Classical model emerges in quantum entanglement: Quantum Monte Carlo study for an Ising-Heisenberg bilayer

Siying Wu, Xiaoxue Ran, Binbin Yin, Qi Fang Li, Bin Bin Mao, Yan Cheng Wang, Zheng Yan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)

Abstract

By developing a cluster sampling of the stochastic series expansion quantum Monte Carlo method, we investigate a spin-12 model on a bilayer square lattice with intralayer ferromagnetic (FM) Ising coupling and interlayer antiferromagnetic Heisenberg interaction. The continuous quantum phase transition which occurs at gc=3.045(2) between the FM Ising phase and the dimerized phase is studied via large-scale simulations. From analysis of the critical exponents we show that this phase transition belongs to the (2+1)-dimensional Ising universality class. In addition, the quantum entanglement is strong between the two layers, especially in the dimerized phase. The effective Hamiltonian of a single layer seems like a transverse-field Ising model. However, we found that the quantum entanglement Hamiltonian is a pure classical Ising model without any quantum fluctuations. Furthermore, we give a more general explanation about how a classical entanglement Hamiltonian emerges.

Original languageEnglish
Article number155121
JournalPhysical Review B
Volume107
Issue number15
DOIs
Publication statusPublished - 15 Apr 2023
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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