Vanita Srinivasa

Coupling semiconductor spin qubits to photons in a microwave cavity enables robust long-range information transfer and entanglement. Building on the promise of long coherence times for spins in silicon, strong spin-photon coupling as well as coherent photon- mediated interaction of two single-electron silicon spin qubits have now been achieved [1–4]. While these results provide a path to scalability for silicon-based quantum information processing, scaling challenges remain for applying this approach to more than two qubits due to the need for tuning qubit frequencies into resonance with the cavity, as well as the fabrication and precise tuning of micromagnets required in silicon for spin-charge coupling and qubit-qubit interaction.

To address these outstanding challenges, we consider a pair of qubits based on electron spins in quantum dots that interact via microwave photons in a superconducting cavity, and that are also driven by classical external electric fields. For this system, we formulate a model for sideband-based parametric entanglement between the two qubits and show that this model can be mapped to both single-electron spin qubits in double quantum dots and resonant exchange qubits in triple quantum dots in the driven resonant regime [5]. We determine common resonance conditions for the two driven qubits and the cavity and identify experimentally relevant regimes of operation. This approach provides a promising route toward scalability and modularity in spin-based quantum information processing through drive-enabled tunability that can also be implemented in micromagnet-free systems for spin-photon coupling.

[1]  X. Mi, M. Benito, S. Putz, D. M. Zajac, J. M. Taylor, G. Burkard, and J. R. Petta, Nature 555, 599 EP (2018).
[2]  N. Samkharadze, G. Zheng, N. Kalhor, D. Brousse, A. Sammak, U. C. Mendes, A. Blais, G. Scappucci, and L. M. K. Vandersypen, Science 359, 1123 (2018).
[3]  F. Borjans, X. G. Croot, X. Mi, M. J. Gullans, and J. R. Petta, Nature 577, 195 (2020).
[4]  P. Harvey-Collard, J. Dijkema, G. Zheng, A. Sammak, G. Scappucci, and L. M. K. Vandersypen, Phys. Rev. X 12, 021026 (2022).
[5]  V. Srinivasa, J. M. Taylor, and C. Tahan, Phys. Rev. B 94, 205421 (2016).