Accelerating multipartite entanglement generation in non-Hermitian superconducting qubits

TL;DR

This paper proposes a theoretical method to rapidly generate multipartite entanglement in non-Hermitian superconducting qubits, leveraging exceptional points to significantly outperform traditional Hermitian systems in speed.

Contribution

It introduces a scalable approach using non-Hermitian qubits and exceptional points to accelerate entanglement generation, with potential applications in quantum technology.

Findings

Non-Hermitian qubits can accelerate entanglement generation by thousands of times.

Approaching higher-order exceptional points enhances entanglement speed.

Hermitian qubits can produce high-fidelity GHZ states but require intense driving.

Abstract

Open quantum systems are susceptible to losses in information, energy, and particles due to their surrounding environment. One novel strategy to mitigate these losses is to transform them into advantages for quantum technologies through tailored non-Hermitian quantum systems. In this work, we theoretically propose a fast generation of multipartite entanglement in non-Hermitian qubits. Our findings reveal that weakly coupled non-Hermitian qubits can accelerate multiparty entanglement generation by thousands of times compared to Hermitian qubits, in particular when approaching the $2^n$-th order exceptional points of $n$ qubits in the ${\cal P}{\cal T}-$ symmetric regime. Furthermore, we show that Hermitian qubits can generate GHZ states with a high fidelity more than $0.9995$ in a timescale comparable to that of non-Hermitian qubits, but at the expense of intense driving and large coupling constant. Our approach is scalable to a large number of qubits, presenting a promising pathway for advancing quantum technologies through the non-Hermiticity and higher-order exceptional points in many-body quantum systems.