We propose the implementation of a light source, which can deterministically generate a rich variety of multi-mode quantum states. The desired states are encoded in the collective population of different ground hyperfine states of an atomic ensemble and converted to multi-mode photonic states by excitation to optically excited levels followed by cooperative spontaneous emission. Among our examples of applications, we demonstrate how two-photon entangled states can be prepared and implemented in a protocol for reference frame free quantum key distribution and how one-dimensional as well as higher-dimensional cluster states can be produced.
@article{arxiv.1001.1429,
title = {Deterministic multi-mode photonic device for quantum information processing},
author = {Anne E. B. Nielsen and Klaus Mølmer},
journal= {arXiv preprint arXiv:1001.1429},
year = {2010}
}