Berlin 2014 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 62: Precision measurements and metrology IV

Q 62.1: Gruppenbericht

Freitag, 21. März 2014, 14:00–14:30, DO24 1.101

States, schemes and detection for quantum atom optics — •Ion Stroescu, Wolfgang Muessel, Daniel Linnemann, Helmut Strobel, Jonas Schulz, David B. Hume, and Markus K. Oberthaler — Kirchhoff-Institut für Physik, Universität Heidelberg, Im Neuenheimer Feld 227, 69120 Heidelberg, Germany

We present our recent advances in creation and detection of quantum states in atomic systems.

We generate spin squeezed states containing more than 10000 Bose condensed atoms by making use of paralleled nonlinear evolution of two component Bose-Einstein condensates in an optical lattice. The access to the on-site properties allows for precise characterization of technical noise sources, which are found to be the only limitation for the scalability of squeezing with atom number.

Moreover, we report on the first experimental implementation of an SU(1,1) interferometer for an atomic system, which uses active beam splitters realized by spin-changing collisions. We measure the phase-dependent output signal for small average atom numbers inside the interferometer (∼1 per side mode) and characterize its phase sensitivity, which is predicted to be at the Heisenberg limit.

Harnessing these resources at the ultimate level requires detection with single-atom resolution. We explore the limits of atom number counting via resonant fluorescence detection, reaching single-particle resolution for atom numbers up to 1200. We also develop a hybrid atom trap capable of simultaneous atom counting for multiple spin states, as required for Heisenberg-limited measurements of spin-entangled atoms.