论文标题
量子自旋水坑和湖泊：非平衡动力学的NISQ时代的自旋液体
Quantum Spin Puddles and Lakes: NISQ-Era Spin Liquids from Non-Equilibrium Dynamics
论文作者
论文摘要
虽然多体系统可以容纳较长的纠缠量子自旋液体（QSL），但要实现这些基态的成分可能非常困难。在许多情况下，需要（i）受约束的希尔伯特空间和（ii）广泛的量子叠加。范式的示例是旋转代码，或$ \ mathbb {z} _2 $旋转液体，它是封闭环状态的叠加。我们展示了非平衡的哈密顿动力学如何为创建这种QSL提供简化的途径。与其冷却到哈密顿量的基态，不如说明一个简单的参数扫描如何将初始产品的家族状态动态投射到受约束的空间中，从而产生QSL。对于复曲面代码，这是在$ e $ - 和$ m $ $ y-ons之间分离的系统中实现的，在这里，人们可以以与前者（后者）的绝热（突然）方式扫荡。 Although this separation of scales does not extend to the thermodynamic limit, we analytically and numerically show that this method efficiently prepares a spin liquid in finite-sized regions, which we brand ``quantum spin lakes.'' This mechanism elucidates recent experimental and numerical observations of the dynamical state preparation of the ruby lattice spin liquid in Rydberg atom arrays.实际上，$ m $ - 每个人的缓慢动力学表明，我们可以通过模拟树晶格上的动态来捕获旋转湖的准备，我们通过张量网络模拟确认。最后，我们使用这种机制提出了新的实验，例如，使用Rydberg Atoms准备有限大小的$ U（1）$ spin液体作为蜂窝状rokhsar-kivelson二聚体模型，这是非常出色的 - 鉴于其均衡性在$ 2 + 1 + 1 $ d $ d中是不稳定的。我们的工作在研究非平衡物理学以及NISQ设备中有限范围的外来状态方面开辟了新的途径。
While many-body systems can host long-ranged entangled quantum spin liquids (QSLs), the ingredients for realizing these as ground states can be prohibitively difficult. In many circumstances, one requires (i) a constrained Hilbert space and (ii) an extensive quantum superposition. The paradigmatic example is the toric code, or $\mathbb{Z}_2$ spin liquid, which is a superposition of closed loop states. We show how non-equilibrium Hamiltonian dynamics can provide a streamlined route toward creating such QSLs. Rather than cooling into the ground state of a Hamiltonian, we show how a simple parameter sweep can dynamically project a family of initial product states into the constrained space, giving rise to a QSL. For the toric code, this is achieved in systems with a separation in energy scales between the $e$- and $m$-anyons, where one can sweep in a way that is adiabatic (sudden) with respect to the former (latter). Although this separation of scales does not extend to the thermodynamic limit, we analytically and numerically show that this method efficiently prepares a spin liquid in finite-sized regions, which we brand ``quantum spin lakes.'' This mechanism elucidates recent experimental and numerical observations of the dynamical state preparation of the ruby lattice spin liquid in Rydberg atom arrays. In fact, the slow dynamics of $m$-anyons suggest that we can capture spin lake preparation by simulating the dynamics on tree lattices, which we confirm with tensor network simulations. Finally, we use this mechanism to propose new experiments, e.g., for preparing a finite-sized $U(1)$ spin liquid as a honeycomb Rokhsar-Kivelson dimer model using Rydberg atoms -- which is remarkable given its equilibrium counterpart is unstable in $2 + 1$D. Our work opens up a new avenue in the study of non-equilibrium physics, as well as the exploration of exotic states of finite extent in NISQ devices.
