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Title: Origin of 1/f charge noise in silicon spin qubits
Plain: Spin qubits in silicon are disturbed by slowly fluctuating electric fields from charges hopping in nearby materials. Where those charges are and why their spectrum follows 1/f is not known.
Precise: In Si/SiGe and Si-MOS quantum-dot qubits, charge noise with $S_E(1\,\mathrm{Hz})^{1/2}$ of order $0.1-1\,\text{micro-eV}/\mathrm{Hz}^{1/2}$ and spectral exponent near 1 limits dephasing and two-qubit gate fidelity, with temperature and frequency dependence that vary between devices. Identify the fluctuator ensemble (defects in gate oxides, in the SiGe barrier, or at interfaces) and its location, using noise correlations between neighboring dots and dependence on the gate stack.
Settled by: Spatially resolved noise correlations between neighboring dots plus heterostructure changes that alter the noise amplitude as a specific defect model predicts.
Kind: well-posed
Answer type: identification
References: (empty)
Literature status: open
Status note: (empty)
Posed since: (empty)