Retargetable compilation for quantum computing systems
A compiler translates programs for execution on a quantum processing system. To facilitate portability of quantum programs across differently configured quantum processors, the compiler accepts a specification of the quantum processor as input along with a quantum program for compilation. A specification may include information about the type of each qubit device in the quantum processor, the number of qubits, the qubit topology, coherence times of individual qubits, and operations that the quantum processor supports. The compilation process may include manipulating operations of the input program to generate equivalent operations that can be performed by the quantum gates and qubit devices on the quantum processor for which the program is being compiled.
1. A computer-implemented method for compiling a quantum program for execution on a quantum processing system, the method comprising:
receiving the quantum program;
receiving, separately from the quantum program, a specification comprising a description of a hardware configuration of the quantum processing system, and calibration information about the current state of the quantum processing system; and
compiling the quantum program, by a computer processor, using the specification, to generate executable instructions in a target language for executing on the quantum processing system to perform operations described in the quantum program.
2. The computer-implemented method of claim 1 , further comprising executing the generated executable instructions on the quantum processing system.
3. The computer-implemented method of claim 1 , wherein the specification comprises identification of types of qubit devices included in the quantum processing system.
4. The computer-implemented method of claim 1 , wherein the specification comprises a number of qubit devices included in the quantum processing system.
5. The computer-implemented method of claim 1 , wherein the specification comprises a description of a topology of the qubit devices included in the quantum processing system.
6. The computer-implemented method of claim 1 , wherein the specification comprises a set of quantum operations that can be executed by the quantum processing system.
7. The computer-implemented method of claim 1 , wherein compiling the quantum program further comprises:
identifying a sequence of applications of quantum gates defined by the program;
determining that the existing configuration of the quantum processing system includes quantum gates that can carry out an equivalent or near equivalent sequence of applications of quantum gates; and
determining an equivalent or near equivalent sequence of quantum gates that can be applied to the qubit devices of the quantum processing system.
8. The computer-implemented method of claim 1 , wherein compiling the quantum program further comprises:
identifying operations in the program that involve interactions between non-adjacent qubit devices; and
generating instructions for routing qubit states between devices such that the qubit states from the non-adjacent qubit devices are transferred to adjacent qubit devices.
9. The computer-implemented method of claim 1 , wherein compiling the quantum program further comprises:
assigning operations to qubit devices giving priority to qubit devices with longer coherence times.
10. The computer-implemented method of claim 1 , wherein compiling the quantum program further comprises:
generating, for each qubit device on the quantum processing system, a schedule of operations for execution.
11. The computer-implemented method of claim 1 , wherein compiling the quantum program further comprises:
assigning operations to gates giving priority to gates with higher gate fidelities.
12. A quantum cloud system comprising:
one or more computer processors for executing computer program instructions; and
a non-transitory computer-readable storage medium storing instructions executable to compile a quantum program for execution on a quantum processing system, the instructions, when executed, causing the one or more processors to:
receive the quantum program;
receive, separately from the quantum program, a specification comprising a description of a hardware configuration of the quantum processing system, and calibration information about the current state of the quantum processing system; and
compile the quantum program, using the specification, to generate executable instructions in a target language for executing on the quantum processing system to perform operations described in the quantum program.
13. The system of claim 12 , the instructions, when executed, further causing the one or more processors to execute the generated executable instructions in a target language on the quantum processing system.
14. The system of claim 12 , wherein the specification comprises identification of types of qubit devices included in the quantum processing system.
15. The system of claim 12 , wherein the specification comprises a number of qubit devices included in the quantum processing system.
16. The system of claim 12 , wherein the specification comprises a description of the topology of the qubit devices included in the quantum processing system.
17. The system of claim 12 , wherein the specification comprises a set of quantum operations that can be executed by the quantum processing system.
18. The system of claim 12 , wherein instructions that, when executed, cause the one or more processors to compile the quantum program further include instructions that, when executed, cause the one or more processors to:
identify a sequence of applications of quantum gates defined by the program;
determine that the existing configuration of the quantum processing system includes quantum gates that can carry out an equivalent sequence of applications of quantum gates; and
determine an equivalent or near equivalent sequence of quantum gates that can be applied to the qubit devices of the quantum processing system.
19. The system of claim 12 , wherein instructions that, when executed, cause the one or more processors to compile the quantum program further includes instructions that, when executed, cause the one or more processors to:
identify operations in the program that involve interactions between non-adjacent qubit devices; and
generate instructions for routing qubit states between devices such that the qubit states from the non-adjacent qubit devices are transferred to adjacent qubit devices.
20. The system of claim 12 , wherein instructions that, when executed, cause the one or more processors to compile the quantum program further includes instructions that, when executed, cause the one or more processors to:
assign operations to qubit devices giving priority to qubit devices with longer coherence times.