Variational quantum algorithm for nonequilibrium steady states
Variational quantum algorithm for nonequilibrium steady states
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DOI：
10.1103/physrevresearch.2.043289
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发表时间：
2020-11-30
影响因子：
4.2
通讯作者：
Fujii, Keisuke
中科院分区：
文献类型：
--
作者：
Yoshioka, Nobuyuki;Nakagawa, Yuya O.;Fujii, Keisuke
本文提出了一种量子-经典混合算法来模拟开放量子多体系统的非平衡定态，称为耗散系统变分量子本征解（dVQE）。为了将变分优化技术应用于幺正量子电路，我们将一个混合态映射到一个具有双倍量子比特数的纯态，并设计出满足密度矩阵要求的幺正量子电路.这使我们能够定义一个成本函数，它由量子主方程的时间演化生成器组成。物理可观测量的评估反过来又由具有原始数量的量子比特的量子电路进行。我们通过经典计算机上的数值模拟和利用Rigetti量子云服务中提供的设备的实际量子模拟来演示我们的dVQE方案。
We propose a quantum-classical hybrid algorithm to simulate the nonequilibrium steady state of an open quantum many-body system, named the dissipative-system variational quantum eigensolver (dVQE). To employ the variational optimization technique for a unitary quantum circuit, we map a mixed state into a pure state with a doubled number of qubits and design the unitary quantum circuit to fulfill the requirements for a density matrix. This allows us to define a cost function that consists of the time evolution generator of the quantum master equation. Evaluation of physical observables is, in turn, carried out by a quantum circuit with the original number of qubits. We demonstrate our dVQE scheme by both numerical simulation on a classical computer and actual quantum simulation that makes use of the device provided in Rigetti quantum cloud service.