Gauge-independence of tunneling rates
C. Tamarit, A.D. Plascencia
It is shown that tunneling rates can be defined in terms of a false-vacuum effective action whose reality and convexity properties differ from those of the corresponding groundstate functional. The tunneling
rate is directly related to the false-vacuum effective action evaluated at an extremal ``quantum bounce''. The Nielsen identities of the false-vacuum functional ensure that the rate remains
independent of the choice of gauge-fixing. Our results are nonperturbative and clarify issues related with convexity and radiative corrections.