近日，伊朗哈拉兹米大学的Ali Vahedi及其研究团队取得一项新进展。经过不懈努力，他们揭示外尔半金属全息景观中的非线性动力学和临界现象。相关研究成果已于2024年8月14日在国际知名学术期刊《高能物理杂志》上发表。

本研究利用D3/D7膜构型，对全息外尔半金属（WSM）中的临界现象进行了详细分析。研究人员研究探索了在零温和有限温度下，纵向电流J受到外部电场E作用时的非线性响应。在零温下，研究发现J-E关系中存在由背景参数（粒子质量和轴向规范势）驱动的潜在量子相变。这种相变的特点是由WSM样行为和传统非线性导电行为之间的相互作用所导致的独特重连现象，表明发生了量子相变。

此外，在有耗散的非零温度下，随着电场和轴向规范势的变化，系统表现出一阶和二阶相变。纵向电导率被用作序参量来识别电流驱动的相变。数值分析揭示了这一非平衡相变中的临界指数，这些指数与金属系统中观察到的平均场值具有相似性。

附：英文原文

Title: Non-linear dynamics and critical phenomena in the holographic landscape of Weyl semimetals

Author: Matsumoto, Masataka, Mirjalali, Mirmani, Vahedi, Ali

Issue&Volume: 2024-08-14

Abstract: This study presents a detailed analysis of critical phenomena in a holographic Weyl semi-metal (WSM) using the D3/D7 brane configuration. The research explores the non-linear response of the longitudinal current J when subjected to an external electric field E at both zero and finite temperatures. At zero temperature, the study identifies a potential quantum phase transition in the J-E relationship, driven by background parameters the particle mass, and axial gauge potential. This transition is characterized by a unique reconnection phenomenon resulting from the interplay between WSM-like and conventional nonlinear conducting behaviors, indicating a quantum phase transition.Additionally, at non-zero temperatures with dissipation, the system demonstrates first- and second-order phase transitions as the electric field and axial gauge potential are varied. The longitudinal conductivity is used as an order parameter to identify the current-driven phase transition. Numerical analysis reveals critical exponents in this non-equilibrium phase transition that show similarities to mean-field values observed in metallic systems.

DOI: 10.1007/JHEP08(2024)104

Source: https://link.springer.com/article/10.1007/JHEP08(2024)104