论文标题
测量作为远程纠缠量子物质的快捷方式
Measurement as a shortcut to long-range entangled quantum matter
论文作者
论文摘要
使用统一电路制备远程纠缠状态受到Lieb-Robinson界限的限制，但是带有投影测量和反馈的电路（``自适应电路''）可以逃避此类限制。我们介绍了三类局部自适应电路，这些电路能够为长期纠缠的量子物质进行低深度制备，这些量子物质的特征是拓扑秩序和保形场理论（CFTS）。这三个类的灵感来自不同的物理见解，包括张量 - 网络结构，多尺度纠缠重归其化ANSATZ（MERA）和PARTON结构。可以在恒定的深度或时间内准备大量的拓扑秩序，包括手性拓扑顺序，并可以在具有系统尺寸的基础上以深度缩放量表来制备一维的CFT状态和具有可解决方案和不可溶解组的非亚伯式拓扑顺序。我们还建立在最近发现的对称性保护的拓扑阶段与远程纠缠之间的对应关系，以得出有效的协议，以制备富含对称性的拓扑秩序和任意CSS（Calderbank-s-s-s-s-s-s-Seane）代码。我们的工作说明了对国家准备的实用和概念多功能性。
The preparation of long-range entangled states using unitary circuits is limited by Lieb-Robinson bounds, but circuits with projective measurements and feedback (``adaptive circuits'') can evade such restrictions. We introduce three classes of local adaptive circuits that enable low-depth preparation of long-range entangled quantum matter characterized by gapped topological orders and conformal field theories (CFTs). The three classes are inspired by distinct physical insights, including tensor-network constructions, multiscale entanglement renormalization ansatz (MERA), and parton constructions. A large class of topological orders, including chiral topological order, can be prepared in constant depth or time, and one-dimensional CFT states and non-abelian topological orders with both solvable and non-solvable groups can be prepared in depth scaling logarithmically with system size. We also build on a recently discovered correspondence between symmetry-protected topological phases and long-range entanglement to derive efficient protocols for preparing symmetry-enriched topological order and arbitrary CSS (Calderbank-Shor-Steane) codes. Our work illustrates the practical and conceptual versatility of measurement for state preparation.
