Form factor approach to the correlation functions of the integrable models.
Nikolai Kitanine (University of Bourgogne)
Friday 8th April, 2011 13:00-14:00 515
Computation of the correlation functions is a central problem in the field of quantum integrable models. It is crucial for effective applications of these models in the condensed matter physics (the associated dynamical structure factors are measurable quantities), but also for better understanding of more fundamental questions about the one-dimensional exactly solvable quantum systems. We study the asymptotic behavior of the correlation functions of the XXZ spin chain in the massless regime. For the equal-time two-point functions the asymptotic expressions can be obtained through the analysis of the form factors, using a simple but very non-trivial identity for hypergeometric series. The main attention will be drawn to the results for the correlation amplitudes and their expressions in terms of some special form factors. It will be shown that these results are quite general and can be easily generalized for a very large class of massless quantum integrable systems.