Quantum deficits and correlations of two superconducting charge qubits

TL;DR

This paper investigates quantum correlations and information deficits in a system of two superconducting charge qubits coupled to a microwave resonator, revealing how entanglement levels affect information extraction capabilities.

Contribution

It provides a detailed analysis of quantum and classical information deficits in coupled superconducting qubits, including numerical results across different regimes, highlighting the impact of entanglement.

Findings

Less entangled states allow greater classical information extraction.

Quantum and classical deficits vary with entanglement levels.

Numerical analysis across multiple regimes demonstrates these effects.

Abstract

Motivated by recent experiments [Pashkin et al. Nature, \textbf{421}, 823 (2003)] which showed coherent oscillations of two superconducting qubits system, we consider a system of two charge qubits coupled to a common stripline microwave resonator. We discuss the separable and entangled behavior as well as the quantum and classical information deficits. Numerical computation of these quantities for several regimes is performed. We find that for less entangled states the partner can extract much more information by means of classical communication and local operations