Abstract: Techniques for obtaining a frequency standard using the crystal field splitting frequency of nitrogen vacancy center in diamond are disclosed. In certain exemplary embodiments, a microwave field is applied to the diamond and optically exciting the diamond under green light. The photoluminescent response of the diamond is measured by a photodetector. The intensity of the photoluminescent response can be used to determine the phase shift between the microwave and the crystal field splitting frequency. The microwave field frequency can be adjusted until the phase shift is below a predetermined threshold, and the microwave frequency can then be output for use as a standard.

Abstract: A quantum information processor (QIP) may include a plurality of quantum registers, each quantum register containing at least one nuclear spin and at least one localized electronic spin. At least some of the quantum registers may be coherently coupled to each other by a dark spin chain that includes a series of optically unaddressable spins. Each quantum register may be optically addressable, so that quantum information can be initialized and read out optically from each register, and moved from one register to another through the dark spin chain, though an adiabatic sequential swap or through free-fermion state transfer. A scalable architecture for the QIP may include an array of super-plaquettes, each super-plaquette including a lattice of individually optically addressable plaquettes coupled to each other through dark spin chains, and separately controllable by confined microwave fields so as to permit parallel operations.

Abstract: Techniques for obtaining a frequency standard using the crystal field splitting frequency of nitrogen vacancy center in diamond are disclosed. In certain exemplary embodiments, a microwave field is applied to the diamond and optically exciting the diamond under green light. The photoluminescent response of the diamond is measured by a photodetector. The intensity of the photoluminescent response can be used to determine the phase shift between the microwave and the crystal field splitting frequency. The microwave field frequency can be adjusted until the phase shift is below a predetermined threshold, and the microwave frequency can then be output for use as a standard.

Abstract: A quantum information processor (QIP) may include a plurality of quantum registers, each quantum register containing at least one nuclear spin and at least one localized electronic spin. At least some of the quantum registers may be coherently coupled to each other by a dark spin chain that includes a series of optically unaddressable spins. Each quantum register may be optically addressable, so that quantum information can be initialized and read out optically from each register, and moved from one register to another through the dark spin chain, though an adiabatic sequential swap or through free-fermion state transfer. A scalable architecture for the QIP may include an array of super-plaquettes, each super-plaquette including a lattice of individually optically addressable plaquettes coupled to each other through dark spin chains, and separately controllable by confined microwave fields so as to permit parallel operations.