Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 16: Correlated Electrons: Low-dimensional Systems - Models 2
TT 16.2: Vortrag
Dienstag, 27. März 2012, 09:45–10:00, H 0104
Accurate determination of the Gaussian transition in spin-1 chains with single-ion anisotropy — •Shijie Hu1,2, Bruce Normand1, Xiaoqun Wang1, and Lu Yu3 — 1Department of Physics, Renmin University of China, Beijing 100872, China — 2Institut fuer Theoretische Physik, Georg-August-Universitaet Goettingen, 37077 Goettingen, Germany — 3Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
The Gaussian transition in the spin-one Heisenberg chain with single-ion anisotropy is extremely difficult to treat, both analytically and numerically. We introduce an improved DMRG procedure with strict error control, which we use to access very large systems. By considering the bulk entropy, we determine the Gaussian transition point to 4-digit accuracy, Dc/J = 0.96845(8), resolving a long-standing debate in quantum magnetism. With this value, we obtain high-precision data for the critical behavior of quantities including the ground-state energy, gap, and transverse string-order parameter, and for the critical exponent, ν = 1.472(2). Applying our improved technique at Jz = 0.5 highlights essential differences in critical behavior along the Gaussian transition line.