Thermal Entanglement and Coherence in a Two-Superconducting Charge Qubits

Abstract

This study investigates the progression of thermal entanglement and quantum coherence in a system composed of two superconducting charge qubits connected through a fixed capacitor. Superconducting materials play a central role in modern quantum technologies due to their ability to sustain coherent states over long timescales, making them an ideal platform for quantum information processing. We employ metrics such as logarithmic negativity and relative entropy of coherence to precisely evaluate these quantum resources. In particular, we analyze how thermal noise affects entanglement and quantum coherence in this capacitively coupled system. A central aspect of this work is the interaction between the reservoir's temperature at equilibrium and various intrinsic parameters of the system. The results show that increasing temperature leads to a gradual degradation of entanglement and coherence. However, these quantum resources are highly sensitive to system variables, and careful tuning of these variables can reduce the harmful impact of absolute temperature. These findings offer promising perspectives for optimizing two-qubit superconducting charge systems, with the aim of enhancing their robustness and fully exploiting the advantages offered by quantum technologies.