Abstract:Models of spin glasses are studied with a phase transition discontinuous in the Parisi order parameter. It is assumed that the leading order corrections to the thermodynamic limit of the high temperature free energy are due to the existence of a metastable saddle point in the replica formalism. An ansatz is made on the form of the metastable point and its contribution to the free energy is calculated. The Random Energy Model is considered along with the p-spin and the p-state Potts Models in their p < ∞ expans… Show more
“…Formulas (22)(23)(24)(25) are exact for the Poisson REM. They summarize all the previous ones in particular (17,20).…”
Section: The Moments Of Z and The Weighted Overlapsmentioning
confidence: 99%
“…in the range where the contour C 1 crosses the real axis). If not one can deform the contour to pass through the saddle point but one should not forget the contribution of the poles at the integer values of r. This is what happens in particular in the high temperature phase [24,42].…”
Section: Some Remarks On the Replica Calculationmentioning
We present a systematict and exact way of computing finite size corrections for the random energy model, in its low temperature phase. We obtain explicit (though complicated) expressions for the finite size corrections of the overlap functions. In its low temperature phase, the random energy model is known to exhibit Parisi's broken symmetry of replicas. The finite size corrections given by our exact calculation can be reproduced using replicas if we make specific assumptions about the fluctuations (with negative variances!) of the number and sizes of the blocks when replica symmetry is broken. As an alternative we show that the exact expression for the non-integer moments of the partition function can be written in terms of coupled contour integrals over what can be thought of as "complex replica numbers". Parisi's one step replica symmetry breaking arises naturally from the saddle point of these integrals without making any ansatz or using the replica method. The fluctuations of the "complex replica numbers" near the saddle point in the imaginary direction correspond to the negative variances we observed in the replica calculation. Finally our approach allows one to see why some apparently diverging series or integrals are harmless.
“…Formulas (22)(23)(24)(25) are exact for the Poisson REM. They summarize all the previous ones in particular (17,20).…”
Section: The Moments Of Z and The Weighted Overlapsmentioning
confidence: 99%
“…in the range where the contour C 1 crosses the real axis). If not one can deform the contour to pass through the saddle point but one should not forget the contribution of the poles at the integer values of r. This is what happens in particular in the high temperature phase [24,42].…”
Section: Some Remarks On the Replica Calculationmentioning
We present a systematict and exact way of computing finite size corrections for the random energy model, in its low temperature phase. We obtain explicit (though complicated) expressions for the finite size corrections of the overlap functions. In its low temperature phase, the random energy model is known to exhibit Parisi's broken symmetry of replicas. The finite size corrections given by our exact calculation can be reproduced using replicas if we make specific assumptions about the fluctuations (with negative variances!) of the number and sizes of the blocks when replica symmetry is broken. As an alternative we show that the exact expression for the non-integer moments of the partition function can be written in terms of coupled contour integrals over what can be thought of as "complex replica numbers". Parisi's one step replica symmetry breaking arises naturally from the saddle point of these integrals without making any ansatz or using the replica method. The fluctuations of the "complex replica numbers" near the saddle point in the imaginary direction correspond to the negative variances we observed in the replica calculation. Finally our approach allows one to see why some apparently diverging series or integrals are harmless.
“…In this limiting the model converges to the random energy model [23]. For recent work see [24] We are interested in the glassy behavior of the Potts model. Our approach will be to numerically solve the equation (17).…”
Section: Static Replica Equations For the Potts Glassmentioning
We study the static as well as the glassy or dynamical transition in the meanfield p-state Potts glass. By numerical solution of the saddle point equations we investigate the static and the dynamical transition for all values of p in the nonperturbative regime p > 4. The static and dynamical Edwards-Anderson parameter increase with p logarithmically. This makes the glassy transition temperature lie very close to the static one. We compare the main predictions of the theory with the numerical simulations.cond-mat/9410093 ROM2F/94/45 1
“…For this purpose we follow the method (introduced in this context by [8,11]) of transforming the previous sum into an integral in the complex plane around the integers r = 0, 1, 2, 3...∞ and then deform the contour of integration to obtain an integral in one variable that can be evaluated by the saddle point method in the complex plane.…”
In this note we introduce a method to calculate the finite volume corrections to the mean field results for the free energy when replica symmetry is broken at one-step. We find that the naive results are modified by the presence of additional corrections: these corrections can be interpreted as arising from fluctuations in the size of the blocks in the replica approach. The computation suggests a new approach for deriving the replica broken results in a rigorous way
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