论文标题
量子相变的折叠状态叠加引起的相干多体振荡
Coherent Many-Body Oscillations Induced by a Superposition of Broken Symmetry States in the Wake of a Quantum Phase Transition
论文作者
论文摘要
现在广泛接受的是，通过量子相变的临界区域淬灭会导致经过拓扑缺陷的过渡状态 - 经典拓扑缺陷的类似物。但是，非常非古典的事实的后果是，淬灭后的状态是具有不同数字和缺陷位置的不同，破碎的对称性真空吸尘器的{\ it叠加}，在很大程度上仍未开发。我们确定了这种叠加引起的相干量子振荡，可观察到与对称性断裂相关的互补。这些振荡以淬灭速率满足千里 - Zurek动力学缩放定律，其瞬时振荡频率主要由系统间隙设置。除了不同破碎对称状态的叠加的明显基本意义外，量子相干振荡还可以用于验证单位性和测试量子模拟器实验实现的不完美。
It is now widely accepted that quenches through the critical region of quantum phase transitions result in post-transition states populated with topological defects -- analogs of the classical topological defects. However, consequences of the very non-classical fact that the state after a quench is a {\it superposition} of distinct, broken-symmetry vacua with different numbers and locations of defects have remained largely unexplored. We identify coherent quantum oscillations induced by such superpositions in observables complementary to the one involved in symmetry breaking. These oscillations satisfy Kibble-Zurek dynamical scaling laws with the quench rate, with an instantaneous oscillation frequency set primarily by the gap of the system. In addition to the obvious fundamental significance of a superposition of different broken symmetry states, quantum coherent oscillations can be used to verify unitarity and test for imperfections of the experimental implementations of quantum simulators.
