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arXiv · 2401.01776

Maximal steady-state entanglement in autonomous quantum thermal machines

Shishir Khandelwal·Björn Annby-Andersson·Giovanni Francesco Diotallevi·Andreas Wacker·Armin Tavakoli
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Abstract

We devise an autonomous quantum thermal machine consisting of three pairwise-interacting qubits, two of which are locally coupled to thermal reservoirs. The machine operates autonomously, as it requires no time-coherent control, external driving or quantum bath engineering, and is instead propelled by a chemical potential bias. Under ideal conditions, we show that this out-of-equilibrium system can deterministically generate a maximally entangled steady-state between two of the qubits, or any desired pure two-qubit entangled state, emerging as a dark state of the system. We study the robustness of entanglement production with respect to several relevant parameters, obtaining nearly-maximally-entangled states well-away from the ideal regime of operation. Furthermore, we show that our machine architecture can be generalised to a configuration with $2n-1$ qubits, in which only a potential bias and two-body interactions are sufficient to generate genuine multipartite maximally entangled steady states in the form of a W state of $n$ qubits.

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Shishir Khandelwal, Björn Annby-Andersson, Giovanni Francesco Diotallevi, Andreas Wacker, Armin Tavakoli. 2024-01-03. Maximal steady-state entanglement in autonomous quantum thermal machines. https://doi.org/10.1038/s41534-025-00981-7

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