Transition of Bery Phase and Pancharatnam Phase and Phase Change

Berry Phase and time-dependent Pancharatnam phase are investigated for nuclear spin polarization in a liquid by a rotation magnetic field, where two-state mixture effect is exactly included in the geometric phases. We find that when the system of nuclear spin polarization is in the unpolarized state, the transitive phenomena of both Berry phase and Pancharatnam phase are taken place. For the polarized system, in contrast, such a transition is not taken place. It is obvious that the transitions of geometric phase correspond to the phase change of physical system.     

FeMnNi合金冲击相变与卸载逆相变历程研究

采用VISAR测试技术,将正向加载和逆向加载实验相结合,研究了不同加载压力下FeMnNi合金的冲击相变和卸载逆相变历程.结果表明:冲击加载压力与冲击相变阈值之差小于逆相变阈值时,即0＜σp-σt＜σn,FeMnNi合金发生α→ε相变,加载段呈现弹性波、塑性波和相变波三波结构,塑性波在自由面反射稀疏波使FeMnNi合金完...     

色味连锁物质的稳定态及其相变

简要介绍和评述了色味连锁物质的稳定态及其相变,指出高密强相互作用物质由于夸克配对出现了一些奇异相。重点介绍色味连锁（CFL）物质及其中的Goldstone-mode凝聚现象。在考虑奇异数对应化学势μs≠0的情况下,CFL物质中K^0和K^-0都可能发生凝聚。随着重子数密度的增高,强作用物质呈现出丰富相结构,在核物质相与CFL相之间可能存在其它相,但最简单的可能相变过程是直接从核物质相变为CFL物质。这种相变可有两种过程,即两相间仅存在一个极小界面或出现两相混合区域。另外还重点讨论了K^-介子凝聚对相变的影响。Quark matter at high density has a rich phase structure. Goidstone-mode may condense in the color-flavor-locked （CFL） phase matter. We review the stability of CFL phase and its phase transition, as well as the effect of nonzero strangeness chemical potential on the CFL phase of dense quark matter. It is pointed out that, depending on the value of μs, both K^0 and K^-0 may condense in the CFL matter. As a function of quark chemical potential, other phases may intervene between the nuclear-matter and CFL phase. The simplest possibility, however, is a transition between nuclear and CFL matter. Such a transition could occur either at a single sharp interface or through a mixed phase region. The effect of discontinuous K^- meson condensation on the phase transition is also discussed. [     

Fluctuations and Phase Transition Dynamics

Kibble and Zurek have provided a unifying causal picture for the appearance ofclassical defects like cosmic strings or vortices at the onset of phase transitionsin relativistic QFT and condensed matter systems, respectively. In condensedmatter the predictions are partially supported by agreement with experiments insuperfluid helium. We provide an alternative picture for the initial appearanceof defects that supports the experimental evidence. When the original predictionsfail, this is understood, in part, as a consequence of thermal fluctuations (noise),which play a comparable role in both condensed matter and QFT.     

Berry几何相与量子跃迁

针对Berry几何相的出现所关联的量子能级,微弱变化跃迁的物理背景条件进行分析研究;对严格产生(获得)Berry几何相与这种微弱变化跃迁之间的内在关系作进一步探讨.结果表明:Berry几何相的严格产生都是由系统在演变过程中所出现的量子能级微弱变化跃迁的绝热极限效应所必然导致的结果.     

High-Pressure Phase Transition in Cyclo-octane

Structural behaviour of cyclo-octane under high pressure is studied by using a synchrotron x-ray source in a diamond anvil cell （DAC） up to 40.2 GPa at room temperature. The cyclo-octane firstly solidifies to the triclinic phase at 0.87 GPa. With the increasing pressure, the phase of cyclo-octane changes to the tetragonal phase at about 6.0 GPa and then transforms to amorphous phase above 18.2 GPa, which is kept till to 40.2 GPa. All the phase transitions of cyclo-octane are irreversible.     

