Boson Sampling on a Photonic Chip

TLDR

Universal quantum computers promise exponential speedups for problems such as factoring, but their construction challenges motivate simpler, problem‑specific algorithms that still offer quantum speedup. The study constructs a quantum boson sampling machine to sample the output distribution of nonclassical photon interference in an integrated photonic circuit, a problem believed to be exponentially hard classically. Boson sampling requires only indistinguishable photons, linear evolution, and detectors, and the authors benchmarked their QBSM with three and four photons while analyzing sampling inaccuracies. The results pave the way for larger devices that could provide the first definitive quantum‑enhanced computation.

Abstract

While universal quantum computers ideally solve problems such as factoring integers exponentially more efficiently than classical machines, the formidable challenges in building such devices motivate the demonstration of simpler, problem-specific algorithms that still promise a quantum speedup. We construct a quantum boson sampling machine (QBSM) to sample the output distribution resulting from the nonclassical interference of photons in an integrated photonic circuit, a problem thought to be exponentially hard to solve classically. Unlike universal quantum computation, boson sampling merely requires indistinguishable photons, linear state evolution, and detectors. We benchmark our QBSM with three and four photons and analyze sources of sampling inaccuracy. Our studies pave the way to larger devices that could offer the first definitive quantum-enhanced computation.