We implement the squeezing operation as a genuine quantum gate, deterministically and reversibly acting `online upon an input state no longer restricted to the set of Gaussian states. More specifically, by applying an efficient and robust squeezing o
peration for the first time to non-Gaussian states, we demonstrate a two-way conversion between a particle-like single-photon state and a wave-like superposition of coherent states. Our squeezing gate is reliable enough to preserve the negativities of the corresponding Wigner functions. This demonstration represents an important and necessary step towards hybridizing discrete and continuous quantum protocols.
