We describe the effect of replica symmetry breaking in the field distribution function P (h) of the T = 0 SK-model as the difference between a split Gaussian and the first excited state ψ1 of a weakly anharmonic oscillator with nonanalytic shift by means of the analogy P (h) ↔ |ψ 1 (x)|.New numerical calculations of the leading 100 orders of replica symmetry breaking (RSB) were performed in order to obtain P (h), employing the exact mapping between density of states ρ(E) of the fermionic SK-model and P (h) of the standard model, as derived by Perez-Castillo and Sherrington. Fast convergence towards a fixed point function ρ(E) for infinite steps of RSB is observed. A surprisingly small number of harmonic oscillator wave-functions suffices to represent this fixed point function. This allows to determine an anharmonic potential V (x) with nonanalytic shift, whose first excited state represents ρ(E) and hence P (h). The harmonic potential with unconventional shift V2(x) ∼ (|x| − x0) 2 = (x − x0 sign(x)) 2 yields already a very good approximation, since anharmonic couplings of V (x) − V2(x) ∼ |x| m , m > 2, decay rapidly with increasing m.We compare the pseudogap-forming effect of replica symmetry breaking, hosted by the fermionic SK-model, with the analogous effect in the Coulomb glass as designed by Davies-Lee-Rice and described by Müller-Pankov.PACS numbers:
I. INTRODUCTIONThe Sherrington-Kirkpatrick (SK-) model 1 has been an extraordinary stimulating source for analytical and numerical studies in the physics of frustrated magnetism and in numerous interdisciplinary applications. Many relevant properties of the SK-model have been explored since its discovery 2-6 .Near the zero temperature limit and at T = 0, the model displays rather simple features but also analytically still unresolved behavior, and therefore remains challenging in our point of view.Along a particular line of theoretical analysis, on which the present article evolves, we searched for explicit analytical solutions deep in the ordered phase and particularly at zero temperature. The limit of zero temperature was recently described to accommodate two critical points related to the criticality of the hierarchical scheme of replica symmetry breaking (RSB) hosted by the SK-model 7-10 . In order to reveal this type of criticality, the finite-step discrete-RSB was utilized. Extreme high order calculations up to 200 orders and Padé-approximants allowed to analyze the limit towards infinite breaking analyzed by means of high-precision numerical work, renormalization group ideas, and scaling theory in addition. 7-10 . The scaling theory allowed to resolve the puzzle of noncommuting zero temperature limit and infinite-step limit of replica symmetry breaking 10 .In this article we present new numerical calculations which led us to a surprisingly simple modeling of the distribution of internal magnetic fields.Pioneering work on this local magnetic field distribution by Thomsen et al 4 presented various analytical limits and numerical studies (TAP theory, simula...