2009/02/18 by S. G. Magalhães, S. G. Magalhaes, F. M. Zimmer +3
Physics and Astronomy · #Complex Network Analysis Techniques #Quantum many-body systems #Theoretical and Computational Physics #cond-mat.dis-nn
paper · pdf · doi:10.1016/j.physa.2009.02.028
15 pages, 4 figures, accepted in Physica A
arxiv created 2009/02/18 · openalex publication_date 2009/02/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/02
The stability of spin-glass (SG) phase is analyzed in detail for a fermionic Ising SG (FISG) model in the presence of a magnetic transverse field Γ. The fermionic path integral formalism, replica method and static approach have been used to obtain the thermodynamic potential within one step replica symmetry breaking ansatz. The replica symmetry (RS) results show that the SG phase is always unstable against the replicon. Moreover, the two other eigenvalues λ± of the Hessian matrix (related to the diagonal elements of the replica matrix) can indicate an additional instability to the SG phase, which enhances when Γ is increased. Therefore, this result suggests that the study of the replicon can not be enough to guarantee the RS stability in the present quantum FISG model, especially near the quantum critical point. In particular, the FISG model allows changing the occupation number of sites, so one can get a first order transition when the chemical potential exceeds a certain value. In this region, the replicon and the λ± indicate instability problems for the SG solution close to all range of first order boundary.