Efficient Classical Simulation of Resource States for Fusion-Based Quantum Computing

In this presentation we establish a fundamental compatibility between the fusion-based quantum computing (FBQC) paradigm and a classical physical model derived from stochastic electrodynamics (SED) and experimental quantum optics. Our model relies especially on the procedure of extit{field reification}, where the quantum vacuum is modeled as a classical stochastic object and transformed in analogy to dynamical processes in quantum optics, such as squeezing. Using field reification in cooperation with a classical model of a single-photon detector based on energy thresholding, we demonstrate a connection to FBQC via numerical simulations which show good agreement with the predictions of quantum mechanics. We introduce protocols for improving the fidelity and efficiency performance of the classical model when producing FBQC resource states. These protocols describe procedures for sampling from tails of the reified vacuum distribution and modifying the energy-thresholding criteria of the detectors. Our final measurement statistics for the resource states are consistent with resource state generators with a quantum fidelity of 94.7\% and a worst-case classical fidelity of 80.1\% for the four-star and six-ring cluster states respectively. This establishes a fundamental applicability of the model to the simulation and evaluation of fault-tolerant quantum computing systems.