  We consider global quantum quenches, a protocol when a continuous field
theoretic system in the ground state is driven by a homogeneous time-dependent
external interaction. When the typical inverse time scale of the interaction is
much larger than all relevant scales except for the UV-cutoff the system's
response exhibits universal scaling behavior. We provide both qualitative and
quantitative explanations of this universality and argue that physics of the
response during and shortly after the quench is governed by the conformal
perturbation theory around the UV fixed point. We proceed to calculate the
response of one and two-point correlation functions confirming and generalizing
universal scalings found previously. Finally, we discuss late time behavior
after the quench and argue that all local quantities will equilibrate to their
thermal values specified by an excess energy acquired by the system during the
quench.
