Dissipation-induced enhancement of quantum fluctuations

We study a quantumharmonic oscillator linearly coupled through the position operator q̂ to a first bath and through themomentumoperator p̂ to a second bath yielding anOhmic–Drude dissipation. We analyse the oscillator’sfluctuations as a function of the ratio between the strength of the two couplings, focusing in particular on the situation inwhich the two dissipative interactions are comparable. Analytic formulas are derived in the relevant regimes corresponding to the low temperature limit andwhen theDrude high frequency cutoff ismuch larger than all other frequencies. At low temperature, each bath operates to suppress the oscillator’s ground state quantum fluctuations áD ñ q̂2 0 or áD ñ p̂2 0 appearing in the corresponding interaction.When one of the two dissipative interactions dominates over the other, thefluctuations 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, thefluctuations of both two quadratures can be enhanced by increasing the dissipative coupling.