Abstract: Quantum computing systems require methods to control energies of qubits and couplers for quantum operations. Flux biasing of qubits and quantum couplers is provided for a superconducting quantum computer using single-flux-quantum (SFQ) technology. This method is applicable to a wide range of superconducting qubit structures and couplers, including transmons, fluxoniums, flux qubits, phase qubits and other superconducting qubits. This method enables arbitrary-amplitude time-varying flux biasing of qubits and couplers, due to a sequence of high-speed SFQ pulses. Several preferred embodiments are disclosed which provide high-fidelity control of fast single-qubit and multi-qubit operations.

Abstract: A high-speed lookup table is designed using Rapid Single Flux Quantum (RSFQ) logic elements and fabricated using superconducting integrated circuits. The lookup table is composed of an address decoder and a programmable read-only memory array (PROM). The memory array has rapid parallel pipelined readout and slower serial reprogramming of memory contents. The memory cells are constructed using standard non-destructive reset-set flip-flops (RSN cells) and data flip-flops (DFF cells). An n-bit address decoder is implemented in the same technology and closely integrated with the memory array to achieve high-speed operation as a lookup table. The circuit architecture is scalable to large two-dimensional data arrays.

Abstract: A high-speed lookup table is designed using Rapid Single Flux Quantum (RSFQ) logic elements and fabricated using superconducting integrated circuits. The lookup table is composed of an address decoder and a programmable read-only memory array (PROM). The memory array has rapid parallel pipelined readout and slower serial reprogramming of memory contents. The memory cells are constructed using standard non-destructive reset-set flip-flops (RSN cells) and data flip-flops (DFF cells). An n-bit address decoder is implemented in the same technology and closely integrated with the memory array to achieve high-speed operation as a lookup table. The circuit architecture is scalable to large two-dimensional data arrays.

Abstract: The present invention discloses an ALU (Arithmetic Logic Unit) that can be operated as an OR gate, an AND gate, an adder gate and an exclusive OR gate using a half adder that uses a superconductor rapid single flux quantum logic device. The ALU using a half adder includes a half adder using a superconductor rapid single flux quantum logic device as a logic circuit, and a switching unit that has input ports respectively connected to a sum output port and a carry output port of the half adder and is operated as an OR gate, an AND gate, an adder gate and an exclusive OR gate using output signals of the half adder. The switching unit includes a first switch having an input port connected to the sum output port of the half adder, a second switch having an input port connected to the carry output port of the half adder and an output port connected to an output port of the first switch, and a third switch having an input port connected to the carry output port of the half adder.