  In this work we address quantum vacuum amplification effects in time-varying
media with an arbitrary time-modulation profile. To this end, we propose a
theoretical formalism based on the concept of conjugated harmonic oscillators,
evaluating the impact on the transition time in temporal boundaries, shedding
light into the practical requirements to observe quantum effects at them. In
addition, we find nontrivial effects in pulsed-modulations, where the swiftest
and strongest modulation does not lead to the highest photon production. Thus,
our results provide key insights for the design of temporal modulation
sequences to enhance quantum phenomena.
