Regensburg 2019 – wissenschaftliches Programm
TT 30.6: Vortrag
Dienstag, 2. April 2019, 15:15–15:30, H4
Understanding the Difference between a Hole in the 1D and 2D Antiferromagnet: Crucial Role of Magnon-Magnon Interactions — •Piotr Wrzosek1, Krzysztof Bieniasz2,3, Andrzej Michał Oleś2,4, and Krzysztof Wolhfeld1 — 1Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warsaw, Poland — 2Marian Smoluchowski Institute of Physics, Jagiellonian University, Prof. S. Łojasiewicza 11, PL-30348 Kraków, Poland — 3Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4 — 4Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
We determine the spectral function of a hole for the one-dimensional (1D) Ising t-Jz model using the variational approximation which converges to the exact result with increasing magnon number, however only when the magnon-magnon interactions are properly included. Surprisingly, although the creation of subsequent magnons beyond the first one does not cost any energy, a (modified) self-consistent Born approximation requires also infinite number of magnons to reproduce the exact 1D spectrum. This demonstrates that a single spinon is reproduced by infinite number of magnons. In contrast, in two dimensions magnon-magnon interactions do not change the spectral function qualitatively, explaining why the hole is subject to the string potential, absent in the 1D model.