1997/01/01 by H. Niggemann, Andreas Klümper, A. Klümper +1 · 5 citations
Physics and Astronomy · #Condensed matter physics #Ground state #Hexagonal lattice #Lattice (music) #Opinion Dynamics and Social Influence #Phase transition #Physics #Quantum many-body systems #Quantum mechanics #Quantum phase transition #Statistical physics #Theoretical and Computational Physics #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1007/s002570050425
published as Z.Phys. B104 (1997) 103-110 · 16 pages, LaTeX 2e, 5 non-embedded figures. 1 figure caption changed
openalex publication_date 1997/01/01 · arxiv created 1997/09/12 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Optimum ground states are constructed in two dimensions by using so called vertex state models. These models are graphical generalizations of the well-known matrix product ground states for spin chains. On the hexagonal lattice we obtain a one-parametric set of ground states for a five-dimensional manifold of S=3/2 Hamiltonians. Correlation functions within these ground states are calculated using Monte-Carlo simulations. In contrast to the one-dimensional situation, these states exhibit a parameter-induced second order phase transition. In the disordered phase, two-spin correlations decay exponentially, but in the Neel ordered phase alternating long-range correlations are dominant. We also show that ground state properties can be obtained from the exact solution of a corresponding free-fermion model for most values of the parameter.