Rapid and Robust generation of Einstein--Podolsky--Rosen pairs with Spin Chains

TL;DR

This paper presents two protocols for rapidly generating high-fidelity EPR pairs using dimerized spin chains with defects, demonstrating robustness to disorder and tunable entangling times for quantum information applications.

Contribution

The authors propose two novel protocols for entangling spin chains that achieve high fidelity and robustness, with tunable entangling times based on coupling ratios.

Findings

High-fidelity EPR pair generation achievable through natural dynamics.

Entangling time can be exponentially reduced by engineering coupling ratios.

Protocols show robustness to disorder up to 50% of weak coupling.

Abstract

We investigate the ability of dimerized spin chains with defects to generate EPR pairs to very high fidelity through their natural dynamics. We propose two protocols based on different initializations of the system, which yield the same maximally entangled Bell state after a characteristic time. This entangling time can be varied through engineering the weak/strong couplings' ratio of the chain, with larger values giving rise to an exponentially faster quantum entangling operation. We demonstrate that there is a set of characteristic values of the coupling, for which the entanglement generated remains extremely high. We investigate the robustness of both protocols to diagonal and off-diagonal disorder. Our results demonstrate extremely strong robustness to both perturbation types, up to strength of 50% of the weak coupling. Robustness to disorder can be further enhanced by increasing the coupling ratio. The combination of these properties makes the use of our proposed device suitable for the rapid and robust generation of Bell states in quantum information processing applications.