Séminaire de Physique Théorique

Existence and uniqueness of a class of semiclassical gravity solutions and the gravitational quantum Cheshire effect
Benito Juárez-Aubry (Université d'York, Angleterre)
Thursday 19 December 2024 14:00 -  Salle des séminaires  -  Salle 1180, bâtiment E2

Résumé :

We consider semiclassical gravity with a non-minimally coupled Klein-Gordon field, with mass term $m^2 \geq 0$ and curvature coupling $\xi = 1/2$. We show that there is a class of Hadamard two-point functions for which the semiclassical Einstein equations coupled to the Klein-Gordon field take the form of a well-posed hyperbolic quasi-linear system. This class defines a set of quasi-free states, subject to the positivity condition, for which (the state-dependent part of) the expectation value of the renormalised stress-energy tensor is proportional to the spacetime metric. The case in which the proportionality constant vanishes is a quantum version of the so-called gravitational Cheshire effect.

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