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MP: Theoretische und Mathematische Grundlagen der Physik

MP 11: Quantengravitation 2 und Quantisierungsmethoden 2

MP 11.2: Vortrag

Donnerstag, 30. März 2006, 15:00–15:30, HG2-HS4

On the quantum back-reaction problem — •Ralf Schuetzhold¹, Michael Uhlmann¹, Yan Xu¹, and Uwe Fischer² — ¹Institut fuer Theoretische Physik, Technische Universitaet Dresden, D-01062 Dresden — ²Eberhard-Karls-Universitaet Tuebingen, Institut fuer Theoretische Physik, Auf der Morgenstelle 14, D-72076 Tuebingen

For many physical systems which can be approximated by a classical background field plus small (linearized) quantum fluctuations, a fundamental question concerns the correct description of the back-reaction of the quantum fluctuations onto the dynamics of the classical background. We investigate this problem for the example of dilute atomic/molecular Bose-Einstein condensates, for which the microscopic dynamical behavior is under control. It turns out that the effective-action technique does not yield the correct result in general and that the knowledge of the pseudo-energy-momentum tensor ${∖langle∖hat T_{∖mu∖nu}∖rangle}$ is not sufficient to describe quantum back-reaction.