Abstract
Disentanglement of a laser source from its target qubit is proposed as a criterion establishing the laser quantum state as a coherent state. It is shown that the source-target density operator has a unique factorization in coherent states when the environmental record monitoring laser pump quanta is ignored. The source-target state conditioned upon the complete environmental record is entangled, though, as a state of known total quanta number (source plus target).
| Original language | English |
|---|---|
| Article number | 120405 |
| Journal | Physical Review Letters |
| Volume | 100 |
| Issue number | 12 |
| DOIs | |
| State | Published - 27 Mar 2008 |