Fisher's scaling relation above the upper critical dimension

Ralph Kenna, B. Berche

    Research output: Contribution to journalArticle

    14 Citations (Scopus)
    11 Downloads (Pure)

    Abstract

    Fisher's fluctuation-response relation is one of four famous scaling formulae and is consistent with a vanishing correlation-function anomalous dimension above the upper critical dimension dc. However, it has long been known that numerical simulations deliver a negative value for the anomalous dimension there. Here, the apparent discrepancy is attributed to a distinction between the system-length and correlation- or characteristic-length scales. On the latter scale, the anomalous dimension indeed vanishes above dc and Fisher's relation holds in its standard form. However, on the scale of the system length, the anomalous dimension is negative and Fisher's relation requires modification. Similar investigations at the upper critical dimension, where dangerous irrelevant variables become marginal, lead to an analogous pair of Fisher relations for logarithmic-correction exponents. Implications of a similar distinction between length scales in percolation theory above dc and for the Ginzburg criterion are briefly discussed.
    Original languageEnglish
    Article number26005
    JournalEPL
    Volume105
    Issue number2
    DOIs
    Publication statusPublished - 13 Feb 2014

    Keywords

    • condensed matter: structural
    • mechanical & thermal
    • statistical physics and nonlinear systems

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