Optimized Perturbation Theory at Finite Temperature
نویسندگان
چکیده
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 method is applied for the O(4) σ model to study the soft modes associated with the chiral transition in quantum chromodynamics. Threshold enhancement of the spectral functions at finite T in the scalar and pseudo-scalar channels is shown to be a typical signal of the chiral transition.
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تاریخ انتشار 1998