2005/05/20 by Eduardo M. M. Santos, Eduardo Muccillo Monteiro Santos, Alba Theumann · 1 citation
Physics and Astronomy · #Complex Network Analysis Techniques #Quantum many-body systems #Theoretical and Computational Physics #cond-mat.dis-nn
paper · pdf · doi:10.1103/physrevb.72.014447
16 pages, 4 figures. to appear in Physical Review B
arxiv created 2005/05/20 · openalex publication_date 2005/07/19 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
We analyze the infinite range Ising spin glass in a transverse-field \ensuremathΓ below the critical temperature by a one step replica symmetry breaking theory. The set of n replicas is divided in r blocks of m replicas each. We present results for different values of the block-size parameter m. The spin operators are represented by bilinear combinations of fermionic fields and we compare the results of two models: In the four-states (4-S) model the diagonal Siz operator has two unphysical vanishing eigenvalues, that are suppressed by a restraint in the two-states (2-S) model. In the static approximation we obtain qualitatively similar results for both models. They both exhibit a critical temperature Tc(\ensuremathΓ) that decreases when \ensuremathΓ increases, until it reaches a quantum critical point at the same value of \ensuremathΓc and they are both unstable under replica symmetry breaking in the whole spin glass phase. Below the critical temperature we present results for the order parameters and free energy.