Efficient execution of a quantum program

The method of claim wherein the backward light-cone analysis comprises:

• identifying a third gate that is connected, directly or indirectly, to the gate;
• determining that the third gate is a full impacting gate;
• and
• determining that all inputs to the second gate are potentially affecting the value of the target qubit.

A non-transitory computer readable medium retaining program instructions, wherein the program instructions are configured, when read, to cause a processor to perform:

• determining a target qubit of a quantum program, wherein the quantum program is configured to manipulate a set of qubits using a set of quantum gates, wherein the set of qubits comprises the target qubit, wherein the quantum program is defined to use a predetermined number of gates;
• determining a target cycle;
• performing an impact analysis of the quantum program with respect to a value of the target qubit at the target cycle, wherein the impact analysis comprises identifying at least one quantum gate that does not impact the value of the target qubit at the target cycle, the impact analysis comprises performing a backward light-cone analysis of a gate in the quantum program, wherein the gate is implemented at the target cycle or prior to the target cycle, wherein the gate is configured to affect the value of the qubit, wherein the backward light-cone analysis comprises:
• identifying a second gate that is connected, directly or indirectly, to the gate;
• determining that the second gate is a partial impacting gate;
• and
• determining only a strict subset of inputs to the second gate are potentially affecting the value of the target qubit;
• modifying the quantum program based on the impact analysis, whereby determining a modified quantum program, wherein said modifying comprises removing the at least one quantum gate from the quantum program, wherein the modified quantum program is defined to use a number of gates that is smaller than the predetermined number of gates;
• and
• executing the modified quantum program a plurality of times.

An apparatus comprising a processor and memory unit, wherein the processor is configured to perform:

• determining a target qubit of a quantum program, wherein the quantum program is configured to manipulate a set of qubits using a set of quantum gates, wherein the set of qubits comprises the target qubit, wherein the quantum program is defined to use a predetermined number of gates;
• determining a target cycle;
• performing an impact analysis of the quantum program with respect to a value of the target qubit at the target cycle, wherein the impact analysis comprises identifying at least one quantum gate that does not impact the value of the target qubit at the target cycle, the impact analysis comprises performing a backward light-cone analysis of a gate in the quantum program, wherein the gate is implemented at the target cycle or prior to the target cycle, wherein the gate is configured to affect the vale of the qubit, wherein the backward light-cone analysis to comprises:
• identifying a second gate that is connected, directly or indirectly, to the gate;
• determining that the second gate is a partial impacting gate;
• and
• determining only a strict subset of inputs to the second gate are potentially affecting the value of the target qubit;
• modifying the quantum program based on the impact analysis, whereby determining a modified quantum program, wherein said modifying comprises removing the at least one quantum gate from the quantum program, wherein the modified quantum program is defined to use a number of gates that is smaller than the predetermined number of gates;
• and
• executing the modified quantum program a plurality of times.