The Sound of Strongly Coupled Field Theories: Quasinormal Modes In AdS

TL;DR

This paper reviews how the AdS/CFT correspondence enables the study of strongly coupled field theories at finite temperature through quasinormal modes, illuminating their hydrodynamics and superfluid behavior.

Contribution

It provides a comprehensive overview of the role of quasinormal modes in holography for understanding strongly coupled systems at finite temperature.

Findings

Quasinormal modes characterize the response of black holes in AdS to perturbations.

Holographic methods connect quasinormal frequencies to hydrodynamic properties.

Applications include modeling quark-gluon plasma and superfluid phases.

Abstract

The AdS/CFT correspondence has developed over the last years into a very useful and powerful tool for studying strongly coupled field theories at finite temperature and density. Of particular interest is the regime of near equilibrium real time evolution that can be captured via linear response theory. The AdS/CFT correspondence allows the calculation of retarded two point functions of gauge invariant operators by studying fluctuations around asymptotically AdS black holes. A major role is played by the poles of these holographic response functions: the quasinormal frequencies. I will review the applications of these ideas to the hydrodynamics of the strongly coupled quark gluon plasma and the holographic realization of strongly coupled superfluids.