Effects of dipolar coupling on an entanglement storage device

TL;DR

This paper investigates how dipolar coupling affects entanglement storage in qubit systems with a common environment, revealing that nonsecular dipolar interactions reduce entanglement and proposing properties for mitigating these effects.

Contribution

It analyzes the impact of dipolar coupling on environment-induced entanglement using a fluctuation-regulated quantum master equation, highlighting the detrimental effects of nonsecular interactions.

Findings

Nonsecular dipolar coupling reduces entanglement.

Dipolar interactions decrease storage efficiency.

Properties of robust storage mitigate dipolar effects.

Abstract

Quantum computation requires efficient long-term storage devices to preserve quantum states. An attractive candidate for such storage devices is qubits connected to a common dissipative environment. The common environment gives rise to persistent entanglements in these qubit systems. Hence these systems act efficiently as a storage device of entanglement. However, the existence of a common environment often requires the physical proximity of the qubits and hence results in direct dipolar coupling between the qubits. In this work, we investigate the total effect of the dipolar coupling on the environment-induced entanglement using a recently-proposed fluctuation-regulated quantum master equation [A. Chakrabarti and R. Bhattacharyya, Phys. Rev. A 97, 063837 (2018)]. We show that nonsecular part of the dipolar coupling results in reduced entanglement and hence less efficiency of the storage devices. We also discuss the properties of efficient storage that mitigates the detrimental effects of the dipolar coupling on the stored entanglement.