Evaluating critical exponents in the optimized perturbation theory
نویسندگان
چکیده
منابع مشابه
Self-similar variational perturbation theory for critical exponents.
We extend field theoretic variational perturbation theory by self-similar approximation theory, which greatly accelerates convergence. This is illustrated by recalculating the critical exponents of O (N) -symmetric phi(4) theory. From only three-loop perturbation expansions in 4-epsilon dimensions, we obtain analytic results for the exponents, which are close to those derived recently from ordi...
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We use variational perturbation theory to calculate various universal amplitude ratios above and below Tc in minimally subtracted straight phi4 theory with N components in three dimensions. In order to best exhibit the method as a powerful alternative to Borel resummation techniques, we consider only two- and three-loops expressions where our results are analytic expressions. For the critical e...
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An optimized perturbation theory (OPT) at finite temperature T , which resums higher order terms in the naive perturbation, is developed in O(N) φ theory. It is proved that (i) the renormalization of the ultra-violet divergences can be carried out systematically in any given order of OPT, and (ii) the Nambu-Goldstone theorem is fulfilled for arbitrary N and for any given order of OPT. The metho...
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We shall now use the results of the previous chapters to derive explicitly the critical exponents of the O(N)-symmetric φ 4-theory. The unique tensor multiplying the product of fields φ α φ β φ γ φ δ in the interaction is [recall (6.25)]
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ژورنال
عنوان ژورنال: Physica A: Statistical Mechanics and its Applications
سال: 2004
ISSN: 0378-4371
DOI: 10.1016/j.physa.2004.05.042