We calculate the density of states of a damped quantum-mechanical harmonic oscillator which is described by a Caldeira-Leggett type model with Ohmic dissipation and a Drude-like cutoff. From the exact expression for the associated partition function, we derive the asymptotic behavior of the density of states using Tauberian theorems. An effective algorithm to evaluate the density of states is presented and examples are given. It is pointed out that the calculated density of states is an experimentally accessible quantity.
Hanke, A., and W. Zwerger. “Density of States of a Damped Quantum Oscillator.” Physical Review E, vol. 52, no. 6, American Physical Society, Dec. 1995, pp. 6875–78, doi:10.1103/PhysRevE.52.6875.
Physical Review E