论文标题
量子纯状态层析成像通过变分杂交量子古典方法
Quantum Pure State Tomography via Variational Hybrid Quantum-Classical Method
论文作者
论文摘要
为了获得量子系统的完整描述,通常使用标准的量子状态断层扫描,但是,这需要指数级的测量数以执行,因此当系统的大小增长时是不切实际的。在这项工作中,我们基于各种杂种量子古典方法介绍了一种自学习的层析成像方案。该方案的关键部分是一个学习过程,在该过程中,我们学习一个能够将未知目标状态连贯地驱动到简单基准状态的控制序列,以便可以通过逆时应用控制序列直接重建目标状态。以这种方式,状态断层扫描问题被转换为州到州的转移问题。为了解决后一个问题,我们使用闭环学习控制方法。我们的方案是使用4 Qubit核磁共振的技术进一步测试的。 {实验结果表明,所提出的层析成像方案可以处理量子信息中的纠缠状态,以及量子多体系统的动态状态,包括凝结物理物理物理学的量子多体系统。
To obtain a complete description of a quantum system, one usually employs standard quantum state tomography, which however requires exponential number of measurements to perform and hence is impractical when the system's size grows large. In this work, we introduce a self-learning tomographic scheme based on the variational hybrid quantum-classical method. The key part of the scheme is a learning procedure, in which we learn a control sequence capable of driving the unknown target state coherently to a simple fiducial state, so that the target state can be directly reconstructed by applying the control sequence reversely. In this manner, the state tomography problem is converted to a state-to-state transfer problem. To solve the latter problem, we use the closed-loop learning control approach. Our scheme is further experimentally tested using techniques of a 4-qubit nuclear magnetic resonance. {Experimental results indicate that the proposed tomographic scheme can handle a broad class of states including entangled states in quantum information, as well as dynamical states of quantum many-body systems common to condensed matter physics.