论文标题

通过脉冲级控制的量子计算机上量子多体疤痕的误差模拟

Error-Mitigated Simulation of Quantum Many-Body Scars on Quantum Computers with Pulse-Level Control

论文作者

Chen, I-Chi, Burdick, Benjamin, Yao, Yongxin, Orth, Peter P., Iadecola, Thomas

论文摘要

量子多体疤痕是一种有趣的动力学状态,在某些初始状态下制备时,量子系统表现出连贯的动力学和远程相关性。我们利用这种相干性和多体相关性的组合来基准在当今的量子计算设备的性能中,通过使用它们模拟混合场ISing链中最多19个地点的抗势磁初始状态的动力学。除了计算局部可观察物的动力学外,我们还计算了Loschmidt Echo和非平底连接的相关函数,该功能见证了疤痕动力学中的远程多体相关性。我们发现连贯的动力学,即使在存在各种误差源的情况下,也可以持续多达40个Trotter步骤。为了获得这些结果,我们利用各种误差缓解技术,包括噪声剪裁,零噪声外推,动力学去耦和测量结果的出现积极动机。至关重要的是,我们还发现,使用脉冲级控制来实现ISIN相互作用,对基于标准的CNOT基于此相互作用的汇编有了实质性的改进。我们的结果证明了误差缓解技术和脉冲级控制的力量,以探测当今量子硬件的多体相干性和相关效果。

Quantum many-body scars are an intriguing dynamical regime in which quantum systems exhibit coherent dynamics and long-range correlations when prepared in certain initial states. We use this combination of coherence and many-body correlations to benchmark the performance of present-day quantum computing devices by using them to simulate the dynamics of an antiferromagnetic initial state in mixed-field Ising chains of up to 19 sites. In addition to calculating the dynamics of local observables, we also calculate the Loschmidt echo and a nontrivial connected correlation function that witnesses long-range many-body correlations in the scarred dynamics. We find coherent dynamics to persist over up to 40 Trotter steps even in the presence of various sources of error. To obtain these results, we leverage a variety of error mitigation techniques including noise tailoring, zero-noise extrapolation, dynamical decoupling, and physically motivated postselection of measurement results. Crucially, we also find that using pulse-level control to implement the Ising interaction yields a substantial improvement over the standard CNOT-based compilation of this interaction. Our results demonstrate the power of error mitigation techniques and pulse-level control to probe many-body coherence and correlation effects on present-day quantum hardware.

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