Aging of coupled qubits

TL;DR

This paper investigates the aging transition in a network of coupled qubits, revealing a sudden drop in excited state population influenced by couplings and laser driving, a phenomenon distinct from classical oscillator behavior.

Contribution

It is the first study to analyze the aging transition in coupled qubits, introducing a model with dissipative and coherent couplings and characterizing the transition through population metrics.

Findings

Identified a sudden drop in excited state population at a threshold ratio of inactive qubits.

Demonstrated the influence of couplings and laser driving on the aging transition threshold.

Used stability analysis to determine the transition region.

Abstract

The aging transition refers to the shift from an oscillatory state to a globally ceased state due to some forms of deterioration in classical physics. Similar behavior has also been observed in quantum oscillators. Although it has received extensive attention in coupled oscillator systems, it has not yet been studied in coupled qubits. In this manuscript, we explore the aging transition in a network of coupled qubits. Our model describes {numerous} qubits driven by a laser, with both dissipative and coherent qubit-qubit couplings. The ratio of inactive qubits to total qubits and the population in the excited state of the qubits are employed to characterize the aging transition. We find a transition where the population in the excited states suddenly drops when the ratio exceeds a threshold. This behavior is intriguing and contrasts with coupled oscillators, where no sudden drop is observed. Additionally, we demonstrate how the couplings and driving laser influence the threshold. The underlying physics of the sudden drop is elucidated. The region where the aging transition occurs is determined based on stability analysis theory.