title: Universal critical coupling constants for the three-dimensional n-vector model from field theory.
abstract: The field-theoretical renormalization group (RG) approach in three dimensions is used to estimate the universal critical values of renormalized coupling constants g6 and g8 for the O(n)-symmetric model. The RG series for g6 and g8 are calculated in the four- and three-loop approximations, respectively, and then resummed by means of the Padé-Borel-Leroy technique. Under the optimal value of the shift parameter b providing the fastest convergence of the iteration procedure, numerical estimates for g*6 are obtained with an accuracy no worse than 0.3%. The RG expansion for g8 demonstrates a stronger divergence, and results in considerably cruder numerical estimates.
authors.affiliation: Department of Physical Electronics, Saint Petersburg Electrotechnical University, Professor Popov Street 5, St. Petersburg 197376, Russia.
authors.forename: A I
authors.initials: AI
authors.lastname: Sokolov
authors.forename: E V
authors.initials: EV
authors.lastname: Orlov
authors.forename: V A
authors.initials: VA
authors.lastname: Ul'kov
authors.forename: S S
authors.initials: SS
authors.lastname: Kashtanov