Parts | Days | Selection | Search | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 11: Quanteneffekte (QED)
Q 11.6: Talk
Monday, March 19, 2007, 15:30–15:45, 5E
Temperature dependence of the Casimir-vdWaals potential — •Lodewijk Arntzen — arntzen@physi.uni-heidelberg.de
The temperature dependence of the Casimir-vdWaals potential will be discussed. For the system He-Si, the Casimir-vdWaals potential is explicitly calculated using a model for the polarizability of the helium atom, and a model for the dielectric function of silicon. Experimental access is obtained with the Atomic Beam Spin Echo (ABSE) spectrometer by quantum reflecting cold 3He atoms from a Si(111) surface. The temperature of the surface is varied between 300K and 1200K. It is found that the quantum reflectivity drops approximately with a factor 3 in this temperature range. It is shown that a potential term proportional to T and r−3 is needed to describe the data, and its value is compared with the zero frequency term from the Lifshitz theory.