We propose a high-rate generation method of optical Schr\"{o}dinger's cat states. Thus far, photon subtraction from squeezed vacuum states has been a standard method in cat-state generation, but its constraints on experimental parameters limit the generation rate. In this paper, we consider the state generation by photon number measurement in one mode of arbitrary two-mode Gaussian states, which is a generalization of conventional photon subtraction, and derive the conditions to generate high-fidelity and large-amplitude cat states. Our method relaxes the constraints on experimental parameters, allowing us to optimize them and attain a high generation rate. Supposing realistic experimental conditions, the generation rate of cat states with large amplitudes (∣α∣≥2) can exceed megacounts per second, about 103 to 106 times better than typical rates of conventional photon subtraction. This rate would be improved further by the progress of related technologies. Ability to generate non-Gaussian states at a high rate is important in quantum computing using optical continuous variables, where scalable computing platforms have been demonstrated but preparation of non-Gaussian states of light remains as a challenging task. Our proposal reduces the difficulty of the state preparation and open a way for practical applications in quantum optics.
@article{arxiv.2009.08580,
title = {Generation of optical Schr\"{o}dinger's cat states by generalized photon subtraction},
author = {Kan Takase and Jun-ichi Yoshikawa and Warit Asavanant and Mamoru Endo and Akira Furusawa},
journal= {arXiv preprint arXiv:2009.08580},
year = {2022}
}