TY  - GEN
Y1  - 2010///
ID  - heidok10626
KW  - Verschränkung 
KW  -  Kollektiver Spin 
KW  -  Nichtlineare Interferometrienonlinear interferometry 
KW  -  Bose-Einstein condensation 
KW  -  collective spin 
KW  -  spin squeezed state
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/10626/
N2  - Interferometry is the most precise measurement technique known today. It is based on interference and therefore on the wave-like nature of the resources ? photons or atoms ? in the interferometer. As given by the laws of quantum mechanics the granular, particle-like features of the individually independent atoms or photons are responsible for the precision limit ? the shot noise limit. However this ?classical? bound is not fundamental and it is the aim of quantum metrology to overcome it by employing quantum correlations ? entanglement ? among the particles. We report on the realization of spin squeezed states suitable for atom interferometry based on two external modes of a Bose-Einstein condensate. We detect manybody entangled states which allow ? in principle ? for a precision gain of 35% over the shot noise limit in atom interferometry. We demonstrate a novel non-linear atom interferometer for Bose-Einstein condensates whose linear analog ? the Ramsey interferometer ? is used for the definition of the time standard. Within the non-linear interferometer we detect a large entangled state of 170 inseparable atoms. A measurement with this interferometer outperforms its ideal linear analog by 15% in phase estimation precision showing directly the feasibility of non-linear atom interferometry with Bose-Einstein condensates beyond ?classical? precision limits.
TI  - Spin squeezing and non-linear atom interferometry with Bose-Einstein condensates
A1  - Groß, Christian
ER  -