Regensburg 1998 – wissenschaftliches Programm

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AM: Magnetismus

AM 11: Postersitzung

AM 11.6: Poster

Dienstag, 24. März 1998, 16:15–20:00, B

Distribution density of the local minima overlaps for various magnetic glasses — •D.V. Berkov — INNOVENT e.V., Goeschwitzer Str. 22, D-07745 Jena, Germany

The overlap distribution density P(q) of various thermodynamic states for spin glasses is of a great interest mainly due to the Parisi solution [1] predicting that for the Sherrington-Kirkpatrick model P(q) is non-self-averaging and contains in addition to the two δ-functions a continuous component. On the other hand, there exist quite strong general arguments [2] that for any realistic spin glass model P(q) is self-averaging.
We have calculated the overlap distribution density of the local energy minima for several ’continuous’ spin glass models: Heisenberg-, RKKI- and dipolar glasses. The overlap distribution was obtained by generating a large number of local minima starting from various initial spin configurations and calculating their mutual overlaps. The overlap distribution obtained this way is supposed to represent the corresponding distribution of the system pure states in the limit of zero temperature if the entropies of various local minima are comparable. For all models the overlap distribution density was found to be self-averaging. Moreover, the finite size scaling of our results indicates that in the thermodynamic limit these distribution densities are single δ-functions at q=0.

[1] G.Parisi, Phys. Rev. Lett., 43, 1754 (1979)

[2] C.M.Newmann, Phys. Rev. Lett., 76, 515 (1996)