# Anomalous attenuation of plasmons in strange metals and holography

## TL;DR

This paper demonstrates that in strongly entangled strange metals, plasmons are inherently short-lived at all wavelengths due to decay into the quantum critical continuum, contrasting with conventional metals where plasmons can be long-lived.

## Contribution

It reveals that in holographic models of strange metals, plasmons are always damped, showing a fundamental difference from Fermi liquids and highlighting the role of quantum criticality.

## Key findings

- Plasmons in strange metals are always short-lived, regardless of wavelength.
- Decay into the quantum critical continuum replaces traditional Landau damping.
- Holographic calculations confirm the universal damping of plasmons in these systems.

## Abstract

The plasmon is a ubiquitous collective mode in charged liquids. Due to the long-range Coulomb interaction, the massless zero sound mode of the neutral system acquires a finite plasmon frequency in the long-wavelength limit. In the zero-temperature state of conventional metals -- the Fermi liquid -- the plasmon lives infinitely long at long wavelength when the system is (effectively) translationally invariant. In contrast, we will show that in strongly entangled strange metals the protection of zero sound fails at finite frequency and plasmons are always short lived regardless of their wavelength. Computing the explicit plasmon response in holographic strange metals as an example, we show that decay into the quantum critical continuum replaces Landau damping and this happens for any wavelength.