Determining dynamic quantum error correction schemes
A method, apparatus and product comprising: obtaining a logical representation of a quantum circuit, wherein the logical representation comprises a plurality of logical qubits manipulated by a plurality of logical gates; and generating a physical representation of the quantum circuit, the physical representation is configured to allocate a set of physical qubits of a quantum computer to the plurality of logical qubits in order to implement error correction operations The generating includes selecting a first quantity of physical qubits from the set of physical qubits for a first separate section of the quantum circuit; selecting a second quantity of physical qubits from the set of physical qubits for a second separate section of the quantum circuit, and synthesizing the quantum circuit using the first and second quantities for the first and second separate sections.
1. A method comprising:
obtaining a logical representation of a quantum circuit, wherein the logical representation comprises a plurality of logical qubits manipulated by a plurality of logical gates; and
generating a physical representation of the quantum circuit, the physical representation is configured to allocate a set of physical qubits of a quantum computer to the plurality of logical qubits in order to implement error correction operations, said generating comprises:
selecting a first quantity of physical qubits from the set of physical qubits for a first separate section of the quantum circuit, wherein said selecting is based on a utility per-qubit metric that is used to define a utility per-qubit score of the first separate section, wherein the utility per-qubit score of the first separate section indicates a utility of each qubit in the first separate section, wherein the utility per-qubit score of the first separate section is determined based on a ratio between a quality score of the first separate section when using the first quantity and between a cost function of the first separate section when using the first quantity, wherein the quality score is defined by a quality metric that is monotonically correlated to error rates of the first separate section;
selecting a second quantity of physical qubits from the set of physical qubits for a second separate section of the quantum circuit, the first and second quantities are different, the first and second separate sections are disjoint sections of the quantum circuit, wherein said selecting is based on a utility per-qubit score of the second separate section that indicates a utility of each qubit in the second separate section, wherein the utility per-qubit score of the second separate section is determined based on a ratio between a quality score of the second separate section when using the second quantity and between a cost function of the second separate section when using the second quantity, wherein the quality score is monotonically correlated to error rates of the second separate section; and
synthesizing the quantum circuit using the first and second quantities for the first and second separate sections, wherein a quantity of the set of physical qubits is greater than a quantity of the plurality of logical qubits.
2. The method of claim 1 , wherein said selecting comprises determining that the first and second quantities optimize values of the utility per-qubit metric for the first and second separate sections, respectively.
3. The method of claim 2 , wherein said optimizing comprises implementing a search algorithm on a plurality of alternative physical representations of the first separate section of the quantum circuit, wherein the first separate section of the quantum circuit is implementable using the plurality of alternative physical representations, wherein each of the plurality of alternative physical representations comprises a different selected quantity of physical qubits for the first separate section, wherein the search algorithm is configured to search for an optimal utility per-qubit score of the first separate section in a solution space that comprises the plurality of alternative physical representations.
4. The method of claim 3 , wherein the quality metric is monotonically correlated to error rates of the first separate section when implementing each alternative physical representation.
5. The method of claim 1 , wherein the cost function of the first separate section is determined based on the first quantity of physical qubits and a quantity of cycles used by the first separate section.
6. The method of claim 1 , wherein said selecting comprises determining that the first quantity of physical qubits optimizes the utility per-qubit score of the first separate section while complying with a constraint on the quality score.
7. The method of claim 1 , wherein said synthesizing the circuit according to the first and second quantities of physical qubits is estimated to provide an error rate of the quantum circuit, wherein said selecting is based on a marginal value of an error unit of the error rate.
