The space of transport coefficients allowed by causality

Heller, Michal P., Serantes, Alexandre, Spaliński, Michał and Withers, Benjamin (2024) The space of transport coefficients allowed by causality. Nature Physics. (doi:10.1038/s41567-024-02635-5).

Record type: Article

Abstract

As an effective theory, relativistic hydrodynamics is fixed by symmetries up to a set of transport coefficients. A lot of effort has been devoted to explicit calculations of these coefficients. Here we adopt a more general approach, deploying bootstrap techniques to rule out theories that are inconsistent with microscopic causality. What remains is a universal convex geometry in the space of transport coefficients, which we call the hydrohedron. The landscape of all consistent theories necessarily lies inside or on the edges of the hydrohedron. We analytically construct cross-sections of the hydrohedron corresponding to bounds on transport coefficients that appear in sound and diffusion modes’ dispersion relations for theories without stochastic fluctuations.

Text

2305.07703v2 - Accepted Manuscript

Available under License Creative Commons Attribution.

Download (1MB)

Text

s41567-024-02635-5 - Version of Record

Available under License Creative Commons Attribution Non-commercial No Derivatives.

Download (13MB)

More information

Accepted/In Press date: 8 August 2024

Published date: 14 October 2024

Additional Information: 10 pages + appendices, 2 figures. Added N=4 SYM, MIS, BDNK, kinetic theory to the hydrohedron plots. Some technical details moved to appendices.

Keywords: cond-mat.stat-mech, gr-qc, hep-th, math-ph, math.MP, nucl-th