasing the number Nt of lattice sites in the temporal direction. Our simulations are performed at Nt=4 ,6 ,8 ,12 , on lattices with spatial extent much larger than the temporal extent. A range of small fermion masses is chosen to make predictions for the chiral (zero mass) limit. We find that the bare lattice coupling does decrease as the lattice spacing is decreased. However, it decreases more slowly than would be predicted by asymptotic freedom. We discuss whether this means that the coupling is approaching a finite value as lattice Nt is increased—the conformal option, or if the apparent disagreement with the scaling predicted by asymptotic freedom is because the lattice coupling is a poor expansion parameter, and the theory walks. Currently, evidence favors QCD with 2 color-sextet quarks being a conformal field theory. Other potential sources of disagreement with the walking hypothesis are also discussed. We also report an estimate of the position of the deconfinement transition for Nt=12 , needed for choosing parameters for zero-temperature simulations.
Novel Lifshitz point for chiral transition in the magnetic field
Toshitaka Tatsumi
2015-04-01
Full Text Available Based on the generalized Ginzburg–Landau theory, chiral phase transition is discussed in the presence of magnetic field. Considering the chiral density wave we show that chiral anomaly gives rise to an inhomogeneous chiral phase for nonzero quark-number chemical potential. Novel Lifshitz point appears on the vanishing chemical potential line, which may be directly explored by the lattice QCD simulation.
Cooper, F. [Los Alamos National Labs., NM (United States)
1997-09-22
This paper contains viewgraphs on unusual dileptons at Brookhaven RHIC. A field theory approach is used based on a non-equilibrium chiral phase transformation utilizing the schroedinger and Heisenberg picture.
The effect of the Polyakov loop on the chiral phase transition
Szép Zs.; Markó G.
2010-01-01
The Polyakov loop is included in the SU(2)_L x SU(2)_R chiral quark-meson model by considering the propagation of the constituent quarks, coupled to the (sigma,pi) meson multiplet, on the homogeneous background of a temporal gauge field, diagonal in color space. The model is solved at finite temperature and quark baryon chemical potential both in the chiral limit and for the physical value of the pion mass by using an expansion in the number of flavors N_f. Keeping the fermion propagator at i...
Chiral and deconfinement phase transitions in N{sub f}=2 and N{sub f}=2+1 quantum chromodynamics
Luecker, Jan
2013-07-15
In this thesis, we investigate the phase structure of quantum chromodynamics (QCD) in the framework of Dyson-Schwinger equations (DSEs). The aim is to study the chiral and deconfinement phase transitions at finite chemical potential. To this end, we employ and test a novel truncation scheme for the quark and gluon Dyson-Schwinger equations. We develop our truncation in three steps. To begin with, we use a quenched gluon propagator from lattice Yang-Mills theory. To account for unquenching, we then add the quark loop in the gluon DSE, firstly with bare quarks and in the final version of our truncation with fully dressed quarks. In the last step it is also possible to take into account the coupling of light and strange quarks. In effective models, fermionic fluctuations have been shown to move the critical end-point to large densities. We confirm this finding within our truncation for the unquenched gluon. However, this effect is suppressed once the full non-perturbative quark in the quark loop is taken into account. For the confinement/deconfinement transition we investigate three order parameters that are accessible from the quark and gluon propagators. These are the dressed Polyakov loop, the Polyakov-loop potential and positivity violations in the quark propagator. From both Polyakov-loop related order parameters, we find that the deconfinement transition can always be found in vicinity of the chiral transition. Especially at the critical end-point the phase transitions coincide. We also find that signals of positivity violations in the quark propagator vanish at the chiral transition for the two-flavour case. However, with 2+1 flavours, we find a region at large density where chiral symmetry is restored but positivity is violated. This requires further investigations. Finally, we improve our truncation by considering the back-reaction of pions in a model that has been developed in previous work. Within this model we find only a small impact on the phase
On the strength of the $U_A(1)$ anomaly at the chiral phase transition in $N_f=2$ QCD
Brandt, Bastian B; Meyer, Harvey B; Philipsen, Owe; Robaina, Daniel; Wittig, Hartmut
2016-01-01
We study the thermal transition of QCD with two degenerate light flavours by lattice simulations using $O(a)$-improved Wilson quarks. Temperature scans are performed at a fixed value of $N_t = (aT)^{-1}=16$, where $a$ is the lattice spacing and $T$ the temperature, at three fixed zero-temperature pion masses between 200 MeV and 540 MeV. In this range we find that the transition is consistent with a broad crossover. As a probe of the restoration of chiral symmetry, we study the static screening spectrum. We observe a degeneracy between the transverse isovector vector and axial-vector channels starting from the transition temperature. Particularly striking is the strong reduction of the splitting between isovector scalar and pseudoscalar screening masses around the chiral phase transition by at least a factor of three compared to its value at zero temperature. In fact, the splitting is consistent with zero within our uncertainties. This disfavours a chiral phase transition in the $O(4)$ universality class.
Hisao Nakkagawa; Hiroshi Yokota; Koji Yoshida; Yuko Fueki
2003-05-01
Chiral phase transition in thermal QCD is studied by using the Dyson–Schwinger (DS) equation in the real time hard thermal loop approximation. Our results on the critical temperature and the critical coupling are signiﬁcantly different from those in the preceding analyses in the ladder DS equation, showing the importance of properly taking into account the essential thermal effects, namely the Landau damping and the unstable nature of thermal quasiparticles.
Chiral transition with magnetic fields
Ayala, Alejandro; Mizher, Ana Julia; Rojas, Juan Cristobal; Villavicencio, Cristian
2014-01-01
We study the nature of the chiral transition for an effective theory with spontaneous breaking of symmetry, where charged bosons and fermions are subject to the effects of a constant external magnetic field. The problem is studied in terms of the relative intensity of the magnetic field with respect to the mass and the temperature. When the former is the smallest of the scales, we present a suitable method to obtain magnetic and thermal corrections up to ring order at high temperature. By these means, we solve the problem of the instability in the boson sector for these theories, where the squared masses, taken as functions of the order parameter, can vanish and even become negative. The solution is found by considering the screening properties of the plasma, encoded in the resummation of the ring diagrams at high temperature. We also study the case where the magnetic field is the intermediate of the three scales and explore the nature of the chiral transition as we vary the field strength, the coupling const...
Chiral Transition Within Effective Quark Models under Strong Magnetic Fields
Garcia, Andre Felipe
2013-01-01
In the recently years it has been argued that spectators in heavy ion collisions are responsible for creating a strong magnetic field that could play an important role in the QCD phase transition. In this work we use the SU(2) Nambu--Jona-Lasinio (NJL) model in order to study the chiral transition in quark matter subject to a strong magnetic field. We show some results involving the breaking of chiral symmetry and its restoration at finite temperature and density.
Nayek, Prasenjit; Li, Guoqiang
2015-01-01
Blue phase liquid crystal (BPLC) has important applications in adaptive lenses and phase modulators due to its polarization-independent property. During our efforts for development of the new materials, we found a novel phenomenology of phase transition, from focal conic smectic to smectic blue phase in a partially fluorinated cyanophenyl alkyl benzoate ester based nematic liquid crystal (LCM-5773) doped by ultra-high twisting power [H.T.P~160 um^-1] chiral dopant (R5011/3 wt%). Polarized optical microscopy (POM) investigations revealed focal conic and fan-shaped textures typical for columnar mesophases. These focal conic domains (FCDs) are squeezed under electric field and finally at a critical electric field they undergo a dark state. When the electric field is withdrawn, the FCDs are regrown in a one dimensional array with smaller domain size. Interestingly, we have observed the domain size of the FCDs can grow several times by decreasing the cooling rate (0.02 degrees(C)/min.) ten times without any change...
A smart polymer stabilized liquid crystal (PSLC) thin film with temperature-controllable light transmittance was prepared based on a smectic-A (SmA)–chiral nematic (N*) phase transition, and then the effect of the composition and the preparation condition of the PSLC film on its thermo-optical (T-O) characteristics has been investigated in detail. Within the temperature range of the SmA phase, the PSLC shows a strong opaque state due to the focal conic alignment of liquid crystal (LC) molecules, while the film exhibits a transparent state result from the parallel alignment of N* phase LC molecules at a higher temperature. Importantly, the PSLC films with different temperature of phase transition and contrast ratio can be prepared by changing the composition of photo-polymerizable monomer/LC/chiral dopant. According to the competition between the polymerization of the curable monomers and the diffusion of LC molecules, the ultraviolet (UV) curing surrounding temperature and the intensity of UV irradiation play a critical role in tuning the size of the polymer network meshes, which in turn influence the contrast ratio and the switching speed of the film. Our observations are expected to pave the way for preparing smart PSLC thin films for applications in areas of smart windows, thermo-detectors and other information recording devices. (paper)
Phases of chiral gauge theories
We discuss the behavior of two non-supersymmetric chiral SU(N) gauge theories, involving fermions in the symmetric and antisymmetric two-index tensor representations respectively. In addition to global anomaly matching, we employ a recently proposed inequality constraint on the number of effective low energy (massless) degrees of freedom of a theory, based on the thermodynamic free energy. Several possible zero temperature phases are consistent with the constraints. A simple picture for the phase structure emerges if these theories choose the phase, consistent with global anomaly matching, that minimizes the massless degree of freedom count defined through the free energy. This idea suggests that confinement with the preservation of the global symmetries through the formation of massless composite fermions is in general not preferred. While our discussion is restricted mainly to bilinear condensate formation, higher dimensional condensates are considered for one case. We conclude by commenting briefly on two related supersymmetric chiral theories. (c) 2000 The American Physical Society
Chiral transition of fundamental and adjoint quarks
Capdevilla, R.M. [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Doff, A., E-mail: agomes@utfpr.edu.br [Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR (Brazil); Natale, A.A., E-mail: natale@ift.unesp.br [Instituto de Física Teórica, UNESP – Universidade Estadual Paulista, Rua Dr. Bento T. Ferraz, 271, Bloco II, 01140-070 São Paulo, SP (Brazil); Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil)
2014-01-20
The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagator and in the coupling constant. In this case the chiral and deconfinement transition temperatures are approximately the same. For quarks in the adjoint representation, due to the larger Casimir eigenvalue, the gluon exchange is operative and the chiral transition happens at a larger temperature than the deconfinement one.
Chiral transition of fundamental and adjoint quarks
The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagator and in the coupling constant. In this case the chiral and deconfinement transition temperatures are approximately the same. For quarks in the adjoint representation, due to the larger Casimir eigenvalue, the gluon exchange is operative and the chiral transition happens at a larger temperature than the deconfinement one
Solé, Ricard V
2011-01-01
Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation o
Chiral transition of fundamental and adjoint quarks
Capdevilla, R. M.; Doff, A.(Universidade Tecnológica Federal do Paraná – UTFPR – DAFIS, Av. Monteiro Lobato Km 04, 84016-210 Ponta Grossa, PR, Brazil); Natale, A. A.
2014-01-01
The chiral symmetry breaking transition of quarks in the fundamental and adjoint representation is studied in a model where the gap equation contains two contributions, one containing a confining propagator and another corresponding to the exchange of one-dressed dynamically massive gluons. When quarks are in the fundamental representation the confinement effect dominates the chiral symmetry breaking while the gluon exchange is suppressed due to the dynamical gluon mass effect in the propagat...
Finite-Temperature Phase Structure in the Chiral σ-ω Model with Dilatons
ZHANG Xiao-Bing ZHANG Xiao-Bing; LI Xue-Qian; NING Ping-Zhi
2000-01-01
We investigate the finite-temperature phase structure in a scaled chiral model which includes the dilaton (glueball) field. It is shown that hot nuclear matter undergoes a discontinuous transition in the mean field of scalar mesons as well as the Lee-Wick abnormal transition. The corresponding behavior of the gluon condensate during the chiral phase transition is also studied.
Chiral liquid crystals: the vestigial chiral phases of T, O, I matter
Nissinen, Jaakko; Liu, Ke; Slager, Robert-Jan; Wu, Kai; Zaanen, Jan
We show how chiral order develops in vestigial isotropic phases of T , O and I liquid crystalline systems in three dimensions. The liquid crystal phases are realized in a lattice model of orientational degrees of freedom with point group symmetries G ⊂ O (3) , represented as O (3) -rotors coupled to G gauge fields. The model incorporates also disclinations via the gauge fields, features an ordered nematic phase with unbroken G rotations at low temperatures and a high temperature isotropic liquid phase. We observe an intermediate phase with spontaneous chirality but isotropic SO (3) symmetry (a liquid) for the gauge groups T, O, and I, the proper symmetry groups of the tetrahedron, cube and icosahedron, respectively. For the other subgroups of SO (3) , Cn <= ∞ and Dn <= ∞, there is generically only a single phase transition from the nematic phase to the isotropic liquid. We discuss the nature of the phase transitions and conditions under which the chiral phase is stabilized by the nematic order parameter fluctuations. The nature of the vestigial chiral phase is reminiscent of the so-called Ising nematic phase in iron based superconductors. Research supported by the Netherlands foundation for Fundamental Research of Matter (FOM).
Insights on some chiral smectic phases
B Pansu
2003-08-01
Combining layered positional order as smectic order and chirality can generate complex architectures since twist parallel to the layers is not allowed. This paper will review some new experimental results on different phases resulting from the competition between smectic positional order and twist orientational order. It concerns the TGBA and the NL*, that is the liquid line phase as well as the SmQ phase. Chiral effects in the isotropic phase will also be discussed.
Unphysical phases in staggered chiral perturbation theory
Aubin, Christopher; Colletti, Katrina; Davila, George
2016-04-01
We study the phase diagram for staggered quarks using chiral perturbation theory. In beyond-the-standard-model simulations using a large number (>8 ) of staggered fermions, unphysical phases appear for coarse enough lattice spacing. We argue that chiral perturbation theory can be used to interpret one of these phases. In addition, we show that only three broken phases for staggered quarks exist, at least for lattice spacings in the regime a2≪ΛQCD2 .
Finite-temperature chiral transition in real-world QCD?
I present and discuss the first physics results of a Langevin simulation of finite-temperature QCD with a realistic current quark spectrum. Up to several caveats which will need to be addressed by future studies, our present results suggest that there is a first-order chiral restoration phase transition in real-world QCD, that it is driven by the light condensate and that it should be accompanied by a partial restoration of U(1)A symmetry. (orig.)
Symmetry structure and phase transitions
Ashok Goyal; Meenu Dahiya; Deepak Chandra
2003-05-01
We study chiral symmetry structure at ﬁnite density and temperature in the presence of external magnetic ﬁeld and gravity, a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of phase transition in the expanding early Universe and possible formation of quark nuggets and their survival.
Zhao Shun-Cai; Liu Zheng-Dong; Zheng Jun; Li Gen
2011-01-01
This paper suggests a scheme of electromagnetic chirality-induced negative refraction utilizing magneto-electric cross coupling in a four-level atomic system. The negative refraction can be achieved with the two chirality coefficients having the same amplitude but the opposite phase, without requiring the simultaneous presence of an electric-dipole and a magnetic-dipole transition near the same transition frequency.
An Anderson-like model of the QCD chiral transition
Giordano, Matteo; Kovács, Tamás G.; Pittler, Ferenc
2016-06-01
We study the problems of chiral symmetry breaking and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We recast the staggered Dirac operator into an unconventional three-dimensional Anderson Hamiltonian ("Dirac-Anderson Hamiltonian") carrying internal degrees of freedom, with disorder provided by the fluctuations of the gauge links. In this framework, we identify the features relevant to chiral symmetry restoration and localisation of the low-lying Dirac eigenmodes in the ordering of the local Polyakov lines, and in the related correlation between spatial links across time slices, thus tying the two phenomena to the deconfinement transition. We then build a toy model based on QCD and on the Dirac-Anderson approach, replacing the Polyakov lines with spin variables and simplifying the dynamics of the spatial gauge links, but preserving the above-mentioned relevant dynamical features. Our toy model successfully reproduces the main features of the QCD spectrum and of the Dirac eigenmodes concerning chiral symmetry breaking and localisation, both in the ordered (deconfined) and disordered (confined) phases. Moreover, it allows us to study separately the roles played in the two phenomena by the diagonal and the off-diagonal terms of the Dirac-Anderson Hamiltonian. Our results support our expectation that chiral symmetry restoration and localisation of the low modes are closely related, and that both are triggered by the deconfinement transition.
