Müller, B; Takigawa, N, *How adiabatic is quantum tunneling?*,
Annals of Physics, vol. 173 no. 1
(1987),
pp. 163-184 .
**Abstract:**

*We consider the coupling between collective and intrinsic degrees of freedom of a many-dimensional quantum system. We give a criterion for the validity of the adiabatic approximation in tunneling processes and derive an equation for the "lag" of the intrinsic wave function with respect to the adiabatic groundstate. Solutions for several simple cases are presented. © 1987.*