Many-Particle Quantum Thermal Machines

In 2013, quantum thermal machines were shown to exhibit quantum supremacy, an enhanced performance boosted by quantum effects with no classical counterpart. In particular, quantum supremacy was found in model of a nonadiabatic many-particle quantum heat engine. This work builds on the quest for quantum supremacy in cooling devices such as a quantum fridge. To this end, we introduce a quantum Otto fridge based on a quantum fluid confined in a time dependent harmonic trap, that acts as a working substance and undergoes an Otto cycle. We characterize the performance of this many-particle quantum fridge and prove that its operation can reach quantum supremacy, outperforming both the efficiency and power output of analogous single-particle and classical devices. We first show that in this setting, quantum supremacy is not achievable in the adiabatic limit. This no-go result however does not apply in finite-time quantum thermodynamics. Thanks to the interplay of nonadiabatic dynamics and many-body quantum effects, it is shown that a single many-body quantum fridge, with N particles as a working substance, outperforms an ensemble of N single-particle quantum fridges in a broad range of settings. Thus, we establish the existence of quantum supremacy for cooling devices