Entanglement spectroscopy of a driven solid-state qubit and its detector

TL;DR

This paper investigates the long-term behavior of a driven quantum two-level system coupled to an environment via a detector, revealing multi-photon resonances caused by entanglement, using various analytical and numerical methods.

Contribution

It introduces a combined perturbative and non-perturbative approach to analyze entanglement-induced resonances in a driven qubit system.

Findings

Identification of multi-photon resonances due to entanglement

Analytical expressions for red and blue sidebands

Agreement between approximate and exact calculations

Abstract

We study the asymptotic dynamics of a driven quantum two level system coupled via a quantum detector to the environment. We find multi-photon resonances which are due to the entanglement of the qubit and the detector. Different regimes are studied by employing a perturbative Floquet-Born-Markov approach for the qubit+detector system, as well as non-perturbative real-time path integral schemes for the driven spin-boson system. We find analytical results for the resonances, including the red and the blue sidebands. They agree well with those of exact ab-initio calculations.