Speaker
Description
In this talk some recent results in understanding gravitationally induced decoherence from the perspective of relational quantum gravity will be discussed. Starting from microscopic models in which matter fields are coupled to linearised gravity, a gauge-invariant formulation is constructed using relational observables defined in terms of geometric clocks in the context of a reduced phase space quantisation. In this framework, gravity is chosen as an environment for the matter system, leading to open system dynamics for the physical degrees of freedom in the matter sector. The dynamics of open quantum systems are described by quantum master equations. Recent relational open QFT models involving either a scalar or a photon field are presented. Particular consideration is given to the role of approximations such as the Markov and rotating wave approximations, as well as to the renormalisation of the master equation in the one-particle sector. Finally phenomenological implications are addressed, with a particular focus on applications in the context of neutrino oscillations. These results illustrate how microscopic, relationally defined models can both complement and constrain existing phenomenological decoherence models. Taken together, these results contribute to establishing a bridge between microscopic models inspired by quantum gravity and the phenomenological models commonly used to determine experimental bounds on decoherence parameters.