Magnetic properties in the inhomogeneous chiral phase
Yoshiike, Ryo; Tatsumi, Toshitaka
2016-01-01
We investigate the magnetic properties of quark matter in the inhomogeneous chiral phase, where both scalar and pseudoscalar condensates spatially modulate. The energy spectrum of the lowest Landau level becomes asymmetric about zero in the external magnetic field, and gives rise to the remarkably magnetic properties: quark matter has a spontaneous magnetization, while the magnetic susceptibility does not diverge on the critical point.
H. Satz(University of Bielefeld)
2000-01-01
At high temperatures or densities, hadronic matter shows different forms of critical behaviour: colour deconfinement, chiral symmetry restoration, and diquark condensation. I first discuss the conceptual basis of these phenomena and then consider the description of colour deconfinement in terms of symmetry breaking, through colour screening and as percolation transition.
Jens O. Andersen; William R. Naylor(Department of Physics, Norwegian University of Science and Technology, Høgskoleringen 5, N-7491 Trondheim, Norway); Anders Tranberg(Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway)
2014-01-01
We use the Polyakov loop coupled quark-meson model to approximate low energy QCD and present results for the chiral and deconfinement transitions in the presence of a constant magnetic background $B$ at finite temperature $T$ and baryon chemical potential $\\mu_B$. We investigate effects of various gluoni potentials on the deconfinement transition with and without a fermionic backreaction at finite $B$. Additionally we investigate the effect of the Polyakov loop on the chiral phase transition,...
Fluctuations and the Phase Transition in a Chiral Model with Polyakov Loops%引入Polyakov环路的手征模型中的涨落与相变
无
2007-01-01
We explore the NJL model with Polyakov loops for a system of three colors and two flavors within the mean-field approximation, where both chiral symmetry and confinement are taken into account. We focus on the phase structure of the model and study the chiral and Polyakov loop susceptibilities.
Cosmological phase transitions
Kolb, E.W. [Fermi National Accelerator Lab., Batavia, IL (United States)]|[Chicago Univ., IL (United States)
1993-10-01
If modern ideas about the role of spontaneous symmetry breaking in fundamental physics are correct, then the Universe should have undergone a series of phase transitions early in its history. The study of cosmological phase transitions has become an important aspect of early-Universe cosmology. In this lecture I review some very recent work on three aspects of phase transitions: the electroweak transition, texture, and axions.
Cosmological phase transitions
If modern ideas about the role of spontaneous symmetry breaking in fundamental physics are correct, then the Universe should have undergone a series of phase transitions early in its history. The study of cosmological phase transitions has become an important aspect of early-Universe cosmology. In this lecture I review some very recent work on three aspects of phase transitions: the electroweak transition, texture, and axions
VIJ, JAGDISH
2009-01-01
PUBLISHED We investigate both the supercooling and the hysteresis phenomena of the phase transitions between the smectic C* and the smectic C *Aphases driven by temperature and electric field, respectively. These two phenomena show similar characteristics for the dependence of transmittance on both the cell thickness and the applied field. The mechanisms for large supercooling and large hysteresis in thin cells are shown to correspond to the suppression of the propagation of solitary wave ...
HPLC SEPARATION OF CHIRAL ORGANOPHOSPHORUS PESTICIDES ON POLYSACCHARIDE CHIRAL STATIONARY PHASES
High-performance liquid chromatographic separation of the individual enantiomers of 12 organophosphorus pesticides (OPs) were obtained on polysaccharide chiral HPLC columns using an alkane-alcohol mobile phase. The OP pesticides were crotoxyphos, dialifor, dyfonate, fenamiphos, ...
In recent years, quantum phase transitions have attracted the interest of both theorists and experimentalists in condensed matter physics. These transitions, which are accessed at zero temperature by variation of a non-thermal control parameter, can influence the behaviour of electronic systems over a wide range of the phase diagram. Quantum phase transitions occur as a result of competing ground state phases. The cuprate superconductors which can be tuned from a Mott insulating to a d-wave superconducting phase by carrier doping are a paradigmatic example. This review introduces important concepts of phase transitions and discusses the interplay of quantum and classical fluctuations near criticality. The main part of the article is devoted to bulk quantum phase transitions in condensed matter systems. Several classes of transitions will be briefly reviewed, pointing out, e.g., conceptual differences between ordering transitions in metallic and insulating systems. An interesting separate class of transitions is boundary phase transitions where only degrees of freedom of a subsystem become critical; this will be illustrated in a few examples. The article is aimed at bridging the gap between high-level theoretical presentations and research papers specialized in certain classes of materials. It will give an overview on a variety of different quantum transitions, critically discuss open theoretical questions, and frequently make contact with recent experiments in condensed matter physics
Chiral Stationary Phases Based on Silica Modified by Helicenes
Bernard, Martin; Církva, Vladimír; Sýkora, Jan; Storch, Jan
- : -, 2014, s. 74. ISBN N. [Belgian Organic Synthesis Symposium (BOSS XIV) /14./. Louvain-la-Neuve (BE), 13.07.2014-18.07.2014] R&D Projects: GA TA ČR TA01010646 Institutional support: RVO:67985858 Keywords : chiral stationary phase * helicene * chiral resolution Subject RIV: CC - Organic Chemistry
A new generation of chiral phase-transfer catalysts.
Kaneko, Shiho; Kumatabara, Yusuke; Shirakawa, Seiji
2016-06-28
Phase-transfer catalysis has long been recognized as a versatile method for organic synthesis. In particular, over more than the past three decades, asymmetric phase-transfer catalysis based on the use of structurally well-defined chiral catalysts has become a topic of great scientific interest. Although various effective chiral catalysts have already been reported and these catalysts were utilized for practical asymmetric transformations, further design and development of new chiral phase-transfer catalysts are still attractive research subjects in organic chemistry due to the high utility and practicability of phase-transfer-catalyzed reactions. This review focuses on the recent examples of newly designed effective chiral phase-transfer catalysts. PMID:26754659
Computing quantum phase transitions
Vojta, Thomas
2007-01-01
This article first gives a concise introduction to quantum phase transitions, emphasizing similarities with and differences to classical thermal transitions. After pointing out the computational challenges posed by quantum phase transitions, a number of successful computational approaches is discussed. The focus is on classical and quantum Monte Carlo methods, with the former being based on the quantum-to classical mapping while the latter directly attack the quantum problem. These methods ar...
Petry, W.; Neuhaus, J. [Techn. Universitaet Muenchen, Physik Department E13, Munich (Germany)
1996-11-01
Many elements transform from a high temperature bcc phase to a more dense packed temperature phase. The great majority of these transitions are of 1st order, displacive and reconstructive. The lattice potentials which govern these martensitic transitions can be probed by inelastic neutron scattering, thereby answering fundamental questions like : Will the transition be announced by dynamical or static fluctuations? What are the trajectories for the displacements needed for the transformation? Does the vibrational entropy stabilize the high temperature phase? Are the unusual transport properties in these materials related to their ability to transform? (author) 17 figs., 1 tab., 46 refs.
Cosmological phase transitions
If the universe stated from conditions of high temperature and density, there should have been a series of phase transitions associated with spontaneous symmetry breaking. The cosmological phase transitions could have observable consequences in the present Universe. Some of the consequences including the formation of topological defects and cosmological inflation are reviewed here. One of the most important tools in building particle physics models is the use of spontaneous symmetry breaking (SSB). The proposal that there are underlying symmetries of nature that are not manifest in the vacuum is a crucial link in the unification of forces. Of particular interest for cosmology is the expectation that are the high temperatures of the big bang symmetries broken today will be restored, and that there are phase transitions to the broken state. The possibility that topological defects will be produced in the transition is the subject of this section. The possibility that the Universe will undergo inflation in a phase transition will be the subject of the next section. Before discussing the creation of topological defects in the phase transition, some general aspects of high-temperature restoration of symmetry and the development of the phase transition will be reviewed. 29 references, 1 figure, 1 table
Phases of N=1 Supersymmetric Chiral Gauge Theories
Craig, Nathaniel; /Princeton, Inst. Advanced Study /Rutgers U., Piscataway; Essig, Rouven; /Princeton, Inst. Advanced Study /YITP, Stony Brook /SLAC /Stanford U., Phys. Dept.; Hook, Anson; Torroba, Gonzalo; /SLAC /Stanford U., Phys. Dept.
2012-02-17
We analyze the phases of supersymmetric chiral gauge theories with an antisymmetric tensor and (anti)fundamental flavors, in the presence of a classically marginal superpotential deformation. Varying the number of flavors that appear in the superpotential reveals rich infrared chiral dynamics and novel dualities. The dualities are characterized by an infinite family of magnetic duals with arbitrarily large gauge groups describing the same fixed point, correlated with arbitrarily large classical global symmetries that are truncated nonperturbatively. At the origin of moduli space, these theories exhibit a phase with confinement and chiral symmetry breaking, an interacting nonabelian Coulomb phase, and phases where an interacting sector coexists with a sector that either s-confines or is in a free magnetic phase. Properties of these intriguing 'mixed phases' are studied in detail using duality and a-maximization, and the presence of superpotential interactions provides further insights into their formation.
Phase transitions modern applications
Gitterman, Moshe
2014-01-01
This book provides a comprehensive review of the theory of phase transitions and its modern applications, based on the five pillars of the modern theory of phase transitions i.e. the Ising model, mean field, scaling, renormalization group and universality. This expanded second edition includes, along with a description of vortices and high temperature superconductivity, a discussion of phase transitions in chemical reaction and moving systems. The book covers a close connection between phase transitions and small world phenomena as well as scale-free systems such as the stock market and the Internet. Readership: Scientists working in different fields of physics, chemistry, biology and economics as well as teaching material for undergraduate and graduate courses.
许可; 李未
1999-01-01
Phase transition is an important feature of SAT problem. For random k-SAT model, it is proved that as r（ratio of clauses to variables） increases, the structure of solutions will undergo a sudden change like satisfiability phase transition when r reaches a threshold point (r=rcr). This phenomenon shows that the satisfying truth assignments suddenly shift from being relatively different from each other to being very similar to each other.##属性不符
Susceptibilities and the Phase Structure of a Chiral Model with Polyakov Loops
Sasaki, C.; Friman, B.; Redlich, K.
2006-01-01
In an extension of the Nambu-Jona-Lasinio model where the quarks interact with the temporal gluon field, represented by the Polyakov loop, we explore the relation between the deconfinement and chiral phase transitions. The effect of Polyakov loop dynamics on thermodynamic quantities, on the phase structure at finite temperature and baryon density and on various susceptibilities is presented. Particular emphasis is put on the behavior and properties of the fluctuations of the (approximate) ord...
An Anderson-like model of the QCD chiral transition
Giordano, Matteo; Pittler, Ferenc
2016-01-01
We study the problems of chiral symmetry breaking and eigenmode localisation in finite-temperature QCD by looking at the lattice Dirac operator as a random Hamiltonian. We recast the staggered Dirac operator into an unconventional three-dimensional Anderson Hamiltonian ("Dirac-Anderson Hamiltonian") carrying internal degrees of freedom, with disorder provided by the fluctuations of the gauge links. In this framework, we identify the features relevant to chiral symmetry restoration and localisation of the low-lying Dirac eigenmodes in the ordering of the local Polyakov lines, and in the related correlation between spatial links across time slices, thus tying the two phenomena to the deconfinement transition. We then build a toy model based on QCD and on the Dirac-Anderson approach, replacing the Polyakov lines with spin variables and simplifying the dynamics of the spatial gauge links, but preserving the above-mentioned relevant dynamical features. Our toy model successfully reproduces the main features of the...
Transitions of Smectic A to Tilted Phases in Thin Free Standing Films of Liquid Crystal
The transition of orthogonal smectic A (SmA) phase to the tilted phases, upon lowering the temperature, is explored with a discrete phenomenological model and the phase diagrams are presented. The results show that the transition of SmA to uniplanar structures can be affected by the effect of chirality. The areas showing the uniplanar phase in the phase diagrams diminish with the increase in effect of chirality. (author)
Inhomogeneous chiral phases in two-flavor quark matter
Abuki, Hiroaki
2015-01-01
We present a systematic study of the phase structure of QCD in a generalized Ginzburg-Landau framework. We find, going up in density, a strongly interacting matter might go through the "pion crystal", an exotic inhomogeneous chiral phase before reaching the full restoration of symmetry.
An analytic treatment of the one Higgs doublet, electroweak phase transition is given. The phase transition is first order, occurs by the nucleation of thin walled bubbles and completes at a temperature where the order parameter, left-angle φ right-angle T is significantly smaller than it is when the origin becomes absolutely unstable. The rate of anomalous baryon number violation is an exponentially function of left-angle φ right-angle T. In very minimal extensions of the standard model it is quite easy to increase left-angle φ right-angle T so that anomalous baryon number violation is suppressed after completion of the phase transition. Hence baryogenesis at the electroweak phase transition is tenable in minimal of the standard model. In some cases additional phase transitions are possible. For a light Higgs boson, when the top quark mass is sufficiently large, the state where the Higgs field has a vacuum expectation value left-angle φ right-angle = 246 GeV is not the true minimum of the Higgs potential. When this is the case, and when the top quark mass exceeds some critical value, thermal fluctuations in the early universe would have rendered the state left-angle φ right-angle = 246 GeV unstable. The requirement that the state left-angle φ right-angle = 246 GeV is sufficiently long lived constrains the masses of the Higgs boson and the top quark. Finally, we consider whether local phase transitions can be induced by heavy particles which act as seeds for deformations in the scalar field
Chen, Zhi; Yu, Clare C.
2006-03-01
Noise is present in many physical systems and is often viewed as a nuisance. Yet it can also be a probe of microscopic fluctuations. There have been indications recently that the noise in the resistivity increases in the vicinity of the metal-insulator transition. But what are the characteristics of the noise associated with well-understood first and second order phase transitions? It is well known that critical fluctuations are associated with second order phase transitions, but do these fluctuations lead to enhanced noise? We have addressed these questions using Monte Carlo simulations to study the noise in the 2D Ising model which undergoes a second order phase transition, and in the 5-state Potts model which undergoes a first order phase transition. We monitor these systems as the temperature drops below the critical temperature. At each temperature, after equilibration is established, we obtain the time series of quantities characterizing the properties of the system, i.e., the energy and magnetization per site. We apply different methods, such as the noise power spectrum, the Detrended Fluctuation Analysis (DFA) and the second spectrum of the noise, to analyze the fluctuations in these quantities.
Kopaev, YuV
1992-01-01
Electronic Phase Transitions deals with topics, which are presently at the forefront of scientific research in modern solid-state theory. Anderson localization, which has fundamental implications in many areas of solid-state physics as well as spin glasses, with its influence on quite different research activities such as neural networks, are two examples that are reviewed in this book. The ab initio statistical mechanics of structural phase transitions is another prime example, where the interplay and connection of two unrelated disciplines of solid-state theory - first principle ele
Three-phase model of a chiral quark bag
Three-phase modification of the model of hybrid chiral quark bag is suggested. Along with the phase of asymptotically free current quarks and completely achromatic meson phase the model contains an intermediate phase including massive quark components. Self-consistent solution of model equations with account of contribution from the Dirac sea is found for (1+1)-dimensional case. The dependence of bag characteristics on theory parameters is investigated in analytical and numerical forms
Phase Transitions in Neutron Stars
Heiselberg, Henning; Hnorth-Jensen, Morten
1998-01-01
Phase transitions in neutron stars due to formation of quark matter, kaon condensates, etc. are discussed with particular attention to the order of these transitions. Observational consequences of phase transitions in pulsar angular velocities are examined.
Brazovskii-Dyugaev effect on the inhomogeneous chiral transition in quark matter
Karasawa, Shintaro; Lee, Tong-Gyu; Tatsumi, Toshitaka
2016-04-01
We investigate the effects of quantum and thermal fluctuations on the phase boundary between the inhomogeneous chiral phase and the chiral-restored phase in the phase diagram in the plane of temperature and chemical potential. Introducing the composite fields made of quark bilinear fields, we construct an effective action for them in quark matter by way of the correlation function method. Utilizing this effective action, we discuss the effects of the quark-antiquark and particle-hole pair fluctuations to find possible modifications of the vertex functions of the order parameter included in the thermodynamic potential. We find that the most important effect of the pair fluctuations is to change the sign of the fourth-order vertex function to make the phase transition always the first, rather than the second, order (we call it the Brazovskii-Dyugaev effect). Another important effect manifests in the second-order vertex function: it exhibits a singular behavior near the critical point, which prohibits the second-order phase transition. It, together with the fourth-order vertex function, alters the location of the phase boundary.
Photoinduced phase transitions
Nasu, K
2004-01-01
A new class of insulating solids was recently discovered. Whenirradiated by a few visible photons, these solids give rise to amacroscopic excited domain that has new structural and electronicorders quite different from the starting ground state. This occurrenceis called "photoinduced phase transition", and this multi-authoredbook reviews recent theoretical and experimental studies of this newphenomenon.
Deconfinement phase transition in neutron star matter
LI Ang; PENG Guang-Xiong; Lombardo U
2009-01-01
The transition from hadron phase to strange quark phase in dense matter is investigated. Instead of using the conventional bag model in quark sect, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates, with a thermodynamic problem improved. In nuclear slot,we adopt the equation of state from Brueckner-Bethe-Goldstone approach with three-body force. It is found that the mixed phase can occur, for reasonable confinement parameter, near the normal saturation density,and transit to pure quark matter at 4-5 times the saturation, which is quite different from the previous results from other quark models that pure quark phase can not appear at neutron-star densities.
Peripheral Nucleon-Nucleon Phase Shifts and Chiral Symmetry
Kaiser, N; Weise, W
1997-01-01
Within the one-loop approximation of baryon chiral perturbation theory we calculate all one-pion and two-pion exchange contributions to the nucleon-nucleon interaction. In fact we construct the elastic NN-scattering amplitude up to and including third order in small momenta. The phase shifts with orbital angular momentum $L\\geq2 $ and the mixing angles with $J\\geq2$ are given parameterfree and thus allow for a detailed test of chiral symmetry in the two-nucleon system. We find that for the D-waves the $2\\pi$-exchange corrections are too large as compared with empirical phase shifts, signaling the increasing importance of shorter range effects in lower partial waves. For higher partial waves, especially for G-waves, the model independent $2\\pi$-exchange corrections bring the chiral prediction close to empirical NN phase shifts. We propose to use the chiral NN phase shifts with $L\\geq 3$ as input in a future phase shift analysis. Furthermore, we compute the irreducible two-pion exchange NN-potentials in coordin...
Geometric Phase and Chiral Anomaly in Path Integral Formulation
Fujikawa, Kazuo
2007-01-01
All the geometric phases, adiabatic and non-adiabatic, are formulated in a unified manner in the second quantized path integral formulation. The exact hidden local symmetry inherent in the Schr\\"{o}dinger equation defines the holonomy. All the geometric phases are shown to be topologically trivial. The geometric phases are briefly compared to the chiral anomaly which is naturally formulated in the path integral.
A novel chiral phase of achiral hard triangles and an entropy-driven demixing of enantiomers.
Gantapara, Anjan P; Qi, Weikai; Dijkstra, Marjolein
2015-11-28
We investigate the phase behavior of a system of hard equilateral and right-angled triangles in two dimensions using Monte Carlo simulations. Hard equilateral triangles undergo a continuous isotropic-triatic liquid crystal phase transition at packing fraction ϕ = 0.7. Similarly, hard right-angled isosceles triangles exhibit a first-order phase transition from an isotropic fluid phase to a rhombic liquid crystal phase with a coexistence region ϕ ∈ [0.733, 0.782]. Both these liquid crystals undergo a continuous phase transition to their respective close-packed crystal structures at high pressures. Although the particles and their close-packed crystals are both achiral, the solid phases of equilateral and right-angled triangles exhibit spontaneous chiral symmetry breaking at sufficiently high packing fractions. The colloidal triangles rotate either in the clockwise or anti-clockwise direction with respect to one of the lattice vectors for packing fractions higher than ϕχ. As a consequence, these triangles spontaneously form a regular lattice of left- or right-handed chiral holes which are surrounded by six triangles in the case of equilateral triangles and four or eight triangles for right-angled triangles. Moreover, our simulations show a spontaneous entropy-driven demixing transition of the right- and left-handed "enantiomers". PMID:26376756
Simultaneous chiral symmetry restoration and deconfinement - Consequences for the QCD phase diagram
Klahn, Thomas; Hempel, Matthias
2016-01-01
For studies of quark matter in astrophysical scenarios the thermodynamic bag model (tdBag) is commonly employed. Although successful, it does not account for dynamical chiral symmetry breaking (D$\\chi$SB) and repulsions due to the vector interaction which is crucial to explain recent observations of massive, two solar mass neutron stars. In Kl\\"ahn & Fischer (2015) we developed the novel vBag quark matter model which takes these effects into account. This article extends vBag to finite temperatures and isospin asymmetry. Another particular feature of vBag is the determination of the deconfinement bag constant $B_{\\rm dc}$ from a given hadronic equation of state (EoS) in order to ensure that chiral and deconfinement transitions coincide. We discuss consequences of this novel approach for the phase transition construction and the phase diagram.
Generalized Ginzburg–Landau approach to inhomogeneous phases in nonlocal chiral quark models
We analyze the presence of inhomogeneous phases in the QCD phase diagram within the framework of nonlocal chiral quark models. We concentrate in particular in the positions of the tricritical (TCP) and Lifshitz (LP) points, which are studied in a general context using a generalized Ginzburg–Landau approach. We find that for all the phenomenologically acceptable model parametrizations considered the TCP is located at a higher temperature and a lower chemical potential in comparison with the LP. Consequently, these models seem to favor a scenario in which the onset of the first order transition between homogeneous phases is not covered by an inhomogeneous, energetically favored phase
无
2002-01-01
Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol (98:2, vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.
BaoHaiSHAO; XiuZhuXU; 等
2002-01-01
Several kinds of racemic naproxen ester were successfully separated on CTMB chiral stationary phase with hexane-ethanol(98:2,vol./vol.) as the mobile phase. The influence of mobile phase composition and structure of racemic naproxen ester on chiral separation was studied and the chiral recognition mechanism of CTMB was discussed.
Emergence and Phase Transitions
Sikkema, Arnold
2006-05-01
Phase transitions are well defined in physics through concepts such as spontaneous symmetry breaking, order parameter, entropy, and critical exponents. But emergence --- also exhibiting whole-part relations (such as top-down influence), unpredictability, and insensitivity to microscopic detail --- is a loosely-defined concept being used in many disciplines, particularly in psychology, biology, philosophy, as well as in physics[1,2]. I will review the concepts of emergence as used in the various fields and consider the extent to which the methods of phase transitions can clarify the usefulness of the concept of emergence both within the discipline of physics and beyond.1. Robert B. Laughlin, A Different Universe: Reinventing Physics from the Bottom Down (New York: Basic Books, 2005). 2. George F.R. Ellis, ``Physics and the Real World'', Physics Today, vol. 58, no. 7 (July 2005) pp. 49-54.
Understanding quantum phase transitions
Carr, Lincoln
2010-01-01
Quantum phase transitions (QPTs) offer wonderful examples of the radical macroscopic effects inherent in quantum physics: phase changes between different forms of matter driven by quantum rather than thermal fluctuations, typically at very low temperatures. QPTs provide new insight into outstanding problems such as high-temperature superconductivity and display fundamental aspects of quantum theory, such as strong correlations and entanglement. Over the last two decades, our understanding of QPTs has increased tremendously due to a plethora of experimental examples, powerful new numerical meth
Anomalous phase sequence in new chiral liquid crystalline materials
Podoliak, Natalia; Novotná, Vladimíra; Kašpar, Miroslav; Hamplová, Věra; Glogarová, Milada; Pociecha, D.
2014-01-01
Roč. 41, č. 2 (2014), s. 176-183. ISSN 0267-8292 R&D Projects: GA ČR GA13-14133S; GA ČR(CZ) GAP204/11/0723 Grant ostatní: AVČR(CZ) M100101211 Institutional support: RVO:68378271 Keywords : chiral chain * lactate unit * TGBA phase * re-entrancy * TGBC phase Subject RIV: JJ - Other Materials Impact factor: 2.486, year: 2014
Phase diagram of 4D field theories with chiral anomaly from holography
Ammon, Martin; Leiber, Julian; Macedo, Rodrigo P.
2016-03-01
Within gauge/gravity duality, we study the class of four dimensional CFTs with chiral anomaly described by Einstein-Maxwell-Chern-Simons theory in five dimensions. In particular we determine the phase diagram at finite temperature, chemical potential and magnetic field. At high temperatures the solution is given by an electrically and magnetically charged AdS Reissner-Nordstroem black brane. For sufficiently large Chern-Simons coupling and at sufficiently low temperatures and small magnetic fields, we find a new phase with helical order, breaking translational invariance spontaneously. For the Chern-Simons couplings studied, the phase transition is second order with mean field exponents. Since the entropy density vanishes in the limit of zero temperature we are confident that this is the true ground state which is the holographic version of a chiral magnetic spiral.
Phase diagram of 4D field theories with chiral anomaly from holography
Ammon, Martin; Macedo, Rodrigo P
2016-01-01
Within gauge/gravity duality, we study the class of four dimensional CFTs with chiral anomaly described by Einstein-Maxwell-Chern-Simons theory in five dimensions. In particular we determine the phase diagram at finite temperature, chemical potential and magnetic field. At high temperatures the solution is given by an electrically and magnetically charged AdS Reissner-Nordstroem black brane. For sufficiently large Chern-Simons coupling and at sufficiently low temperatures and small magnetic fields, we find a new phase with helical order, breaking translational invariance spontaneously. For the Chern-Simons couplings studied, the phase transition is second order with mean field exponents. Since the entropy density vanishes in the limit of zero temperature we are confident that this is the true ground state which is the holographic version of a chiral magnetic spiral.
Entanglement and quantum phase transitions
Gu, Shi-Jian; Tian, Guang-Shan; Lin, Hai-Qing
2005-01-01
We examine several well known quantum spin models and categorize behavior of pairwise entanglement at quantum phase transitions. A unified picture on the connection between the entanglement and quantum phase transition is given.
Chirality effects on 2D phase transitions
Scalas, E.; Brezesinski, G.; Möhwald, H.; Kaganer, V.M.; Bouwman, W.G.; Kjær, K.
1996-01-01
Monolayers of the racemate and pure enantiomers of 1-hexadecyl-glycerol were investigated by grazing incidence X-ray diffraction (GID) at 5 and 20 degrees C on compression from 0 mN m(-1) to pressures greater than 30 mN m(-1). The racemate Lattice is centred-rectangular for both temperatures at a...
The Standard Model from New Phase transition on the Lattice
A lattice gauge theory with a higher derivative Higgs action is considered. We predict the existence of a normal Higgs phase and a new, exotic Higgs phase, characterized by the condensation of a gauge invariant vector field that breaks the lattice cubic symmetries spontaneously. The continuum limit is defined by approaching the new phase transition from the normal Higgs phase. In this limit the gauge bosons become massless, but the Higgs VEV stays finite in lattice units. This allows us to introduce fermions chirally coupled to the gauge field. The continuum Lagrangian that governs the new critical point describes a chiral gauge theory quantized in a renormalizable gauge. Thus, the model can be regarded as a non-perturbative realization of the Roma approach, which invokes gauge fixing as an essential ingredient. in the formulation of lattice chiral gauge theories. (author)
Chiral rings and phases of supersymmetric gauge theories
We solve for the expectation values of chiral operators in supersymmetric U(N) gauge theories with matter in the adjoint, fundamental and anti-fundamental representations. A simple geometric picture emerges involving a description by a meromorphic one-form on a Riemann surface. The equations of motion are equivalent to a condition on the integrality of periods of this form. The solution indicates that all semiclassical phases with the same number of U(1) factors are continuously connected. (author)
Akram, F; Gutierrez-Guerrero, L X; Masud, B; Rodriguez-Quintero, J; Calcaneo-Roldan, C; Tejeda-Yeomans, M E
2012-01-01
We study chiral symmetry breaking for fundamental charged fermions coupled electromagnetically to photons with the inclusion of four-fermion contact self-interaction term. We employ multiplicatively renormalizable models for the photon dressing function and the electron-photon vertex which minimally ensures mass anomalous dimension = 1. Vacuum polarization screens the interaction strength. Consequently, the pattern of dynamical mass generation for fermions is characterized by a critical number of massless fermion flavors above which chiral symmetry is restored. This effect is in diametrical opposition to the existence of criticality for the minimum interaction strength necessary to break chiral symmetry dynamically. The presence of virtual fermions dictates the nature of phase transition. Miransky scaling laws for the electromagnetic interaction strength and the four-fermion coupling, observed for quenched QED, are replaced by a mean-field power law behavior corresponding to a second order phase transition. T...
[Enantioseparation behavior of chiral stationary phases AD, AS and OD].
Li, Liqun; Fan, Jun; Zhang, Jing; Chen, Xiaodong; Wang, Tai; He, Jianfeng; Zhang, Weiguang
2016-01-01
Over the past decades, HPLC enantioseparation with chiral stationary phases (CSPs) has been widely applied in chiral analysis and preparation of new pharmaceuticals, pesticides, food, etc. Herein, enantioseparation of 20 chiral compounds have been carried out on three polysaccharide-based CSPs (EnantioPak AD, AS and OD) with normal phases by HPLC, separately. The influences of skeletal structure and the kinds of derivative groups on separation behaviors of these CSPs have been studied in detail. As results indicated, except for compound 13, the other compounds were baseline separated on EnantioPak AD, with most of resolution over 2. 0; in addition, better separation for acidic or basic compounds was achieved through adding acidic/basic additives into the mobile phase of hexane-alcohol. For four aromatic alcohols (compounds 13-16), their retention in the EnantioPak AD column showed a weakening tendency with increase of carbon number in side chain group, and the reverse trend of their resolution was observed. Furthermore, EnantioPak AD showed much better separation performance for eight compounds (13-20) than the others. In short, these results have provided some references for further investigation of separation behavior and applications of polysaccharide-based CSPs. PMID:27319174
Cancelliere; D'Acquarica; Gasparrini; Misiti; Villani
1999-12-01
This review provides an overview of the synthesis and application of stable and versatile HPLC chiral stationary phases (CSPs), with emphasis placed on the binding strategies developed to anchor several structurally different chiral selectors to silica-gel microparticles. In addition, selected applications relating to the use of these CSPs for the direct resolution of racemates of biological and pharmaceutical relevance will be described. This review discusses enantioselective molecular recognition and dynamic stereochemistry of stereolabile compounds with reference to receptor-based chiral stationary phases (CSPs) and dynamic HPLC on CSPs, respectively. PMID:10603466
Park, Soohyun; Kim, Sang Jun; Hyun, Myung Ho [Pusan National Univ., Busan (Korea, Republic of)
2012-10-15
Optically active chiral amines are important as building blocks for pharmaceuticals and as scaffolds for chiral ligands and, consequently, many efforts have been devoted to the development of efficient methods for their preparation. For example, reduction of amine precursors with chiral catalysts, enzymatic kinetic resolution or dynamic kinetic resolution of racemic amines and the direct amination of ketones with transaminases have been developed as the efficient methods for the preparation of optically active chiral amines. During the process of developing or utilizing optically active chiral amines, the methods for the determination of their enantiomeric composition are essential. Among various methods, liquid chromatographic resolution of enantiomers on chiral stationary phases (CSPs) have been known to be one of the most accurate and economic means for the determination of the enantiomeric composition of optically active chiral compounds. Especially, CSPs based on chiral crown ethers have been successfully used for the resolution of racemic primary amines. For example, CSPs based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (CSP 1, Figure 1) or (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 (CSP 2 and CSP 3, Figure 1) have been known to be quite effective for the resolution of cyclic and non-cyclic amines, various fluoroquinolone antibacterials containing a primary amino group, tocainide (antiarrhythmic agent) and its analogues, aryl-a-amino ketones and 3-amino-1,4-benzodiazepin-2-ones.
Dynamic Phase Transitions in Superconductivity
Ma, Tian; Wang, Shouhong
2007-01-01
In this Letter, the dynamic phase transitions of the time-dependent Ginzburg-Landau equations are analyzed using a newly developed dynamic transition theory and a new classification scheme of dynamics phase transitions. First, we demonstrate that there are two type of dynamic transitions, jump and continuous, dictated by the sign of a nondimensional parameter R. This parameter is computable, and depends on the material property, the applied field, and the geometry of domain that the sample oc...
