A matter-wave Fabry-P\'erot cavity in the ultrastrong driving regime

TL;DR

This paper demonstrates a matter-wave analog of a Fabry-Pérot cavity under ultra-strong modulation, revealing fixed point trajectories and complex dynamics, with implications for advanced signal processing.

Contribution

It introduces a novel matter-wave cavity experiment that mimics relativistic optical phenomena, overcoming experimental limitations of traditional relativistic mirror acceleration.

Findings

Observation of stable and unstable fixed point trajectories

Control of fixed point stability via modulation waveform

Detection of nontrivial dynamics beyond photon-based predictions

Abstract

When the length of an optical cavity is modulated, theory predicts exponential concentration of energy around particular space-time trajectories. Viewed stroboscopically, photons in such a driven cavity propagate as if in a curved spacetime, with black hole and white hole event horizons corresponding to unstable and stable fixed points of the evolution. Such phenomena have resisted direct experimental realization due to the difficulty of relativistically accelerating massive cavity mirrors. We report results of an experiment which overcomes this limitation by exchanging the roles of light and matter. A matter wave endowed with quasi-relativistic dispersion is confined between two barriers made of light, one of which is periodically translated at speeds comparable to the matter wave group velocity. In this strongly-modulated cavity we observe the emergence of the predicted bright and dark fixed point trajectories, and demonstrate that changing the modulation waveform can vary the number of fixed points and exchange their stability character. We observe signatures of nontrivial dynamics beyond those predicted for photons, and attribute them to residual curvature in the dispersion relation. In addition to experimentally realizing and characterizing cavity dynamics in the ultra-strong driving regime, these results point the way to implementations of related dynamics in electro-optic materials, with potential applications in pulse generation and signal compression.