Mojaveri B, Ahmadi Z
Department of Physics, Azarbaijan Shahid Madani University, PO Box 51745-406, Tabriz, Iran.
Sci Rep. 2025 Apr 12;15(1):12669. doi: 10.1038/s41598-025-96717-w.
The challenge of harnessing entanglement during the non-equilibrium dynamics of open quantum systems, especially at high temperatures, is highly prominent within recent scientific researches. Due to the ongoing trend of miniaturization of quantum devices that exploit quantum correlations, proposing novel schemes to overcome this challenge is itself a crucial task within current quantum technological research. We contribute to this research by proposing a new scheme to control entanglement dynamics of a non-equilibrium two-qubit Heisenberg XXZ spin chain model in an external magnetic field. The design of the scheme is based on a coupling asymmetry in the model induced by the asymmetrical connection of qubits to two independent thermal reservoirs. While in the absence of the coupling asymmetry, non-equilibrium effects generally suppress the dynamical generation of thermal entanglement, making entanglement production impossible at high mean temperatures of reservoirs, it is shown that this asymmetry in the coupling potentially enables us to generate a maximal non-equilibrium entanglement even in the high mean temperature regime. We show that the coupling asymmetry can also lead to a complete protection of the maximum initial entanglement between the qubits at high mean temperatures of the reservoirs thanks to the non-equilibrium conditions. Depending on the initial state of the two qubits, this can be achieved either by accessing a coherence-free subspace or by fully reviving the initial qubit-qubit entanglement. Furthermore, we investigate the quantum heat transport of the chain, and find that by turning on the asymmetry in the qubit-reservoir coupling, although the chain loses its initial thermal rectification property over time, it regains this property and maintain it until the non-equilibrium steady state is reached. Our results show that, at higher temperature gradients, the chain leverages the steady-state entanglement to completely block the heat released from the hot reservoir. Our findings can be significant for heat management in quantum computing devices such as solid-state thermal circuits.
在开放量子系统的非平衡动力学过程中，尤其是在高温下，利用纠缠的挑战在近期的科学研究中极为突出。由于利用量子关联的量子器件不断小型化的趋势，提出新颖的方案来克服这一挑战本身就是当前量子技术研究中的一项关键任务。我们通过提出一种新方案来控制处于外磁场中的非平衡两比特海森堡XXZ自旋链模型的纠缠动力学，为这项研究做出了贡献。该方案的设计基于由量子比特与两个独立热库的不对称连接所诱导的模型中的耦合不对称性。虽然在没有耦合不对称性的情况下，非平衡效应通常会抑制热纠缠的动态产生，使得在热库的高平均温度下无法产生纠缠，但研究表明这种耦合不对称性有可能使我们即使在高平均温度 regime下也能产生最大的非平衡纠缠。我们表明，由于非平衡条件，耦合不对称性还可以在热库的高平均温度下导致对量子比特之间最大初始纠缠的完全保护。根据两个量子比特的初始状态，这可以通过进入无相干子空间或通过完全恢复初始的量子比特 - 量子比特纠缠来实现。此外，我们研究了该链的量子热输运，发现通过开启量子比特 - 热库耦合中的不对称性，尽管随着时间的推移链会失去其初始的热整流特性，但它会重新获得并保持这一特性，直到达到非平衡稳态。我们的结果表明，在更高的温度梯度下，该链利用稳态纠缠来完全阻止从热库释放的热量。我们的发现对于诸如固态热电路等量子计算设备中的热管理可能具有重要意义。
