Causality and Stability from the Acoustic Metric

量子物理学・ナノサイエンス第104回特別セミナー

概要

I will discuss the acoustic metric for the propagation of scalar perturbation in scalar-tensor theories of gravity for general background configurations, illustrating with concrete examples. I will show how the acoustic metric encodes all the necessary information regarding causality and stability of these backgrounds: hyperbolicity and causal evolution, and whether the background is free of ghosts. I will discuss choosing a good Cauchy surface and how predictivity appears to fail when a bad one is selected, as well as the appearance of Čerenkov radiation in transonic flows. I will contrast this approach with the more common Hamiltonian picture, showing how they are equivalent.

• 量子物理学・ナノサイエンス第104回特別セミナー

• 東京科学大学理学院・物理学系 ナノサイエンスを拓く量子物理学拠点　共催