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

Area of Science:

• Quantum optics
• Quantum information science
• Condensed matter physics

Background:

• Driven quantum systems exhibit complex dynamics.
• Quantum detectors play a crucial role in probing quantum states.
• Entanglement is a key resource in quantum information processing.

Purpose of the Study:

• To investigate the asymptotic dynamics of a driven quantum two-level system coupled to an environment via a quantum detector.
• To understand the origin and characteristics of multiphoton resonances in such systems.
• To provide analytical results for these resonances and compare them with exact calculations.

Main Methods:

• Perturbative Floquet-Born-Markov approach for the qubit+detector system.
• Nonperturbative real-time path integral schemes for the driven spin-boson system.
• Analytical derivation of resonance conditions.

Main Results:

• Identified multiphoton resonances arising from qubit-detector entanglement.
• Analyzed different dynamical regimes using both perturbative and nonperturbative methods.
• Derived analytical expressions for resonances, including red and blue sidebands.

Conclusions:

• The entanglement between a quantum two-level system (qubit) and a quantum detector is responsible for observed multiphoton resonances.
• The employed theoretical methods accurately describe the system's dynamics and predict resonance phenomena.
• Analytical results show excellent agreement with high-accuracy ab initio calculations, validating the theoretical framework.