Fermion-induced dynamical critical point

Article

关键词: STATISTICAL-MECHANICS;    UNIVERSAL DYNAMICS;    PHASE-TRANSITIONS;    QUANTUM;    THERMALIZATION;    RELAXATION;    CHAOS;   

DOI  :  10.1103/PhysRevB.103.125116

来源: SCIE

【 摘 要 】

Dynamical phase transition (DPT) characterizes the abrupt change in dynamical properties in nonequilibrium quantum many-body systems. It has been demonstrated that extra fluctuating modes besides the conventional order parameter field can bring about the Landau-forbidden quantum critical points by changing the order of the equilibrium phase transition. However, the counterpart phenomena in DPTs have rarely been explored. Here, we study the DPT in the Dirac system after a sudden quench and find that the fermion fluctuations can round a putative first-order DPT into a dynamical critical point, which is referred to as a fermion-induced dynamical critical point (FIDCP). This FIDCP gives the universal short-time scaling behavior controlled by the dynamical chiral fixed point despite the system going through a first-order transition after thermalization. In the novel scenario of FIDCP, the quantum Yukawa coupling g(q) is indispensable for inducing the FIDCP even though it is irrelevant in the infrared scale. We call these variables dynamical dangerously irrelevant scaling variable. Moreover, a dynamical tricritical point which separates the first-order DPT and the FIDCP is discovered by tuning this dynamical dangerously irrelevant scaling variable. We further mention possible experimental realizations.

【 授权许可】

Free