A uniqueness criterion for the Fock quantization of scalar fields with time dependent mass Cortez, Jerónimo Mena Marugán, Guillermo A. Olmedo Nieto, Javier Antonio Velhinho, Jose M. A major problem in the quantization of fields in curved spacetimes is the ambiguity in the choice of a Fock representation for the canonical commutation relations. There exists an infinite number of choices leading to different physical predictions. In stationary scenarios, a common strategy is to select a vacuum (or a family of unitarily equivalent vacua) by requiring invariance under the spacetime symmetries. When stationarity is lost, a natural generalization consists in replacing time invariance by unitarity in the evolution. We prove that, when the spatial sections are compact, the criterion of a unitary dynamics, together with the invariance under the spatial isometries, suffices to select a unique family of Fock quantizations for a scalar field with time dependent mass. 2024-02-03T19:11:25Z 2024-02-03T19:11:25Z 2011-08-12 journal article Class. Quantum Grav. 28 172001 (2011) https://hdl.handle.net/10481/88051 https://doi.org/10.1088/0264-9381/28/17/172001 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional