Published in PRL: Phase driving of hole spin qubits


The spin-orbit interaction in spin qubits enables Rabi oscillations when an external microwave field is resonant with the qubit frequency. In this work, we introduce an alternative driving mechanism of hole spin qubits, where a far-detuned oscillating field couples to the qubit phase. Phase driving at radio frequencies, orders of magnitude slower than the microwave qubit frequency, induces highly non-trivial spin dynamics, violating the Rabi resonance condition. Weak driving Z<0.5 gives regular Rabi oscillations, while stronger driving results in complex dynamics, see Figure.

With a Si FinFET hole spin qubit, we demonstrate a controllable suppression of resonant Rabi oscillations, and their revivals at tunable sidebands. These sidebands enable alternative qubit control schemes using global fields and local far-detuned pulses, facilitating the design of dense large-scale qubit architectures with local qubit addressability. Phase driving also decouples Rabi oscillations from noise, an effect due to a gapped Floquet spectrum and can enable Floquet engineering high-fidelity gates in future quantum processors.

Theory by Stefano Bosco, Carlos Egues and Daniel Loss, experiments done in our lab by Simon Geyer, Andreas Kuhlmann and team, supported by NCCR SPIN of the Swiss NSF. 

Phase driving hole spin qubits
Stefano Bosco, Simon Geyer, Leon C. Camenzind, Rafael S. Eggli, Andreas Fuhrer, Richard J. Warburton, Dominik M. Zumbühl, J. Carlos Egues, Andreas V. Kuhlmann, Daniel Loss
Phys. Rev. Lett 131, 197001 (Nov 7, 2023), manuscript pdf, supplementary pdf