Digital quantum simulations of Hong-Ou-Mandel interference

Quantum computers can efficiently simulate quantum systems evolving according to local interactions, making them valuable for exploring quantum many-body dynamics, despite current hardware and algorithmic challenges. In this work, we address the digital quantum simulations of linear optical elements which are inherently bosonic quantum systems. We adopt an encoding scheme based on Gray code to map bosonic states to qubits, which is efficient in terms of qubits and gate counts. Using a beam splitter as a representative example, we demonstrate the construction of quantum algorithms to simulate linear optical elements in quantum computers. To validate our algorithm, we performed a digital quantum simulation of the Hong-Ou-Mandel interference, a two-photon experiment. Our simulations, conducted both in quantum simulators and IBM quantum hardwares, successfully reproduced the characteristics of Hong-Ou-Mandel interference, validating our approach.