Surface tension in the cold and dense chiral transition and astrophysical applications
Palhares, L F
2011-01-01
The surface tension of cold and dense QCD phase transitions has appeared recently as a key ingredient in different astrophysical scenarios, ranging from core-colapse supernovae explosions to compact star structure. If the surface tension is low enough, observable consequences are possible. Its value is however not known from first-principle methods in QCD, calling for effective approaches. Working within the framework of homogeneous nucleation by Langer, we discuss the steps that are needed to obtain the nucleation parameters from a given effective potential. As a model for deriving the effective potential for the chiral transition, we adopt the linear sigma model with constituent quarks at very low temperatures, which provides an effective description for the thermodynamics of the strong interaction in cold and dense matter, and predict a surface tension of Sigma ~ 5--15 MeV/fm^2, well below previous estimates. Including temperature effects and vacuum logarithmic corrections, we find a clear competition betw...
OZI violating eight-quark interactions as a thermometer for chiral transitions
Osipov, A A; Moreira, J; Blin, A H
2008-01-01
This work is a follow-up of our recent observation that in the SU(3) flavor limit with vanishing current quark masses the temperature for the chiral transition is substantially reduced by adding eight-quark interactions to the Nambu - Jona-Lasinio Lagrangian with U_A(1) breaking. Here we generalize the case to realistic light and strange quark masses and confirm our prior result. Additionally, we demonstrate that depending on the strength of OZI violating eight-quark interactions, the system undergoes either a rapid crossover or a first order phase transition. The meson mass spectra of the low lying pseudoscalars and scalars at T=0 are not sensitive to the difference in the parameter settings that correspond to these two alternatives, except for the singlet-octet mixing scalar channels, mainly the sigma meson.
Quantum phase transitions of topological insulators without gap closing.
Rachel, Stephan
2016-10-12
We consider two-dimensional Chern insulators and time-reversal invariant topological insulators and discuss the effect of perturbations breaking either particle-number conservation or time-reversal symmetry. The appearance of trivial mass terms is expected to cause quantum phase transitions into trivial phases when such a perturbation overweighs the topological term. These phase transitions are usually associated with a bulk-gap closing. In contrast, the chiral Chern insulator is unaffected by particle-number breaking perturbations. Moreover, the [Formula: see text] topological insulator undergoes phase transitions into topologically trivial phases without bulk-gap closing in the presence of any of such perturbations. In certain cases, these phase transitions can be circumvented and the protection restored by another U(1) symmetry, e.g. due to spin conservation. These findings are discussed in the context of interacting topological insulators. PMID:27530509
NN Scattering Phase Shifts in a Chiral Constituent Quark Model
Bartz, D.; Stancu, Fl
2000-01-01
We study the nucleon-nucleon interaction within a chiral constituent quark model which reproduces succesfully the baryon spectra. We calculate the 3S1 and 1S0 phase shifts by using the resonating group method. They clearly indicate the presence of a strong repulsive interaction at short distance, due to the spin-flavor symmetry of the quark-quark interaction and of the quark interchange between the two interacting nucleons. A sigma-exchange quark-quark interaction, providing a medium-range at...
Entropy-driven formation of chiral nematic phases by computer simulations
Dussi, Simone; Dijkstra, Marjolein
2016-04-01
Predicting the macroscopic chiral behaviour of liquid crystals from the microscopic chirality of the particles is highly non-trivial, even when the chiral interactions are purely entropic in nature. Here we introduce a novel chiral hard-particle model, namely particles with a twisted polyhedral shape and obtain a stable fully entropy-driven cholesteric phase by computer simulations. By slightly modifying the triangular base of the particle, we are able to switch from a left-handed prolate (calamitic) to a right-handed oblate (discotic) cholesteric phase using the same right-handed twisted particle model. Furthermore, we show that not only prolate and oblate chiral nematic phases, but also other novel entropy-driven phases, namely chiral blue phases, chiral nematic phases featuring both twist and splay deformations, chiral biaxial nematic phases with one of the axes twisted, can be obtained by varying particle biaxiality and chirality. Our results allow to identify general guidelines for the stabilization of these phases.
Magnetic resonance of phase transitions
Owens, Frank J; Farach, Horacio A
1979-01-01
Magnetic Resonance of Phase Transitions shows how the effects of phase transitions are manifested in the magnetic resonance data. The book discusses the basic concepts of structural phase and magnetic resonance; various types of magnetic resonances and their underlying principles; and the radiofrequency methods of nuclear magnetic resonance. The text also describes quadrupole methods; the microwave technique of electron spin resonance; and the Mössbauer effect. Phase transitions in various systems such as fluids, liquid crystals, and crystals, including paramagnets and ferroelectrics, are also
Wagdy, Hebatallah A; Hanafi, Rasha S; El-Nashar, Rasha M; Aboul-Enein, Hassan Y
2013-09-01
Pharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics-based columns (Chirobiotic V and T), polysaccharide-based chiral column (Chiralpak AD-RH), and protein-based chiral column (Ultron ES-OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. PMID:23775938
QCD phase transitions via a refined truncation of Dyson-Schwinger equations
Gao, Fei
2016-01-01
We investigate both the chiral and deconfinement phase transitions of QCD matter in a refined scheme of Dyson-Schwinger equations, which have been shown to be successful in giving the meson mass spectrum and matching the interaction with the results from ab initio computation. We verify the equivalence of the chiral susceptibility criterion with different definitions for the susceptibility and confirm that the chiral susceptibility criterion is efficient to fix not only the chiral phase boundary but also the critical end point (CEP), especially when one could not have the effective thermodynamical potential. We propose a generalized Schwinger function criterion for the confinement. We give the phase diagram of both phase transitions and show that in the refined scheme the position of the CEP shifts to lower chemical potential and higher temperature. Based on our calculation and previous results of the chemical freeze out conditions, we propose that the CEP locates in the states of the matter generated by the ...
Non-equilibrium phase transitions
Henkel, Malte; Lübeck, Sven
2009-01-01
This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.
Multiobjective Optimization and Phase Transitions
Seoane, Luís F
2015-01-01
Many complex systems obey to optimality conditions that are usually not simple. Conflicting traits often interact making a Multi Objective Optimization (MOO) approach necessary. Recent MOO research on complex systems report about the Pareto front (optimal designs implementing the best trade-off) in a qualitative manner. Meanwhile, research on traditional Simple Objective Optimization (SOO) often finds phase transitions and critical points. We summarize a robust framework that accounts for phase transitions located through SOO techniques and indicates what MOO features resolutely lead to phase transitions. These appear determined by the shape of the Pareto front, which at the same time is deeply related to the thermodynamic Gibbs surface. Indeed, thermodynamics can be written as an MOO from where its phase transitions can be parsimoniously derived; suggesting that the similarities between transitions in MOO-SOO and Statistical Mechanics go beyond mere coincidence.
Vortex driven phase transition in Topologically Massive QED
Hoshino, Yuichi
2016-01-01
There is chiral like symmetry for 4-component massless fermion in (2+1)-dimensional gauge theory.Since QED$_{3}$ with Chern-Simons term contains vortex solution for vector potential,one may expect vortex driven phase transition as Kosterlitz-Thouless type where chiral condensate is washed away at zero temperature.To study this possibility,we evaluate the fermion propagator by Dyson-Schwinger equation numerically and spectral function analytically in the Landau gauge.For quenched case we adopt Ball-Chiu vertex to keep gauge invariance of the results.The critical value of topological mass,above which chiral condensate washed away, turned out to be $O(10^{-2})e^{2}$ at least for weak coupling in both cases.
Chiral two-body currents in nuclei: Gamow-Teller transitions and neutrinoless double-beta decay
Menéndez, J.; Gazit, D.; Schwenk, A.
2011-01-01
We show that chiral effective field theory (EFT) two-body currents provide important contributions to the quenching of low-momentum-transfer Gamow-Teller transitions, and use chiral EFT to predict the momentum-transfer dependence that is probed in neutrinoless double-beta decay. We then calculate for the first time the neutrinoless double-beta decay operator based on chiral EFT currents and study the nuclear matrix elements at successive orders. The contributions from chiral two-body currents...
Phase transitions and dark matter problems
The possible relationships between phase transitions in the early universe and dark matter problems are discussed. It is shown that there are at least 3 distinct cosmological dark matter problems 1) halos; 2) galaxy formation and clustering; and 3) Ω = 1, each emphasizing different attributes for the dark matter. At least some of the dark matter must by baryonic but if problems 2 and 3 are real they seem to also require non-baryonic material. However, if seeds are generated at the quark-hadron-chiral symmetry transition then alternatives to the standard scenarios may occur. At present no simple simultaneous solution (neither ''hot'', ''warm'', nor ''cold'') exists for all 3 problems, but non-standard solutions with strings, decaying particles or light not tracing to mass may work. An alternative interpretation of the relationship of the cluster-cluster and galaxy-galaxy correlation functions using renormalized scaling is mentioned. In this interpretation galaxies are more strongly correlated and the cluster-cluster function is not expected to go negative until > or approx. 200 Mpc. Possible phase transition origins for the cluster-cluster renormalized scale are presented as ways to obtain a dimension 1.2 fractal. (orig.)
Phase diagram and the pseudogap state in a linear chiral homopolymer model
Sinelnikova, A.; Niemi, A. J.; Ulybyshev, M.
2015-09-01
The phase structure of a single self-interacting homopolymer chain is investigated in terms of a universal theoretical model, designed to describe the chain in the infrared limit of slow spatial variations. The effects of chirality are studied and compared with the influence of a short-range attractive interaction between monomers, at various ambient temperature values. In the high-temperature limit the homopolymer chain is in the self-avoiding random walk phase. At very low temperatures two different phases are possible: When short-range attractive interactions dominate over chirality, the chain collapses into a space-filling conformation. But when the attractive interactions weaken, there is a low-temperature unfolding transition and the chain becomes like a straight rod. Between the high- and low-temperature limits, several intermediate states are observed, including the θ regime and pseudogap state, which is a novel form of phase state in the context of polymer chains. Applications to polymers and proteins, in particular collagen, are suggested.
Phase transition in finite systems
Chomaz, Ph.; Duflot, V. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Duflot, V.; Gulminelli, F. [Laboratoire de Physique Corpusculaire, LPC-ISMRa, CNRS-IN2P3, 14 - Caen (France)
2000-07-01
The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)
Phase transition in finite systems
The general problem of the definition of a phase transition without employing the thermodynamical limit is addressed. Different necessary conditions are considered and illustrated with examples from different nuclear and general physics phenomenologies. (authors)
Phenomenology of cosmic phase transitions
The evolution of the cosmic matter from Planck temperature to the atomic combination temperature is considered from a phenomenological point of view. Particular emphasis is devoted to the sequence of cosmic phase transitions. The inflationary era at the temperature of the order of the grand unification energy scale and the quantum chromodynamic confinement transition are dealt with in detail. (author) 131 refs.; 26 figs
Application of Δ- and Λ-Isomerism of Octahedral Metal Complexes for Inducing Chiral Nematic Phases
Hisako Sato
2009-10-01
Full Text Available The Δ- and Λ-isomerism of octahedral metal complexes is employed as a source of chirality for inducing chiral nematic phases. By applying a wide range of chiral metal complexes as a dopant, it has been found that tris(β-diketonatometal(III complexes exhibit an extremely high value of helical twisting power. The mechanism of induction of the chiral nematic phase is postulated on the basis of a surface chirality model. The strategy for designing an efficient dopant is described, together with the results using a number of examples of Co(III, Cr(III and Ru(III complexes with C2 symmetry. The development of photo-responsive dopants to achieve the photo-induced structural change of liquid crystal by use of photo-isomerization of chiral metal complexes is also described.
Nonequilibrium Chiral Dynamics and Effective Lagrangians
Nicola, A G
2001-01-01
We review our recent work on Chiral Lagrangians out of thermal equilibrium, which are introduced to analyse the pion gas formed after a Relativistic Heavy Ion Collision. Chiral Perturbation Theory is extended by letting $\\fpi$ be time dependent and allows to describe explosive production of pions in parametric resonance. This mechanism could be relevant if hadronization occurs at the chiral phase transition.
Quantum Phase Transition, Dissipation, and Measurement
Chakravarty, Sudip
2009-01-01
A selected set of topics in quantum phase transition is discussed. It includes dissipative quantum phase transitions, the role of disorder, and the relevance of quantum phase transition to measurement theory in quantum mechanics.
Phase transition in Liouville theory
We suggest that the vortices arising in a Kosterlitz-Thouless phase transition in Liouville theory correspond to transitions between different genera, producing the ''plumber's nightmare'' and other phases that have been predicted in fluid membrane theory from energetic considerations. This transition has previously been invoked by Cates to explain the degeneration of numerical simulations of Gaussian random surfaces into branched polymers. The difficulty in quantizing Liouville theory for d>1 is conjectured to be due to our insistence on working at a fixed genus
Berry Phases and Quantum Phase Transitions
Hamma, A
2006-01-01
We study the connection between Berry phases and quantum phase transitions of generic quantum many-body systems. Consider sequences of Berry phases associated to sequences of loops in the parameter space whose limit is a point. If the sequence of Berry phases does not converge to zero, then the limit point is a quantum critical point. Quantum critical points are associated to failures of adiabaticity. We discuss the remarkable example of the anisotropic XY spin chain in a transverse magnetic field and detect the XX region of criticality.
Phase transitions in field theory
By means of an example for which the effective potential is explicitly calculable (up to the one loop approximation), it is discussed how a phase transition takes place as the temperature is increased and pass from spontaneously broken symmetry to a phase in which the symmetry is restored. (Author)
Chern-Simons diffusion rate across different phase transitions
Rougemont, Romulo; Finazzo, Stefano Ivo
2016-05-01
We investigate how the dimensionless ratio given by the Chern-Simons diffusion rate ΓCS divided by the product of the entropy density s and temperature T behaves across different kinds of phase transitions in the class of bottom-up nonconformal Einstein-dilaton holographic models originally proposed by Gubser and Nellore. By tuning the dilaton potential, one is able to holographically mimic a first order, a second order, or a crossover transition. In a first order phase transition, ΓCS/s T jumps at the critical temperature (as previously found in the holographic literature), while in a second order phase transition it develops an infinite slope. On the other hand, in a crossover, ΓCS/s T behaves smoothly, although displaying a fast variation around the pseudo-critical temperature. In all the cases, ΓCS/s T increases with decreasing T . The behavior of the Chern-Simons diffusion rate across different phase transitions is expected to play a relevant role for the chiral magnetic effect around the QCD critical end point, which is a second order phase transition point connecting a crossover band to a line of first order phase transition. Our findings in the present work add to the literature the first predictions for the Chern-Simons diffusion rate across second order and crossover transitions in strongly coupled nonconformal, non-Abelian gauge theories.
Incommensurate phase transitions
Currat, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1996-11-01
We review the characteristic aspects of modulated crystals from the point of view of inelastic neutron scattering. We discuss the phenomenological Landau theory of the normal-to-incommensurate displacive instability and its predictions concerning the fluctuation spectrum of the modulated phase. General results on the form of the normal-mode eigenvectors and on the inelastic scattering channels through which they couple to the probe are established using the superspace approach. We illustrate these results on a simple discrete model symmetry and we review available inelastic neutron scattering data on several displacively modulated compounds. (author) 21 figs., 73 refs.
Phase transition in black holes
Roychowdhury, Dibakar
2014-01-01
The present thesis is devoted towards the study of various aspects of the phase transition phenomena occurring in black holes defined in an Anti-de-Sitter (AdS) space. Based on the fundamental principles of thermodynamics and considering a grand canonical framework we examine various aspects of the phase transition phenomena occurring in AdS black holes. We analytically check that this phase transition between the smaller and larger mass black holes obey Ehrenfest relations defined at the critical point and hence confirm a second order phase transition. This include both the rotating and charged black holes in Einstein gravity. Apart from studying these issues, based on a canonical framework, we also investigate the critical behavior in charged AdS black holes. The scaling laws for these black holes are found to be compatible with the static scaling hypothesis. Finally, based on the usual framework of AdS/CFT duality, we investigate the phase transition phenomena occurring in charged hairy black holes defined...
