# Density response of holographic metallic IR fixed points with translational pseudo-spontaneous symmetry breaking

## TL;DR

This paper investigates how density responses in holographic metallic systems with pseudo-spontaneous translational symmetry breaking differ from those with perfect translational invariance, revealing broad asymmetric peaks instead of sharp modes.

## Contribution

It demonstrates that pseudo-spontaneous symmetry breaking leads to a broad, asymmetric density response, contrasting with the zero-sound dominated response in translationally invariant systems.

## Key findings

- Density response exhibits broad asymmetric peaks.
- Attenuation does not increase monotonically with momentum and temperature.
- No single isolated mode dominates the low-momentum response.

## Abstract

The density response of charged liquids contains a collective excitation known as the plasmon. In holographic systems with translational invariance the origin of this collective excitation is traced back to the presence of zero-sound. Using a holographic model in which translational symmetry is broken pseudo-spontaneously, we show the density response is not dominated by a single isolated mode at low momentum and temperature. As a consequence, the density response contains a broad asymmetric peak with an attenuation which does not increase monotonically with momentum and temperature.