Entangling semiconductor spin qubits via the Coulomb interaction
Many proposed realizations of quantum information processing rely on rapid and robust entanglement of coherent qubits over a wide range of distances. While solid-state implementations based on electron spin qubits are potentially scalable, spin manipulation and coupling methods that take advantage of rapid control of the electron charge are often limited in range and remain susceptible to charge noise and relaxation. I will describe our theoretical approaches to addressing these challenges for spin qubits encoded in multiple electrons within systems of coupled quantum dots. We analyze a new regime for capacitive coupling of two-electron spin qubits that leads to high theoretical fidelities for entangling gates within silicon-based implementations in the presence of charge-based decoherence. We also show that the three-electron resonant exchange qubit provides both a protected operating point for rapid single-qubit manipulation and an electric dipole moment that enables multiple approaches for long-range entangling gates via a superconducting microwave resonator. These methods are inspired by techniques from circuit quantum electrodynamics, Hartmann-Hahn double resonance in NMR, and the Cirac-Zoller gate for trapped ions.
(Free lunch served at 12:00pm)