Long-distance entangling gates in three-qubit quantum dot spin systems mediated by microwave photons

Attaining quantum dot (QD)-based processors with large number of qubits remains as a major experimental challenge. Recently, long-distance entangling gates between two electronic spins in double QDs mediated by microwave resonators have been developed. While this serves as an important initial step, scaling the systems to qubit numbers larger than two is crucial. We focus on three-qubit—resonator system, a two-electron triple QD coupled to a single-electron double QD via the resonator. We derive an effective Hamiltonian for this system and build protocols for high-fidelity entangling gates. This study paves the way for modular quantum computing using QD arrays with manageable number of qubits and resonators as quantum information busses.

This work is supported by U.S. Army Research Office (Grant No. W911NF-17-0287)