Yin Shuai, Huang Guang-Yao, Lo Chung-Yu, Chen Pochung
Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan.
Institute for Advanced Study, Tsinghua University, Beijing 100084, People's Republic of China.
Phys Rev Lett. 2017 Feb 10;118(6):065701. doi: 10.1103/PhysRevLett.118.065701.
We study the driven dynamics across the critical points of the Yang-Lee edge singularities (YLESs) in a finite-size quantum Ising chain with an imaginary symmetry-breaking field. In contrast to the conventional classical or quantum phase transitions, these phase transitions are induced by tuning the strength of the dissipation in a non-Hermitian system and can occur even at finite size. For conventional phase transitions, universal behaviors in driven dynamics across critical points are usually described by the Kibble-Zurek mechanism, which states that the scaling in dynamics is dictated by the critical exponents associated with one critical point and topological defects will emerge after the quench. While the mechanism leading to topological defects breaks down in the YLES, we find that for small lattice size, the driven dynamics can still be described by the Kibble-Zurek scaling with the exponents determined by the (0+1)-dimensional YLES. For medium finite size, however, the driven dynamics can be described by the Kibble-Zurek scaling with two sets of critical exponents determined by both the (0+1)-dimensional and the (1+1)-dimensional YLESs.
我们研究了在具有虚对称破缺场的有限尺寸量子伊辛链中,跨越杨 - 李边缘奇点(YLESs)临界点的驱动动力学。与传统的经典或量子相变不同,这些相变是通过调节非厄米系统中的耗散强度来诱导的,并且即使在有限尺寸下也可能发生。对于传统相变,跨越临界点的驱动动力学中的普适行为通常由基布尔 - 祖雷克机制描述,该机制指出动力学中的标度由与一个临界点相关的临界指数决定,并且在猝灭后会出现拓扑缺陷。虽然导致拓扑缺陷的机制在YLEs中失效,但我们发现对于小晶格尺寸,驱动动力学仍可由基布尔 - 祖雷克标度描述,其指数由(0 + 1)维YLEs确定。然而,对于中等有限尺寸,驱动动力学可由基布尔 - 祖雷克标度描述,其两组临界指数由(0 + 1)维和(1 + 1)维YLEs共同确定。