Performance Boost of a Collective Qutrit Refrigerator

A single qutrit with transitions selectively driven by weakly coupled reservoirs can implement one of the world's smallest refrigerators. We analyze the performance of N such fridges that are collectively coupled to the reservoirs. We observe a quantum boost, made manifest in a quadratic scaling of the steady-state cooling current with N. As N grows further, the scaling reduces to linear, since the transitions responsible for the quantum boost become energetically unfavorable. Fine-tuned interqutrit interactions may be used to maintain the quantum boost for all N and also for not perfectly collective scenarios.

Automated summary

By selectively driving the transitions of a single qutrit with weakly coupled reservoirs, one of the world's smallest refrigerators can be implemented. We analyze the performance of N such fridges that are collectively coupled to the reservoirs. We observe a quantum boost, seen in a quadratic scaling of the steady-state cooling current with N. As N increases, the scaling reduces to linear due to energetically unfavorable transitions responsible for the quantum boost.