Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 65: Quantum-Critical Phenomena II

TT 65.4: Vortrag

Mittwoch, 14. März 2018, 15:45–16:00, HFT-FT 131

Tricriticality in the spin-1 XXZ chain with explicit bond dimerization — •Satoshi Ejima¹, Tomoki Yamaguchi², Florian Lange¹, Yukinori Ohta², and Holger Fehske¹ — ¹Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany — ²Department of Physics, Chiba University, Chiba 263-8522, Japan

Applying the matrix-product-state based density-matrix renormalization group technique to the spin-1 XXZ chain with bond dimerization, we explore the competition between two different symmetry-protected-topological phases, Peierls and Haldane states. The bond dimerization narrows the Haldane phase, and only dimerized and Néel state survive for large dimerization. The critical line between these two states exhibits the continuous Ising transition with central charge c=1/2, which terminates at a tricritical point, belonging to the universality class of the dilute Ising model with central charge c=7/10. Above this point, the quantum phase transition becomes first order. We provide compelling evidence for the (tricritical) Ising quantum phase transition, simulating corresponding critical exponents, β=1/8 (1/24) and ν=1 (5/9).