发表机构
Department of Physics, Institute of Science Tokyo（东京科学大学物理系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究探究量子临界点附近小猝灭后的短时洛施密特动力学，明确洛施密特速率函数初始二次增长的决定因素，通过横场伊辛链验证算符依赖性，还讨论了二次 regime 外的首次修正。
AI 中文摘要
我们研究量子临界点附近发生小突然猝灭后的短时洛施密特动力学。研究表明，洛施密特速率函数的初始二次增长由单位系统尺寸的猝灭算符方差决定。对于局域猝灭算符，该方差密度恰好等于初始基态中同等时间下的连通两点关联函数的空间求和。这一关系将早期洛施密特响应与静态临界关联关联起来。假设临界点处存在幂律关联，我们通过猝灭算符的标度维度对短时系数的有限尺寸标度进行分类。在一维情况下，该系数随系统尺寸表现为有限、对数增强或代数增强。我们在横场伊辛链中阐明了这种算符依赖性，其中横场和纵场猝灭与不同的临界算符耦合。我们还利用猝灭后哈密顿量的四阶累积量，讨论了二次 regime 之外的首次修正。
英文摘要
We study the short-time Loschmidt dynamics after a small sudden quench near a quantum critical point. We show that the initial quadratic growth of the Loschmidt rate function is governed by the variance of the quench operator per system size. For a local quench operator, this variance density is exactly equal to the spatial sum of the equal-time connected two-point correlation function in the initial ground state. This relation connects the early-time Loschmidt response to static critical correlations. Assuming power-law correlations at criticality, we classify the finite-size scaling of the short-time coefficient by the scaling dimension of the quench operator. In one dimension, the coefficient is finite, logarithmically enhanced, or algebraically enhanced with system size. We illustrate this operator dependence in the transverse-field Ising chain, where transverse-field and longitudinal-field quenches couple to different critical operators. We also discuss the first correction beyond the quadratic regime using the fourth cumulant of the post-quench Hamiltonian.
Comments19 pages, 0 figure
