Coupling Electron Spins in Quantum Rings to Microwave Photons

We derive an effective analytic model describing the coupling of electron spins in quantum rings to microwave photons. Dividing a quantum ring symmetrically with two barriers creates a double dot system in which quantum ring states can be achieved for specific interdot potential detunings. By applying an in plane magnetic field, the ring states are highly spin-charge hybridized which effectively enables the coupling of electronic spin states to microwave photons. Furthermore, the ring configuration can be broken by detuning the interdot potential which disables the microwave coupling and increases the coherence time. The switchable microwave interaction allows spin control and interconnectivity which are both vital to quantum computing applications. Recent experiments have shown that these quantum ring states can be created in InAs nanowire double quantum dots [1].

[1] H. Potts, et al., Nature Comm. 10, 5740 (2019).