Roulet, Alexandre

Date:  Tuesday, March 21, 2017
Time: 16:30
Place: ETH Zurich, Hönggerberg, HIT E 41.1
Host:  Renato Renner

Quantum Absorption Refrigerator with Trapped Ions

Alexandre Roulet
NUS Singapore

In this work (arXiv:1702.08672), we report on the experimental realization of a quantum absorption refrigerator, one of the standard examples of a heat machine, using the modes of trapped ytterbium ions. The refrigerator is evolving under a trilinear Hamiltonian such that heat from the work mode is transferred to the hot mode, cooling down the cold mode in the process. By implementing the refrigerator in the pulsed (or single-shot) regime, we experimentally cool down the cold mode faster and to a lower occupation compared to the steady-state regime. We show theoretically that this feature is enabled by quantum coherence, as an incoherent evolution of the quantum refrigerator precludes the device from cooling further than the steady-state occupation. This is in agreement with previous predictions for qubit-based refrigerators and highlights the role of quantum coherence in improving the cooling efficiency of the quantum refrigerator. We also consider squeezed thermal states and find that they are not a useful resource for cooling further in the single-shot regime, comparing them with thermal states of the same average energy.