Multiphoton interaction of a qutrit with single-mode quantized field in the ultrastrong and deep strong coupling regimes

TL;DR

This paper explores the complex multiphoton dynamics of a three-level atom interacting with a quantized field in ultra- and deep-strong coupling regimes, revealing novel phenomena like generalized Rabi oscillations and nonclassical ground states.

Contribution

It provides a detailed analysis of multiphoton interactions in a qutrit-field system at extreme coupling strengths, highlighting new quantum effects and ground state properties.

Findings

Observation of generalized Rabi oscillations in ultrastrong coupling

Identification of collapse and revival phenomena in atomic excitation

Ground state exhibits strictly nonclassical properties in deep strong coupling

Abstract

We consider multiphoton dynamics of a quantum system composed of a three-state atom (a qutrit) and a single-mode photonic field in the ultrastrong and deep strong coupling regimes, when the coupling strength is comparable to or larger than the oscillator energy scale. We assume a qutrit to be in a polar-$\Lambda $ configuration in which two lower levels have mean dipole moments. Direct multiphoton resonant transitions revealing generalized Rabi oscillations, collapse, and revivals in atomic excitation probabilities for the ultrastrong couplings are studied. In the deep strong coupling regime particular emphasis is placed on the ground state of considering system which exhibits strictly nonclassical properties.