8. An apparatus comprising a processor and coupled memory, said processor being adapted to:
obtain a logical representation of a quantum circuit, wherein the logical representation comprises a plurality of logical qubits manipulated by a plurality of logical gates; and
generate a physical representation of the quantum circuit, the physical representation is configured to allocate a set of physical qubits of a quantum computer to the plurality of logical qubits in order to implement error correction operations, said generate comprises:
selecting a first quantity of physical qubits from the set of physical qubits for a first separate section of the quantum circuit, wherein said selecting is based on a utility per-qubit metric that is used to define a utility per-qubit score of the first separate section, wherein the utility per-qubit score of the first separate section indicates a utility of each qubit in the first separate section, wherein the utility per-qubit score of the first separate section is determined based on a ratio between a quality score of the first separate section when using the first quantity and between a cost function of the first separate section when using the first quantity, wherein the quality score is defined by a quality metric that is monotonically correlated to error rates of the first separate section;
selecting a second quantity of physical qubits from the set of physical qubits for a second separate section of the quantum circuit, the first and second quantities are different, the first and second separate sections are disjoint sections of the quantum circuit, wherein said selecting is based on a utility per-qubit score of the second separate section that indicates a utility of each qubit in the second separate section, wherein the utility per-qubit score of the second separate section is determined based on a ratio between a quality score of the second separate section when using the second quantity and between a cost function of the second separate section when using the second quantity, wherein the quality score is monotonically correlated to error rates of the second separate section; and
synthesizing the quantum circuit using the first and second quantities for the first and second separate sections, wherein a quantity of the set of physical qubits is greater than a quantity of the plurality of logical qubits.
9. The apparatus of claim 8 , wherein said selecting comprises determining that the first and second quantities optimize values of the utility per-qubit metric for the first and second separate sections, respectively.
10. The apparatus of claim 9 , wherein said optimizing comprises implementing a search algorithm on a plurality of alternative physical representations of the first separate section of the quantum circuit, wherein the first separate section of the quantum circuit is implementable using the plurality of alternative physical representations, wherein each of the plurality of alternative physical representations comprises a different selected quantity of physical qubits for the first separate section, wherein the search algorithm is configured to search for an optimal utility per-qubit score of the first separate section in a solution space that comprises the plurality of alternative physical representations.
11. The apparatus of claim 10 , wherein the quality metric is monotonically correlated to error rates of the first separate section when implementing each alternative physical representation.
12. The apparatus of claim 8 , wherein the cost function of the first separate section is determined based on the first quantity of physical qubits and a quantity of cycles used by the first separate section.
13. The apparatus of claim 8 , wherein said selecting comprises determining that the first quantity of physical qubits optimizes the utility per-qubit score of the first separate section while complying with a constraint on the quality score.
14. The apparatus of claim 8 , wherein said synthesizing the circuit according to the first and second quantities of physical qubits is estimated to provide an error rate of the quantum circuit, wherein said selecting is based on a marginal value of an error unit of the error rate.
15. A computer program product comprising a non-transitory computer readable medium retaining program instructions, which program instructions, when read by a processor, cause the processor to:
obtain a logical representation of a quantum circuit, wherein the logical representation comprises a plurality of logical qubits manipulated by a plurality of logical gates; and
generate a physical representation of the quantum circuit, the physical representation is configured to allocate a set of physical qubits of a quantum computer to the plurality of logical qubits in order to implement error correction operations, said generate comprises:
selecting a first quantity of physical qubits from the set of physical qubits for a first separate section of the quantum circuit, wherein said selecting is based on a utility per-qubit metric that is used to define a utility per-qubit score of the first separate section, wherein the utility per-qubit score of the first separate section indicates a utility of each qubit in the first separate section, wherein the utility per-qubit score of the first separate section is determined based on a ratio between a quality score of the first separate section when using the first quantity and between a cost function of the first separate section when using the first quantity, wherein the quality score is defined by a quality metric that is monotonically correlated to error rates of the first separate section;
selecting a second quantity of physical qubits from the set of physical qubits for a second separate section of the quantum circuit, the first and second quantities are different, the first and second separate sections are disjoint sections of the quantum circuit, wherein said selecting is based on a utility per-qubit score of the second separate section that indicates a utility of each qubit in the second separate section, wherein the utility per-qubit score of the second separate section is determined based on a ratio between a quality score of the second separate section when using the second quantity and between a cost function of the second separate section when using the second quantity, wherein the quality score is monotonically correlated to error rates of the second separate section; and
synthesizing the quantum circuit using the first and second quantities for the first and second separate sections, wherein a quantity of the set of physical qubits is greater than a quantity of the plurality of logical qubits.