Energy density and particle creation inside an oscillating cavity with mixed boundary conditions

We consider the dynamical Casimir effect for a massless scalar field in a two-dimensional space-time, inside an oscillating cavity with mixed boundary conditions. We obtain the energy-momentum tensor for this model, verifying the occurrence of traveling wave packets for the energy density and also studying the time evolution of the total energy stored in the cavity. We compare our results with those found in the literature for the Dirichlet-Dirichlet case.