论文标题
无论初始状态如何
Maximal coin-position entanglement generation in a quantum walk for the third step and beyond regardless of the initial state
论文作者
论文摘要
我们通过离散时间量子步行研究最大硬币位置纠缠生成，其中将硬币操作从每个步骤设置的两个硬币操作员之一中随机选择。我们将最大的纠缠生成作为优化问题，将量子过程保真度作为成本函数。然后，我们确定最大纠缠，无论使用适当的硬币序列如何，无论初始条件如何，都可以严格生成第二个步骤。最简单的硬币序列包括Hadamard和身份操作，等效于广义大象量子步行，它在概率分布方面表现出越来越快的扩散。在实验上，我们证明了由线性光学元件驱动的十个步骤量子步行，从而显示了所需的高维二分之一的纠缠以及更快扩散的传输行为。
We study maximal coin-position entanglement generation via a discrete-time quantum walk, in which the coin operation is randomly selected from one of two coin operators set at each step. We solve maximal entanglement generation as an optimization problem with quantum process fidelity as the cost function. Then we determine the maximal entanglement that can be rigorously generated for any step beyond the second regardless of initial condition with appropriate coin sequences. The simplest coin sequence comprising Hadamard and identity operations is equivalent to the generalized elephant quantum walk, which exhibits an increasingly faster spreading in terms of probability distribution. Experimentally, we demonstrate a ten-step quantum walk driven by such coin sequences with linear optics, and thereby show the desired high-dimensional bipartite entanglement as well as the transport behavior of faster spreading.
