Multi-flavor massless QED${}_2$ at finite densities via Lefschetz thimbles

Abstract

We consider multi-flavor massless $(1+1)$-dimensional QED with chemical potentials at finite spatial length and the zero-temperature limit. Its sign problem is solved using the mean-field calculation with complex saddle points.

Comments: 25 pages, 4 figures; (v2) reference updated; (v3) minor changes