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arXiv · 1811.05349

Extended quantum Maxwell demon acting over macroscopic distances

A. V. Lebedev·G. B. Lesovik·V. M. Vinokur·G. Blatter
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Abstract

A quantum Maxwell demon is a device that can lower the entropy of a quantum system by providing it with purity. The functionality of such a quantum demon is rooted in a quantum mechanical SWAP operation exchanging mixed and pure states. We describe the setup and performance of a quantum Maxwell demon that purifies an energy-isolated system from a distance. Our cQED-based design involves two transmon qubits, where the mixed-state target qubit is purified by a pure-state demon qubit connected via an off-resonant transmission line; this configuration naturally generates an iSWAP gate. Although less powerful than a full SWAP gate, we show that assuming present-day performance characteristics of a cQED implementation, such an extended quantum Maxwell demon can purify the target qubit over macroscopic distances on the order of meters and tolerates elevated temperatures of the order of a few Kelvin in the transmission line.

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A. V. Lebedev, G. B. Lesovik, V. M. Vinokur, G. Blatter. 2018-11-13. Extended quantum Maxwell demon acting over macroscopic distances. https://doi.org/10.1103/physrevb.98.214502

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