Abstract: A method for executing a quantum error correction cycle in a quantum computer provided with a substrate of qubits arranged in repeated unit cells, wherein data qubits (D1, D2, D3, D4) are coupled to respective X- and Z-ancillary qubits (X1, X2, Z1, Z2), wherein a nearest neighbor interaction is provided by detuning a transition frequency of any of the data qubits and ancillary qubits into a coupling frequency for providing a coherent 2-qubit gate, wherein said method comprises the steps of simultaneous coupling of first ones (X1, X2 or Z1, Z2) of the ancillary qubits (X1, X2, Z1, Z2) with a respective neighboring data qubit; and subsequent couplings of said first ones with the other neighboring data qubits; followed by simultaneous coupling of second ones (Z1, Z2 or X1, X2) of the ancillary qubits with a neighboring data qubit; and subsequent couplings of said second ancillary qubit with the other neighboring data qubits.

Abstract: A method for executing a quantum error correction cycle in a quantum computer provided with a substrate of qubits arranged in repeated unit cells, wherein data qubits (D1, D2, D3, D4) are coupled to respective X- and Z-ancillary qubits (X1, X2, Z1, Z2), wherein a nearest neighbor interaction is provided by detuning a transition frequency of any of the data qubits and ancillary qubits into a coupling frequency for providing a coherent 2-qubit gate, wherein said method comprises the steps of simultaneous coupling of first ones (X1, X2 or Z1, Z2) of the ancillary qubits (X1, X2, Z1, Z2) with a respective neighboring data qubit; and subsequent couplings of said first ones with the other neighboring data qubits; followed by simultaneous coupling of second ones (Z1, Z2 or X1, X2) of the ancillary qubits with a neighboring data qubit; and subsequent couplings of said second ancillary qubit with the other neighboring data qubits.

Abstract: Embodiments of the present disclosure provide improved layout designs for quantum circuit assemblies employing qubits, e.g. superconducting qubits. One proposed design involves increasing a capacitance between a first qubit and a coupling component that couples the first qubit to a second qubit. Another design involves rounding of one or more corners at the end portions of coupling components. Yet another design involves varying the distance between two electrically conductive elements of a given superconducting qubit device which are connected to one another via one or more non-linear inductive elements. Qubit layout designs described herein may help increase coupling strength between qubits, allow greater design flexibility in achieving faster multi-qubit gates, and/or reduce or mitigate the negative effects of two-level systems.

Abstract: A qubit system is provided wherein successive sets of M RF pulses are generated simultaneously, for application to qubit circuits in a plurality of N groups of M qubit circuits. M switching multiplexer circuits are used, each to pass a respective one of the M RF pulses in the set to a selected one of a plurality of N M to one RF combiners in a multiplexing mode. Combined RF pulses at M different RF frequencies are transmitted from each of the N combiners to a transmission structure for a respective one of the groups. Individual ones of the combined RF pulses are coupled from the transmission structure for the group to respective ones of the qubit circuits of the groups via respective frequency selective filters. In a broadcast mode the M switching multiplexer circuits are used to transmit the simultaneous pulses to all of RF combiners.

Abstract: A qubit system is provided wherein successive sets of M RF pulses are generated simultaneously, for application to qubit circuits in a plurality of N groups of M qubit circuits. M switching multiplexer circuits are used, each to pass a respective one of the M RF pulses in the set to a selected one of a plurality of N M to one RF combiners in a multiplexing mode. Combined RF pulses at M different RF frequencies are transmitted from each of the N combiners to a transmission structure for a respective one of the groups. Individual ones of the combined RF pulses are coupled from the transmission structure for the group to respective ones of the qubit circuits of the groups via respective frequency selective filters. In a broadcast mode the M switching multiplexer circuits are used to transmit the simultaneous pulses to all of RF combiners.