Quantum state of an ideal propagating laser field

Phys Rev Lett. 2002 Jan 14;88(2):027902. doi: 10.1103/PhysRevLett.88.027902. Epub 2001 Dec 26.

Abstract

We give a quantum information-theoretic description of an ideal propagating cw laser field and reinterpret typical quantum-optical experiments in light of this. In particular, we show that, contrary to recent claims [T. Rudolph and B. C. Sanders, Phys. Rev. Lett. 87, 077903 (2001)], a conventional laser can be used for quantum teleportation with continuous variables and for generating continuous-variable entanglement. Optical coherence is not required, but phase coherence is. We also show that coherent states play a privileged role in the description of laser light.