Speaker
Description
We show that accelerated systems exhibit a novel dissipative transport effect, driven by the gravitational trace anomaly. Unlike other famous anomalous effects, it is dissipative and manifests itself in shear viscosity, and originates from quantum entanglement across the Rindler horizon.
To this end, we explicitly derive using Kubo formulas the shear and bulk viscosities - the entanglement viscosities - for thermal radiation in Rindler space using the universal spectral representation. We demonstrate that the unitarity of quantum field theory, through the positivity of spectral densities, underlies thermodynamic irreversibility for a subsystem separated by a horizon, in direct analogy with the irreversibility of renormalization-group flows.
We show that the entanglement shear viscosity locally satisfies a novel relation $\eta/s=1/(4\pi c_s^2)$ involving the speed of sound, thereby establishing a direct connection between the celebrated Kovtun-Son-Starinets minimal viscosity bound, and relativistic causality, while the bulk viscosity saturates another famous bound known from holography. We also demonstrate that the isotropy of thermal radiation in the Rindler space leads to a novel sum rule relating spin-0 and spin-2 fundamental spectral densities, which plays a key role in the above derivation. We verify this sum rule explicitly for conformal fields and massive Dirac fields in arbitrary dimensions.
