Helicity modulus and chiral symmetry breaking for boundary conditions with finite twist.

IF 2.2 3区 物理与天体物理 Q2 PHYSICS, FLUIDS & PLASMAS
Gaurav Khairnar, Thomas Vojta
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引用次数: 0

Abstract

We study the response of a two-dimensional classical XY model to a finite (noninfinitesimal) twist of the boundary conditions. We use Monte Carlo simulations to evaluate the free energy difference between periodic and twisted-periodic boundary conditions and find deviations from the expected quadratic dependence on the twist angle. Consequently, the helicity modulus (spin stiffness) shows a nontrivial dependence on the twist angle. We show that the deviation from the expected behavior arises because of the mixing of states with opposite chirality which leads to an additional entropy contribution in the quasi-long-range ordered phase. We give an improved prescription for the numerical evaluation of the helicity modulus for a finite twist, and we discuss the spontaneous breaking of the chiral symmetry for the antiperiodic boundary conditions. We also discuss applications to discrete spin systems and some experimental scenarios where boundary conditions with finite twist are necessary.

有限扭转边界条件下的螺旋模和手性对称破缺。
研究了二维经典XY模型对边界条件有限(非无穷小)扭转的响应。我们使用蒙特卡罗模拟来评估周期和扭转周期边界条件之间的自由能差,并找到与期望的二次依赖于扭转角的偏差。因此,螺旋模量(自旋刚度)对扭转角有重要的依赖关系。我们发现,与预期行为的偏差是由于具有相反手性的态的混合而引起的,这导致了准远程有序相的额外熵贡献。给出了有限扭转的螺旋模数值计算的改进公式,并讨论了反周期边界条件下手性对称的自发破缺。我们还讨论了在离散自旋系统中的应用,以及一些需要有限扭转边界条件的实验场景。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Physical Review E
Physical Review E PHYSICS, FLUIDS & PLASMASPHYSICS, MATHEMAT-PHYSICS, MATHEMATICAL
CiteScore
4.50
自引率
16.70%
发文量
2110
期刊介绍: Physical Review E (PRE), broad and interdisciplinary in scope, focuses on collective phenomena of many-body systems, with statistical physics and nonlinear dynamics as the central themes of the journal. Physical Review E publishes recent developments in biological and soft matter physics including granular materials, colloids, complex fluids, liquid crystals, and polymers. The journal covers fluid dynamics and plasma physics and includes sections on computational and interdisciplinary physics, for example, complex networks.
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