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P: Plasmaphysik
P 5: Theory
P 5.3: Talk
Wednesday, April 4, 2001, 16:30–16:45, 2053
Response function for interacting quantum liquids — •Klaus Morawetz1 and Uwe Fuhrmann2 — 1Max-Planck-Institute for the Physics of Complex Systems, Noethnitzer Str. 38, 01187 Dresden, Germany — 2Fachbereich Physik, University Rostock, D-18055 Rostock,Germany
Linearizing the appropriate kinetic equation we derive
general response functions including selfconsistent mean fields or
density functionals and collisional dissipative contributions. The
latter ones are considered in relaxation time approximation conserving
successively different balance equations. We find
that momentum conservation leads exactly to the local field
corrections for both cases respecting only density conservation and
respecting density and energy conservation. This
rewriting simplifies the formulae dramatically. We discuss the
higher order sum rules and small wave vector expansion and
find that the response function shows
a high frequency dependence of ω−5 which allows to fulfill
higher order sum rules. The presented results are applicable to
finite temperature response of interacting quantum systems with
quasiparticle or mean field energies.
We present results for collective modes like the plasmon in plasma
systems and the giant resonance in nuclei. The collisions lead in
general
to an enhanced damping of collective modes. If the collision frequency
is close to the frequency of the collective mode, resonance occurs and
the collective mode is enhanced showing a collisional narrowing.
Phys. Rev. E 62 (2000) 4382: Momentum conservation and local
field corrections for the
response of interacting Fermi gases
K. Morawetz, Uwe Fuhrmann
Phys. Rev. E 61 (2000) 2272-2280: General response function
for interacting quantum liquids,
K. Morawetz, U. Fuhrmann