Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session A24: 2D Frustrated Spin Systems: Shastry Sutherland and Bipartite Lattices
8:00 AM–11:00 AM,
Monday, March 5, 2018
LACC Room: 403A
Sponsoring Units: GMAG DMP
Chair: Vivien Zapf, Los Alamos National Laboratory
Abstract: A24.00009 : The phase diagram of spin-1/2 square J1-J2 Heisenberg model: U(1)-symmetric infinite PEPS study*
10:00 AM–10:12 AM
The tensor-network states have shown to be quite promising in studying the frustrated systems. Specifically, infinite projected entangled-pair state (iPEPS) anstaz, a generalization of powerful DMRG, could efficiently address the low-lying excited states of such systems and provide quite competitive variational energy. In this talk, we aim to introduce an "improved" U(1)-symmetric iPEPS anstaz and study phase diagram of the canonical spin-1/2 square J1-J2 Heisenberg model. We discuss a simple strategy to selects automatically relevant symmetric sectors without losing accuracy and also discuss an improved optimization method. We show variational ground-state energies of the model set better upper bound on the true energy, improving previous tensor-network-based results. By studying magnetization parameter and correlation functions, we find a direct Néel-to-VBS transition at J2=0.53. The estimated critical anomalous exponents ηs=0.65(5) and ηd=1.9(1) show strong deviation from those of the well-known J-Q models, suggesting possibly different universality class. We compare our results with earlier DMRG and PEPS studies and suggest future directions for resolving remaining issues.
*This research is supported by National Science Foundation Grants PREM DMR-1205734 and DMR-1408560.
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