Quench dynamics of collective modes in fractional quantum Hall bilayers

TL;DR

This paper investigates the non-equilibrium dynamics of collective modes in bilayer fractional quantum Hall states using quenches, revealing how electric fields and anisotropy changes excite specific modes, supported by effective field theory and numerical validation.

Contribution

It introduces a framework for probing collective modes in fractional quantum Hall bilayers through quenches and develops an effective field theory matching numerical results.

Findings

Electric field induces spin-1 mode oscillations.

Band mass anisotropy activates quadrupole and combined modes.

Effective field theory accurately describes quench dynamics.

Abstract

We introduce different types of quenches to probe the non-equilibrium dynamics and multiple collective modes of bilayer fractional quantum Hall states. We show that applying an electric field in one layer induces oscillations of a spin-1 degree of freedom, whose frequency matches the long-wavelength limit of the dipole mode. On the other hand, oscillations of the long-wavelength limit of the quadrupole mode, i.e., the spin-2 graviton, as well as the combination of two spin-1 states, can be activated by a sudden change of band mass anisotropy. We construct an effective field theory to describe the quench dynamics of these collective modes. In particular, we derive the dynamics for both the spin-2 and the spin-1 states and demonstrate their excellent agreement with numerics.