Compiling quantum programs

An apparatus comprising a processor and coupled memory, the processor being adapted to:

• obtain a quantum program comprising a first quantum function and a second quantum function;
• obtain a first function-specific synthesis module that is configured to synthesize an implementation of the first quantum function;
• obtain a first function-specific propagator module that is configured to implement variable assignment propagation with respect to an implementation of the first quantum function as generated by the first function-specific synthesis module;
• obtain a second function-specific synthesis module that is configured to synthesize an implementation of the second quantum function;
• obtain a second function-specific propagator module that is configured to implement variable assignment propagation with respect to an implementation of the second quantum function as generated by the second function-specific synthesis module;
• generate a constraint problem representing implementations of the quantum program, the constraint problem comprising at least a first constraint associated with the first quantum function and a second constraint associated with the second quantum function;
• implement a Maintain Arc Consistency (MAC) algorithm to determine a solution to the constraint problem, wherein said implementing the MAC algorithm comprises utilizing the first function-specific propagator module and the second function-specific propagator module;
• and
• synthesize a quantum circuit that implements the quantum program, the quantum circuit comprising a first portion representing the first quantum function and a second portion representing the second quantum function, wherein said synthesizing comprises utilizing the first function-specific synthesis module to generate the first portion of the quantum circuit and utilizing the second function-specific synthesis module to generate the second portion of the quantum circuit.

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 quantum program comprising a first quantum function and a second quantum function;
• obtain a first function-specific synthesis module that is configured to synthesize an implementation of the first quantum function;
• obtain a first function-specific propagator module that is configured to implement variable assignment propagation with respect to an implementation of the first quantum function as generated by the first function-specific synthesis module;
• obtain a second function-specific synthesis module that is configured to synthesize an implementation of the second quantum function;
• obtain a second function-specific propagator module that is configured to implement variable assignment propagation with respect to an implementation of the second quantum function as generated by the second function-specific synthesis module;
• generate a constraint problem representing implementations of the quantum program, the constraint problem comprising at least a first constraint associated with the first quantum function and a second constraint associated with the second quantum function;
• implement a Maintain Arc Consistency (MAC) algorithm to determine a solution to the constraint problem, wherein said implementing the MAC algorithm comprises utilizing the first function-specific propagator module and the second function-specific propagator module;
• and
• synthesize a quantum circuit that implements the quantum program, the quantum circuit comprising a first portion representing the first quantum function and a second portion representing the second quantum function, wherein said synthesizing comprises utilizing the first function-specific synthesis module to generate the first portion of the quantum circuit and utilizing the second function-specific synthesis module to generate the second portion of the quantum circuit.