[Zurück]


Vorträge und Posterpräsentationen (ohne Tagungsband-Eintrag):

H.-J. Schmiedmayer:
"Sensing magnetic fields with Bose-Einstein-Condensates";
Vortrag: Seminar Institut für Allgemeine Physik (IAP), TU Wien; 14.11.2006.



Kurzfassung englisch:
Bose-Einstein condensates (BECs) can be used as a very sensitive tool for measuring magnetic and electric fields [1]. The basis of our sensor is a trapped highly elongated quasi 1d BEC (1 mm long, 100nm wide) which can be precisely positioned microns above a sample to be probed. The variation of both magnetic and electric fields can be inferred as even slightest inhomogeneities in these fields measurably alter the trapping potentials, and lead to variations in the 1d density of atoms n1d(z). The sensitivity of a BEC to potential variations is given by the chemical potential. The local density of trapped thermal clouds or BECs is imaged in situ by high resolution (3µm) absorption imaging.

In demonstration experiments we have reached a sensitivity to potential variations of ~ 10-14 eV at a spatial resolution of 3µm limited only by the resolution of our imaging system.
For magnetic field measurements this corresponds to a sensitivity of ~ 1 nT.

Other sensors, such as scanning Hall probe microscopes, can attain finer spatial resolution and some others, such as superconducting quantum interference devices (SQUIDs), can attain higher magnetic sensitivity. In the resolution range from 1-10 µm the BEC sensor has orders of magnitude better sensitivity to magnetic field variations. The sensor's nT field sensitivity and micron spatial resolution should make it useful for discovering new solid state and surface physics phenomena.

[1] S.Wildermuth, et al. Nature 435, 440 (2005); Appl. Phys. Lett. 88, 264103 (2006)

Erstellt aus der Publikationsdatenbank der Technischen Universität Wien.