Achieving strong spin-photon coupling with a semiconductor hole spin
Talk given at the ICE-7 and the SiQEW 2022
Abstract of the talk: Confined spins in semiconductor structures have recently proven to be a promising quantum technology for scalable quantum computation. Latest milestones in both electron- and hole-based qubits are the demonstrations of high-fidelity operation of a 6-qubit and a 4-qubit processor, respectively. These processors rely on the exchange interactions between neighboring qubits, which can be extremely fast and electrically tunable, allowing high-fidelity two-qubit gates. The exchange interaction, however, is local and, hence, limited to nearest-neighbor interactions. One of the most promising technologies for achieving long-range multi-qubit operation is through the use of superconducting cavities as links between distant qubits. Recently, the strong spin-photon coupling has been achieved with electron spins. Due to the weak spin-orbit coupling of electrons, the demonstrated couplings, in the order of 10 MHz, are still far from what is needed to perform high-fidelity gates. In this work, I will cover our recent theoretical and experimental results on spin-photon coupling with hole spins in Silicon. Unlike electrons, holes couple naturally to electrical degrees of freedom due to their large spin-orbit coupling. As I will show, this extremely large electrical susceptibility theoretically allows to couple hole spins to superconducting cavities both in the single- and double-dot regimes. We provide the first experimental demonstration of such coupling, exceeding the electron spin-photon couplings by one order of magnitude, bordering the ultrastrong coupling regime.
Related to the preprint arXiv:2206.14082.