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JP-7854943-B2 - Asynchronous quantum information processing

JP7854943B2JP 7854943 B2JP7854943 B2JP 7854943B2JP-7854943-B2

Inventors

  • ウィリアム ジョセフ ゼン

Assignees

  • ゴールドマン サックス アンド カンパニー エルエルシー

Dates

Publication Date
20260507
Application Date
20210419
Priority Date
20200422

Claims (20)

  1. A non-temporary computer-readable recording medium containing stored instructions that cause a computing system to perform an operation when executed by the computing system, wherein the operation is: Determining the first and second sets of parameter values for the quantum program, The quantum program having the first and second sets of parameter values is transmitted to the quantum processing queue of a quantum information processing unit (QIPU), wherein the quantum processing queue is configured to store the quantum program for execution by the QIPU. Receiving a first expected value of the quantum program executed by the QIPU having the parameter values of the first set of parameter values, While the QIPU evaluates the second expected value of the quantum program having the parameter values of the second set of parameter values, a third set of parameter values of the quantum program is calculated based on the first set of parameter values and the first expected value. A non-temporary computer-readable recording medium characterized by modifying the quantum processing queue by transmitting the quantum program along with the third set of parameter values to the quantum processing queue.
  2. The operation involves receiving a second expected value of the quantum program executed by the QIPU having the parameter values of the second set of parameter values, While the QIPU evaluates the third expected value of the quantum program having the parameter values of the third set of parameter values, a fourth set of parameter values of the quantum program is calculated based on the first and second sets of parameter values and the first and second expected values. The non-temporary computer-readable recording medium according to claim 1, further comprising modifying the quantum processing queue by transmitting the quantum program along with the fourth set of parameter values to the quantum processing queue.
  3. The operation involves calculating a parameter set for a second quantum program while the QIPU evaluates the first expected value of the quantum program having the parameter values of the first parameter set, or the third expected value of the quantum program having the parameter values of the third parameter set. The non-temporary computer-readable recording medium according to claim 1, further comprising modifying the quantum processing queue by transmitting the second quantum program together with the parameter value set of the second quantum program to the quantum processing queue.
  4. The non-temporary computer-readable recording medium according to claim 1, wherein the QIPU is one of a set of QIPUs, and the quantum processing queue is configured to store quantum programs for execution by one or more QIPUs of the set.
  5. The non-temporary computer-readable recording medium according to claim 4, further comprising transmitting the quantum program having the third set of parameter values as transmitting instructions for the quantum program having the third set of parameter values to be executed by the QIPU.
  6. The non-temporary computer-readable recording medium according to claim 4, further comprising transmitting the quantum program having the third set of parameter values to transmit instructions for the quantum program having the third set of parameter values, which is executed by the QIPU having substantially the same noise profile as the noise profile of the QIPU.
  7. The non-temporary computer-readable recording medium according to claim 1, wherein modifying the quantum processing queue comprises adding the third set of parameter values to the end of the quantum processing queue.
  8. The non-temporary computer-readable recording medium according to claim 1, comprising changing the queue by instructing the QIPU to interrupt the current execution and evaluate the expected value of the quantum program having the parameter values of the third set of parameter values.
  9. The quantum program is a quantum circuit for a variational optimization problem, and the third set of parameter values corresponds to the next variational step. The non-temporary computer-readable recording medium according to claim 1.
  10. A non-temporary computer-readable recording medium according to claim 1, wherein, in response to the quantum processing queue having fewer than a threshold number of programs, the quantum program having the first set of parameter values is retransmitted to the quantum processing queue.
  11. It is a method, The steps of generating a set of quantum programs, The steps include: transmitting at least a portion of the set of quantum programs to a combined quantum information processing unit (QIPU) for execution; The steps include receiving the results generated by the composite QIPUs asynchronously in a continuous or batch manner, The steps include performing single- or multi-threaded generation of a new set of quantum programs based on the generated results, The steps include: sending at least a portion of the new set of quantum programs to the plurality of QIPUs for execution; The step of transmitting at least a portion of the new set of quantum programs is to stop processing the current quantum program and send instructions to at least one QIPU to process the new set of quantum programs. A method characterized by including the following.
  12. The method according to claim 11, further comprising the step of processing the transmitted program using the plurality of quantum information processing units.
  13. The method according to claim 11, wherein the set of quantum programs is generated by a classical controller by optimizing the objective function for the execution of variational quantum programs.
  14. A quantum processing system, One or more controllers, We compute a set of initial parameter values for a quantum program, The quantum program having the aforementioned set of initial parameter values is sent to the quantum processing queue. A first expectation value corresponding to the quantum program having the parameter values of the first initial parameter value set of the series of initial parameter value sets is received, One or more controllers configured to calculate a next set of parameter values based on the first initial set of parameter values and the first expected value, and to send the next set of parameter values to the quantum processing queue, A quantum information processing unit (QIPU) equipped with qubits, Evaluate the first expected value of the quantum program having the parameter values of the first initial parameter value set, The first expected value is transmitted to one or more controllers, While the next set of parameter values is being calculated, a first quantum operation is performed on the qubit according to the quantum program having the parameter values of the second set of initial parameter values from the series of initial parameter value sets, and a first quantum state is generated by the first quantum operation performed on the qubit. A quantum processing system characterized by comprising a QIPU configured to receive the next set of parameter values and to evaluate the next expected value of the quantum program having the parameter values of the next set of parameter values.
  15. The quantum processing system according to claim 14, further configured such that the quantum processor unit stops performing the first quantum operation on the qubit according to the quantum program having the parameter values of the second initial parameter value set before completing in response to the reception of the next set of parameter values.
  16. The quantum processing system according to claim 14, wherein the QIPU is one of a set of QIPUs, and the quantum processing queue is configured to store quantum programs for execution by the set of QIPUs.
  17. The quantum processing system according to claim 16, further comprising transmitting the following set of parameter values as transmitting instructions for the quantum program having the following set of parameter values to be executed by the QIPU.
  18. The quantum processing system according to claim 16, wherein transmitting the following set of parameter values includes transmitting instructions for the quantum program having the following set of parameter values, which is executed by a second QIPU having a noise profile substantially identical to the noise profile of the QIPU.
  19. The quantum processing system according to claim 14, wherein one or more controllers are further configured to retransmit the quantum program having the set of initial parameter values to the quantum processing queue in response to the quantum processing queue having fewer than a threshold number of programs.
  20. The aforementioned QIPU further, The first initial parameter value set is retrieved from the quantum processing queue. A second quantum operation is performed on the qubit according to the quantum program having the parameter values of the first initial parameter value set, and a second quantum state is generated. The second quantum state of the qubit is measured, and the first expectation value is evaluated based on the measurement of the second quantum state. A third quantum operation is performed on the qubit according to the quantum program having the parameter values of the following set of parameter values, and a third quantum state is generated. The quantum processing system according to claim 14, wherein the third quantum state of the qubit is measured, and the next expected value of the quantum program is evaluated based on the measurement of the third quantum state.

