A quantum heat engine driven by atomic collisions

Abstract

Quantum heat engines are subjected to quantum fluctuations related to their discrete energy spectra. Such fluctuations question the reliable operation of thermal machines in the quantum regime. Here, we realize an endoreversible quantum Otto cycle in the large quasi-spin states of Cesium impurities immersed in an ultracold Rubidium bath. Endoreversible machines are internally reversible and irreversible losses only occur via thermal contact. We employ quantum control to regulate the direction of heat transfer that occurs via inelastic spin-exchange collisions. We further use full-counting statistics of individual atoms to monitor quantized heat exchange between engine and bath at the level of single quanta, and additionally evaluate average and variance of the power output. We optimize the performance as well as the stability of the quantum heat engine, achieving high efficiency, large power output and small power output fluctuations.

Stochastic dynamics of a few sodium atoms in presence of a cold potassium cloud

“…Going one step beyond the statistical analysis of ensemble averages, we use the single atom resolution of sodium to extract its full counting statistics 57 , 58 . This requires the digitization of camera counts into discrete atom numbers 31 , as presented in Fig.…”

Quantum Heat Engines with Singular Interactions

“…Implementations have been proposed in a wide variety of systems including harmonically confined single ions [42], magnetic systems [43], atomic clouds [44], transmon qubits [45], optomechanical systems [46,47], and quantum dots [48,49]. Quantum heat engines have been experimentally implemented using nanobeam oscillators [50], atomic collisions [51], and two-level ions [52].…”

Steady-State Tunable Entanglement Thermal Machine Using Quantum Dots

“…Besides this, quantum thermodynamics has also provided useful implementations of quantum thermal machines including quantum engines [14][15][16][17][18], quantum refrigerators [19][20][21][22][23], diodes [24] and amplifiers [25][26][27]. Numerous experiments have followed theoretical studies to elucidate various aspects of quantum thermal machines [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44].…”