International Business Machines Corporation

Lev Samuel Bishop

Jay Michael Gambetta

Hanhee Paik

Andrew W Cross

Jason Scott Orcutt

Ismael Faro Sertage

Antonio Corcoles-Gonzalez

Stefan Filipp

Salvatore Bernardo Olivadese

Paul Kristan Temme

Christopher James Wood

Ali Javadiabhari

James Robert Rozen

John Aaron Smolin

Renier Rodriguez Morales

Helena Zhang

Blake Johnson

Eric Peterson

Petar Jurcevic

Jinsung Kim

A method for a classical computer to synthesize a quantum circuit for use on a quantum computational device includes receiving information for a target operation to be implemented on said quantum computational device, and receiving information regarding native qubit gates that are available on said quantum computational device to be used to implement said quantum circuit; The method further includes determining each of a plurality of quantum circuits formed from said native qubit gates such that each of said plurality of quantum circuits will perform a function substantially equivalent to said target operation when implemented on the quantum computational device. The method further includes selecting one of said plurality of quantum circuits formed from said native qubit gates, based on a performance criterion of said quantum computational device.

Synthesis of quantum circuits from native gates

Techniques for improving a quantum simulator are provided. In one example, a system includes a simulation component and a snapshot component. The simulation component determines a set of random numbers and simultaneously provides the set of random numbers to an arithmetic decoder to perform a stochastic simulation process. The snapshot component generates snapshot data indicative of a state of the stochastic simulation process based on data associated with a stochastic branching point for the stochastic simulation process.

Generating samples of outcomes from a quantum simulator

A compatibility is ascertained between a configuration of a quantum processor (q-processor) of a quantum cloud compute node (QCCN) in a quantum cloud environment (QCE) and an operation requested in a first instruction in a portion (q-portion) of a job submitted to the QCE, the QCE including the QCCN and a conventional compute node (CCN), the CCN including a conventional processor configured for binary computations. In response to the ascertaining, a quantum instruction (q-instruction) is constructed corresponding to the first instruction. The q-instruction is executed using the q-processor of the QCCN to produce a quantum output signal (q-signal). The q-signal is transformed into a corresponding quantum computing result (q-result). A final result is returned to a submitting system that submitted the job, wherein the final result comprises the q-result.

Job processing in quantum computing enabled cloud environments

A method, system and computer program product for mitigating errors in measurements from a quantum system. A discriminator is trained to classify the measurement results of the quantum states of qubits as corresponding to a first quantum state (e.g., quantum state of 0) or a second quantum state (e.g., quantum state of 1). A first region of trust (corresponding to trusted measurements of a first quantum state) with a first discriminator boundary and a second region of trust (corresponding to trusted measurements of a second quantum state) with a second discriminator boundary are defined using the trained discriminator. If a shot-to-shot measurement result of a qubit state falls outside such regions of trust, the measurement result is rejected. In this manner, measurement errors from a quantum system are effectively mitigated, including measurement errors involving shot-to-shot measurement results of the quantum states read from the execution of the quantum circuits.

Mitigating errors in measurements from a quantum system by defining regions of trust

Systems and techniques that facilitate backend quantum runtimes are provided. In various embodiments, a system can comprise a backend receiver component that can access a computer program provided by a client device, wherein the computer program is configured to indicate a quantum computation. In various aspects, the system can further comprise a backend runtime manager component that can host the computer program by instantiating a backend classical computing resource. In various instances, the backend classical computing resource can orchestrate both classical execution of the computer program and quantum execution of the quantum computation indicated by the computer program.

Backend quantum runtimes

Techniques for automating quantum circuit debugging are provided that simulate standard debugging behaviors. The technology includes rewriting a source quantum circuit into instrumented circuits based on instrumentation instruction information inserted into software code that corresponds to the source quantum circuit. The instrumented circuits can executed to obtain measurement data corresponding to different state data of qubits within the source quantum circuit. The measurement data can be processed to output generated information corresponding to one or more internal states or processes of a quantum computer associated with the source quantum circuit.

Debugging quantum circuits by circuit rewriting

A method for characterizing noise in a quantum system, the quantum system including a plurality of qubits and a plurality of entangling gates native to the quantum system, includes generating a random quantum circuit on a quantum processor, the random quantum circuit comprising the plurality of entangling gates native to the quantum system. The method includes running a simulation of the random quantum circuit on a classical computer a plurality of times to obtain ideal outcomes, and running the random quantum circuit on the quantum processor a plurality of times to obtain experimental outcomes. The method includes grouping the experimental outcomes based on probabilities of the ideal outcomes to obtain a first distribution, and grouping the experimental outcomes based on probabilities of the experimental outcomes to obtain a second distribution. The method includes characterizing noise in the quantum system based on the first distribution and the second distribution.

Noise classification through the output of random quantum circuits

The technology is generally directed towards a pulse generation component that outputs a control pulse with a timing delay. A qubit state decision component uses an analog kernel to perform a linear filtering operation on (e.g., multiplies and integrates) a qubit signal to obtain a result corresponding to a qubit state, and compares the result to a threshold value to determine a measurement outcome result corresponding to the qubit state. A conditional gate component conditionally gates the control pulse based on the measurement outcome result.

Fast quantum feedback using analog integration and control pulse gating

Techniques facilitating reduction and/or mitigation of crosstalk in quantum bit gates of a quantum computing circuit are provided. A system can comprise a memory that stores computer executable components and a processor that executes the computer executable components stored in the memory. The computer executable components can comprise a signal generation component that implements a control sequence that comprises a single pulse type for a first quantum bit and at least a second quantum bit of a quantum circuit. The computer-executable components can also comprise a coordination component that synchronizes a first pulse of a first channel of the first quantum bit and at least a second pulse of at least a second channel of the second quantum bit. The coordination component can simultaneously apply the first pulse to the first quantum bit and at least the second pulse to at least the second quantum bit.

Reduction and/or mitigation of crosstalk in quantum bit gates

Techniques for facilitating quantum tomography are provided. In one example, a system includes a circuit generation component and a tomography analysis component. The circuit generation component generates tomography experiment data indicative of information for a set of tomography experiments based on quantum circuit data indicative of a machine-readable description of a quantum circuit. The tomography analysis component generates tomogram data based on experimental result data indicative of information associated with the tomography experiment data.

Facilitating quantum tomography

Systems, computer-implemented methods, and computer program products to facilitate external port measurement of qubit port responses are provided. According to an embodiment, a system can comprise a memory that stores computer executable components and a processor that executes the computer executable components stored in the memory. The computer executable components can comprise an analysis component that can analyze responses of a multi-mode readout device coupled to a qubit. The computer executable components can further comprise an assignment component that can assign a readout state of the qubit based on the responses. In some embodiments, the multi-mode readout device can be electrically coupled to at least one of the qubit or an environment of the qubit based on a defined electrical coupling value.

Multi-mode qubit readout and qubit state assignment

Techniques are provided for improving quantum circuits. The technology includes approximately expanding, by a system operatively coupled to a processor, using zero to a number of applications of a super controlled basis gate, a target two-qubit operation, with the approximately expanding resulting in instances of the target two-qubit operation corresponding to the zero to the number of applications, and the target two-qubit operation is part of a source quantum circuit associated with a quantum computer. The system analyzes the instances and the super controlled basis gate, and automatically rewrites the source quantum circuit into a deployed quantum circuit based on the analyzing.

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Dobbs Ferry, NY, United States of America

Lev Samuel Bishop