We propose a scheme allowing a conditional implementation of suitably truncated general single- or multi-mode operators acting on states of traveling optical signal modes. The scheme solely relies on single-photon and coherent states and applies beam splitters and zero- and single-photon detections. The signal flow of the setup resembles that of a multi-mode quantum teleportation scheme thus allowing the individual signal modes to be spatially separated from each other. Some examples such as the realization of cross-Kerr nonlinearities, multi-mode mirrors, and the preparation of multi-photon entangled states are considered.
@article{arxiv.quant-ph/0303004,
title = {Linear optics substituting scheme for multi-mode operations},
author = {J. Clausen and L. Knoell and D. -G. Welsch},
journal= {arXiv preprint arXiv:quant-ph/0303004},
year = {2016}
}