Patent US 11,699,004

One embodiment described herein provides a system and method for simulating behavior of a quantum circuit that includes a plurality of quantum gates. During operation, the system receives information that represents the quantum circuit and constructs an undirected graph corresponding to the quantum circuit. A respective vertex within the undirected graph corresponds to a distinct variable in a Feynman path integral used for computing amplitude of the quantum circuit, and a respective edge corresponds to one or more quantum gates. The system identifies a vertex within the undirected graph that is coupled to at least two two-qubit quantum gates; simplifies the undirected graph by removing the identified vertex, thereby effectively removing the two-qubit quantum gates coupled to the identified vertex; and evaluates the simplified undirected graph, thereby facilitating simulation of the behavior of the quantum circuit.