Proposal for generating complex microwave graph states using superconducting circuits

TL;DR

This paper proposes a method to generate complex microwave graph states using superconducting transmon qubits and microwave devices, aiming to enhance quantum communication capabilities with current technology.

Contribution

It introduces a scheme to construct 2D lattice and tree-like microwave graph states with transmon qubits, expanding beyond previous 1D implementations.

Findings

Fidelity estimates for complex graph states using current parameters

Comparison of fixed- and tunable-frequency transmon qubits

Identification of main performance-limiting factors

Abstract

Microwave photonic graph states provide a promising approach for robust quantum communication between remote superconducting chips using microwave photons. Recently, Besse et al. [Nat. Commun. 11, 4887 (2020)] demonstrated that 1D graph states can be generated using two transmon qubits. In this paper, we propose to use transmon qubits combined with other microwave devices to construct more complex graph states. Specifically, we consider 2D lattice and tree-like graph states. We compare the performance using fixed- versus tunable-frequency transmon qubits and also for different photonic qubit encodings. In each case, we estimate the fidelity of the resulting microwave graph state assuming current experimental parameters and identify the main factors that limit performance.