Minimal quantum heat manager boosted by bath spectral filtering

Abstract

We reveal the potentially important role of a general mechanism in quantum heat management schemes, namely, spectral filtering of the coupling between the heat baths in the setup and the quantum system that controls the heat flow. Such filtering is enabled by interfaces between the system and the baths by means of harmonic-oscillator modes whose resonant frequencies and coupling strengths are used as control parameters of the system-bath coupling spectra. We show that this uniquely quantum-electrodynamic mechanism, here dubbed bath spectral filtering, boosts the performance of a minimal quantum heat manager comprised of two interacting qubits or an analogous optomechanical system, allowing this device to attain either perfect heat diode action or strongly enhanced heat transistor action.

Ground-state cooling of mechanical resonators by hot thermal light

“…where the interaction of the baths with the system is described by Liouville superoperatorsL x , which are given by [43,44,48]L…”

“…is the mean number of quanta in the respective bath. For the cooling of mechanical resonator, bath spectral filtering is applied only to optical baths, which yields [37,44]…”

“…By analogy with laser sideband cooling, we may want to drive the cavity at the lower sideband and suppress the upper sideband. This can be achieved by using bath spectral filtering [37][38][39][40][41][42][43][44].…”

“…In addition, simultaneous ground-state cooling of multiple degenerate or near-degenerate mechanical resonators is also possible, which is otherwise challenging to accomplish. A key to realize this method is bath spectral filtering (BSF) [37][38][39][40][41][42][43][44], in which unwanted frequencies are filtered out from the systembath coupling spectra. The BSF has previously been shown to enhance performance of different thermal functions [43,44].…”

“…A key to realize this method is bath spectral filtering (BSF) [37][38][39][40][41][42][43][44], in which unwanted frequencies are filtered out from the systembath coupling spectra. The BSF has previously been shown to enhance performance of different thermal functions [43,44]. Finally, we reveal a direct connection between the laser sideband cooling and cooling by heating in the optomechanical setting, which also explains the underlying physical mechanism of cooling in our scheme.…”