Berlin 2005 – wissenschaftliches Programm

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VA: Vakuumphysik und Vakuumtechnik

VA 2: Quanten, Neutronen und Positronen

VA 2.1: Hauptvortrag

Montag, 7. März 2005, 10:40–11:20, TU E20

Lots of whirl about the vacuum? A quantitative experiment on the Casimir force. — •Maarten DeKieviet — Physikalisches Institut, Universität Heidelberg, 69120 Heidelberg

The existence of electromagnetic vacuum fluctuations manifests itself most impressively in the Casimir force, a stochastic and feeble force, so hard to measure properly, that it was considered to be solely of academic interest for a long time. With the current revolution in nano-technology, however, there is a rising, yet even economic need for a quantitative understanding.

I will present an experiment, in which the Casimir-Polder force between a single atom and the surface of a solid was determined quantitatively. It is based on the Atomic Beam Spin Echo method, developed in Heidelberg. This technique will be introduced and its high resolving power shown in some simple scattering experiments. Subsequently, I will discuss the physical origin of the phenomenon of quantum reflection and show that it depends very sensitively on the long-range details of the attractive atom-surface interaction. Utilizing quantum reflection as a tool, we have been able to identify the C4- (Casimir) and C3-branches (van der Waals) for different types of surfaces.

Theoretical relevance of these experiments is addressed in particular with respect to temperature dependency and non-Newtonian gravity. Finally, I will discuss how we may put the quantum field to work by specifically modifying the Casimir interaction through the nano-crafting of surfaces.