We experimentally verify the quantum non-Gaussian character of a conditionally generated noisy squeezed single-photon state with a positive Wigner function. Employing an optimized witness based on probabilities of squeezed vacuum and squeezed single-photon states, we prove that the state cannot be expressed as a mixture of Gaussian states. In our experiment, the non-Gaussian state is generated by conditional subtraction of a single photon from a squeezed vacuum state. The state is probed with a homodyne detector and the witness is determined by averaging a suitable pattern function over the measured homodyne data. Our experimental results are in good agreement with a theoretical fit obtained from a simple yet realistic model of the experimental setup.
Bibliographical note©2012 American Physical Society
Jezek, M., Tipsmark, A., Dong, R., Fiurásek, J., Mista, Jr., L., Filip, R., & Andersen, U. L. (2012). Experimental test of the strongly nonclassical character of a noisy squeezed single-photon state. Physical Review A, 86(4), 043813. https://doi.org/10.1103/PhysRevA.86.043813