Simulating quantum dissipation in many-body systems

¹ Istituto Nazionale per la Fisica della Materia (INFM), Unità di Ricerca di Firenze Via G. Sansone 1, I-50019 Sesto Fiorentino (FI), Italy
² Dipartimento di Fisica dell'Università di Firenze Via G. Sansone 1, I-50019 Sesto Fiorentino (FI), Italy
³ Istituto di Elettronica Quantistica del Consiglio Nazionale delle Ricerche Via Panciatichi 56/30, I-50127 Firenze, Italy

Received: 30 October 2001
Accepted: 31 January 2002

Abstract

An efficient Path Integral Monte Carlo procedure is proposed to simulate the behavior of quantum many-body dissipative systems described within the framework of the influence functional. Thermodynamic observables are obtained by Monte Carlo sampling of the partition function after discretization and Fourier transformation in imaginary time of the dynamical variables. The method is tested extensively for model systems, using realistic dissipative kernels. Results are also compared with the predictions of a recently proposed semiclassical approximation, thus testing the reliability of the latter approach for weak quantum coupling. Our numerical method opens the possibility to quantitatively describe real quantum dissipative systems as, e.g., Josephson junction arrays.