Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 22: Quantum Gases: Bosons III
Q 22.7: Talk
Tuesday, March 7, 2017, 12:30–12:45, P 204
Measuring finite-range phase coherence in an optical lattice using Talbot interferometry — •Christian Baals1,2, Bodhaditya Santra1,4, Ralf Labouvie1,2, Aranya B. Bhattacherjee3, Axel Pelster1, and Herwig Ott1 — 1Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany — 2Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany — 3School of Physical Sciences, Jawaharlal Nehru University, New Delhi-110067, India — 4Zentrum für optische Quantentechnologien, Universität Hamburg, 22761 Hamburg, Germany
The temporal Talbot effect is exploited in our experiment to measure finite-range first-order correlations of a matter-wave field. The working principle relies on the fast blanking of the lattice potential: Upon switching off, the wave-packets at each lattice site expand and interfere with each other. After a variable time, the lattice potential is switched on again resulting in a projection of the time-evolved wave-function onto the potential landscape of the lattice. The additional energy brought into the system becomes observable in an increase of temperature or excitation of atoms into higher energy bands. At integer multiples of the Talbot time, the atomic density distribution shows revivals, where the emerging contrast depends on the phase coherence between the interfering wave packets. Thereby, later revivals correspond to the interference of matter waves from more distant lattice sites. We apply this interferometer to study the build-up of phase coherence after a quantum quench [arXiv:1611.08430].