Rigetti & Co, LLC

Harvard College

Matthew J Reagor

Chad Tyler Rigetti

Eyob Alebachew Sete

Nikolas Anton Tezak

Shane Arthur Caldwell

William J Zeng

Benjamin Jacob Bloom

Nasser Alidoust

Nicolas Didier

Alexander Papageorge

Michael James Curtis

Marcus Palmer Da Silva

Prasahnt Sivarajah

Alexa Nitzan Staley

Dane Christoffer Thompson

Robert Stanley Smith

Colm Andrew Ryan

Sabrina Sae Byul Hong

Peter Jonathan Karalekas

Christopher Butler Osborn

Michael Justin Gerchick Scheer

Deanna Margo Abrams

Mehrnoosh Vahidpour

Eric Christopher Peterson

Blake Robert Johnson

Nicholas Charles Rubin

Johannes Sebastian Otterbach

Michael Karunendra Selvanayagam

Maxwell Benjamin Block

Jeffrey Cole Holzgrafe

Marko Lončar

Alexei N Marchenkov

Anthony Polloreno

Rodney Franklyn Sinclair

Alexei N Marchenokov

Glenn Jones

Kamal Yadav

Yuvraj Mohan

John Morrison Macaulay

Gregory M Stiehl

Anand Desai

Michael Rust

David Bryant

In a general aspect, a parametrically activated single-qubit quantum logic gate is performed in a quantum computing system. In some cases, a superconducting quantum processing unit includes a tunable qubit device. A single-qubit quantum logic gate is performed on a qubit defined by the tunable qubit device by communicating one or more control signals from a control system to the tunable qubit device. The tunable qubit device has a range of qubit operating frequencies, and the one or more control signals include only frequencies that are below the range of qubit operating frequencies.

Low-frequency activation of single-qubit quantum logic gates

In a general aspect, a photonic quantum network is disclosed. In some implementations, microwave modes and optical modes are generated on first and second quantum processing units (QPUs) by operation of a first transducer device of the first QPU and a second transducer device of the second QPU. The microwave modes are transmitted within the first and second QPUs from the first and second transducer devices to respective first and second qubit devices. The optical modes are transmitted from the first and second QPUs to an interferometer device. By operation of the interferometer device, output signals are generated on respective output channels based on the optical modes from the first and second QPUs. Based on the output signals detected by operation of photodetector devices coupled to the respective output channels, quantum entanglement transferred to the first and second qubit devices by the microwave modes is identified.

Photonic quantum networking for large superconducting qubit modules

In a general aspect, a quantum processor has a modular architecture. In some aspects, a modular quantum processor includes first and second quantum processor chips and a cap structure. The first quantum processor chip is supported on a substrate layer and includes a first plurality of qubit devices. The second quantum processor chip is supported on the substrate layer and includes a second plurality of qubit devices. The cap structure is supported on the first and second quantum processor chips and includes a coupler device that provides coupling between at least one of the first plurality of qubit devices with at least one of the second plurality of qubit devices. In some instances, the coupler device is an active coupler device that is configured to selectively couple at least one of the first plurality of qubit devices with at least one of the second plurality of qubit devices.

Modular quantum processor architectures

In a general aspect, a quantum logic gate is performed in a quantum computing system. In some cases, a pair of qubits are defined in a quantum processor; the pair of qubits can include a first qubit defined by a first qubit device in the quantum processor and a second qubit defined by a tunable qubit device in the quantum processor. A quantum logic gate can be applied to the pair of qubits by communicating a control signal to a control line coupled to the tunable qubit device. The control signal can be configured to modulate a transition frequency of the tunable qubit device at a modulation frequency, and the modulation frequency can be determined based on a transition frequency of the first qubit device.

Parametrically activated quantum logic gates

In a general aspect, calibration is performed in a quantum computing system. In some cases, domains of a quantum computing system are identified, where the domains include respective domain control subsystems and respective subsets of quantum circuit devices in a quantum processor of the quantum computing system. Sets of measurements are obtained from one of the domains and stored in memory. Device characteristics of the quantum circuit devices of the domain are obtained based on the set of measurements, and the device characteristics are stored in a memory of the control system. Quantum logic control parameters for the subset of quantum circuit devices of the domain are obtained based on the set of measurements and stored in memory.

Performing a calibration process in a quantum computing system

In a general aspect, a quantum computing method is described. In some aspects, a control system in a quantum computing system assigns subsets of qubit devices in a quantum processor to respective cores. The control system identifies boundary qubit devices residing between the cores in the quantum processor and generates control sequences for each respective core. A signal delivery system in communication with the control system and the quantum processor receives control signals to execute the control sequences, and the control signals are applied to the respective cores in the quantum processor.

Modular control in a quantum computing system

In a general aspect, a method executed in a quantum computing system includes performing a calibration process in the quantum computing system to identify a value of a parameter of the quantum computing system. The method also includes analyzing a variation of the value in response to a change in a condition of the quantum computing system, thereby determining a stability of the parameter. The method additionally includes scheduling a recalibration of the parameter based on the stability of the parameter and executing a quantum algorithm in the quantum computing system based on the value of the parameter identified by the calibration process.

Maintaining calibration in a quantum computing system

In a general aspect, quantum computing system performance is tested. Systems and methods for testing hardware in a quantum computing system are described. The methods may include certification/decertification of data produced by the quantum computing system, detection of faults, correction of errors and/or recalibration/replacement of the quantum computing system or a quantum computing subsystem.

Testing hardware in a quantum computing system

A quantum computing system that includes a quantum circuit device having at least one operating frequency; a first substrate having a first surface on which the quantum circuit device is disposed; a second substrate having a first surface that defines a recess of the second substrate, the first and second substrates being arranged such that the recess of the second substrate forms an enclosure that houses the quantum circuit device; and an electrically conducting layer that covers at least a portion of the recess of the second substrate.

Microwave integrated quantum circuits with vias and methods for making the same

In a general aspect, a plurality of distinct quantum processor unit (QPU) instances are utilized to execute a quantum computation. Hybrid classical-quantum computing methods and systems are described which utilize the plurality of QPU instances in the execution of quantum computations.

Utilizing multiple quantum processor unit (QPU) instances

Quantum logic control pulse determination

In a general aspect, a computing system is configured to execute a quantum approximate optimization algorithm. In some aspects, a control system identifies a pair of qubit devices in a quantum processor. The quantum processor includes a connection that provides coupling between the pair of qubit devices. ZZ coupling between the pair of qubit devices is activated to execute a cost function defined in the quantum approximate optimization algorithm. The cost function is associated with a maximum cut problem, and the ZZ coupling is activated by allowing the pair of qubits to evolve under a natural Hamiltonian for a time period &#x3c4;. One or more of the pair of qubit devices is measured to obtain an output from an execution of the quantum approximate optimization algorithm.

Quantum approximate optimization

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Corte Madera, CA, United States of America

Matthew J Reagor