A new method for fermionic singular-drift problem in complex Langevin method

by Dr Keitaro Nagata (KEK)

Monday 21 Dec 2015, 13:30 → 14:30 Asia/Tokyo

Main Research Building 433 (RIKEN Wako)

Date: Dec 21 (Mon) Time: 13:30 - Place: Main Research bldg. 433 Speaker: Keitaro Nagata (RIKEN) Title: A new method for fermionic singular-drift problem in complex Langevin method Abstract: I will talk about our recent study on the complex Langevin method. Recently, a gauge cooling has been proposed in the complex Langevin method, which enables us to study QCD at high density in the deconfinement phase. Additional problem will happen in the confinement phase with light quarks, where Dirac low-modes cause the singularity in the fermion drift term and leads to the convergence to wrong limits. We propose a new method to overcome this singular-drift problem caused by Dirac low-modes by generalizing the gauge cooling. We test the method for the chiral random matrix theory, and find that the new method allows us to reproduce the exact result at zero temperature with light quarks. I will also discuss the validity and possible limitation of the method. Reference K. Nagata, J. Nishimura, S. Shimasaki, arXiv:1511.08580. See more QHP seminars