Decay of a Dissipative Object by Quantum Noise

The decay time, τ, of a dissipative object out of the metastable minimum of a (cubic) potential due to quantum noise is determined by a numerical investigation of the quasiclassical Langevin equation. In the zero temperature limit, and for moderate to large damping (γω o ), we find that σ=ln (ω o τ/2π) can be approximated by a σ≃κ·γΔV/ω o 2 where the constant κ is κ≃3.20. This is in good agreement with an analytic treatment of the Langevin equation, but about a factor three smaller than the result obtained by Caldeira and Leggett by the instanton method.