Lefshetz thimble method for sign problem

Lefshetz thimble method for sign problem

To solve the sign problem, we develop the “generalized thimble method”and its extension, the “Worldvolume Hybrid Monte Carlo method”. We apply the algorithms to the Hubbard model,which is an important model of strongly correlated electron systems, and compare the results with those obtained by other methods.

We also investigate the real-time dynamics of quantum fields and establish relevant algorithms for simulating nonequilibrium relaxation processes.