Quantum dynamics simulations beyond the coherence time on noisy intermediate-scale quantum hardware by variational Trotter compression
Quantum dynamics simulations beyond the coherence time on noisy intermediate-scale quantum hardware by variational Trotter compression
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DOI：
10.1103/physrevresearch.4.023097
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发表时间：
2022-05-04
影响因子：
4.2
通讯作者：
Orth, Peter P.
中科院分区：
文献类型：
--
作者：
Berthusen, Noah F.;Trevisan, Thais, V;Orth, Peter P.
我们展示了一个postquench动力学模拟海森堡模型在当今的IBM量子硬件，扩展到设备的相干时间之外。这是使用混合量子经典算法来实现的，该算法使用Trotter演化来传播状态，然后执行经典优化，该经典优化有效地将时间演化状态压缩成变分形式。当迭代时，该过程使得能够模拟到任意时间，其中误差由压缩保真度和固定的Trotter步长控制。我们展示了如何测量所需的成本函数，时间演化和变分状态之间的重叠，在当今的硬件，利用几种错误缓解方法。除了在真实的硬件上进行模拟之外，我们还通过无噪和有噪经典模拟来研究该算法的性能和缩放行为。我们发现，在去更大的系统尺寸的主要瓶颈是进行噪声成本函数的优化的困难。
We demonstrate a postquench dynamics simulation of a Heisenberg model on present-day IBM quantum hardware that extends beyond the coherence time of the device. This is achieved using a hybrid quantum-classical algorithm that propagates a state using Trotter evolution and then performs a classical optimization that effectively compresses the time-evolved state into a variational form. When iterated, this procedure enables simulations to arbitrary times with an error controlled by the compression fidelity and a fixed Trotter step size. We show how to measure the required cost function, the overlap between the time-evolved and variational states, on present-day hardware, making use of several error mitigation methods. In addition to carrying out simulations on real hardware, we investigate the performance and scaling behavior of the algorithm with noiseless and noisy classical simulations. We find the main bottleneck in going to larger system sizes to be the difficulty of carrying out the optimization of the noisy cost function.