量子自旋链中假真空泡壁的碰撞
Collisions of false-vacuum bubble walls in a quantum spin chain
AI总结：
该研究拓展矩阵乘积态拟设，模拟接近临界态的量子自旋链中假真空泡的扭结-反扭结壁碰撞，观测不同相互作用下的散射结果与纠缠演化，指出经典模拟的局限，提出该体系可作为量子计算的基准问题。
摘要：
我们采用非微扰方法，模拟了接近临界态的量子自旋链中“假真空”小气泡的实时动力学，该系统的低能物理由相对论性（1+1）维量子场论描述。我们考虑壁为扭结（kink）和反扭结（antikink）准粒子激发的气泡，因此壁碰撞即为扭结-反扭结散射事件。为在强关联存在的情况下构建这些气泡，我们拓展了近期提出的用于准粒子波包的矩阵乘积态（matrix product state, MPS）拟设。我们在嵌入无限长链的约1000个自旋的窗口内模拟动力学，能量最高可达约5倍质量隙。通过适当选择波包宽度和气泡尺寸，我们规避了强晶格效应并观测到相对论性扭结-反扭结碰撞。我们利用MPS准粒子拟设来检测散射结果：（i）在具有横向和纵向场的Ising模型中，尽管系统不可积，我们未观测到粒子产生（支持了近期在该模型中关于非热化态的观测结果）；（ii）开启额外相互作用后，我们观测到禁闭和非禁闭粒子对的产生。我们表征了产生的纠缠量随能量和时间的变化关系，并得出结论：随着能量和时间增加，我们的经典模拟方法最终将失效。我们预计，1+1维中的扭结-反扭结散射将成为未来量子计算机和模拟量子模拟器的有指导意义的基准问题。
英文摘要：
We simulate, using nonperturbative methods, the real-time dynamics of small bubbles of "false vacuum" in a quantum spin chain near criticality, where the low-energy physics is described by a relativistic (1+1)-dimensional quantum field theory. We consider bubbles whose walls are kink and antikink quasiparticle excitations, so that wall collisions are kink-antikink scattering events. To construct these bubbles in the presence of strong correlations, we extend a recently proposed matrix product state (MPS) ansatz for quasiparticle wavepackets. We simulate dynamics within a window of about 1000 spins embedded in an infinite chain at energies of up to about 5 times the mass gap. By choosing the wavepacket width and the bubble size appropriately, we avoid strong lattice effects and observe relativistic kink-antikink collisions. We use the MPS quasiparticle ansatz to detect scattering outcomes. (i) In the Ising model, with transverse and longitudinal fields, we do not observe particle production despite nonintegrability (supporting recent observations of nonthermalizing states in this model). (ii) Switching on an additional interaction, we see production of confined and unconfined particle pairs. We characterize the amount of entanglement generated as a function of energy and time and conclude that our classical simulation methods will ultimately fail as these increase. We anticipate that kink-antikink scattering in 1+1 dimensions will be an instructive benchmark problem for future quantum computers and analog quantum simulators.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
