Thermalization in the quantum Ising model—approximations, limits, and beyond
Thermalization in the quantum Ising model—approximations, limits, and beyond
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DOI：
10.1088/2058-9565/ab1a71
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发表时间：
2018-05
影响因子：
6.7
通讯作者：
Daniel Jaschke;L. Carr;I. de Vega
中科院分区：
文献类型：
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作者：
Daniel Jaschke;L. Carr;I. de Vega
我们提出了定量预测伊辛模型的量子模拟实验从被困离子里德堡链，并显示如何热化，从而退相干时间，可以通过考虑共同的，独立的，和端盖耦合浴控制。我们发现：（i）独立的浴，使更快的热化相比，一个共同的;（ii）热化的时间尺度强烈依赖于伊辛相图中的位置;（iii）对于一个共同的浴较大的系统尺寸显示显着放缓热化过程中;和（iv）有限尺寸的缩放表示亚辐射效应减慢热化率向无限自旋链限制。我们发现，有必要处理完整的多通道Lindblad主方程，而不是常用的单通道局部Lindblad近似，使精确的预测在经典的计算机上。这种方法减少了量子比特的数量，人们可以实际上经典模拟至少4倍，反过来又显示了量子优势，这种热化问题的量子比特数量为4倍，而不是封闭的量子系统。因此，我们的研究结果鼓励在嘈杂的中间尺度量子技术中探索开放的量子系统。
We present quantitative predictions for quantum simulator experiments on Ising models from trapped ions to Rydberg chains and show how the thermalization, and thus decoherence times, can be controlled by considering common, independent, and end-cap couplings to the bath. We find (i) independent baths enable more rapid thermalization in comparison to a common one; (ii) the thermalization timescale depends strongly on the position in the Ising phase diagram; (iii) for a common bath larger system sizes show a significant slow down in the thermalization process; and (iv) finite-size scaling indicates a subradiance effect slowing thermalization rates toward the infinite spin chain limit. We find it is necessary to treat the full multi-channel Lindblad master equation rather than the commonly used single-channel local Lindblad approximation to make accurate predictions on a classical computer. This method reduces the number of qubits one can practically classical simulate by at least a factor of 4, in turn showing a quantum advantage for such thermalization problems at a factor of 4 smaller qubit number for open quantum systems as opposed to closed ones. Thus, our results encourage open quantum system exploration in noisy intermediate-scale quantum technologies.