Telegraph flux noise induced beating Ramsey fringe in transmon qubits

TL;DR

This paper investigates how flux-noise, modeled as random telegraph noise, causes beating patterns in Ramsey fringes of transmon qubits, revealing flux-noise's significant role in qubit decoherence.

Contribution

The study introduces a flux-RTN model that explains nonmonotonic Ramsey fringes, aligning simulations with experimental data and highlighting flux-noise's impact on qubit coherence.

Findings

Flux-RTN sources induce beating patterns in Ramsey fringes.

Simulations match experimental observations of flux-noise effects.

Flux-noise significantly contributes to qubit decoherence.

Abstract

Ramsey oscillations typically exhibit an exponential decay envelope due to environmental noise. However, recent experiments have observed nonmonotonic Ramsey fringes characterized by beating patterns, which deviate from the standard behavior. These beating patterns have primarily been attributed to charge-noise fluctuations. In this paper, we investigate the flux-noise origin of these nonmonotonic Ramsey fringes in frequency-tunable transmon qubits. We develop a random telegraph noise (RTN) model to simulate the impact of telegraph-like flux-noise sources on Ramsey oscillations. Our simulations demonstrate that strong flux-RTN sources can induce beating patterns in the Ramsey fringes, showing excellent agreement with experimental observations in transmon qubits influenced by electronic environment-induced flux-noise. Our findings provide valuable insights into the role of flux-noise in qubit decoherence and underscore the importance of considering flux-noise RTN when analyzing nonmonotonic Ramsey fringes.