Do micromagnets expose spin qubits to charge and Johnson noise?

Abstract

An ideal quantum dot spin qubit architecture requires a local magnetic field for one-qubit rotations. Such an inhomogeneous magnetic field, which could be implemented via a micromagnet, couples the qubit subspace with background charge fluctuations causing dephasing of spin qubits. In addition, a micromagnet generates magnetic field evanescent-wave Johnson noise. We derive an effective Hamiltonian for the combined effect of a slanting magnetic field and charge noise on a single-spin qubit and estimate the free induction decay dephasing times T2* for Si and GaAs. The effect of the micromagnet on Si qubits is comparable in size to that of spin-orbit coupling at an applied field of B=1T, whilst dephasing in GaAs is expected to be dominated by spin-orbit coupling. Tailoring the magnetic field gradient can efficiently reduce T2* in Si. In contrast, the Johnson noise generated by a micromagnet will only be important for highly coherent spin qubits.

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• Do micromagnets expose spin qubits to charge and Johnson noise?
• High Fidelity Singlet-Triplet $S$-$T_{-}$ Qubits in Inhomogeneous Magnetic Fields
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Cited by in corpus (22)

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• Spatial noise correlations beyond nearest-neighbor in ${}^{28}$Si/SiGe spin qubits
• Quantum Computing with Acceptor Spins in Silicon
• Spatial Noise Correlations in a Si/SiGe Two-Qubit Device from Bell State Coherences
• Extending comb-based spectral estimation to multiaxis quantum noise
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• Controlling Synthetic Spin-Orbit Coupling in a Silicon Quantum Dot with Magnetic Field
• Single spin qubit geometric gate in a silicon quantum dot
• Evanescent-wave Johnson Noise in small devices
• A spin dephasing mechanism mediated by the interplay between the spin-orbit coupling and the asymmetrical confining potential in semiconductor quantum dot
• Charge noise induced spin dephasing in a nanowire double quantum dot with spin-orbit coupling
• Probing two-qubit capacitive interactions beyond bilinear regime using dual Hamiltonian parameter estimations
• Optimisation of electrically-driven multi-donor quantum dot qubits
• Spin relaxation of a donor electron coupled to interface states
• Spin manipulation and spin dephasing in quantum dot integrated with a slanting magnetic field
• A SWAP Gate for Spin Qubits in Silicon
• Spin-relaxation anisotropy in a nanowire quantum dot with strong spin-orbit coupling
• Micromagnet-free operation of electron spin qubits in Si/Si${}_{1-x}$Ge${}_x$ vertical double quantum dots