Description

The subject matter described generally concerns quantum computing, and more specifically, asynchronous methods for quantum information processing. This application is a claim of priority under U.S. Patent Application No. 63/014,066, 35 U.S.C. §119(e), filed on 22 April 2020, entitled "Asynchronous Quantum Information Processing," which is incorporated herein by reference in its entirety. Quantum algorithms can encompass numerous quantum circuits interconnected by classical computation. As a result, modern quantum information processing can include communication between quantum processors and other computing units, such as CPUs, GPUs, FPGAs, or other digital or analog processors. Complete quantum algorithms can perform hybrid execution between quantum processors and classical computation. Examples of hybrid algorithms include (i) variational quantum algorithms such as variational quantum eigenvalue solvers, quantum approximation algorithms, or various quantum machine learning methods; (ii) quantum error correction; (iii) associative quantum learning; and other methods. A serial method for implementing a quantum algorithm may include a controller that computes a first parameter set of a quantum program and a quantum information processing unit (QIPU) that executes the quantum program using the first parameter set (examples of QIPUs include quantum processor units (QPUs), quantum sensors, a network of QPUs, or a network of quantum sensors). The controller receives the execution results and determines an updated parameter set based on those results. The QIPU is instructed to execute the quantum program with the updated parameter set. This process is repeated until a termination condition is met (e.g., the solution converges). While the updated parameter set is being determined, the QIPU may remain in a waiting state. The embodiment relates to an asynchronous method for implementing a quantum algorithm in which the dead time of the QIPU is reduced or eliminated. A variety of parameter sets are determined for a quantum program, and the QIPU is instructed to execute the quantum program for each parameter set. Individual or aggregated results (e.g., expected values) from each program execution may be returned to the controller. One or more results are received, and the controller determines an updated parameter set while the QIPU continues to execute the quantum program for the remaining parameter sets. The QIPU is then instructed to execute a quantum program for the updated parameter set (e.g., immediately, after the execution of the current program, or after the remaining parameter sets have been processed). This asynchronous method allows the QIPU to be used more efficiently because there is little to no dead time for the QIPU. Furthermore, by determining which parameters to update when results are received from the QIPU and adjusting the QIPU queue in real time, the asynchronous method is more flexible and dynamic than the serial method, and as a result, the termination condition may be met sooner. Furthermore, asynchronous methods can provide more results than serial methods, and because QIPU is inherently probabilistic, it can lead to more reliable results and solutions. In one embodiment, the quantum processing system includes one or more (e.g., classical) controllers and a QIPU. One or more controllers compute a set of initial parameter sets for a quantum program. The quantum program having the set of initial parameter sets is sent to a quantum processing queue. The QIPU evaluates a first expectation value for a quantum program having the parameters of a first initial parameter set and transmits the first expectation value to one or more controllers. While the QIPU evaluates a second expectation value for a quantum program having the parameters of a second initial parameter set, one or more controllers compute the next parameter set based on the first initial parameter set and the first expectation value. The next parameter set is sent to the quantum processing queue, and the QIPU evaluates the next expectation value for a quantum program having the parameters of the next parameter set. Further features and advantages of the present invention will become apparent from the following detailed description of the invention with reference to the accompanying figures. In one embodiment, this is a block diagram of a quantum processing system. This is a block diagram showing a quantum processor unit (QPU) in one embodiment. Figure 1A shows an example of the execution of a hybrid quantum-classical routine on the quantum processing system. This figure shows the step time in a serial variational program that includes significant unused QPU dead time. This figure shows the step time in a serial variational program, including the efficient use of the QPU, in one embodiment. This block diagram shows the use of multiple control processors to transmit quantum programs (for example, simultaneously) in parallel to a set of Q