We study quantum tunneling in a biased double-well potential in the presence of Ohmic dissipation with a friction coefficient $\alpha >1\mathrm{}$. The tunneling rate out of the metastable well is calculated in real time as a function of the temperature $T$ and bias energy $\epsilon$. The $T=0\mathrm{}$ result agrees with a droplet-model calculation in imaginary time. At low temperatures we find an enhancement to the $T=0\mathrm{}$ rate varying as ${\left(\frac{T}{\epsilon }\right)}^2$.

• Received 21 January 1985

DOI:https://doi.org/10.1103/PhysRevLett.54.1609