Geometric potentials in quantum optics: A semi-classical interpretation M. Cheneau, S. P. Rath, T. Yefsah, K. J. Günter, G. Juzeliūnas and J. Dalibard EPL, 83 6 (2008) 60001 Published online: 22 August 2008 DOI: 10.1209/0295-5075/83/60001