Cookies

We use cookies to ensure that we give you the best experience on our website. You can change your cookie settings at any time. Otherwise, we'll assume you're OK to continue.

Department of Mathematical Sciences

Seminar Archives

On this page you can find information about seminars in this and previous academic years, where available on the database.

Maths HEP Lunchtime Seminars: Hydrodynamics of spacetime and vacuum viscosity

Presented by Chris Eling, Hebrew University of Jerusalem

31 October 2008 13:00 in CM221

Recent work has shown that spacetime dynamics can be deduced from the non-equilbrium thermodynamics of all local causal horizons. In particular, by postulating an entropy balance law dS = dQ/T + d_i S connecting notions of horizon entropy, heat flux, temperature, and entropy production one can derive the Einstein equation. In this talk I will describe how this derivation can be reformulated in the language of hydrodynamics. I will argue that the vacuum thermal state ("thermal atmosphere") outside a local causal horizon can be treated as a fluid. The entropy balance law and Einstein equation then follow as a consequence of hydrodynamics. Interestingly, horizon fluid has universal properties: its entropy density is the Bekenstein-Hawking density and its shear viscosity to entropy density ratio is \hbar/4\pi. The \hbar/4\pi ratio also arises in gauge theory/gravity dualities, where it has received considerable attention recently. I will describe a possible relationship between the two pictures and discuss open questions.

Contact pau.figueras@durham.ac.uk or charles.young@durham.ac.uk for more information