Speaker
Описание
We discuss higher-loop calculations of renormalization-group (RG)
flows of quantum field theories. We focus on properties at infrared
fixed points of the RG in vectorial asymptotically free gauge
theories with various gauge groups and fermion contents, including the
anomalous dimensions of the fermion bilinear operator $\bar\psi\psi$.
We have calculated these with inputs up to five-loop order in powers
of the IR coupling $\alpha_{IR}$. It is also valuable to perform
corresponding calculations with a method that is independent of the
scheme used for regularization and renormalization, and we have done
this, using a manifestly scheme-independent variable. Much of this
work is in collaboration with T. Ryttov. Comparisons are made with
lattice measurements of these anomalous dimensions. We also mention
the results of our investigations, using the six-loop beta function,
to assess the possibility of an ultraviolet fixed point of the RG in a
non-asymptotically free model, namely the O($N$) $\lambda |\vec \phi|^4$
theory.
