TY - JOUR

T1 - Lefschetz-thimble approach to the Silver Blaze problem of one-site fermion model

AU - Tanizaki, Yuya

AU - Hidaka, Yoshimasa

AU - Hayata, Tomoya

N1 - Funding Information:
Y. T. is supported by the Special Postdoctoral Researchers Program of RIKEN. Y. H. is partially supported by JSPS KAKENHI Grant No. 15H03652 and 16K17716 and by RIKEN iTHES project. T. H. is supported by Grants-in-Aid for the fellowship of JSPS (No: JP16J02240)

PY - 2016

Y1 - 2016

N2 - The sign problem of finite-density QCD at the zero temperature becomes very severe if the quark chemical potential exceeds half of the pion mass. In order to understand its property, we consider the sign problem of the one-site fermion model appearing in its path-integral expression by using the Lefschetz-thimble method. We show that the original integration cycle becomes decomposed into multiple Lefschetz thimbles at a certain value of the fermion chemical potential, which would correspond to half of the pion mass of finite-density QCD. This triggers a fictitious phase transition on each Lefschetz thimble, and the interference of complex phases among them plays an important role for the correct description of the system. We also show that the complex Langevin method does not work in this situation.

AB - The sign problem of finite-density QCD at the zero temperature becomes very severe if the quark chemical potential exceeds half of the pion mass. In order to understand its property, we consider the sign problem of the one-site fermion model appearing in its path-integral expression by using the Lefschetz-thimble method. We show that the original integration cycle becomes decomposed into multiple Lefschetz thimbles at a certain value of the fermion chemical potential, which would correspond to half of the pion mass of finite-density QCD. This triggers a fictitious phase transition on each Lefschetz thimble, and the interference of complex phases among them plays an important role for the correct description of the system. We also show that the complex Langevin method does not work in this situation.

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M3 - Conference article

AN - SCOPUS:85025827865

VL - Part F128557

JO - Proceedings of Science

JF - Proceedings of Science

SN - 1824-8039

T2 - 34th Annual International Symposium on Lattice Field Theory, LATTICE 2016

Y2 - 24 July 2016 through 30 July 2016

ER -