Simulating ultrastrong-coupling processes breaking parity conservation in Jaynes-Cummings systems

TL;DR

This paper demonstrates how to simulate parity-breaking ultrastrong-coupling processes in Jaynes-Cummings systems using a single classical drive, enabling broader nonlinear quantum protocols with fewer resources.

Contribution

It introduces a simplified method to simulate parity-non-conserving processes in Jaynes-Cummings systems, expanding the range of quantum phenomena that can be emulated.

Findings

Simulated processes include virtual transitions breaking parity conservation.

Implemented nonlinear protocols like two-photon excitation and frequency conversion.

Achieved broader process simulation with fewer resources and simpler setup.

Abstract

We propose the effective simulation of light-matter ultrastrong-coupling phenomena with strong-coupling systems. Recent theory and experiments have shown that the quantum Rabi Hamiltonian can be simulated by a Jaynes--Cummings system with the addition of two classical drives. This allows to implement nonlinear processes that do not conserve the total number of excitations. However, parity is still a conserved quantity in the quantum Rabi Hamiltonian, which forbids a wide family of processes involving virtual transitions that break this conservation. Here, we show that these parity-non-conserving processes can be simulated, and that this can be done in an even simpler setup: a Jaynes-Cummings type system with the addition of a single classical drive. By shifting the paradigm from simulating a particular model to simulating a particular process, we are able to implement a much wider family of nonlinear coherent protocols than in previous simulation approaches, doing so with fewer resources and constraints. We focus our analysis on three particular examples: a single atom exciting two photons, frequency conversion, and a single photon exciting two atoms.