Vacuum decay in the Lorentzian path integral

Abstract We apply the Lorentzian path integral to decay of a false vacuum and estimate false-vacuum rate. To make convergent, deformation an integration contour is performed by following Picard-Lefschetz theory. show that nucleation rate critical bubble, for which corresponding bounce action extremized, has same exponent as Euclidean approach. also extend our computation bubble larger or smaller than one formalism not applicable.