Microwave response of fractional quantum Hall droplets with quasiparticle tunneling

TL;DR

This paper develops a nonperturbative computational method to analyze microwave absorption in fractional quantum Hall droplets, revealing how quasiparticle tunneling affects edge dynamics and resonance features, providing a new experimental probe.

Contribution

It introduces a path-integral Monte Carlo approach for finite-temperature response calculations, capturing tunneling effects beyond perturbative methods in quantum Hall systems.

Findings

Tunneling causes measurable shifts and broadening of resonance peaks.

Resonance shifts depend systematically on tunneling strength and device geometry.

Microwave spectroscopy can serve as a quantitative tool to study quasiparticle dynamics.

Abstract

We theoretically study microwave absorption spectroscopy of fractional quantum Hall droplets in the presence of quasiparticle tunneling across a quantum point contact. This contact-free probe provides access to collective edge dynamics beyond conventional transport measurements. We develop a nonperturbative path-integral Monte Carlo approach that enables computation of the frequency-dependent response at finite temperature and for arbitrary droplet geometries, and benchmark the method against analytical results in the weak-tunneling regime. We find that tunneling produces measurable shifts and broadening of resonance peaks, with systematic dependence on tunneling strength and device geometry. Such shifts and broadenings are not obtained in perturbative treatments acting directly on the response function, but emerge when interaction-kernel effects are properly incorporated. Our results indicate experimentally accessible signatures of edge-mode interference and tunneling-induced renormalization of collective excitations, and support the use of microwave spectroscopy as a quantitative probe of quasiparticle dynamics in mesoscopic quantum Hall structures.