Landau-Zener-Stueckelberg interferometry with driving fields in the quantum regime

TL;DR

This paper investigates the quantum dynamics of a two-level system under strong sinusoidal driving, comparing classical and quantum models, and revealing quantum effects in Landau-Zener-Stueckelberg interferometry.

Contribution

It derives expressions for TLS oscillation frequencies using a quantum field approach and compares them with classical models, highlighting quantum effects in strong coupling regimes.

Findings

Quantum model predicts differences from classical in strong coupling, small photon number regimes.

In weak coupling or large photon number, classical and quantum models agree.

Results interpret Landau-Zener-Stueckelberg interferometry within a fully quantum framework.

Abstract

We analyze the dynamics of a two-level quantum system (TLS) under the influence of a strong sinusoidal driving signal whose origin is the interaction of the two-level system with a quantum field. In this approach the driving field is replaced by a harmonic oscillator that is either strongly coupled to the TLS or populated with a large number of photons. Starting from the Rabi model, we derive expressions for the TLS's oscillation frequencies and compare the results with those obtained from the model where the driving signal is treated classically. We show that in the limits of weak coupling and large photon number, the well-known expression for the Rabi frequency in the strong driving regime is recovered. In the opposite limit of strong coupling and small photon number, we find differences between the predictions of the semiclassical and quantum models. The results of the quantum picture can therefore be understood as Landau-Zener-Stueckelberg interferometry in the fully quantum regime.