  As proposed to describe putative continuous phase transitions between two
ordered phases, the deconfined quantum critical point (DQCP) goes beyond the
prevalent Landau-Ginzburg-Wilson (LGW) paradigm since its critical theory is
not expressed in terms of the order parameters characterizing either state, but
involves fractionalized degrees of freedom and an emergent symmetry. So far,
great efforts have been spent on its equilibrium properties, but the
nonequilibrium properties therein are largely unknown. Here we study the
nonequilibrium dynamics of the DQCP via the imaginary-time evolution in the
two-dimensional (2D) J-Q$_3$ model. We discover fascinating nonequilibrium
scaling behaviors hinging on the process of fractionization and the dynamics of
emergent symmetry associated with two length scales. Our findings not only
constitute a new realm of nonequilibrium criticality in DQCP, but also offer a
controllable knob by which to investigate the dynamics in strongly correlated
systems.
