  We study gauge and gravity backreaction in a holographic model of quantum
quench across a superfluid critical transition. The model involves a complex
scalar field coupled to a gauge and gravity field in the bulk. In earlier work
(arXiv:1211.1776) the scalar field had a strong self-coupling, in which case
the backreaction on both the metric and the gauge field can be ignored. In this
approximation, it was shown that when a time dependent source for the order
parameter drives the system across the critical point at a rate slow compared
to the initial gap, the dynamics in the critical region is dominated by a zero
mode of the bulk scalar, leading to a Kibble-Zurek type scaling function. We
show that this mechanism for emergence of scaling behavior continues to hold
without any self-coupling in the presence of backreaction of gauge field and
gravity. Even though there are no zero modes for the metric and the gauge
field, the scalar dynamics induces adiabaticity breakdown leading to scaling.
This yields scaling behavior for the time dependence of the charge density and
energy momentum tensor.
