Speaker
Prof.
Jun Nishimura
Description
Monte Carlo simulations of quantum time-evolution based on the real-
time path integral have been thought to be extremely difficult since it involves a
phase factor exp(iS) in the integrand, which causes a severe sign
problem. We apply the Lefschetz thimble method with various new
techniques to such systems. In this talk, I would like to discuss a new
understanding of quantum tunneling and quantum decoherence that arises
as complex saddle point configurations. I would also like to discuss how
one can apply this method to investigate the beginning of the universe
based on quantum gravity.
