Non-vanishing boundary effects and quasi-first-order phase transitions in high dimensional Ising models

• In order to gain a better understanding of the Ising model in higher dimensions we have made a comparative study of how the boundary, open versus cyclic, of a d-dimensional simple lattice, for d = 1,...,5, affects the behaviour of the specific heat C and its microcanonical relative, the entropy derivative -partial derivative(2)S/partial derivative U(2). In dimensions 4 and 5 the boundary has a strong effect on the critical region of the model and for cyclic boundaries in dimension 5 we find that the model displays a quasi-first-order phase transition with a bimodal energy distribution. The latent heat decreases with increasing systems size but for all system sizes used in earlier papers the effect is clearly visible once a wide enough range of values for K is considered. Relations to recent rigorous results for high dimensional percolation and previous debates on simulation of Ising models and gauge fields are discussed. (C) 2010 Elsevier B.V. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

Nyckelord

ising model

phase transitions

boundary effects

lattice

field

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art (ämneskategori)