Nonunity gain quantum nondemolition measurements based on measurement and repreparation.
We demonstrate experimentally a nonunity gain quantum nondemolition measurement based on a simple homodyne measurement and recreation strategy. Although the output state is an amplified version of the input state, the device meets standard criteria for QND measurements: the transfer coefficient was measured to 1.78, and the conditional variance was measured to 0.66.
Schneider
Jessica
J
Institut für Optik, Information und Photonik, Max-Plank Forschungsgruppe, Universität Erlangen-Nürnberg, Günther-Scharowsky-Strasse, Erlangen, Germany. schneider@kerr.physik.uni-erlangen.de
Glöckl
Oliver
O
Leuchs
Gerd
G
Andersen
Ulrik L
UL