Resonance phenomena in the interaction of a many-photon wave packet and a qubit

TL;DR

This paper explores unique resonance phenomena in a highly excited quantum electromagnetic mode interacting with a single qubit, revealing non-classical effects like Rabi oscillation collapse and entanglement, with detailed theoretical analysis.

Contribution

It introduces a new understanding of resonance phenomena beyond the Bloch-Siegert resonance in quantum electromagnetic interactions with qubits, using a semiclassical phase-space approach.

Findings

Identification of multiple resonance conditions in quantum field-qubit interactions

Observation of non-classical effects such as Rabi collapse and wave packet splitting

Resonance detuning curves split into multiple branches at higher orders

Abstract

We demonstrate that a highly excited quantum electromagnetic mode strongly interacting with a single qubit exhibits several distinct resonances in addition to the Bloch-Siegert resonance condition that arises in the interaction with classical radiation. The resonance phenomena are associated with non-classical effects: Collapse of Rabi oscillations, splitting of the photon wave packet, and field-qubit entanglement. The analysis is based on a semiclassical phase-space flow of 2-by-2 matrices and becomes exact when the photon number tends to infinity. The flow equations are solved perturbatively and numerically, showing that the resonant detuning of the field and qubit frequencies lie on two branches in the leading order, that further split into distinct curves in higher orders.