论文标题
交替分层ANSATZ进行量子计算的表达性
Expressibility of the alternating layered ansatz for quantum computation
论文作者
论文摘要
杂交量子古典算法被积极研究为适用于中等规模量子计算机的技术。要执行此算法，由于其可实现性和表现性，经常使用硬件有效的ANSATZ；但是，这个安萨兹在训练性上有一个关键的问题，从某种意义上说，它通常遭受了所谓的梯度消失问题。可以通过将电路限制为浅层交替分层ANSATZ的类别来解决此问题。但是，即使证明了该安萨茨的高训练性，但仍不清楚它在州一代中是否具有丰富的表现力。在本文中，有了适当的定义文献中发现的明确性，我们表明浅层交替分层ANSATZ具有与硬件有效Ansatz的表达级别几乎相同的表达性。因此，表达性和训练性可以共存，为中等规模量子计算时代提供了一种新的设计方法。
The hybrid quantum-classical algorithm is actively examined as a technique applicable even to intermediate-scale quantum computers. To execute this algorithm, the hardware efficient ansatz is often used, thanks to its implementability and expressibility; however, this ansatz has a critical issue in its trainability in the sense that it generically suffers from the so-called gradient vanishing problem. This issue can be resolved by limiting the circuit to the class of shallow alternating layered ansatz. However, even though the high trainability of this ansatz is proved, it is still unclear whether it has rich expressibility in state generation. In this paper, with a proper definition of the expressibility found in the literature, we show that the shallow alternating layered ansatz has almost the same level of expressibility as that of hardware efficient ansatz. Hence the expressibility and the trainability can coexist, giving a new designing method for quantum circuits in the intermediate-scale quantum computing era.
