Evolution of $1/f$ Flux Noise in Superconducting Qubits with Weak Magnetic Fields

Abstract

The microscopic origin of $1/f$ magnetic flux noise in superconducting circuits has remained an open question for several decades despite extensive experimental and theoretical investigation. Recent progress in superconducting devices for quantum information has highlighted the need to mitigate sources of qubit decoherence, driving a renewed interest in understanding the underlying noise mechanism(s). Though a consensus has emerged attributing flux noise to surface spins, their identity and interaction mechanisms remain unclear, prompting further study. Here we apply weak in-plane magnetic fields to a capacitively-shunted flux qubit (where the Zeeman splitting of surface spins lies below the device temperature) and study the flux-noise-limited qubit dephasing, revealing previously unexplored trends that may shed light on the dynamics behind the emergent $1/f$ noise. Notably, we observe an enhancement (suppression) of the spin-echo (Ramsey) pure dephasing time in fields up to $B=100\text{G}$. With direct noise spectroscopy, we further observe a transition from a $1/f$ to approximately Lorentzian frequency dependence below 10 Hz and a reduction of the noise above 1 MHz with increasing magnetic field. We suggest that these trends are qualitatively consistent with an increase of spin cluster sizes with magnetic field. These results should help to inform a complete microscopic theory of $1/f$ flux noise in superconducting circuits.

References in corpus (16)

• Charge insensitive qubit design derived from the Cooper pair box
• Dynamical decoupling and noise spectroscopy with a superconducting flux qubit
• Decoherence of flux qubits due to 1/f flux noise
• Measurement and Control of Quasiparticle Dynamics in a Superconducting Qubit
• 1/f Flux Noise in Josephson Phase Qubits
• Dephasing of a superconducting flux qubit
• Magnetism in SQUIDs at Millikelvin Temperatures
• Microscopic origin of low frequency flux noise in Josephson circuits
• Observation of classical-quantum crossover of 1/f flux noise and its paramagnetic temperature dependence
• Trapping a single vortex and reducing quasiparticles in a superconducting resonator
• Direct identification of dilute surface spins on Al${}_2$O${}_3$: Origin of flux noise in quantum circuits
• Geometrical dependence of low frequency noise in superconducting flux qubits
• Magnetic-field resilience of 3D transmons with thin-film Al/AlO${}_x$/Al Josephson junctions approaching 1 T
• H-T phase diagram of the bi-dimensional Ising model with exchange and dipolar interactions
• An Ising-Glauber Spin Cluster Model for Temperature Dependent Magnetization Noise in SQUIDs
• Flux noise in disordered spin systems

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