Finite-Temperature variational monte carlo method for strongly correlated electron systems

Kensaku Takai, Kota Ido, Takahiro Misawa, Youhei Yamaji, Masatoshi Imada

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

A new computational method for finite-Temperature properties of strongly correlated electrons is proposed by extending the variational Monte Carlo method originally developed for the ground state. The method is based on the path integral in the imaginary-Time formulation, starting from the infinite-Temperature state that is well approximated by a small number of certain random initial states. Lower temperatures are progressively reached by the imaginary-Time evolution. The algorithm follows the framework of the quantum transfer matrix and finite-Temperature Lanczos methods, but we extend them to treat much larger system sizes without the negative sign problem by optimizing the truncated Hilbert space on the basis of the time-dependent variational principle (TDVP). This optimization algorithm is equivalent to the stochastic reconfiguration (SR) method that has been frequently used for the ground state to optimally truncate the Hilbert space. The obtained finite-Temperature states allow an interpretation based on the thermal pure quantum (TPQ) state instead of the conventional canonical-ensemble average. Our method is tested for the one-And two-dimensional Hubbard models and its accuracy and efficiency are demonstrated.

Original languageEnglish
Article number034601
JournalJournal of the Physical Society of Japan
Volume85
Issue number3
DOIs
Publication statusPublished - 2016 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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