Single-step multipartite entangled states generation from coupled circuit cavities

TL;DR

This paper proposes a method to generate high-fidelity multipartite GHZ entangled states in superconducting qubits using coupled circuit cavities, with tunable qubit-cavity interactions enabled by classical fields, improving over single cavity setups.

Contribution

It introduces a scheme for generating multipartite entangled states with tunable interaction strengths in coupled cavity systems, ensuring high fidelity and scalability.

Findings

High-fidelity GHZ states can be generated numerically.

Coupled cavities outperform single cavity setups.

Tunable qubit-cavity coupling is achieved via classical fields.

Abstract

Green-Horne-Zeilinger states are a typical type of multipartite entangled states, which plays a central role in quantum information processing. For the generation of multipartite entangled states, the single-step method is more preferable as the needed time will not increase with the increasing of the qubit number. However, this scenario has a strict requirement that all the two-qubit interaction strengths should be the same, or the generated state will be of low quality. Here, we propose a scheme for generating multipartite entangled states of superconducting qubits, from a coupled circuit cavities scenario, where we rigorously achieve the requirement via adding an extra z-direction ac classical field for each qubit, leading the individual qubit-cavity coupling strength to be tunable in a wide range, and thus can be tuned to the same value. Meanwhile, in order to obtain our wanted multi-qubits interaction, x-direction ac classical field for each qubit is also introduced. By selecting the appropriate parameters, we numerically shown that high-fidelity multi-qubit GHZ states can be generated. In addition, we also show that the coupled cavities scenario is better than a single cavity case. Therefore, our proposal represents a promising alternative for multipartite entangled states generation.