Fischer, Tobias; Hempel, Matthias
2016-01-01
The thermodynamic bag model (tdBag) has been applied widely to model quark matter properties in both heavy-ion and astrophysics communities. Several fundamental physics aspects are missing in tdBag, e.g., dynamical chiral symmetry breaking (D$\\chi$SB) and repulsions due to the vector interaction are both included explicitly in the novel vBag quark matter model of Kl\\"ahn and Fischer (2015) (Astrophys. J. 810, 134 (2015)). An important feature of vBag is the simultaneous D$\\chi$SB and deconfinement, where the latter links vBag to a given hadronic model for the construction of the phase transition. In this article we discuss the extension to finite temperatures and the resulting phase diagram for the isospin symmetric medium.
Non-uniform chiral phase studied within the Polyakov NJL model
Partyka, Tomasz L.
2010-01-01
We consider how does the introduction of a Polyakov loop affects the spatially inhomogeneous quark condensate. The primary result of our work is that the existence of the spatially non-uniform chiral phase is confirmed within the Polyakov NJL model in a chiral limit. These findings are obtained both in a 3d-cutoff and in a Schwinger (proper time) regularization schemes.
The QCD phase transition. From the microscopic mechanism to signals
This talk consists of two very different parts: the first one deals with non-perturbative QCD and physics of the chiral restoration, the second with rather low-key (and still unfinished) work aiming at obtaining EOS and other properties of hot/dense hadronic matter from data on heavy ion collisions. The microscopic mechanism for chiral restoration phase transition is a transition from randomly placed tunneling events (instantons) at low T to a set of strongly correlated tunneling-anti-tunneling events (known as instanton-anti-instanton molecules) at high T. Many features of the transition can be explained in this simple picture, especially the critical line and its dependence on quark masses. This scenario predicts qualitative change of the basic quark-quark interactions around the phase transition line, with some states (such as pion-sigma ones) probably surviving event at T > Tc. In the second half of the talk experimental data on collective flow in heavy ion collision are discussed its hydro-based description and relation to equation of state (EOS). A distinct feature of the QCD phase transition region is high degree of 'softness', (small ratio pressure/energy density). (author)
Phase transition in evolutionary games
Cao, Z J; Cao, Zhen; Hwa, Rudolph C
1995-01-01
The evolution of cooperative behaviour is studied in the deterministic version of the Prisoners' Dilemma on a two-dimensional lattice. The payoff parameter is set at the critical region 1.8 < b < 2.0 , where clusters of cooperators are formed in all spatial sizes. Using the factorial moments developed in particle and nuclear physics for the study of phase transition, the distribution of cooperators is studied as a function of the bin size covering varying numbers of lattice cells. From the scaling behaviour of the moments a scaling exponent is determined and is found to lie in the range where phase transitions are known to take place in physical systems. It is therefore inferred that when the payoff parameter is increased through the critical region the biological system of cooperators undergoes a phase transition to defectors. The universality of the critical behaviour is thus extended to include also this particular model of evolution dynamics.
Feng, Zhengyu; Ishikawa, Ken
2016-05-01
A novel experimental setup used to measure the important optical properties of liquid crystal materials is proposed. The setup allows us to measure electric-field-induced birefringence, optical rotational power, and transmission spectra consecutively. This system can be widely applied to characterize liquid crystal materials including blue phases, ferroelectric liquid crystals, and other chiral phases. We adopted this system to study the phase transition behavior of a V-shape switching ferroelectric liquid crystal mixture and made an important correction of experimental results previously reported by Sandhya et al. [ Europhys. Lett. 90, 56005 (2010)]. This finding proves the advantage of this system compared with the measurement method using individual systems.
The helical phase of chiral nematic liquid crystals as the Bianchi VII(0) group manifold
Gibbons, G W
2011-01-01
We show that the optical structure of the helical phase of a chiral nematic is naturally associated with the Bianchi VII(0) group manifold. The Joets-Ribotta metric governing propagation of the extraordinary rays is invariant under the simply transitive action of the universal cover of the three dimensional Euclidean group of two dimensions. Thus extraordinary light rays are geodesics of a left-invariant metric on this Bianchi type VII(0) group. We are able to solve by separation of variables both the wave equation and the Hamilton-Jacobi equation for this metric. The former reduces to Mathieu's equation and the later to the quadrantal pendulum equation. We further discuss Maxwell's equations for uniaxial optical materials where the configuration is invariant under a group action. The material is not assumed to be impedance matched, thus going beyond the usual scope of transformation optics. We show that for a chiral nematic in its helical phase Maxwell's equations reduce to a generalised Mathieu equation. Ou...
Phase transitions precipitated by solitosynthesis
Kusenko, A
1997-01-01
Solitosynthesis of Q-balls in the false vacuum can result in a phase transition of a new kind. Formation and subsequent growth of Q-balls via the charge accretion proceeds until the solitons reach a critical charge, at which point it becomes energetically favorable for the Q-ball interior to expand filling space with the true vacuum phase. Solitosynthesis can destabilize a false vacuum even when the tunneling rate is negligible. In models with low-energy supersymmetry, where the Q-balls associated with baryon and lepton number conservation are generically present, solitosynthesis can precipitate transitions between the vacua with different VEV's of squarks and sleptons.
Superunification, phase transitions and cosmology
We survey the main features behind the idea of grand unification, both without and with (local) supersymmetry. We then study the high-temperature phase transitions in the theories so realized, and their relevance to the cosmology of the early universe. In particular, we review the basic ingredients of (super) grand unified models and we give the basic tools needed for the study of their phase transitions. After a short introduction to cosmology, we focus on the interplay between unified particle physics models and cosmology, with particular emphasis on the inflationary universe scenario. In the same perspective, new research directions, in the context of higher-dimensional theories, are also discussed. (author)
Chiral gap effect in curved space
Flachi, Antonino
2014-01-01
We discuss a new type of QCD phenomenon induced in curved space. In the QCD vacuum a mass gap of Dirac fermions is attributed to the spontaneous breaking of chiral symmetry. If the curvature is positive large, the chiral condensate melts but a chiral invariant mass gap can still remain, which we name the chiral gap effect in curved space. This leads to decoupling of quark deconfinement which implies a view of black holes surrounded by a first-order QCD phase transition.
Artificiality of multifractal phase transitions
Wolf, Martin; Schmiegel, Jürgen; Greiner, Martin
1999-01-01
A multifractal phase transition is associated to a nonanalyticity in the generalised dimensions. We show that its occurrence is an artifact of the asymptotic scaling behaviour of integral moments and that it is not observed in an analysis based on differential n-point correlation densities.
Phase transitions in finite systems
In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)
Phase transitions in finite systems
Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire
2002-07-01
In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)
Phase transitions in quantum chromodynamics
Meyer-Ortmanns, H
1996-01-01
The current understanding of finite temperature phase transitions in QCD is reviewed. A critical discussion of refined phase transition criteria in numerical lattice simulations and of analytical tools going beyond the mean-field level in effective continuum models for QCD is presented. Theoretical predictions about the order of the transitions are compared with possible experimental manifestations in heavy-ion collisions. Various places in phenomenological descriptions are pointed out, where more reliable data for QCD's equation of state would help in selecting the most realistic scenario among those proposed. Unanswered questions are raised about the relevance of calculations which assume thermodynamic equilibrium. Promising new approaches to implement nonequilibrium aspects in the thermodynamics of heavy-ion collisions are described.
Pairing Phase Transitions of Matter under Rotation
Jiang, Yin
2016-01-01
The phases and properties of matter under global rotation have attracted much interest recently. In this paper we investigate the pairing phenomena in a system of fermions under the presence of rotation. We find that there is a generic suppression effect on pairing states with zero angular momentum. We demonstrate this effect with the chiral condensation and the color superconductivity in hot dense QCD matter as explicit examples. In the case of chiral condensation, a new phase diagram in the temperature-rotation parameter space is found, with a nontrivial critical point.
Transition State Models for Understanding the Origin of Chiral Induction in Asymmetric Catalysis.
Sunoj, Raghavan B
2016-05-17
In asymmetric catalysis, a chiral catalyst bearing chiral center(s) is employed to impart chirality to developing stereogenic center(s). A rich and diverse set of chiral catalysts is now available in the repertoire of synthetic organic chemistry. The most recent trends point to the emergence of axially chiral catalysts based on binaphthyl motifs, in particular, BINOL-derived phosphoric acids and phosphoramidites. More fascinating ideas took shape in the form of cooperative multicatalysis wherein organo- and transition-metal catalysts are made to work in concert. At the heart of all such manifestations of asymmetric catalysis, classical or contemporary, is the stereodetermining transition state, which holds a perennial control over the stereochemical outcome of the catalytic process. Delving one step deeper, one would find that the origin of the stereoselectivity is delicately dependent on the relative stabilization of one transition state, responsible for the formation of the predominant stereoisomer, over the other transition state for the minor stereoisomer. The most frequently used working hypothesis to rationalize the experimentally observed stereoselectivity places an undue emphasis on steric factors and tends to regard the same as the origin of facial discrimination between the prochiral faces of the reacting partners. In light of the increasing number of asymmetric catalysts that rely on hydrogen bonding as well as other weak non-covalent interactions, it is important to take cognizance of the involvement of such interactions in the sterocontrolling transition states. Modern density functional theories offer a pragmatic and effective way to capture non-covalent interactions in transition states. Aided by the availability of such improved computational tools, it is quite timely that the molecular origin of stereoselectivity is subjected to more intelligible analysis. In this Account, we describe interesting molecular insights into the stereocontrolling
Alho, T; Kajantie, K; Kiritsis, E; Tuominen, K
2015-01-01
We consider the finite temperature phase diagram of holographic QCD in the Veneziano limit (Nc large, Nf large with xf=Nf/Nc fixed) and calculate one string-loop corrections to the free energy in certain approximations. Such corrections, especially due to the pion modes are unsuppressed in the Veneziano limit. We find that under some extra assumptions the first order transition following from classical gravity solutions can become second order. If stringy asymptotics are of a special form and there are residual interactions it may even become of third order. Operationally these computations imply modelling the low temperature chiral symmetry breaking phase with a hadron gas containing Nf^2 massless Goldstone bosons and an exponential spectrum of massive hadrons. A third order transition is possible only if repulsive hadron interactions via the excluded volume effect are included.
Phase transitions and critical phenomena
Domb, Cyril
2000-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. It has moved into a central place in condensed matter studies.Statistical physics, and more specifically, the theory of transitions between states of matter, more or less defines what we know about 'everyday' matter and its transformations.The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable in
Phase Transitions in the Universe
Gleiser, Marcello
1998-01-01
During the past two decades, cosmologists turned to particle physics in order to explore the physics of the very early Universe. The main link between the physics of the smallest and largest structures in the Universe is the idea of spontaneous symmetry breaking, familiar from condensed matter physics. Implementing this mechanism into cosmology leads to the interesting possibility that phase transitions related to the breaking of symmetries in high energy particle physics took place during the early history of the Universe. These cosmological phase transitions may help us understand many of the challenges faced by the standard hot Big Bang model of cosmology, while offering a unique window into the very early Universe and the physics of high energy particle interactions.
'Magnetic' phase transition in silver
Experimental and theoretical investigations of the magnetic susceptibility near the phase transition into the Condon domain state in silver are presented. We report about the precursor of the Condon instability of an electron gas by using data of the measurement of the magnetic field-dependence of the susceptibility. Experimental results are explained theoretically within the framework of the Lifshitz-Kosevich-Shoenberg theory. A good agreement between the theory and the experiment is obtained when de Haas-van Alphen oscillations are only originated from 'belly' oscillations, and as a result of this, the spherical modelling of the Fermi surface in silver is justified. It is shown that the phase transition into the Condon domain state is the critical point of the liquid-gas type at which the isothermal susceptibility does not diverge but possesses a finite value due to the nonzero demagnetization factor
Electroweak phase transition recent results
Csikor, Ferenc
2000-01-01
Recent results of four-dimensional (4d) lattice simulations on the finite temperature electroweak phase transition (EWPT) are discussed. The phase transition is of first order in the SU(2)-Higgs model below the end point Higgs mass 66.5$\\pm$1.4 GeV. For larger masses a rapid cross-over appears. This result completely agrees with the results of the dimensional reduction approach. Including the full Standard Model (SM) perturbatively the end point is at 72.1$\\pm$1.4 GeV. Combined with recent LEP Higgs mass lower bounds, this excludes any EWPT in the SM. A one-loop calculation of the static potential makes possible a precise comparison of the lattice and perturbative results. Recent 4d lattice studies of the Minimal Supersymmetric SM (MSSM) are also mentioned.
Mechanical stresses upon phase transitions
Pedersen, Tom Peder Leervad
2003-01-01
Mechanical stress studies were carried out on three different groups of functional coatings using a purpose-built system. Functional coatings have become increasingly important in recent years due to their interesting technological applications. In this work three different groups of coatings were studied. Transition metal oxides are used as optical coatings, hard coatings, etc., phase change films find application in optical data storage technology, while optically switchable coatings have b...
We calculate the temperature T and angular (θ, ϕ) dependencies of the upper critical induction Bc2(θ, ϕ, T) for parallel-spin superconductors with an axially symmetric p-wave pairing interaction pinned to the lattice and a dominant ellipsoidal Fermi surface (FS). For all FS anisotropies, the chiral Scharnberg–Klemm (SK) state Bc2(θ, ϕ, T) exceeds that of the chiral Anderson–Brinkman–Morel (ABM) state and exhibits a kink at θ = θ*(T, ϕ), indicative of a first-order transition from its chiral, nodal-direction behavior to its non-chiral, antinodal-direction behavior. Applicabilities to Sr2RuO4, UCoGe and the candidate topological superconductor CuxBi2Se3 are discussed. (fast track communication)
De Klerck, Katrijn; Vander Heyden, Yvan; Mangelings, Debby
2014-02-01
Since their introduction on the market the applicability of immobilized polysaccharide-based chiral stationary phases in high-performance liquid chromatography has been thoroughly investigated. These immobilized phases have the benefit to be applicable with a wide range of modifiers, potentially extending the application range of the polysaccharide-based stationary phases. Because an increasing number of stationary phases are being introduced in the field of chiral chromatography it is important to evaluate their enantioselectivity in different techniques in order to get an idea about their applicability. In this study, three immobilized chiral polysaccharide-based stationary phases (Chiralpak IA, IB, and IC) are evaluated in supercritical fluid chromatography (SFC) with a test set of pharmaceutical racemates. This is done in a three-fold manner: their performance is evaluated (1) using traditional modifiers, (2) using mixtures of atypical modifiers, and (3) the results were compared to those on coated stationary phases with an equivalent chiral selector. To get a visual overview of the enantioselective patterns of the different chromatographic systems (mobile and stationary phase combinations), a Principal Component Analysis is performed, which allows determining the (dis)similarity between individual systems. To assess the complementarity cumulative success rates are determined. The immobilized chiral stationary phases prove to yield high cumulative success rates. PMID:24438871
Zhang, Xiaoli; Wang, Litao; Dong, Shuqing; Zhang, Xia; Wu, Qi; Zhao, Liang; Shi, Yanping
2016-05-01
Nanocrystalline cellulose (NCC) with high surface area and high ordered crystalline structure was prepared from microcrystalline cellulose (MCC) under the hydrolysis of sodium hypochlorite. NCC was further reacted with 3,5-dimethylphenyl isocyanate to obtain the nanocellulose derivative, and then coated successfully on the surface of silica gel to a prepared NCC-coated chiral stationary phase (CSP) as a new kind of chiral separation material. Similarly, MCC derivative-coated CSP was also prepared as contrast. The chiral separation performance of NCC-based CSP was evaluated and compared with MCC-based CSP by high-performance liquid chromatography. Moreover, the effects of the alcohol modifiers, mobile phase additives, and flow rates on chiral separations were investigated in detail. The results showed that 10 chiral compounds were separated on NCC-based CSP with better peak shape and higher column efficiency than MCC-based CSP, which confirmed that NCC-based CSP was a promising packing material for the resolution of chiral compounds.Chirality 28:376-381, 2016. © 2016 Wiley Periodicals, Inc. PMID:26949227
Bai, Fan; Wang, Wenqing
2002-01-01
The origin of chirality, closely related to the evolution of life on the earth, has long been debated. In 1991, Abdus Salam suggested a novel approach to achieve biomolecular homochirality by a phase transition. In his subsequent publication, he predicted that this phase transition could eventually change D-amino acids to L-amino acids as C -H bond would break and H atom became a superconductive atom. Since many experiments denied the configuration change in amino acids, Salam hypothesis arou...
