Pole-skipping without master variable and holographic superfluids

TL;DR

This paper introduces a new formalism for analyzing pole-skipping phenomena in holographic systems that does not depend on the existence of a master variable, demonstrated through holographic superfluids.

Contribution

It proposes an alternative approach to pole-skipping analysis applicable to multiple fields, expanding the understanding beyond the traditional single-field master variable method.

Findings

Not all hydrodynamic poles are pole-skipping points.

The new formalism successfully analyzes pole-skipping without a master variable.

Application to holographic superfluids illustrates the method's effectiveness.

Abstract

The pole-skipping is a universal property of Green's functions at strong coupling found by the AdS/CFT duality. There is a conventional formalism of the pole-skipping, but it relies on the existence of a "master variable." Namely, it is applicable to a system with a single field. We propose an alternative formalism that does not rely on a master variable. As an example, we study the pole-skipping of holographic superfluids. A "hydrodynamic" pole such as the diffusion pole is usually regarded as a pole-skipping point. But we point out that not all hydrodynamic poles are pole-skipping points.