Influence of Dissipation on Quantum Coherence

Abstract

A quantum mechanical particle which moves in a symmetric double-well potential, and whose interaction with the environment is described in the classical regime by a phenomenological friction coefficient $\ensuremath{\eta}$, is considered. It is shown that, provided $\frac{\ensuremath{\eta}{{q}_{0}}^{2}}{\ensuremath{\hbar}}$ exceeds a critical value of order unity ($\ifmmode\pm\else\textpm\fi{}{q}_{0}$ are the locations of the potential minima), the mean rate of tunneling between the degenerate minima decreases with temperature, leading at $T=0$ to spontaneous symmetry breaking.