2025/05/27 by Vojtěch Kala, Kala, Vojtěch, Breum, Casper A. +5 · 2 citations
Computer Science · Physics and Astronomy · #Quantum Information and Cryptography #Cold Atom Physics and Bose-Einstein Condensates #Mechanical and Optical Resonators
paper · pdf · doi:10.48550/arxiv.2505.21066
In continuous variable optical platforms, large-scale Gaussian cluster states have already been demonstrated, but non-Gaussian resources are essential to achieve universality and fault tolerance in measurement-based quantum computation. However, characterizing and certifying non-Gaussian cluster states remains an outstanding challenge. Here, we introduce a general framework for the characterization of non-Gaussian cluster states based on non-Gaussian nullifiers, extending the widely used Gaussian nullifier concept. We show that these nullifiers can be directly evaluated from homodyne measurement data, making them experimentally accessible. As an illustration, we derive and experimentally demonstrate non-Gaussian nullifiers for photon-subtracted squeezed states. Our results provide a practical and operational tool for certifying quantum non-Gaussianity in large-scale optical cluster states.