We derive a rigorous quantum-to-classical mapping for interacting spin systems at finite temperatures. Specifically, the large-$S$ asymptotic form of the partition function is given by the partition function of a classical model for vectors of length $S_C=\sqrt{S(S+1)}$. Quantum corrections to the asymptotic result form a series in powers of $1/[S(S+1)]$. We calculate the leading temperature-independent quantum correction to the magnetic anisotropy constant. The established mapping justifies the use of classical Monte Carlo simulations for realistic magnetic Hamiltonians, including anisotropic and frustrated interactions. As an application, we compute the Curie and Néel temperatures for a range of magnetic materials with known microscopic interaction constants. The obtained transition temperatures are in good agreement with measured values. Monte Carlo results for the magnetic susceptibility of the collinear antiferromagnet MnF$_2$ above and below the transition are also compared with experimental data.
Quantum-Classical Correspondence Principle for Work Distributions in a Chaotic System
我们用数值方法研究了混沌系统中的功分布，考察了量子功和经典功之间的关系。数值结果表明，在混沌系统中，量子功分布与经典功分布之间存在着对应原理。在最近的工作[Jarzynski，Quan，and Rahav，Phys. Rev. X 5，031038（2015）]中证明了一维（1D）可积系统的这种对应关系。我们的研究通过两点能量测量进一步证明了量子功的定义。
Embedding Quantum Information into Classical Spacetime: Information Geometrical Perspectives on anti-de Sitter space / conformal field theory Correspondence
Fair sampling with temperature-targeted QAOA based on quantum-classical correspondence theory
Graduate School of Science and Technology, Keio University（庆应义塾大学理工学研究科）；Department of Applied Physics and Physico-Informatics, Keio University（庆应义塾大学应用物理与物理信息学系）；Keio University Sustainable Quantum Artificial Intelligence Center (KSQAIC), Keio University（庆应义塾大学可持续量子人工智能中心）；Human Biology-Microbiome-Quantum Research Center (WPI-Bio2Q), Keio University（庆应义塾大学人类生物学-微生物组-量子研究中心）；Green Computing System Research Organization, Waseda University（早稻田大学绿色计算系统研究组织）
