分析QGP相变级次的一种可能方法

在推广的Ginzburg-Landau理论框架内,解析地研究了在QGP转化为强子的相变过程中多重数差关联矩F_q与相空间间隔δ的依赖关系,提出了一种在实验中判断QGP相变级次的可能方法.此方法的特点在于它不依赖系统温度这个未知的参量,对于低维和高维的实验数据均可以得出相同的相变信息.     

Tetrasulphur Tetranitride: Phase Transition and Crystal Structure at Elevated Temperature

Rietveld X‐ray crystal structure investigations on S₄N₄ give evidence for a new orthorhombic high‐temperature phase (Pbcn, a = 883.9(1) pm, b = 875.5(1) pm, c = 725.81(9) pm) very close to the explosion temperature of the solid‐state material. The phase transition can be described using Landau's theory, yielding a critical temperature of 397 K and a critical exponent of 0.50.     

Amplitude equation for the stochastic reaction‐diffusion equations with random Neumann boundary conditions

In this paper, we consider a quite general class of reaction‐diffusion equations with cubic nonlinearities and with random Neumann boundary conditions. We derive rigorously amplitude equations, using the natural separation of time‐scales near a change of stability and investigate whether additive degenerate noise and random boundary conditions can lead to stabilization of the solution of the stochastic partial differential equation or not. The nonlinear heat equation (Ginzburg–Landau equation) is used to illustrate our result. Copyright © 2015 John Wiley & Sons, Ltd.     

广义Ginzburg-Landau方程和Rangwala Rao方程的显式精确解

该文通过适当代换并结合假设待定法，求出了具高阶非线性项的Liénard方程a″(ξ)+la(ξ)+ma\+\{2p+1\}(ξ)+na\+\{4p+1\}(ξ)=0的三类精确解. 据此求出了广义Ginzburg Landau方程、Rangwala Rao方程及若干 导数schr〖AKo¨D〗dinger型方程的孤波解和三角函数型周期波解.     

Generalized effective-potential Landau theory for the two-dimensional extended Bose-Hubbard model

We analytically study the quantum phase diagrams of ultracold dipolar Bose gases in an optical square lattice at zero temperature by using the generalized effective-potential Landau theory (GEPLT). For a weak nearest-neighbor repulsion, our analytical results are better than the third-order strong-coupling expansion theory calculation. In contrast to a previous quantum Monte Carlo (QMC) simulation, we analytically calculate phase transition boundaries up to the third-order hopping, which are in excellent agreement with QMC simulations for second-order phase transition.     

Magnetospectroscopy of double HgTe/CdHgTe QWs with inverted band structure in high magnetic fields up to 30 T

Magnetoabsorption in far and mid IR ranges in double HgTe/CdHgTe quantum wells with inverted band structure has been studied in high magnetic fields up to 30 T. Numerous intraband and interband transitions have been revealed in the spectra and interpreted within axial 8 × 8 k·p model. Splitting of dominant magnetoabsorption lines resulting from optical transitions from hole-like zero-mode Landau level has been discovered and discussed in terms of a built-in electric field and collective phenomena.     

Effect of density variation on the Sm A–I phase transition properties

Based on a thermodynamic model, we investigate how the density variation influences the smectic (Sm A)–isotropic (I) phase transition. We find that the density variation shifts the smectic A–isotropic transition temperature, however, first-order nature of the transition remains the same. Here, we also examine the effect of high pressure on the thermodynamic quantities. The present analysis shows that the pressure strongly influences the enthalpy and density step at the clearing transition. The pressure dependence of the thermodynamic properties is incorporated through the pressure dependent second Landau coefficient and the coefficients which couple the nematic and smectic order parameters to the density. We find a close agreement between theoretical and experimental results. Furthermore, we discuss the implications of the results for achiral liquid crystals.     

贝利相与非线性输运

电子输运现象包含一系列很重要的材料性质,并可以用来提供关于载体物理系统的很多信息。在 最近的二三十年,人们逐渐认识到除了电子能谱之外,电子在布里渊区的几何性质,比如贝利曲率和 轨道磁矩,会在电子输运中起到关键性的作用。在线性输运现象中的此种关联已引起广泛的兴趣并得 到深入的研究。然而,在非线性输运现象中的电子几何性质的作用的研究最近才逐渐起步。此种关联 可以大大加深对各种非线性输运现象的认识,并对如何从材料控制上调节非线性现象的强度提供有价 值的研究视角和指导原则。基于此背景,本文试图引入研究输运现象的半经典理论框架,并在几种输 运现象中举例说明贝利相的作用。     

贝利相与非线性输运

电子输运现象包含一系列很重要的材料性质,并可以用来提供关于载体物理系统的很多信息。在 最近的二三十年,人们逐渐认识到除了电子能谱之外,电子在布里渊区的几何性质,比如贝利曲率和 轨道磁矩,会在电子输运中起到关键性的作用。在线性输运现象中的此种关联已引起广泛的兴趣并得 到深入的研究。然而,在非线性输运现象中的电子几何性质的作用的研究最近才逐渐起步。此种关联 可以大大加深对各种非线性输运现象的认识,并对如何从材料控制上调节非线性现象的强度提供有价 值的研究视角和指导原则。基于此背景,本文试图引入研究输运现象的半经典理论框架,并在几种输 运现象中举例说明贝利相的作用。     

Evidence of anisotropic Landau level splitting in topological semimetal ZrSiS under high magnetic fields

Magneto-transport study has been performed in topological semimetal ZrSiS single crystals under high pulsed magnetic fields. Obvious dependence of Landau level splitting on temperature and angular was investigated. The strong three-dimensional anisotropic nature of Landau level splitting under high pulsed magnetic fields was revealed by the angular dependent measurements, in which the orbital contribution is more dominant than Zeeman splitting. Our studies provide more insights into the physical properties of topological semimetals ZrSiS and shed light on future spintronic applications of ZrSiS.