Two-color QCD with chiral chemical potential
Braguta, V. V.; Goy, V. A.; Ilgenfritz, E.-M.; Kotov, A. Yu.; Molochkov, A. V.; Müller-Preussker, M.; Petersson, B.; Schreiber, A.
2016-01-01
The phase diagram of two-color QCD with a chiral chemical potential is studied on the lattice. The focus is on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulations are carried out with dynamical staggered fermions without rooting. The dependence of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented.
Xiaoli Zhang; Litao Wang; Shuqing Dong; Xia Zhang; Qi Wu; Liang Zhao; Yanping Shi
2016-01-01
Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs) we...
Phase diagram of the chiral magnet Cr1 /3NbS2 in a magnetic field
Tsuruta, K.; Mito, M.; Deguchi, H.; Kishine, J.; Kousaka, Y.; Akimitsu, J.; Inoue, K.
2016-03-01
We construct the phase diagram of the chiral magnet Cr1 /3NbS2 in a dc magnetic field (Hdc) using ac magnetic susceptibility measurements. At Hdc=0 , the ac response at the transition from the helical magnetic (HM) state to the paramagnetic (PM) state consists of a giant third-order harmonic component (M3 ω) and a first-order harmonic component (M1 ω). By applying Hdc perpendicular to the c axis, the HM state is transformed to the chiral soliton lattice (CSL) state, which is a superlattice tuned by Hdc. The above giant M3 ω is markedly suppressed at small Hdc. The CSL state is found to consist of CSL-1, with dominant helical texture and a poor ferromagnetic array, and CSL-2, with a large ferromagnetic array. The transition between CSL-1 and the PM state causes a linear magnetic response, the dominant component of which is the in-phase M1 ω. With increasing temperature, CSL-2 is transformed into the forced ferromagnetic (FFM) state, and ultimately the PM state is reached. The transition between CSL-2 and the FFM state consists of a large M3 ω and large out-of-phase M1 ω as well as in-phase M1 ω. The transition between the FMM and PM states also yields a linear magnetic response, like the CSL-1-PM-state transition. Five typical magnetic dynamics in the transitions among the HM state, CSL-1, CSL-2, FFM state, and PM state were identified according to the equivalent dynamical motion equation of a nonlinear spring model.
The Wigner solution and QCD phase transitions in a modified PNJL model
Cui, Zhu-fang [Nanjing University, Department of Physics, Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing (China); Shi, Chao [Nanjing University, Department of Physics, Nanjing (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing (China); Sun, Wei-min; Zong, Hong-shi [Nanjing University, Department of Physics, Nanjing (China); Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing (China); Wang, Yong-long [Nanjing University, Department of Physics, Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing (China); Linyi University, Department of Physics, School of Science, Linyi (China); Massachusetts Institute of Technology, Center for Theoretical Physics, Cambridge, MA (United States)
2014-02-15
By employing some modification to the widely used two-flavor Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model, we discuss the Wigner solution of the quark gap equation at finite temperature and zero quark chemical potential beyond the chiral limit, and then we try to explore its influence on the chiral and deconfinement phase transitions of QCD at finite temperature and zero chemical potential. The discovery of the coexistence of the Nambu and the Wigner solutions of the quark gap equation with nonzero current quark mass at zero temperature and zero chemical potential, as well as their evolutions with temperature, is very interesting for the studies of the phase transitions of QCD. According to our results, the chiral phase transition might be of first order (while the deconfinement phase transition is still a crossover, as in the normal PNJL model), and the corresponding phase transition temperature is lower than that of the deconfinement phase transition, instead of coinciding with each other, which are not the same as the conclusions obtained from the normal PNJL model. In addition, we also discuss the sensibility of our final results on the choice of model parameters. (orig.)
Phase transitions and critical phenomena
Domb, Cyril
2000-01-01
The field of phase transitions and critical phenomena continues to be active in research, producing a steady stream of interesting and fruitful results. No longer an area of specialist interest, it has acquired a central focus in condensed matter studies. The major aim of this serial is to provide review articles that can serve as standard references for research workers in the field, and for graduate students and others wishing to obtain reliable information on important recent developments.The two review articles in this volume complement each other in a remarkable way. Both deal with what m
Light scattering near phase transitions
Cummins, HZ
1983-01-01
Since the development of the laser in the early 1960's, light scattering has played an increasingly crucial role in the investigation of many types of phase transitions and the published work in this field is now widely dispersed in a large number of books and journals.A comprehensive overview of contemporary theoretical and experimental research in this field is presented here. The reviews are written by authors who have actively contributed to the developments that have taken place in both Eastern and Western countries.
Zhang, Zhao
2014-01-01
The flavor-mixing induced by the mismatched vector-isoscalar and vector-isovector interactions at finite baryon chemical potential $\\mu$ and isospin chemical potential $\\mu_I$ is demonstrated in the Nambu-Jona-Lasinio (NJL) type model of QCD. The influence of this non-anomaly flavor-mixing on the possible separate chiral transitions at nonzero $\\mu_I$ is studied under the assumption of the effective restoration of the $U(1)_A$ symmetry. We find that for the weak isospin asymmetry, the two separate phase boundaries found previously can be converted into one only if the vector-isovector coupling $g_v^v$ is significantly stronger than the vector-isoscalar one $g_v^s$ without the axial anomaly. When the weak Kabayashi-Maskawa-'t Hooft (KMT) interaction is included, we find that the separation of the chiral transition with two critical endpoints for the relatively strong isospin asymmetry can still be removed owning to the vector interactions. In this case, it is not the vector coupling difference but the strength...
Landau-Peierls instability in a Fulde-Ferrell type inhomogeneous chiral condensed phase
Lee, Tong-Gyu; Tsue, Yasuhiko; Tatsumi, Toshitaka; Friman, Bengt
2015-01-01
We investigate the stability of an inhomogeneous chiral condensed phase against low energy fluctuations about a spatially modulated order parameter. This phase corresponds to the so-called dual chiral density wave in the context of quark matter, where the chiral condensate is spatially modulated with a finite wavevector in a single direction. From the symmetry viewpoint, the phase realizes a locking of flavor and translational symmetries. Starting with a Landau-Ginzburg-Wilson effective Lagrangian, we find that the associated Nambu-Goldstone modes, whose dispersion relations are spatially anisotropic and soft in the direction normal to the wavevector of the modulation, wash out the long-range order at finite temperatures, but support algebraically decaying long-range correlations. This implies that the phase can exhibit a quasi-one-dimensional order as in liquid crystals.
Volume phase transitions of cholesteric liquid crystalline gels
Matsuyama, Akihiko, E-mail: matuyama@bio.kyutech.ac.jp [Department of Bioscience and Bioinformatics, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Kawazu 680-4, Iizuka, Fukuoka 820-8502 (Japan)
2015-05-07
We present a mean field theory to describe anisotropic deformations of a cholesteric elastomer without solvent molecules and a cholesteric liquid crystalline gel immersed in isotropic solvents at a thermal equilibrium state. Based on the neoclassical rubber theory of nematic elastomers, we derive an elastic energy and a twist distortion energy, which are important to determine the shape of a cholesteric elastomer (or gel). We demonstrate that when the elastic energy dominates in the free energy, the cholesteric elastomer causes a spontaneous compression in the pitch axis and elongates along the director on the plane perpendicular to the pitch axis. Our theory can qualitatively describe the experimental results of a cholesteric elastomer. We also predict the first-order volume phase transitions and anisotropic deformations of a gel at the cholesteric-isotropic phase transition temperature. Depending on a chirality of a gel, we find a prolate or oblate shape of cholesteric gels.
Light sterile neutrinos from a late phase transition
Vecchi, Luca
2016-01-01
Light sterile neutrinos represent a well-motivated extension of the 3-neutrino paradigm. However, the impressive agreement between standard cosmology and data casts doubts on their existence. Here we present a class of scenarios that robustly avoids this tension. In these models the sterile neutrinos are light, chiral states of a new sector interacting with the Standard Model via the right-handed neutrino portal and, crucially, active-sterile neutrino oscillations require a phase transition in the hidden sector. We explore the hidden-couplings/critical-temperature plane and identify regions where several sterile neutrinos can be accommodated. A late phase transition is usually preferred and may also ward off a potential threat posed by the formation of topologically stable defects.
Dynamical constraints on phase transitions
The numerical solutions of nonlocal and local Boltzmann kinetic equations for the simulation of central heavy ion reactions are parameterized in terms of time dependent thermodynamical variables in the Fermi liquid sense. This allows to discuss dynamical trajectories in phase space. The nonequilibrium state is characterized by non-isobaric, non-isochoric etc conditions, called iso-nothing conditions. Therefore a combination of thermodynamical observables is constructed which allows to locate instabilities and points of possible phase transition in a dynamical sense. We find two different mechanisms of instability, a short time surface - dominated instability and later a spinodal - dominated volume instability. The latter one occurs only if the incident energies are not exceeding much the Fermi energy and might be attributed to spinodal decomposition. Oppositely the fast surface explosion occurs far outside the spinodal and pertains also in the cases where the system develops too fast for suffering the spinodal decomposition and where the system approaches equilibrium outside the spinodal. (author)
Chiral magnetic effect in the PNJL model
Fukushima, Kenji; Gatto, Raoul
2010-01-01
We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop (PNJL model) in the presence of a strong magnetic field and a chiral chemical potential $\\mu_5$ which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. Firstly we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of $\\mu_5$ on the phase structure. Finally the chirality charge, electric current, and their susceptibility, which are relevant to the Chiral Magnetic Effect, are computed in the model.
Dynamic Phase Transitions in PVT Systems
Ma, Tian
2007-01-01
The main objective of this article are two-fold. First, we introduce some general principles on phase transition dynamics, including a new dynamic transition classification scheme, and a Ginzburg-Landau theory for modeling equilibrium phase transitions. Second, apply the general principles and the recently developed dynamic transition theory to study dynamic phase transitions of PVT systems. In particular, we establish a new time-dependent Ginzburg-Landau model, whose dynamic transition analysis is carried out. It is worth pointing out that the new dynamic transition theory, along with the dynamic classification scheme and new time-dependent Ginzburg Landau models for equilibrium phase transitions can be used in other phase transition problems, including e.g. the ferromagnetism and superfluidity, which will be reported elsewhere. In addition, the analysis for the PVT system in this article leads to a few physical predications, which are otherwise unclear from the physical point of view.
Symmetry and Phase Transitions in Nuclei
Phase transitions in nuclei have received considerable attention in recent years, especially after the discovery that, contrary to expectations, systems at the critical point of a phase transition display a simple structure. In this talk, quantum phase transitions (QPT), i.e. phase transitions that occur as a function of a coupling constant that appears in the quantum Hamiltonian, H, describing the system, will be reviewed and experimental evidence for their occurrence in nuclei will be presented. The phase transitions discussed in the talk will be shape phase transitions. Different shapes have different symmetries, classified by the dynamic symmetries of the Interacting Boson Model, U(5), SU(3) and SO(6). Very recently, the concept of Quantum Phase Transitions has been extended to Excited State Quantum Phase Transitions (ESQPT). This extension will be discussed and some evidence for incipient ESQPT in nuclei will be presented. Systems at the critical point of a phase transition are called 'critical systems'. Approximate analytic formulas for energy spectra and other properties of 'critical nuclei', in particular for nuclei at the critical point of the second order U(5)-SO(6) transition, called E(5), and along the line of first order U(5)-SU(3) transitions, called X(5), will be presented. Experimental evidence for 'critical nuclei' will be also shown. Finally, the microscopic derivation of shape phase transitions in nuclei within the framework of density functional methods will be briefly discussed.(author)
Yan, Jin; Zhang, Renke; Wang, Xinru; Wang, Yao; Wang, Dezhen; Zhou, Zhiqiang; Zhu, Wentao
2016-05-01
Enantiomeric separation of six chiral pesticides by high-performance liquid chromatography with permethylated β-cyclodextrin (β-PM) chiral stationary phase were tested under reversed phase conditions. The influences of water composition from 10% to 45% in the mobile phase and column temperatures from 0°C to 40°C on the separation were investigated. Baseline separation was obtained for diclofop-methyl, fenoxaprop-ethyl, tebuconazole and triticonazole, and Rs of these pesticides were greater than 1.5. However, etoxazole and lactofen were partially separated in all experiments. PMID:26992448
Quark Deconfinement Phase Transition in Neutron Stars
Alaverdyan, G B
2009-01-01
The hadron-quark phase transition in the interior of compact stars is investigated, when the transition proceeds through a mixed phase. The hadronic phase is described in the framework of relativistic mean-field theory, when also the scalar-isovector delta-meson mean-field is taken into account. The changes of the parameters of phase transition caused by the presence of delta-meson field are explored. The results of calculation of structure of the mixed phase (Glendenning construction) are compared with the results of usual first-order phase transition (Maxwell construction).
Takahashi, Y.; Eby, P. B.
1985-01-01
Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.
Spontaneous magnetization of quark matter in the inhomogeneous chiral phase
Yoshiike, Ryo; Tatsumi, Tositaka
2015-01-01
Considering the density wave of scalar and pseudoscalar condensates, we study the response of quark matter to a weak external magnetic field. In an external magnetic field, the energy spectrum of the lowest Landau level becomes asymmetric about zero, which is closely related to chiral anomaly, and gives rise to the spontaneous magnetization. This mechanism may be one of candidates for the origin of the strong magnetic field in pulsars and/or magnetars.
QCD Phase Transitions, Volume 15
Schaefer, T.; Shuryak, E.
1999-03-20
The title of the workshop, ''The QCD Phase Transitions'', in fact happened to be too narrow for its real contents. It would be more accurate to say that it was devoted to different phases of QCD and QCD-related gauge theories, with strong emphasis on discussion of the underlying non-perturbative mechanisms which manifest themselves as all those phases. Before we go to specifics, let us emphasize one important aspect of the present status of non-perturbative Quantum Field Theory in general. It remains true that its studies do not get attention proportional to the intellectual challenge they deserve, and that the theorists working on it remain very fragmented. The efforts to create Theory of Everything including Quantum Gravity have attracted the lion share of attention and young talent. Nevertheless, in the last few years there was also a tremendous progress and even some shift of attention toward emphasis on the unity of non-perturbative phenomena. For example, we have seen some efforts to connect the lessons from recent progress in Supersymmetric theories with that in QCD, as derived from phenomenology and lattice. Another example is Maldacena conjecture and related development, which connect three things together, string theory, super-gravity and the (N=4) supersymmetric gauge theory. Although the progress mentioned is remarkable by itself, if we would listen to each other more we may have chance to strengthen the field and reach better understanding of the spectacular non-perturbative physics.
Phase Transition Induced Fission in Lipid Vesicles
Leirer, C.; Wunderlich, B.; Myles, V.M.; Schneider, M F
2009-01-01
Abstract In this work we demonstrate how the first order phase transition in giant unilamellar vesicles (GUVs) can function as a trigger for membrane fission. When driven through their gel-fluid phase transition GUVs exhibit budding or pearl formation. These buds remain connected to the mother vesicle presumably by a small neck. Cooling these vesicles from the fluid phase (T>Tm) through the phase transition into the gel state (T
Berry phase of light Bragg-reflected by chiral liquid crystal media
Barboza, Raouf; Residori, Stefania; Clerc, Marcel G
2016-01-01
Berry phase is revealed for circularly polarized light when it is Bragg-reflected by a chiral liquid crystal medium of the same handedness. By using a chiral nematic layer we demonstrate that if the input plane of the layer is rotated with respect to a fixed reference frame, then, a geometric phase effect occurs for the circularly polarized light reflected by the periodic helical structure of the medium. Theory and numerical simulations are supported by an experimental observation, disclosing novel applications in the field of optical manipulation and fundamental optical phenomena.
Xiaoli Zhang
2016-05-01
Full Text Available Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material.