A Fully Magnetizing Phase Transition

We analyze the Farey spin chain, a one-dimensional spin system with long-range multibody interactions. Using a polymer model technique, we show that when the temperature is decreased below the (single) critical temperature T _c=1/2, the magnetization jumps from zero to one.     

Phase Transition and Physical Properties of InS

Using the crystal structure prediction method based on particle swarm optimization algorithm, three phases(P nnm, C2/m and Pm-3 m) for InS are predicted. The new phase Pm-3m of InS under high pressure is firstly reported in the work. The structural features and electronic structure under high pressure of InS are fully investigated. We predicted the stable ground-state structure of InS was the P nnm phase and phase transformation of InS from P nnm phase to P m-3 m phase is firstly found at the pressure of about 29.5 GPa. According to the calculated enthalpies of InS with four structures in the pressure range from 20 GPa to 45 GPa, we find the C2/m phase is a metastable phase. The calculated band gap value of about 2.08 eV for InS with P nnm structure at 0 GPa agrees well with the experimental value. Moreover, the electronic structure suggests that the C2/m and P m-3m phase are metallic phases.     

Phase Transition and Uniqueness of Levelset Percolation

The main purpose of this paper is to introduce and establish basic results of a natural extension of the classical Boolean percolation model (also known as the Gilbert disc model). We replace the balls of that model by a positive non-increasing attenuation function \(l:(0,\infty ) \rightarrow [0,\infty )\) to create the random field \(\Psi (y)=\sum _{x\in \eta }l(|x-y|),\) where \(\eta \) is a homogeneous Poisson process in \({\mathbb {R}}^d.\) The field \(\Psi \) is then a random potential field with infinite range dependencies whenever the support of the function l is unbounded. In particular, we study the level sets \(\Psi _{\ge h}(y)\) containing the points \(y\in {\mathbb {R}}^d\) such that \(\Psi (y)\ge h.\) In the case where l has unbounded support, we give, for any \(d\ge 2,\) a necessary and sufficient condition on l for \(\Psi _{\ge h}(y)\) to have a percolative phase transition as a function of h. We also prove that when l is continuous then so is \(\Psi \) almost surely. Moreover, in this case and for \(d=2,\) we prove uniqueness of the infinite component of \(\Psi _{\ge h}\) when such exists, and we also show that the so-called percolation function is continuous below the critical value \(h_c\).     

Chiral Magnetic Effect and Chiral Phase Transition

We study the influence of the chiral phase transition on the chiral magnetic effect. The azimuthal charge-particle 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.     

Incomplete-Fusion-Fragmentation Model and Nuclear Liquid-Gas Phase Transition

Incomplete-Fusion-Fragmentation Model is used to analyze the multifragmentation of the projectile remnant in 600MeV/u Au+Au reaction.The theoretical resultsof the mass number,the excitation energy and the thermodynamical temperature of the projectile remnant agree well with experimental data.The backbending structure in the curve of temperature as a function of the excitation energy per nucleon,i.e. the evidence of liquid-gas phase transition,is reproduced and reasonably related to the decay modes phase transformation from dominance of the multifragmentation mode to the vaporization mode.     

A New Spin-Crossover-Complex Phase Generated by Photo-Induced Phase Transition

We clarified that photo-induced phase is quite different in structure from the thermally-induced phase by resonant Raman and infrared absorption spectroscopy in the spin-crossover complex, [Fe-(2-pic) 3 ]Cl 2 EtOH. In the photo-induced phase we observed a number of additional Raman lines which are not observed in the thermally-induced phases. The infrared absorption spectrum of the photo-induced phase has different structures from those of thermally-induced phases. The additional Raman lines are assigned to infrared-active vibrational modes that are strongly prohibited by selection rules in the thermally-induced phase. These results indicate that a dramatic symmetry lowering should take place in the photo-induced phase.     

