Numerical simulation of the false vacuum decay at finite temperature

The false vacuum decay rate is of important meaning in understanding the Universe, such as the symmetry breaking process in the early universe and the age of our universe, which is conventionally calculated with the saddle-point approximation in the field theory. Utilizing the extension of the Wigner function in quantum field theory, we numerically calculate the decay rate of the false vacuum through path integral. We study the decay rate for the thermal fluctuation scenarios and its dependence on the potential shape, and found that the false vacuum decay occurs following an exponentially decay rate, and the speed of vacuum decay decreases when the initial energy of the system decreases and the potential height increase. The discrepancy between the simulation results and the theoretical prediction of finite temperature effective field theory is observed.