Wolf, Michael M. Theory, Max Planck Institute of Quantum Optics, Max Planck Society;
Cirac, J. Ignacio Theory, Max Planck Institute of Quantum Optics, Max Planck Society;
Wolf, M. M., & Cirac, J. I. (2008). Dividing Quantum Channels. Communications in Mathematical Physics, 279(1), 147-168. doi:10.1007/s00220-008-0411-y.