A semiconductor memory device includes a memory region from which first data and second data are sequentially read, and a data output circuit suitable for selectively performing a reset operation on a data pad according to a logical relationship between the first and second data during an output disable period between a first output enable period corresponding to first output data and a second output enable period corresponding to second output data, when sequentially outputting the first and second output data corresponding to the first and second data through the data pad.

A novel and useful quantum computing machine architecture that includes a classic computing core as well as a quantum computing core. A programmable pattern generator executes sequences of instructions that control the quantum core. In accordance with the sequences, a pulse generator functions to generate the control signals that are input to the quantum core to perform quantum operations. A partial readout of the quantum state in the quantum core is generated that is subsequently re-injected back into the quantum core to extend decoherence time. Access gates control movement of quantum particles in the quantum core. Errors are corrected from the partial readout before being re-injected back into the quantum core. Internal and external calibration loops calculate error syndromes and calibrate the control pulses input to the quantum core. Control of the quantum core is provided from an external support unit via the pattern generator or can be retrieved from classic memory where sequences of commands for the quantum core are stored a priori in the memory. A cryostat unit functions to provide several temperatures to the quantum machine including a temperature to cool the quantum computing core to approximately 4 Kelvin.

A novel and useful quantum computing machine architecture that includes a classic computing core as well as a quantum computing core. A programmable pattern generator executes sequences of instructions that control the quantum core. In accordance with the sequences, a pulse generator functions to generate the control signals that are input to the quantum core to perform quantum operations. A partial readout of the quantum state in the quantum core is generated that is subsequently re-injected back into the quantum core to extend decoherence time. Access gates control movement of quantum particles in the quantum core. Errors are corrected from the partial readout before being re-injected back into the quantum core. Internal and external calibration loops calculate error syndromes and calibrate the control pulses input to the quantum core. Control of the quantum core is provided from an external support unit via the pattern generator or can be retrieved from classic memory where sequences of commands for the quantum core are stored a priori in the memory. A cryostat unit functions to provide several temperatures to the quantum machine including a temperature to cool the quantum computing core to approximately 4 Kelvin.

One example describes a superconducting current source system comprising a linear flux-shuttle. The linear flux-shuttle includes an input and a plurality of Josephson transmission line (JTL) stages. Each of the JTL stages includes at least one Josephson junction, an output inductor, and a clock input. The linear flux-shuttle can be configured to generate a direct current (DC) output current via the output inductor associated with each of the JTL stages in response to the at least one Josephson junction triggering in a sequence in each of the JTL stages along the linear flux-shuttle in response to receiving an input pulse at the input and in response to a clock signal provided to the clock input in each of the JTL stages.

One example describes a superconducting current source system comprising a linear flux-shuttle. The linear flux-shuttle includes an input and a plurality of Josephson transmission line (JTL) stages. Each of the JTL stages includes at least one Josephson junction, an output inductor, and a clock input. The linear flux-shuttle can be configured to generate a direct current (DC) output current via the output inductor associated with each of the JTL stages in response to the at least one Josephson junction triggering in a sequence in each of the JTL stages along the linear flux-shuttle in response to receiving an input pulse at the input and in response to a clock signal provided to the clock input in each of the JTL stages.

A system comprises time-tracking circuitry and phase parameter generation circuitry. The time-tracking circuitry is operable to generate a time-tracking value corresponding to time elapsed since a reference time. The phase parameter generation circuitry operable to: receive the time-tracking value; receive a control signal that conveys a frequency parameter corresponding to a desired frequency of an oscillating signal; and generate a plurality of phase parameters used for generation of an oscillating signal, wherein the generation of the plurality of phase parameters is based on the time-tracking value and the frequency parameter such that the oscillating signal maintains phase continuity across changes in the frequency parameter.

A system comprises time-tracking circuitry and phase parameter generation circuitry. The time-tracking circuitry is operable to generate a time-tracking value corresponding to time elapsed since a reference time. The phase parameter generation circuitry operable to: receive the time-tracking value; receive a control signal that conveys a frequency parameter corresponding to a desired frequency of an oscillating signal; and generate a plurality of phase parameters used for generation of an oscillating signal, wherein the generation of the plurality of phase parameters is based on the time-tracking value and the frequency parameter such that the oscillating signal maintains phase continuity across changes in the frequency parameter.

A radio-frequency (RF) to direct current (DC) converter is provided. When a DC electrical current is applied via a DC input port of the converter, the DC electrical current is shunted to ground through a Josephson junction (JJ) of the converter and substantially no DC electrical current flows through a resistor of the converter, and when an RF electrical current is applied via an RF input port of the converter, output trains of SFQ current pulses from a DC to SFQ converter of the RF-to-DC converter with pulse-to-pulse spacing inversely proportional to the RF electrical current frequency cause the JJ to switch at a rate commensurate with an RF frequency of the RF electrical current to generate a steady state voltage across the JJ linearly dependent on the RF frequency.

A radio-frequency (RF) to direct current (DC) converter is provided. When a DC electrical current is applied via a DC input port of the converter, the DC electrical current is shunted to ground through a Josephson junction (JJ) of the converter and substantially no DC electrical current flows through a resistor of the converter, and when an RF electrical current is applied via an RF input port of the converter, output trains of SFQ current pulses from a DC to SFQ converter of the RF-to-DC converter with pulse-to-pulse spacing inversely proportional to the RF electrical current frequency cause the JJ to switch at a rate commensurate with an RF frequency of the RF electrical current to generate a steady state voltage across the JJ linearly dependent on the RF frequency.

Methods, systems, and apparatus for implementing a unitary quantum gate on one or more qubits. In one aspect, a method includes the actions designing a control pulse for the unitary quantum gate, comprising: defining a universal quantum control cost function, wherein the control cost function comprises a qubit leakage penalty term representing i) coherent qubit leakage, and ii) incoherent qubit leakage across all frequency components during a time dependent Hamiltonian evolution that realizes the unitary quantum gate; adjusting parameters of the time dependent Hamiltonian evolution to vary a control cost according to the control cost function such that leakage errors are reduced; generating the control pulse using the adjusted parameters; and applying the control pulse to the one or more qubits to implement the unitary quantum gate.