arXiv subjects

Y. Schröder

Publications and source records attributed to Y. Schröder.

3 recordsLinked to original sources

arXiv2025

Anomalous dimensions and critical exponents for the Gross-Neveu-Yukawa model at five loops

We renormalize the Gross-Neveu-Yukawa model with an $O(N)$ symmetry to $\mathcal{O}(ε^5)$ in $d=4-ε$ dimensions and determine the anomalous dimensions of the fermion and scalar fields, $β$-functions as well as the scalar field's mass operator. These are used to construct several $N$ dependent critical exponents relevant for quantum transitions in semi-metals and in particular those connected with graphene in three dimensions when $N=2$. Improved exponent estimates for scalar fermion transitions on a honeycomb lattice, when $N=1$, as well as for $N=5$ are also given to compare with results from other techniques such as the conformal bootstrap.

hep-th↗

arXiv2004

Two-Loop Static QCD Potential for General Colour State

In this letter, we extend the known results for the QCD potential between a static quark and its antiquark by computing the two-loop corrections to the colour-octet state.

hep-ph↗

arXiv1997

Thermal variational principle and gauge fields

A Feynman-Jensen version of the thermal variational principle is applied to hot gauge fields, Abelian as well as non-Abelian: scalar electrodynamics (without scalar self-coupling) and the gluon plasma. The perturbatively known self-energies are shown to derive by variation from a free quadratic (''Gaussian'') trial Lagrangian. Independence of the covariant gauge fixing parameter is reached (within the order $g^3$ studied) after a reformulation of the partition function such that it depends on only even powers of the gauge field. Also static properties (Debye screening) are reproduced this way. But because of the present need to expand the variational functional, the method falls short of its potential nonperturbative power.

hep-ph↗