Zhang, Xiaoli; Wang, Litao; Dong, Shuqing; Zhang, Xia; Wu, Qi; Zhao, Liang; Shi, Yanping
2016-01-01
Core-shell silica microspheres with a nanocellulose derivative in the hybrid shell were successfully prepared as a chiral stationary phase by a layer-by-layer self-assembly method. The hybrid shell assembled on the silica core was formed using a surfactant as template by the copolymerization reaction of tetraethyl orthosilicate and the nanocellulose derivative bearing triethoxysilyl and 3,5-dimethylphenyl groups. The resulting nanocellulose hybrid core-shell chiral packing materials (CPMs) were characterized and packed into columns, and their enantioseparation performance was evaluated by high performance liquid chromatography. The results showed that CPMs exhibited uniform surface morphology and core-shell structures. Various types of chiral compounds were efficiently separated under normal and reversed phase mode. Moreover, chloroform and tetrahydrofuran as mobile phase additives could obviously improve the resolution during the chiral separation processes. CPMs still have good chiral separation property when eluted with solvent systems with a high content of tetrahydrofuran and chloroform, which proved the high solvent resistance of this new material. PMID:27153055
Cloud regimes as phase transitions
Stechmann, Samuel N.; Hottovy, Scott
2016-06-01
Clouds are repeatedly identified as a leading source of uncertainty in future climate predictions. Of particular importance are stratocumulus clouds, which can appear as either (i) closed cells that reflect solar radiation back to space or (ii) open cells that allow solar radiation to reach the Earth's surface. Here we show that these clouds regimes -- open versus closed cells -- fit the paradigm of a phase transition. In addition, this paradigm characterizes pockets of open cells as the interface between the open- and closed-cell regimes, and it identifies shallow cumulus clouds as a regime of higher variability. This behavior can be understood using an idealized model for the dynamics of atmospheric water as a stochastic diffusion process. With this new conceptual viewpoint, ideas from statistical mechanics could potentially be used for understanding uncertainties related to clouds in the climate system and climate predictions.
Phases and phase transitions in disordered quantum systems
Vojta, Thomas
2013-01-01
These lecture notes give a pedagogical introduction to phase transitions in disordered quantum systems and to the exotic Griffiths phases induced in their vicinity. We first review some fundamental concepts in the physics of phase transitions. We then derive criteria governing under what conditions spatial disorder or randomness can change the properties of a phase transition. After introducing the strong-disorder renormalization group method, we discuss in detail some of the exotic phenomena...
Overlap fermions are particularly well suited to study the finite temperature dynamics of the chiral symmetry restoration transition of QCD, which might be just an analytic crossover. Using gauge field configurations on a 243 x 10 lattice with Nf=2 flavours of dynamical Wilson-clover quarks generated by the DIK collaboration, we compute the lowest 50 eigenmodes of the overlap Dirac operator and try to locate the transition by fermionic means. We analyse the spectral density, local chirality and localisation properties of the low-lying modes and illustrate the changing topological and (anti-) selfdual structure of the underlying gauge fields across the transition. (orig.)
Spontaneous Magnetization of Quark Matter in Inhomogeneous Chiral Phase
Yoshiike, Ryo; Tatsumi, Toshitaka
2015-01-01
Considering the density wave of scalar and pseudoscalar condensates, we study the response of quark matter to a weak external magnetic field. In an external magnetic field, the energy spectrum of the lowest Landau level becomes asymmetric about zero, which is closely related to chiral anomaly. This spectral asymmetry gives rise to spontaneous magnetization. This mechanism may be one of candidates for the origin of the strong magnetic field in magnetars. Furthermore, using the generalized Ginzburg-Landau(gGL) expansion, we show that magnetic susceptibility exhibits a peculiar feature
Tawfik, Abdel Nasser
2015-01-01
Effects of external magnetic field on various properties of the quantum chromodynamics under extreme conditions of temperature and density have been analysed. To this end, we use SU(3) Polyakov linear sigma-model and assume that the external magnetic field eB adds some restrictions to the quarks energy due to the existence of free charges in the plasma phase. In doing this, we apply the Landau theory of quantization. This requires an additional temperature to drive the system through the chiral phase-transition. Accordingly, the dependence of the critical temperature of chiral and confinement phase-transitions on the magnetic field is characterized. Based on this, we have studied the thermal evolution of thermodynamic quantities and the first four higher-order moment of particle multiplicity. Having all these calculations, we have studied the effects of magnetic field on chiral phase-transition. We found that both critical temperature T_c and critical chemical potential increase with increasing the magnetic f...
Magnetic Phase Transition in FeRh
Gu, R. Y.; Antropov, V.P.
2005-01-01
Density functional calculations are performed to investigate the phase transition in FeRh alloy. The effective exchange coupling, the critical temperature of magnetic phase transition and the adiabatic spin wave spectrum have been obtained. Different contributions to the free energy of different phases are estimated. It has been found that the antiferro-ferromagnetic transition in FeRh occurs mostly due to the spin wave excitations.
Shape Transitions and Chiral Symmetry Breaking in the Energy Landscape of the Mitotic Chromosome
Zhang, Bin; Wolynes, Peter G.
2016-06-01
We derive an unbiased information theoretic energy landscape for chromosomes at metaphase using a maximum entropy approach that accurately reproduces the details of the experimentally measured pairwise contact probabilities between genomic loci. Dynamical simulations using this landscape lead to cylindrical, helically twisted structures reflecting liquid crystalline order. These structures are similar to those arising from a generic ideal homogenized chromosome energy landscape. The helical twist can be either right or left handed so chiral symmetry is broken spontaneously. The ideal chromosome landscape when augmented by interactions like those leading to topologically associating domain formation in the interphase chromosome reproduces these behaviors. The phase diagram of this landscape shows that the helical fiber order and the cylindrical shape persist at temperatures above the onset of chiral symmetry breaking, which is limited by the topologically associating domain interaction strength.
Shape Transitions and Chiral Symmetry Breaking in the Energy Landscape of the Mitotic Chromosome
Zhang, Bin
2015-01-01
We derive an unbiased information theoretic energy landscape for chromosomes at metaphase using a maximum entropy approach that accurately reproduces the details of the experimentally measured pair-wise contact probabilities between genomic loci. Dynamical simulations using this landscape lead to cylindrical, helically twisted structures reflecting liquid crystalline order. These structures are similar to those arising from a generic ideal homogenized chromosome energy landscape. The helical twist can be either right or left handed so chiral symmetry is broken spontaneously. The ideal chromosome landscape when augmented by interactions like those leading to topologically associating domain (TAD) formation in the interphase chromosome reproduces these behaviors. The phase diagram of this landscape shows the helical fiber order and the cylindrical shape persist at temperatures above the onset of chiral symmetry breaking which is limited by the TAD interaction strength.
Alaasar, Mohamed; Prehm, Marko; Tschierske, Carsten
2016-05-01
Spontaneous generation of macroscopic homochirality in soft matter systems by self-assembly of exclusively achiral molecules under achiral conditions is a challenging task with relevance for fundamental scientific research and technological applications. Dark conglomerate phases (DC phases), being optically isotropic mesophases composed of conglomerates of macroscopic chiral domains and formed by some non-chiral bent-core mesogens, represent such a case. Here we report two new series of non-symmetric bent-core molecules capable of forming a new type of mirror symmetry broken DC phases. In the synthesized molecules, a bent 4-bromoresorcinol core is connected to a phenyl benzoate wing and an azobenzene wing with or without additional peripheral fluorine substitution. The self-assembly was investigated by DSC, polarizing microscopy, electro-optical studies and XRD. Chiral and apparently achiral DC phases were observed besides distinct types of lamellar liquid crystalline phases with different degree of polar order, allowing the investigation of the transition from smectic to DC phases. This indicates a process in which increased packing density at first gives rise to restricted rotation and thus to growing polar order, which then leads to chirality synchronization, layer frustration and nano-scale crystallization. Topological constraints arising from the twisted packing of helical conformers in lamellar crystals is proposed to lead to amorphous solids composed of helical nano-crystallites with short coherence length (HNC phases). This is considered as a third major type of DC phases, distinct from the previously known liquid crystalline sponge phases and the helical nano-filament phases (HNF phases). Guidelines for the molecular design of new materials capable of self-assembly into these three types of DC phases are proposed. PMID:27006203
Inoue, Yoshihisa
2004-01-01
Direct Asymmetric Photochemistry with Circularly Polarized Light, H. RauCoherent Laser Control of the Handedness of Chiral Molecules, P. Brumer and M. ShapiroMagnetochiral Anisotropy in Asymmetric Photochemistry, G.L.J.A.RikkenEnantiodifferentiating Photosensitized Reactions, Y. InoueDiastereodifferentiating Photoreactions, N. Hoffmann and J.-P. PeteChirality in Photochromism, Y. Yokoyama and M. SaitoChiral Photochemistry with Transition Metal Complexes, S. Sakaki and T. HamadaTemplate-Induced Enantioselective Photochemical Reactions in S
Phase transitions in semidefinite relaxations.
Javanmard, Adel; Montanari, Andrea; Ricci-Tersenghi, Federico
2016-04-19
Statistical inference problems arising within signal processing, data mining, and machine learning naturally give rise to hard combinatorial optimization problems. These problems become intractable when the dimensionality of the data is large, as is often the case for modern datasets. A popular idea is to construct convex relaxations of these combinatorial problems, which can be solved efficiently for large-scale datasets. Semidefinite programming (SDP) relaxations are among the most powerful methods in this family and are surprisingly well suited for a broad range of problems where data take the form of matrices or graphs. It has been observed several times that when the statistical noise is small enough, SDP relaxations correctly detect the underlying combinatorial structures. In this paper we develop asymptotic predictions for several detection thresholds, as well as for the estimation error above these thresholds. We study some classical SDP relaxations for statistical problems motivated by graph synchronization and community detection in networks. We map these optimization problems to statistical mechanics models with vector spins and use nonrigorous techniques from statistical mechanics to characterize the corresponding phase transitions. Our results clarify the effectiveness of SDP relaxations in solving high-dimensional statistical problems. PMID:27001856
Synthetic-gauge-field stabilization of the chiral-spin-liquid phase
Chen, Gang; Hazzard, Kaden R. A.; Rey, Ana Maria; Hermele, Michael
2016-06-01
We explore the phase diagram of the SU (N ) Hubbard models describing fermionic alkaline-earth-metal atoms in a square optical lattice with, on average, one atom per site, using a slave rotor mean-field approach. We find that the chiral spin liquid (CSL) predicted for N ≥5 and large interactions passes through a fractionalized state with a spinon Fermi surface as interactions are decreased before transitioning to a weakly interacting metal. We show that by adding a uniform artificial gauge field with 2 π /N flux per plaquette, the CSL becomes the ground state for all N ≥3 at intermediate interactions, persists to weaker interactions, and exhibits a larger spin gap. For N ≥5 we find the CSL is the ground state everywhere the system is a Mott insulator. The gauge field stabilization of the CSL at lower interactions, and thus at weaker lattice depths, together with the increased spin gap, can relax the temperature constraints required for its experimental realization in ultracold atom systems.
Zhao, Licong; Yang, Limin; Wang, Qiuquan
2016-05-13
Glutathione (GSH)-, somatostatin acetate (ST)- and ovomucoid (OV)-functionalized silica-monolithic stationary phases were designed and synthesized for HILIC and chiral separation using capillary electrochromatography (CEC). GSH, ST and OV were covalently incorporated into the silica skeleton via the epoxy ring-opening reaction between their amino groups and the glycidyl moiety in γ-glycidoxypropyltrimethoxysilane (GPTMS) together with polycondensation and copolymerization of tetramethyloxysilane and GPTMS. Not only could the direction and electroosmotic flow magnitude on the prepared GSH-, ST- and OV-silica hybrid monolithic stationary phases be controlled by the pH of the mobile phase, but also a typical HILIC behavior was observed so that the nucleotides and HPLC peptide standard mixture could be baseline separated using an aqueous mobile phase without any acetonitrile during CEC. Moreover, the prepared monolithic columns had a chiral separation ability to separate dl-amino acids. The OV-silica hybrid monolithic column was most effective in chiral separation and could separate dl-glutamic acid (Glu) (the resolution R=1.07), dl-tyrosine (Tyr) (1.57) and dl-histidine (His) (1.06). Importantly, the chiral separation ability of the GSH-silica hybrid monolithic column could be remarkably enhanced when using gold nanoparticles (AuNPs) to fabricate an AuNP-mediated GSH-AuNP-GSH-silica hybrid monolithic column. The R of dl-Glu, dl-Tyr and dl-His reached 1.19, 1.60 and 2.03. This monolithic column was thus applied to separate drug enantiomers, and quantitative separation of all four R/S drug enantiomers were achieved with R ranging from 4.36 to 5.64. These peptide- and protein-silica monolithic stationary phases with typical HILIC separation behavior and chiral separation ability implied their promise for the analysis of not only the future metabolic studies, but also drug enantiomers recognition. PMID:27083263
无
2002-01-01
Amylose tris (phenylcarbamate) chiral stationary phase (ATPC-CSP) was prepared and used for optical resolution of clusters 1 and 2. n-Hexane/2-propanol ( 99/1; v/v) were found to be the most suitable mobile phase on ATPC-CSP.
In this thesis the thermodynamical properties of strongly interacting hadronic matter and the microscopic in-medium properties of hadrons are investigated at high temperatures and high baryonic densities within a chiral flavor-SU(3) model. The applied model is a generalized σ-ω model in mean-field approximation with baryons and mesons as effective degrees of freedom. It is built on spontaneously broken chiral symmetry and scale invariance. The phase transition behavior is systematically analyzed and is thus shown to depend significantly on the couplings of additional heavier hadronic degrees of freedom. A phase diagram in qualitative agreement with current lattice QCD (lQCD) calculations can result from an according coupling of the lowest lying baryonic decuplet to the model. Alternatively, the coupling of a heavy baryonic test-resonance is investigated, which effectively represents the spectrum of the heavy hadronic states. For a certain range of parameters one can even obtain a phase diagram in quantitative agreement with the lQCD calculations and, simultaneously, a successful description of the ground state properties of nuclear matter. It is shown that (within the model assumptions) the phase transition region is experimentally accessible for the CBM experiment at the upcoming FAIR facility at GSI Darmstadt. The chiral model is further applied to particle yield ratios measured in heavy-ion collisions from AGS, SPS and RHIC. For these investigations parameter sets with strongly differing phase diagrams due to different couplings of the baryon decuplet are used and in addition an ideal hadron gas. At the lower and mid collision energies the chiral parameter sets show an improved description as compared to the ideal hadron gas, especially for parameter sets with phase diagrams similar to the lQCD predictions. The interaction within the chiral model leads to in-medium modifications of the chemical potentials and the hadron masses. Therefore the resulting freeze
Pion-to-photon transition distribution amplitudes in the non-local chiral quark model
Kotko, Piotr
2008-01-01
We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross section of pion annihilation into the real and virtual photon. We use a simple form of the non-locality that allows to perform all calculations in the Minkowski space and guaranties polynomiality of the TDA's. We note only residual dependence on the precise form of the cut-off function, however vector TDA that is symmetric in skewedness parameter in the local quark model is no longer symmetric in the non-local case. We calculate also the transition form-factors and compare them with existing experimental parametrizations.
Pion-to-Photon Transition Distribution Amplitudes in the Non-Local Chiral Quark Model
Kotko, P.; Praszałowicz, M.
2009-01-01
We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross-section of pion annihilation into the real and virtual photon. We use a simple form of the non-locality that allows to perform all calculations in the Minkowski space and guaranties polynomiality of the TDAs. We note only residual dependence on the precise form of the cut-off function, however vector TDA that is symmetric in skewedness parameter in the local quark model is no longer symmetric in the non-local case. We calculate also the transition form-factors and compare them with existing experimental parametrizations.
Switchable thermal antenna by phase transition
Ben-Abdallah, Philippe; Besbes, Mondher
2013-01-01
We introduce a thermal antenna which can be actively switched by phase transition. The source makes use of periodically patterned vanadium dioxide, a metal-insulator phase transition material which supports a surface phonon-polariton (SPP) in the infrared range in its crystalline phase. Using electrodes properly registred with respect to the pattern, the phase transition of VO2 can be localy triggered within few microseconds and the SPP can be diffracted making the thermal emission highly directionnal. This switchable antenna could find broad applications in the domain of active thermal coatings or in those of infrared spectroscopy and sensing.
