Limitations on the quantum non-Gaussian characteristic of Schr\"{o}dinger kitten state generation

Abstract

A quantitative analysis is conducted on the impacts of experimental imperfections in the input state, the detector properties, and their interactions on photon-subtracted squeezed vacuum states in terms of a quantum non-Gaussian character witness and Wigner function. Limitations of the non-classicality and quantum non-Gaussian characteristic of Schr\"{o}dinger kitten states are identified and addressed. The detrimental effects of a photon-number detector on the generation of odd Schr\"{o}dinger kitten state at near-infrared wavelengths ($\sim$ 860 nm) and telecommunication wavelengths ($\sim$ 1550 nm) are presented and analysed. This analysis demonstrates that the high dark count probability of telecommunication-wavelength photon-number detectors significantly undermines the negativity of the Wigner function in Schr\"{o}dinger kitten state generation experiments. For a one-photon-subtracted squeezed vacuum state at $\sim$ 1550 nm, an APD-based photon-number-resolving detector provides no significant advantage over a non-photon-number-resolving detector when imperfections, such as dark count probability and inefficiency, are taken into account.