8 papers
Path optimization method for the sign problem: Insights from random matrix models
Kouji Kashiwa, Yusuke Namekawa, Hayato Takase
The path optimization method is applied to the Stephanov model and the chiral random matrix model, both of which share several properties with QCD, to mitigate the sign problem cau…
The canonical approach at high temperature revisited
Kouji Kashiwa, Hiroaki Kouno
This paper discusses a paradox encountered when employing the canonical approach, particularly in the high-temperature region where the Roberge-Weiss transition exists at finite im…
Effective degrees of freedom, trace anomaly and c-theorem like condition in the hadron resonance gas model
Hiroaki Kouno, Riki Oshima, Kouji Kashiwa
The relation between the effective degrees of freedom (EDOF) and the trace anomaly is studied in the hadron resonance gas (HRG) model. If we regard the thermodynamical relation as…
Thermodynamic geometry in hadron resonance gas model at real and imaginary baryon chemical potential and a simple sufficient condition for quark deconfinement
Riki Oshima, Hiroaki Kouno, Motoi Tachibana +1
The thermodynamic geometry of the hadron resonance gas model with (without) excluded volume effects (EVE) of baryons is investigated. The case with imaginary mu, where mu is the ba…
Polyakov-loop phase, Roberge-Weiss periodicity and thermodynamics
Kouji Kashiwa, Hiroaki Kouno
In this paper, we discuss the role of Roberge-Weiss periodicity in the thermodynamics of quantum chromodynamics at moderately high temperature, where the semi-quark-gluon plasma is…
Path optimization method for the sign problem caused by fermion determinant
Kazuki Hisayoshi, Kouji Kashiwa, Yusuke Namekawa +1
The path optimization method with machine learning is applied to the one-dimensional massive lattice Thirring model, which has the sign problem caused by the fermion determinant. T…