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A: Fachverband Atomphysik

A 13: Quantum meets gravity and metrology I

A 13.3: Hauptvortrag

Dienstag, 19. März 2013, 12:00–12:30, E 415

Interferometry with Bose-Einstein condensates in microgravity — •Ernst Rasel — QUEST, Institut für Quantenoptik-Leibniz Universität, Hannover, Germany

A new field in matter wave optics is emerging, which is based on very long baseline atom interferometry (VLBAI). These interferometers strive to increase the sensitivity by coherently spitting and separating wave packets over macroscopic spatial and temporal scales. Bose-Einstein condensates (BECs), representing a textbook example for a macroscopic wave packet, are the ideal source for performing this kind of interferometry and were exploited for the first time in the extended free fall with a chip-based atom laser for Rubidium ⁸⁷Rb. Combining delta kick cooling with BEC we can produce ensembles with energies equal to temperatures falling below one nK. Employing an asymmetric Mach-Zehnder type interferometer we could study over hundreds of milliseconds the coherent evolution of a wave-packet and analyse delta kick cooling with the help of the observed interference fringes. This experiment can be considered as a gigantic double slit experiment in microgravity. A novel generation of atom chips allows to improve the performance of these flexible devices. We could demonstrate loading of the chip with far more than 10⁹ atoms in roughly a second and generate large condensates of more than 100000 atoms, up to now only achievable in room filling devices, in a shoebox sized setup. We discuss as a possible spin-off a chip based quantum gravimeter for ground based applications, recently demonstrated with our device. The design will be employed for a rocket based test of such an interferometer, which will demonstrate the feasibility of satellite based tests of Einsteins principle of equivalence as pursued by the STE-QUEST mission.

The QUANTUS cooperation comprises the group of C. Lämmerzahl (Univ. Bremen), A. Peters (Humboldt Univ. Berlin), T. Hänsch/J.Reichel (MPQ/ENS), K. Sengstock (Univ. Hamburg), R. Walser (TU Darmstadt), and W.P. Schleich (Univ. Ulm).

This project is supported by the German Space Agency Deutsches Zentrum für Luft- und Raumfahrt (DLR) with funds provided by the Federal Ministry of Economics and Technology (BMWI) under grant number DLR 50 WM 0346. We thank the German Research Foundation for funding the Cluster of Excellence QUEST Centre for Quantum Engineering and Space-Time Research