# Tunable Superconducting Qubits with Flux-Independent Coherence

## TL;DR

This paper demonstrates that superconducting transmon qubits with reduced tunability can achieve flux-independent coherence times, improving stability and scalability for quantum computing.

## Contribution

The study shows how to design flux-tunable qubits with suppressed flux noise dephasing, achieving consistent coherence times across a tunable frequency range.

## Key findings

- Flux noise impact is reduced in less tunable qubits.
- Achieved flux-independent dephasing times T2* ~ 15 μs.
- Potential for high-fidelity, scalable quantum gates.

## Abstract

We have studied the impact of low-frequency magnetic flux noise upon superconducting transmon qubits with various levels of tunability. We find that qubits with weaker tunability exhibit dephasing that is less sensitive to flux noise. This insight was used to fabricate qubits where dephasing due to flux noise was suppressed below other dephasing sources, leading to flux-independent dephasing times T2* ~ 15 us over a tunable range of ~340 MHz. Such tunable qubits have the potential to create high-fidelity, fault-tolerant qubit gates and fundamentally improve scalability for a quantum processor.