Phenomenological noise model for superconducting qubits: two-state fluctuators and 1=f noise

Abstract

We present a general phenomenological model for superconducting qubits subject to noise produced by two-state fluctuators whose couplings to the qubit are all roughly the same. In flux qubit experiments where the working point can be varied, it is possible to extract both the form of the noise spectrum and the number of fluctuators. We find that the noise has a broad spectrum consistent with 1=f noise and that the number of fluctuators with slow switching rates is surprisingly small: less than 100. If the fluctuators are interpreted as unpaired surface spins, then the size of their magnetic moments is surprisingly large.

7 pages, 2 figures, 1 table

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Cited by in corpus (5)

• Spectral Analysis and Identification of Noises in Quantum Systems
• An Ising-Glauber Spin Cluster Model for Temperature Dependent Magnetization Noise in SQUIDs
• Magnetization Noise Induced Collapse and Revival of Rabi Oscillations in circuit QED
• 1/f Flux Noise in low-T${}_c$ SQUIDs due to Superparamagnetic Phase Transitions in Defect Clusters
• Telegraph flux noise induced beating Ramsey fringe in transmon qubits