# Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators

## TL;DR

This paper investigates low-frequency noise in superconducting transmon qubits, linking decoherence to microscopic two-level systems at the edges of the superconducting film, through long-term correlated measurements.

## Contribution

It provides the first detailed correlation analysis between coherence times, transition frequency, and microscopic noise sources in a highly coherent transmon qubit.

## Key findings

- Low-frequency burst noise affects coherence and frequency.
- Correlations suggest microscopic two-level systems as noise sources.
- Spectral noise analysis supports the microscopic origin hypothesis.

## Abstract

We report on long-term measurements of a highly coherent, non-tunable superconducting transmon qubit, revealing low-frequency burst noise in coherence times and qubit transition frequency. We achieve this through a simultaneous measurement of the qubit's relaxation and dephasing rate as well as its resonance frequency. The analysis of correlations between these parameters yields information about the microscopic origin of the intrinsic decoherence mechanisms in Josephson qubits. Our results are consistent with a small number of microscopic two-level systems located at the edges of the superconducting film, which is further confirmed by a spectral noise analysis.