Heidelberg 2015 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 27: Quantum Gases: Bosons IV

Q 27.1: Talk

Tuesday, March 24, 2015, 14:30–14:45, P/H2

Non-destructive detection of a BEC phase transition — •Romain Müller, Robert Heck, Aske Thorsen, Mario Napolitano, Mark Bason, Jan Arlt, and Jacob Sherson — Aarhus Universitet, Ny Munkegade 120, 8000 Aarhus Denmark

Quantum non-demolishing (QND) measurements of atomic ensembles- both at room and (ultra-)cold temperatures - have over the past decade proven to be a versatile tool for quantum information processing.

We have recently demonstrated that a QND variant, dark field Faraday imaging, is a valuable and simple tool for single shot characterization of experimental parameters such as trap frequencies and the ambient vector magnetic field [1]. In this work we expand these efforts to the domain of single shot characterization of quantum phase transitions; explicitly the transition from a thermal cloud to a BEC. This has previously been investigated phenomenologically in a single experiment [2] in which a series of in-situ pictures of the cloud allowed for the observation of the formation of the condensate. Since observation with high signal to noise is inherently associated with heating [1], it is crucial to have a detailed understanding of the destructivity imparted by the 'non-destructive' probing. This tradeoff is investigated in this work and we make a detailed comparison with the shape of the phase transition inferred using destructive TOF probing.

[1] Gajdacz et al., Rev. Sci. Instrum. 84, 083105 (2013)

[2] Miesner et al., Science, Vol. 279 no. 5353 pp. 1005-1007 (1998)