Cloning of Continuous Quantum Variables
Nicolas J. Cerf, A. Ipe, X. Rottenberg · Physical Review Letters · 2000
The cloning of quantum variables with continuous spectra is analyzed. A Gaussian quantum cloning machine is exhibited that copies equally well the states of two conjugate variables such as position and momentum. It also duplicates all coherent states with a fidelity of 2/3. More generally, the copies are shown to obey a no-cloning Heisenberg-like uncertainty relation.