We take into account the subcritical case for dielectric media by exploiting an approximation allowing us to perform perturbative analytical calculations and still not implying low dispersive effects. We show that in the background of a specific solitonlike solution, pair-creation occurs and can display a thermal behavior governed by an effective temperature. The robustness of the approach is also corroborated by the analysis of the $\varphi \psi$-model related to the standard Hopfield model, for which analogous results are obtained.

• Received 7 March 2023
• Accepted 14 June 2023

DOI:https://doi.org/10.1103/PhysRevD.108.025001

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Published by the American Physical Society