Zhao Bo, Kerridge Merritt C, Huse David A
Physics Department, Princeton University, Princeton, New Jersey 08544, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Aug;90(2):022104. doi: 10.1103/PhysRevE.90.022104. Epub 2014 Aug 5.
We explore a transverse-field Ising model that exhibits both spontaneous symmetry breaking and eigenstate thermalization. Within its ferromagnetic phase, the exact eigenstates of the Hamiltonian of any large but finite-sized system are all Schrödinger cat states: superpositions of states with "up" and "down" spontaneous magnetization. This model exhibits two dynamical phase transitions within its ferromagnetic phase: In the lowest-temperature phase the magnetization can macroscopically oscillate between up and down. The relaxation of the magnetization is always overdamped in the remainder of the ferromagnetic phase, which is divided into phases where the system thermally activates itself over the barrier between the up and down states, and where it quantum tunnels.
我们研究了一个具有自发对称性破缺和本征态热化现象的横场伊辛模型。在其铁磁相内，任何大但有限尺寸系统的哈密顿量的精确本征态都是薛定谔猫态：具有“上”和“下”自发磁化的态的叠加。该模型在其铁磁相内表现出两个动力学相变：在最低温度相，磁化强度可以在宏观上在上下之间振荡。在铁磁相的其余部分，磁化强度的弛豫总是过阻尼的，该部分被分为系统通过上下态之间的势垒进行热激活的相，以及系统进行量子隧穿的相。
