A scheme, where three atomic ensembles can be prepared in the states of the W-class via Raman type interaction of strong classical field and a projection measurement involved three single-photon detectors and two beamsplitters, are considered. The obtained atomic entanglement consists of the Dicke or W-states of each of the ensembles.
@article{arxiv.quant-ph/0211087,
title = {On preparation of the W-states from atomic ensembles},
author = {V. N. Gorbachev and A. A. Rodichkina and A. I. Trubilko},
journal= {arXiv preprint arXiv:quant-ph/0211087},
year = {2009}
}