  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.
