Dissipation-induced enhancement of quantum fluctuations

Year: 2016

Authors: Rastelli G.

Autors Affiliation: Univ Konstanz, Fachbereich Phys, D-78457 Constance, Germany

Abstract: We study a quantum harmonic oscillator linearly coupled through the position operator (q) over cap to a first bath and through the momentum operator (p) over cap to a second bath yielding an Ohmic-Drude dissipation. We analyse the oscillator´s fluctuations as a function of the ratio between the strength of the two couplings, focusing in particular on the situation in which the two dissipative interactions are comparable. Analytic formulas are derived in the relevant regimes corresponding to the low temperature limit and when the Drude high frequency cutoff is much larger than all other frequencies. At low temperature, each bath operates to suppress the oscillator´s ground state quantum fluctuations (0) or (0) appearing in the corresponding interaction. When one of the two dissipative interactions dominates over the other, the fluctuations for the coupling operator are squeezed. When the two interactions are comparable, the two baths enter in competition as the two conjugate operators do not commute yielding quantum frustration. In this regime, remarkably, the fluctuations of both two quadratures can be enhanced by increasing the dissipative coupling.


Volume: 18      Pages from: 053033-1  to: 053033-5

More Information: GR acknowledges S Andergassen and W Belzig for a careful reading of the manuscript and E Buks for an interesting discussion. This research was supported by the Zukunftskolleg of the University of Konstanz, by the DFG through SFB 767 and by the MWK-RiSC program, project No. 13551400.
KeyWords: Quantum dissipation, Quantum frustration, Squeezing
DOI: 10.1088/1367-2630/18/5/053033