Spectral collapse via two-phonon interactions in trapped ions

TL;DR

This paper proposes a realistic implementation of two-phonon quantum models in trapped ions, revealing rich dynamics and spectral collapse phenomena when two-phonon interactions become comparable to system frequencies.

Contribution

It introduces a method to explore effective two-phonon processes in trapped ions across all parameter regimes, highlighting novel spectral phenomena.

Findings

Observation of interaction-induced spectral collapse.

Rich dynamics in bichromatically driven ion chains.

Feasible implementation of two-phonon quantum models.

Abstract

Two-photon processes have so far been considered only as resulting from frequency-matched second-order expansions of light-matter interaction, with consequently small coupling strengths. However, a variety of novel physical phenomena arises when such coupling values become comparable with the system characteristic frequencies. Here, we propose a realistic implementation of two-photon quantum Rabi and Dicke models in trapped-ion technologies. In this case, effective two-phonon processes can be explored in all relevant parameter regimes. In particular, we show that an ion chain under bichromatic laser drivings exhibits a rich dynamics and highly counterintuitive spectral features, such as interaction-induced spectral collapse.