Münster 1999 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Dynamik und Statistische Physik
DY 20: POSTER I
DY 20.7: Poster
Dienstag, 23. März 1999, 09:30–13:00, F
Θ-point behavior of diluted polymer solutions: can one observe the universal logarithmic corrections predicted by field theory? — •Johannes Hager and Lothar Schäfer — Universität-Gesamthochschule-Essen, 45117 Essen, Germany
In recent large scale Monte-Carlo simulations
of various models of Θ-point polymers
in three dimensions Grassberger and Hegger [1] found
logarithmic corrections to mean field theory with amplitudes
much larger than the universal amplitudes of the
leading logarithmic corrections
calculated by Duplantier [2] in the framework of
tricritical O(n) field theory.
To resolve this issue we calculate the universal sub leading
correction of field theory, which turns out to be of the
same magnitude as the leading correction for all
chain lengths available in present days simulations.
Furthermore we present results of Monte-Carlo simulations
on a Domb-Joyce like model of weakly interacting random walks,
which show much smaller corrections than [1], indicating
that the effective corrections of [1] are not yet
in the asymptotic regime. All together our findings show
that the existing simulations of Θ-polymers can be
explained within the framework
of tricritical field theory
invoking a very slow crossover to
the asymptotic regime as was found earlier for self avoiding
walks at their upper critical
dimension dc=4.
[1] P. Grassberger, Phys. Rev.
E 56 , 3682, (1997)
[2] B. Duplantier, J. Chem. Phys. 30, 4233, (1987)