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SYDC: Symposium Decoherence in the light of modern experiments

SYDC 1: Decoherence in the Light of Modern Experiments I

SYDC 1.4: Hauptvortrag

Dienstag, 9. März 2010, 15:30–16:00, E 415

Decoherence of free electron waves and visualization of the transition from quantum- to classical-behaviour — •Franz Hasselbach — Institut für Angewandte Physik der Universität Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany

Controlled decoherence of free electron waves due to Coulomb interaction with a truly macroscopic, dissipative environment (namely: the electron and phonon gas inside a semiconducting plate of 10mm in length) is studied experimentally by electron biprism interferometry. The electron is one of the most elementary particles, and due to the absence of magnetic fields in the setup, spin is irrelevant. Consequently, no inner degrees freedom can be excited and entangled with the center of mass coordinates. Decoherence is exclusively caused by electromagnetic interaction through irreversible deposition of energy into the environment. In the experiment, two parameters are varied, the height of the coherent electron waves above the plate and, in this plane the lateral distance between the coherent beams. The experiment confirms the main features of the theory of decoherence and can be interpreted in terms of which-path information. The quantitative results are compared with different theoretical models. In contrast to previous model experiments on decoherence, the obtained interferograms directly visualize the transition from quantum- to classical-behaviour.