Abstract: The present application discloses methods and apparatus for optically addressing qubits. An optical addressing system includes a source of electromagnetic radiation, at least one multi-frequency modulator configured to modulate electromagnetic radiation generated by the source of electromagnetic radiation to simultaneously produce at least two beams of electromagnetic radiation having different frequencies, each of which is configured to, when applied to multi-level quantum objects, at least partially drive one or more transitions between energy levels of the multi-level quantum objects, and a router configured to selectively direct the at least two beams of electromagnetic radiation to the multi-level quantum objects.

Abstract: A scalable point defect qubit control system may include a diamond waveguide array comprising one or more diamond waveguides and a microwave line disposed proximally to the diamond waveguide array. Each diamond waveguide in the diamond waveguide array may include one or more qubits encoded in point defect sites. The microwave line may be configured to receive a direct current (DC) signal configured to shift an energy level of each point defect qubit of the one or more point defect qubits based on a position of the point defect in the diamond waveguide array, and receive an alternating current (AC) signal configured to control a quantum state of a point defect qubit of the one or more point defect qubits, wherein one or more properties of the AC signal are based on the shift in the energy level induced by the DC signal.

Abstract: A process is provided for the high-yield heterogeneous integration of ‘quantum micro-chiplets’ (QMCs, diamond waveguide arrays containing highly coherent color centers) with an aluminum nitride (AlN) photonic integrated circuit (PIC). As an example, the process is useful for the development of a 72-channel defect-free array of germanium-vacancy (GeV) and silicon-vacancy (SiV) color centers in a PIC. Photoluminescence spectroscopy reveals long-term stable and narrow average optical linewidths of 54 MHz (146 MHz) for GeV (SiV) emitters, close to the lifetime-limited linewidth of 32 MHz (93 MHz). Additionally, inhomogeneities in the individual qubits can be compensated in situ with integrated tuning of the optical frequencies over 100 GHz. The ability to assemble large numbers of nearly indistinguishable artificial atoms into phase-stable PICs is useful for development of multiplexed quantum repeaters and general-purpose quantum computers.

Abstract: A process is provided for the high-yield heterogeneous integration of ‘quantum micro-chiplets’ (QMCs, diamond waveguide arrays containing highly coherent color centers) with an aluminum nitride (AlN) photonic integrated circuit (PIC). As an example, the process is useful for the development of a 72-channel defect-free array of germanium-vacancy (GeV) and silicon-vacancy (SiV) color centers in a PIC. Photoluminescence spectroscopy reveals long-term stable and narrow average optical linewidths of 54 MHz (146 MHz) for GeV (SiV) emitters, close to the lifetime-limited linewidth of 32 MHz (93 MHz). Additionally, inhomogeneities in the individual qubits can be compensated in situ with integrated tuning of the optical frequencies over 100 GHz. The ability to assemble large numbers of nearly indistinguishable artificial atoms into phase-stable PICs is useful for development of multiplexed quantum repeaters and general-purpose quantum computers.