Forschergruppe der Leibniz Universität Hannover experimentiert mit Bose-Einstein Kondensaten auf Forschungsrakete Ein Bose-Einstein Kondensat in der Schwerelosigkeit: Erstmals haben deutsche Wissenschaftlerinnen und Wissenschaftler am 23. Januar 2017 unter Federführung der Leibniz Universität Hannover an Bord einer Forschungsrakete Interferenzexperimente mit „gebändigten“ ultrakalten Materiewellen, so genannten Bose-Einstein Kondensaten (BEK), durchgeführt. Hierzu wurden Rubidium-Atome mittels einer Kühlung durch Laserlicht und anderer atom-optischer Methoden in einen extrem niedrigen ...
date: 23. January 2017
date: 14. November 2016
date: 31. August 2016
date: 29. April 2016
We recently published a paper on Lamb-Dicke spectroscopy of the 1S0 - 3P0 transition of magnesium atoms trapped in a magic wavelength optical lattice. The magic wavelength, quadratic magnetic Zeeman shift and transition frequency has been measured to 468.48(21) nm, -206.6(2.0) MHz/T² and 655 058 646 691 (101) kHz respectively.
date: 25. January 2016
Our recent publication on the experimental realization of a continuously replenished reservoir of ultracold atoms has been covered in an overview article of Physics World, the journal of the Bristish physical society IoP. It is also featured at the popular science Website 2physics.org.
date: 06. November 2015
date: 23. October 2015
date: 01. July 2015
Abstract: A comparative analysis of rogue waves in different physical systems comes to the surprising conclusion that these rare events are not completely unpredictable. Metereological events often prove to be rather unpredictable, i.e., the "storm of the century" may well prove to be surpassed by yet another storm just in the subsequent year. From an insurance point of view, resulting damage often proves to be be well beyond any statistical prediction. Such phenomena generally underlie extreme value statistics, featuring a prevalent appearance of extreme events and contrasting ...
date: 10. June 2015
We have recently proposed a very long baseline atom interferometer test of the universality of free fall. In the envisaged experiment, ultracold ensembles of rubidium and ytterbium will be dropped over a vertical free fall distance of 10m and undergo Mach-Zehnder-type atom interferometer geometries. In a first stage, an accuracy in the Eötvös ratio of 7x10-13 will be achieved. We treat the technical realization in the new infrastructure of the Hanover Institute of Technology (HITec) and discuss requirements on the apparatus needed to reach the projected uncertainty. Our ...
date: 07. April 2015
An interaction-free measurement allows for the detection of a classical object - seemingly without any interaction with it. In a recent publication, we demonstrate that this concept can be implemented with ultracold atoms by utilizing the Quantum Zeno Effect in a Bose-Einstein condensate.
date: 05. March 2015
Ultrashort light pulses from modern lasers enable temporal resolution of even the fastest processes in molecules or solid-state materials. For example, chemical reactions can, in principle, be traced down to the 10-fs time scale (1 femtosecond (fs) = 10-15 s). Ten femtoseconds correspond to a few oscillation cycles of the light field itself. Nevertheless, there is a class of optical processes that does not exhibit any measurable delay relative to the ultrafast light oscillation and which has been termed “instantaneous”. This class of processes includes nonlinear optical harmonic generation at ...
date: 11. February 2015
Two major theories exist in modern physics: general relativity, the principle which governs our current understanding of gravity, and quantum mechanics, which explains the nature of extremely tiny objects such as electrons. Unfortunately, they are currently inconsistent with each other. Certain modifications reconcile the two by allowing a violation of the so called universality of free fall, a cornerstone of Einstein’s general relativity. The universality of free fall states: that two bodies will drop at the same rate in a given gravitational field. We have recently performed an ...
date: 22. May 2014
date: 22. April 2014
Random processes in nature often underlie a so-called normal distribution that enables reliable estimation for the appearance of extreme statistical events. Meteorological systems are an exception to this rule, with extreme events appearing at a much higher rate than could be predicted from long-term observation at much lower magnitude. One such example is the appearance of unexpectedly strong storms, yet another are rare reports of waves of extreme height in the ocean, which are also known as rogue waves or monster waves. About 5 years ago, rogue behavior was first reported for propagation ...
date: 03. February 2014
http://prl.aps.org/abstract/PRL/v110/i23/e233901 Researchers from the Leibniz Universität Hannover, the Weierstrass Institute for Applied Analysis and Stochastics as well as the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy have developed a new concept to generate optical white-light pulses in the visible and near infrared. These pulses can be compressed to extremely short pulse duration, comprising only a single oscillation of the optical carrier field. The generation of broadband whitelight supercontinua from spectrally narrow input laser light is one of the most ...
date: 19. July 2013
date: 29. May 2013
date: 09. April 2013
date: 18. July 2012
date: 21. June 2012