High-fidelity multipartite entanglement creation in non-Hermitian qubits

TL;DR

This paper demonstrates that non-Hermitian superconducting qubits can generate high-fidelity multipartite entangled states, such as GHZ states, under specific conditions, highlighting their potential for advanced quantum engineering.

Contribution

It introduces a theoretical framework for creating near-perfect multipartite entanglement in non-Hermitian qubits, a novel approach compared to traditional Hermitian systems.

Findings

High-fidelity GHZ state generation in non-Hermitian qubits

Fidelity approaches unity at low decay rates

Potential for advanced quantum engineering in non-Hermitian systems

Abstract

Non-Hermitian quantum systems showcase many distinct and intriguing features with no Hermitian counterparts. One of them is the exceptional point which marks the PT (parity and time) symmetry phase transition, where an enhanced spectral sensitivity arises and leads to novel quantum engineering. Here we theoretically study the multipartite entanglement properties in non-Hermitian superconducting qubits, where high-fidelity entangled states can be created under strong driving fields or strong couplings among the qubits. Under an interplay between driving fields, couplings, and non-Hermiticity, we focus on generations of GHZ states or GHZ classes in three and four qubits with all-to-all couplings, which allows a fidelity approaching unity when relatively low non-Hermitian decay rates are considered. This presents an ultimate capability of non-Hermitian qubits to host a genuine and maximal multipartite entanglement. Our results can shed light on novel quantum engineering of multipartite entanglement generations in non-Hermitian qubit systems.