Protecting Superconducting Qubits with Universal Quantum Degeneracy Point

TL;DR

This paper introduces a universal quantum degeneracy point method to protect superconducting qubits from low-frequency noise, enabling high-fidelity quantum gates and robustness against fabrication errors.

Contribution

The paper proposes a universal quantum degeneracy point approach that shields encoded qubits from arbitrary low-frequency noise in superconducting systems.

Findings

Protection of encoded qubits from arbitrary low-frequency noise.

High-fidelity quantum logic gates on encoded qubits.

Robustness against fabrication parameter spreads.

Abstract

Low-frequency noise can induce serious decoherence in superconducting qubits. Due to its diverse physical origin, such noise can couple with the qubits either as transverse or as longitudinal noise. Here, we present a universal quantum degeneracy point approach that can protect an encoded qubit from arbitrary low-frequency noise. We further show that universal quantum logic gates can be performed on the encoded qubits with high fidelity. The proposed scheme can be readily implemented with superconducting flux qubits or with a qubit coupling with a superconducting resonator. Meanwhile, the scheme is also robust against small parameter spreads due to fabrication errors in the superconducting systems.