Semiconductor Qubits for Quantum Networks

Synopsis

Semiconductor spin qubits in quantum dots have made substantial recent progress in coherent quantum control and memory.  This progress spans from the optically addressed self-assembled InGaAs/GaAs quantum dot system to the system of electrostatically gated dots in GaAs/AlGas or Si/SiGe.  Here I present the possibility of combining self-assembled dots with gated dots to enable an optically loaded quantum memory register, capable of interconverting photonic qubits to a multi-qubit memory and then providing high fidelity quantum logic on that memory.   Such a device would be critical to improve the relevant distance and speed of a quantum network.  I motivate this proposal with the results of several recent quantum control experiments in both self-assembled InGaAs/GaAs quantum dot molecules and in gated quantum dot molecules in isotopically enhanced Si/SiGe.  For more detail, see Phys. Rev. Applied 5, 024014 (2016).