Activity Phase Transition for Constrained Dynamics

We consider two cases of kinetically constrained models, namely East and FA-1f models. The object of interest of our work is the activity A(t){\mathcal {A}(t)} defined as the total number of configuration changes in the interval [0, t] for the dynamics on a finite domain. It has been shown in Garrahan et al. (J Phys A 42:075007, 2009; Phys Rev Lett 98:195702, 2007) that the large deviations of the activity exhibit a non-equilibrium phase transition in the thermodynamic limit and that reducing the activity is more likely than increasing it due to a blocking mechanism induced by the constraints. In this paper, we study the finite size effects around this first order phase transition and analyze the phase coexistence between the active and inactive dynamical phases in dimension 1. In higher dimensions, we show that the finite size effects are determined by the dimension and the choice of the boundary conditions.     

Pressure-Induced Phase Transition of Ruthenium Diboride

Based on the first-principles calculations, we firstly predict that RuB2 undergoes a phase transition from the orthorhombic phase to the hexagonal phase with a volume collapse of 1% when the applied pressure is 15. 7 GPa. The values of calculated elastic moduli indicate that RuB2 and RuN2 are low compressibility materials. Based on the calculated electronic density of states and valence charge density distribution, the bonding nature of RuB2 is examined to obtain a deeper insight into the physical origin of the mechanical properties. The metallieity and high elastic moduli of RuB2 and FuN2 suggest that they axe potential hard conductors.     

Information Dynamics at a Phase Transition

We propose a new way of investigating phase transitions in the context of information theory. We use an information-entropic measure of spatial complexity known as configurational entropy (CE) to quantify both the storage and exchange of information in a lattice simulation of a Ginzburg–Landau model with a scalar order parameter coupled to a heat bath. The CE is built from the Fourier spectrum of fluctuations around the mean-field and reaches a minimum at criticality. In particular, we investigate the behavior of CE near and at criticality, exploring the relation between information and the emergence of ordered domains. We show that as the temperature is increased from below, the CE displays three essential scaling regimes at different spatial scales: scale free, turbulent, and critical. Together, they offer an information-entropic characterization of critical behavior where the storage and fidelity of information processing is maximized at criticality.     

Phase Transition in Two-Dimensional Josephson-Junction Arrays

The self-charging model of two-dimensional Josephson-junction arrays at T = 0 is studied by the coupled cluster expansion method. The calculated results for the mass gap converge nicely. Besides the critical point, we also determine the critical parameters at T = 0. The system displays a second-order phase transition and the results are consistent with those obtained by other methods.     

Noise-Induced Phase Transition in Traffic Flow

One of the dynamic phases of the traffic flow is the traffic jam. It appears in traffic flow when the vehicledensity is larger than the critical value. In this paper, a new method is presented to investigate the traffic jam when thevehicle density is smaller than the critical value. In our method, we introduce noise into the traffic system after sufficienttransient time. Under the effect of noise, the traffic jam appears, and the phase transition from tree to synchronized flowoccurs in traffic flow. Our method is tested for the deterministic NaSch traffic model. The simulation results demonstratethat there exist a broad range of lower densities at which the noise effect leading to traffic jam can be observed.     

Topological Phase Transition and Phase Diagrams in a Two-Leg Kitaev Ladder System

A scheme to investigate the topological properties in a two-leg Kitaev ladder system composed of two Kitaev chains is proposed. In the case of two identical Kitaev chains, it is found that the interchain hopping amplitude plays a significant role in the separation of the energy spectrum and in inducing a topologically nontrivial phase, while the interchain pairing strength only affects the size of the energy gap. Moreover, another situation that the system consists of two non-identical Kitaev chains is also investigated and the corresponding phase diagram is calculated. It is found that two pairs of degenerate nonzero edge modes will, respectively, appear in the upper and lower energy gaps when the interchain hopping amplitude or the interchain pairing strength is large enough. Furthermore, it is pointed out that the winding number is quantitatively equivalent to half of the number of zero energy edge modes in our system.