Physics Colloquium - Tight-binding in a new light: Photons in optical lattices

Geneva University
Physics Department

24, Quai Ernest Ansermet
CH-1211 Geneva 4


Lundi 21 mars 2011, 17h00
Ecole de Physique, Auditoire Stueckelberg

Tight-binding in a new light: Photons in optical lattices
Dr. Niels Madsen
Department of Physics, Swansea University, Singleton Park,
Swansea, United Kingdom


Antihydrogen, the bound state of an antiproton and a positron, has been produced at low energies at CERN (the European Organization for Nuclear Research) since 2002. Antihydrogen is of interest for use in a precision test of nature's fundamental symmetries. The charge conjugation/parity/time reversal (CPT) theorem, a crucial part of the foundation of the standard model of elementary particles and interactions, demands that hydrogen and antihydrogen have the same spectrum. Given the current experimental precision of measurements on the hydrogen atom, subjecting antihydrogen to rigorous spectroscopic examination would constitute a compelling, model-independent test of CPT. Antihydrogen could also be used to study the gravitational behaviour of antimatter.

However, until recently, experiments have produced antihydrogen that was not confined, precluding detailed study of its structure. Experimenters working to trap antihydrogen have faced the challenge of trapping and cooling relativistic antiprotons and use them to make antihydrogen cold enough to be trapped in a magnetic minimum trap with a depth of only 50 µV. In November 2010 the ALPHA collaboration demonstrated the first trapping of antihydrogen thus opening the door to precision measurements on anti-atoms, which can soon be subjected to many of the same techniques as developed for atoms.

In this talk I will show how we succeeded in observing the release of trapped antihydrogen from our magnetic trap and how some of the key challenges faced to reach this milestone were met.

A drink with Dr. Niels Madsen will be held after the Colloquium.

Prof. Markus Büttiker


by Ecole de Physique - Université de Genève