Decoherence and entropy production due to quantum fluctuations of spacetime

The intersection between quantum mechanics and gravitational physics has been providing challenging puzzles for quite some time. In this presentation I discuss the dynamics of an open quantum system coupled with a bath of gravitons, the quanta of the gravitational field in the linear limit of general relativity. The focus is on two main aspects. First, I analyze the decoherence induced by gravitons when considering the open system to be described by both external and internal degrees of freedom. Since gravity is universal, the internal variables also interact with the gravitons, and it is shown that this interaction cannot be neglected in gravitational decoherence models as it turns out to be responsible for greater contributions to the decoherence rate once we treat both gravitons and internal degrees of freedom as environments. I then proceed to the second main aspect, which is the entropy production that arises when an external agent drives a quantum system through the graviton bath. This irreversibility comes from quantum fluctuations of spacetime itself and, as such, has a fundamental universal aspect.