Abstract: Disclosed herein is a quantum processor comprising a substrate, a qubit structure formed on the substrate, an electroplated phonon downconversion material, and furrows through the electroplated phonon downconversion material forming a plurality of electroplated phonon downconversion islands coupled to the substrate configured to channel deposited energy away from the qubit structure. Also disclosed are methods of making and using the same.

Abstract: Superconducting metamaterials composed of lumped-element inductors and capacitors are used to implement microwave photonics with novel dispersion relations and dense mode spectra that can be coupled to qubits. Metamaterial lattices may have qubits coupled to different unit cells in the metamaterial such that each qubit will couple strongly to modes with an antinode at the qubit location. Through simultaneous driving of combinations of modes, large amplitudes are produced at only one or a few unit cells, resulting in large ac Stark shifts of qubits located there, and providing a frequency-addressable qubit array without requiring flux-tunability and with reduced control wiring.

Abstract: A quantum computing transducer having a dense, tunable superconducting metamaterial transmission line (SMTL) spectrum that can resonantly enhance sideband scattering. The resonant enhancement of scattering boosts the scattering rate, and hence also the microwave-to-optical-interface (MOQI) transduction efficiency. Moreover, the integration of mechanical elements with the SMTL to realize the MOQI yields a platform that can be readily interfaced on chip, such as in an integrated circuit, with superconducting-qubit architectures to facilitate the local implementation of two of the essential functionalities required for a quantum repeater, i.e., data egress/ingress and a quantum processing module.

Abstract: A quantum computing transducer having a dense, tunable superconducting metamaterial transmission line (SMTL) spectrum that can resonantly enhance sideband scattering. The resonant enhancement of scattering boosts the scattering rate, and hence also the microwave-to-optical-interface (MOQI) transduction efficiency. Moreover, the integration of mechanical elements with the SMTL to realize the MOQI yields a platform that can be readily interfaced on chip, such as in an integrated circuit, with superconducting-qubit architectures to facilitate the local implementation of two of the essential functionalities required for a quantum repeater, i.e., data egress/ingress and a quantum processing module.