Phase-transitions and nuclear clusterization
After reviewing some basic features of the temperature-governed phase-transitions in macroscopic systems and in atomic nuclei we consider non-thermal phase-transitions of nuclear structure in the example of cluster states. Phenomenological and semimicroscopical algebraic cluster models with identical interactions are applied to binary cluster systems of closed and non-closed shell clusters. Phase-transitions are observed in each case between the rotational (rigid molecule-like) and vibrational (shell-like) cluster states. The phase of this finite quantum system shows a quasi-dynamical symmetry. (author)
Inhomogeneous nucleation in quark hadron phase transition
Shukla, P K; Sen-Gupta, S K; Gleiser, Marcello; Gleiser, Marcelo
2000-01-01
The effect of subcritical hadron bubbles on a first-order quark-hadron phase transition is studied. These subcritical hadron bubbles created due to thermal fluctuations introduce a finite amount of phase mixing (quark phase mixed with hadron phase) even at and above the critical temperature. For sufficiently strong transitions, as is expected to be the case for the quark-hadron transition, we show that the amount of phase mixing at the critical temperature remains much below the percolation threshold. Thus, as the system cools below the critical temperature, the transition proceeds through the nucleation of critical-size hadron bubbles from a metastable quark-gluon phase (QGP) within an inhomogeneous background populated by an equilibrium distribution of subcritical hadron bubbles. The inhomogenity of the medium is incorporated consistently by modelling the subcritical bubbles as Gaussian fluctuations, resulting in a large reduction of the nucleation barrier for the critical bubbles. Using the corrected nucle...
Intersubband-transition-induced phase matching
Almogy, Gilad; Segev, Mordechai; Yariv, Amnon
1994-01-01
We suggest the use of the refractive-index changes associated with the intersubband transitions in quantum wells for phase matching in nonlinear materials. An improvement in the conversion efficiency of mid-IR second-harmonic generation by almost 2 orders of magnitude over non-phase-matched bulk GaAs is predicted. We also show that the linear phase contributions of intersubband transitions used for resonant enhancement of second-harmonic generation must be considered, as they could limit the ...
The Cosmological QCD Phase Transition Revisited
Schettler, Simon; Boeckel, Tillmann; Schaffner-Bielich, Jurgen
2010-01-01
The QCD phase diagram might exhibit a first order phase transition for large baryochemical potentials. We explore the cosmological implications of such a QCD phase transition in the early universe. We propose that the large baryon-asymmetry is diluted by a little inflation where the universe is trapped in a false vacuum state of QCD. The little inflation is stopped by bubble nucleation which leads to primordial production of the seeds of extragalactic magnetic fields, primordial black holes a...
Chiral Symmetry Restoration from a Boundary
Tiburzi, B C
2013-01-01
The boundary of a manifold can alter the phase of a theory in the bulk. We explore the possibility of a boundary-induced phase transition for the chiral symmetry of QCD. In particular, we investigate the consequences of imposing homogeneous Dirichlet boundary conditions on the quark fields. Such boundary conditions are employed on occasion in lattice gauge theory computations, for example, when including external electromagnetic fields, or when computing quark propagators with a reduced temporal extent. Homogeneous Dirichlet boundary conditions force the chiral condensate to vanish at the boundary, and thereby obstruct the spontaneous breaking of chiral symmetry in the bulk. As the restoration of chiral symmetry due to a boundary is a non-perturbative phenomenon, we utilize the sigma model to exemplify the issues. Using this model, we find that chiral symmetry is completely restored if the length of the compact direction is less than 2.0 fm. For lengths greater than about 4 fm, an approximately uniform chiral...
Shi-jun Zheng; Zi-fa Li; Shu-yuan Zhang; Shao-kui Cao; Ming-sheng Tang; Qiu-jun Fen; Qi-feng Zhou
1999-01-01
A new series of chiral shish-kebab type liquid crystal block copolymers that form the smectic C(Sc*) phase was synthesized by solution polycondensation. The copolymers were characterized by GPC,DSC, TG, POM, X-ray diffraction and polarimeter. The copolymers 7 entered into liquid crystal phase when they were heated to their melting temperatures (Tm) and the copolymers 8 were in liquid crystal phase at room temperature with low viscosities. The smectic sanded texture or focal-conic texture were observed on POM.All the chiral block copolymers showed high optical activity. No racemization has happened. Temperaturevariable X-ray diffraction study together with POM and polarimetric analysis realized that they are chiral smectic C(Sc*) phase. Thus we offer in this report the first example of shish-kebab type liquid crystal block copolymers that form a chiral smectic C(Sc*) phase. The variation of melting and isotropization temperatures with molecular structure was also discussed.
Phase transitions in QCD and string theory
We develop a unified effective field theory approach to the high-temperature phase transitions in QCD and string theory, incorporating winding modes (time-like Polyakov loops, vortices) as well as low-mass states (pseudoscalar mesons and glueballs, matter and dilaton supermultiplets). Anomalous scale invariance and the Z3 structure of the centre of SU(3) decree a first-order phase transition with simultaneous deconfinement and Polyakov loop condensation in QCD, whereas string vortex condensation is a second-order phase transition breaking a Z2 symmetry. We argue that vortex condensation is accompanied by a dilaton phase transition to a strong coupling regime, and comment on the possible role of soliton degrees of freedom in the high-temperature string phase. (orig.)
Two-Color QCD with Non-zero Chiral Chemical Potential
Braguta, V V; Ilgenfritz, E -M; Kotov, A Yu; Molochkov, A V; Muller-Preussker, M; Petersson, B
2015-01-01
The phase diagram of two-color QCD with non-zero chiral chemical potential is studied by means of lattice simulation. We focus on the influence of a chiral chemical potential on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulation is carried out with dynamical staggered fermions without rooting. The dependences of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. The critical temperature is observed to increase with increasing chiral chemical potential.
Two-color QCD with non-zero chiral chemical potential
Braguta, V. V.; Goy, V. A.; Ilgenfritz, E. M.; Kotov, A. Yu.; Molochkov, A. V.; Müller-Preussker, M.; Petersson, B.
2015-06-01
The phase diagram of two-color QCD with non-zero chiral chemical potential is studied by means of lattice simulation. We focus on the influence of a chiral chemical potential on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulation is carried out with dynamical staggered fermions without rooting. The dependences of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. The critical temperature is observed to increase with increasing chiral chemical potential.
Dynamics of weak first order phase transitions
Gleiser, Marcello
1994-01-01
The dynamics of weak vs. strong first order phase transitions is investigated numerically for 2+1 dimensional scalar field models. It is argued that the change from a weak to a strong transition is itself a (second order) phase transition, with the order parameter being the equilibrium fractional population difference between the two phases at the critical temperature, and the control parameter being the coefficient of the cubic coupling in the free-energy density. The critical point is identified, and a power law controlling the relaxation dynamics at this point is obtained. Possible applications are briefly discussed.
Phase transitions in copper(II) orthovanadate
Data on the polymorphs of copper(II) orthovanadate are reported. The Cu3V2O8 phase synthesized in this laboratory exhibits phase transitions between 460deg and 560degC. These phase transitions are identified through detailed DTA and high temperature XRD techniques; it is observed that these structural transitions are rapid and reversible. The crystal structure of Cu3V2O8 is similar to that of Mg3V2O8, Zn3V2O8, Co3V2O8 and Ni3V2O8. (author). 12 refs., 3 figs., 1 tab
Finite-temperature phase transition of $N_{f}=3$ QCD with exact center symmetry
Misumi, Tatsuhiro; Itou, Etsuko
2015-01-01
For the $Z_{3}$-symmetric lattice QCD-like theory ($Z_3$-QCD), in which $SU(3)$ gauge theory is coupled with three fundamental Wilson quarks with flavor-dependent twisted boundary conditions, we calculate the expectation values of Polyakov loop and chiral condensate as functions of temperature on $16^3 \\times4$ and $20^3 \\times 4$ lattices with $m_{PS}/m_{V}=0.70$ fixed. We find the first-order phase transition with respect to the $Z_{3}$ center symmetry, where the Polyakov loop exhibits a hysteresis depending on the initial condition of thermalization process. We also show that the crossover behavior of chiral condensate around the critical temperature of the center transition and the manifestation of flavor symmetry breaking in the high-temperature phase.
Phase transitions in dissipative Josephson chains
The authors of this paper study the zero temperature phase transitions of a chain of Josephson junctions, taking into account the quantum fluctuations due to the charging energy and the effects of an Ohmic dissipation. The authors map the problem onto a generalized coulomb gas model, which then is transformed into a sine-Gordon field theory. Apart from the expected dipole unbinding transition, which describes a transition between globally superconducting and resistive behavior, the authors find a quadrupole unbinding transition at a critical strength of the dissipation. This transition separates two superconducting states characterized by different local properties
The QCD chiral transition, $\\ua$ symmetry and the Dirac spectrum using domain wall fermions
Buchoff, Michael I; Christ, Norman H; Ding, H -T; Jung, Chulwoo; Karsch, F; Mawhinney, R D; Mukherjee, Swagato; Petreczky, P; Renfrew, Dwight; Schroeder, Chris; Vranas, P M; Yin, Hantao; Lin, Zhongjie
2013-01-01
We report on a study of the finite-temperature QCD transition region for temperatures between 139 and 196 MeV, with a pion mass of 200 MeV and two space-time volumes: $24^3\\times8$ and $32^3\\times8$, where the larger volume varies in linear size between 5.6 fm (at T=139 MeV) and 4.0 fm (at T=195 MeV). These results are compared with the results of an earlier calculation using the same action and quark masses but a smaller, $16^3\\times8$ volume. The chiral domain wall fermion formulation with a combined Iwasaki and dislocation suppressing determinant ratio gauge action are used. This lattice action accurately reproduces the $\\sua$ and $\\ua$ symmetries of the continuum. Results are reported for the chiral condensates, connected and disconnected susceptibilities and the Dirac eigenvalue spectrum. We find a pseudo-critical temperature, $T_c$, of approximately 165 MeV consistent with previous results and strong finite volume dependence below $T_c$. Clear evidence is seen for $\\ua$ symmetry breaking above $T_c$ whi...
A Review of Salam Phase Transition in Protein Amino Acids Implication for Biomolecular Homochirality
Bai, F; Bai, Fan; Wang, Wenqing
2002-01-01
The origin of chirality, closely related to the evolution of life on the earth, has long been debated. In 1991, Abdus Salam suggested a novel approach to achieve biomolecular homochirality by a phase transition. In his subsequent publication, he predicted that this phase transition could eventually change D-amino acids to L-amino acids as C -H bond would break and H atom became a superconductive atom. Since many experiments denied the configuration change in amino acids, Salam hypothesis aroused suspicion. This paper is aimed to provide direct experimental evidence of a phase transition in alanine, valine single crystals but deny the configuration change of D- to L- enantiomers. New views on Salam phase transition are presented to revalidate its great importance in the origin of homochirality.
Comparative Optical Separation of Racemic Ibuprofen by Using Chiral Stationary Phase
Dalkeun; PARK; Joong; Kee; LEE; 等
2002-01-01
Ibprofen is widely used as a non-steroidal anti-inflammatory drug and poduced as racemic mixture.Its pharmacological activity resides only is S-(+)-enantiomer,and R-(-)-enantiomer is not only inactive but also has many side effects.Thus it is necessary to separate Renantiomer from racemic ibuprofen.We studied optical separation of racemic Ibuprofen with chiral high performance liquid chromatography(HPLC).,Out of three different chiral stationary phases,which were selected on the basis of structure and availability,two were found to be effective.There was optimum eluent composition for each stationary phase for good resolution in optical separation.Resolution decreased with increase of eluent flow rate,but effect of injection volume on resolution was insignificant at high eluent flow rate.
Influence of an inhomogeneous and expanding medium on signals of the QCD phase transition
According to a fluid dynamic expansion of the fireball we investigate how the inhomogeneity of the system influences the chiral phase transition of QCD. We compare the averaged values of the order parameter in equilibrium with that of a homogeneous system. If the temperature is averaged over a certain region of the fireball the corresponding correlation length does not diverge in an expansion with a critical point
Classifying the Phases of Gauge Theories by Spectral Density of Probing Chiral Quarks
Alexandru, Andrei
2015-01-01
We describe our recent proposal that distinct phases of gauge theories with fundamental quarks translate into specific types of low-energy behavior in Dirac spectral density. The resulting scenario is built around new evidence substantiating the existence of a phase characterized by bimodal (anomalous) density, and corresponding to deconfined dynamics with broken valence chiral symmetry. We argue that such anomalous phase occurs quite generically in these theories, including in "real world" QCD above the crossover temperature, and in zero-temperature systems with many light flavors.
Optical phase conjugation in azo-dye doped chiral liquid crystal
We report on optical phase conjugation phenomenon observed in chiral nematic liquid crystal showing band gap type Bragg reflection. The phase conjugate to the signal beam is observable only in the small temperature interval when the Bragg condition is fulfilled and only for circularly polarized light. The optical phase conjugation signals were observed at low cw laser light intensities (2, λ = 532 nm). Estimated value of third order optical susceptibility χ(3) = 2.8 × 10-17 m2/V2 is attributed to enhancement due to photoisomerisation of azo-dye (disperse red 1) inducing molecular reorientation process of liquid crystal molecules.
sprotocols
2015-01-01
Authors: Ren-Qi Wang, Teng-Teng Ong, Ke Huang, Weihua Tang & Siu-Choon Ng ### Abstract We described a facile and effective protocol wherein radical copolymerization is employed to covalently bond cationic β-cyclodextrin (β-CD) onto silica particles with extended linkage, resulting in a chiral stationary phase (IMPCSP) that can be used for the enantioseparation of racemic drugs in both high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Start...
Lejček, Lubor
2010-01-01
Roč. 83, 10-11 (2010), s. 1001-1013. ISSN 0141-1594 R&D Projects: GA AV ČR IAA100100911; GA AV ČR(CZ) GA202/09/0047; GA MŠk(CZ) OC10006 Institutional research plan: CEZ:AV0Z10100520 Keywords : B 2 phase * bent-shaped molecules * domains of opposite chirality * π-walls * superstructural chirality Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.006, year: 2010
无
2006-01-01
Using four β-cyclodextrin derivatives, 2,6-di-O-benzyl-3-O-heptanonyl-β-CD, 2,6-di-O-benzyl-3-O-octanonyl-β-CD, 2,3-di-O-benzyl-6-O-heptanonyl-β-CD, and 2,3-di-O-benzy1-6-O-octanonyl-β-CD, as chiral stationary phases of capillary gas chromatography (CGC), the enantiomers of Sharpless epoxides were well separated. The enantiomer excess values (e.e.%) of some chiral Sharpless epoxides were also determined successfully using these CDs.
Phase transition phenomenon: A compound measure analysis
Kang, Bo Soo; Park, Chanhi; Ryu, Doojin; Song, Wonho
2015-06-01
This study investigates the well-documented phenomenon of phase transition in financial markets using combined information from both return and volume changes within short time intervals. We suggest a new measure for the phase transition behaviour of markets, calculated as a return distribution conditional on local variance in volume imbalance, and show that this measure successfully captures phase transition behaviour under various conditions. We analyse the intraday trade and quote dataset from the KOSPI 200 index futures, which includes detailed information on the original order size and the type of each initiating investor. We find that among these two competing factors, the submitted order size yields more explanatory power on the phenomenon of market phase transition than the investor type.
Quantum Phase Transitions in Quantum Dots
Rau, I. G.; Amasha, S.; Oreg, Y.; Goldhaber-Gordon, D.
2013-01-01
This review article describes theoretical and experimental advances in using quantum dots as a system for studying impurity quantum phase transitions and the non-Fermi liquid behavior at the quantum critical point.
The Structural Phase Transition in Octaflournaphtalene
Mackenzie, Gordon A.; Arthur, J. W.; Pawley, G. S.
1977-01-01
The phase transition in octafluoronaphthalene has been investigated by Raman scattering and neutron powder diffraction. The weight of the experimental evidence points to a unit cell doubling in the a direction, but with no change in space group symmetry. Lattice dynamics calculations support this...... evidence and indicate that the mechanism of the phase transition may well be the instability of a zone boundary acoustic mode of librational character. The structure of the low-temperature phase has been refined and the Raman spectra of the upper and lower phases are reported....