Fermion-induced dynamical critical point

Dynamical phase transition (DPT) characterizes the abrupt change of dynamical properties in nonequilibrium quantum many-body systems. It has been demonstrated that extra fluctuating modes besides conventional order parameter field can drastically equilibrium transitions. However, counterpart phenomena DPTs have rarely explored. Here, we study DPT Dirac system after a sudden quench, and find fermion fluctuations round putative first-order into critical point, which is referred to as fermion-induced point (FIDCP). also nonthermal universal short-time scaling behavior emerges despite goes through thermalization. In novel scenario FIDCP, Yukawa coupling $g_q$ indispensable for inducing FIDCP albeit irrelevant infrared scale. We call these variables {\it variables}. Moreover, tricritical separates discovered by tuning this variable. further mention possible experimental realizations.