  We explore non-analytic quantum phase dynamics of dipolar exciton condensates
formed in a system of 1D quantum layers subjected to voltage quenches. We map
the exciton condensate physics on to the pseudospin ferromagnet model showing
an additional oscillatory metastable and paramagnetic phase beyond the
well-known ferromagnetic phase by utilizing a time-dependent, non-perturbative
theoretical model. We explain the coherent phase of the exciton condensate in
quantum Hall bilayers, observed for currents equal to and slightly larger than
the critical current, as a stable time-dependent phase characterized by
persistent charged meron flow in each of the individual layers with a
characteristic AC Josephson frequency. As the magnitude of the voltage quench
is further increased, we find that the time-dependent current oscillations
associated with the charged meron flow decay, resulting in a transient
pseudospin paramagnet phase characterized by partially coherent charge transfer
between layers, before the state relaxes to incoherent charge transfer between
the layers.

Mesoscale and Nanoscale Physics