Variational tensor network simulation of Gaussian boson sampling and beyond
Phys. Rev. A 112, 022605 – Published 6 August, 2025
DOI: https://doi.org/10.1103/z463-7gqy
Abstract
The continuous variable quantum computing platform constitutes a promising candidate for realizing quantum advantage, as exemplified in Gaussian boson sampling. While noise in the experiments makes the computation attainable for classical simulations, it has been suggested that the addition of nonlinear elements to the experiment will help retain the quantum advantage. We propose a classical simulation tool for general continuous variable sampling problems, including Gaussian boson sampling and beyond. We reformulate the sampling problem as that of finding the ground state of a simple few-body Hamiltonian. This allows us to employ powerful variational methods based on tensor networks and to read off the simulation error directly from the expectation value of the Hamiltonian. We validate our method by simulating Gaussian boson sampling, where we achieve results comparable to the state of the art. We also consider a non-Gaussian sampling problem, for which we develop alternative local basis optimization techniques based on a nonlinear parametrization of the implicit basis, resulting in high effective cutoffs with diminished computational overhead.