Photon energy absorption rate of a striped Hall gas

TL;DR

This paper investigates how a striped Hall gas absorbs photon energy, revealing a sharp zero-energy absorption due to a Nambu-Goldstone mode and analyzing its directional dependence, extending understanding of cyclotron resonance.

Contribution

It demonstrates the impact of spontaneous symmetry breaking on photon absorption and characterizes the NG mode's influence on absorption rates in striped Hall gases.

Findings

Sharp absorption at zero energy caused by NG mode

Directional dependence of absorption at NG mode frequency

Cyclotron resonance remains unaffected in the striped Hall gas

Abstract

Using symmetries of the current correlation function, we analyze the frequency dependence of the photon energy absorption rate of a striped Hall gas. Since the magnetic translational symmetry is spontaneously broken in the striped Hall gas, a Nambu-Goldstone (NG) mode appears. It is shown that the NG mode causes a sharp absorption at the zero energy in the long wavelength limit by using the single mode approximation. The photon energy absorption rate at the NG mode frequency strongly depends on the direction of the wave number vector. Whereas, the absorption rate at the cyclotron frequency does not depend on the direction of the wave number vector in the long wavelength limit. The cyclotron resonance is not affected in the striped Hall gas. Our result supplements the Kohn's theorem in the system of the NG mode.