School Seminars and Colloquia

Susceptibilities and correlation functions of integrable quantum spin chains at finite temperature

Statistical Mechanics/Combinatorics Seminar

by Professor Andreas Klumper

Institution: Wuppertal University, Germany
Date: Wed 15th November 2006
Time: 4:15 PM
Location: Russell Love Theatre, Richard Berry Building, The University of Melbourne

Abstract: The calculation of thermodynamic properties of integrable quantum spin
chains constitutes a problem since many years despite the early successes of the
so-called "thermodynamic Bethe ansatz". Today we know of about three different, however equivalent methods with different merits and drawbacks.

In the talk I will present my favourite method applied to the integrable su(4)
invariant quantum spin chain. The phase diagram will be presented as well as
susceptibilities showing divergencies at critical fields in the
low-temperature limit and logarithmic singularities at the isotropic point.

Time permitting, I'd like to sketch some new ideas and results on the computation of correlation functions for the spin-1/2 Heisenberg chain. The
main observation is the characteristic factorization of multiple-spin correlations into two-spin correlations for arbitrary temperatures and fields (and far from the free fermion point).

For More Information: Dr. Iwan Jensen Phone: +61 3 8344 5214