arXiv subjects

Mika Lauk

Publications and source records attributed to Mika Lauk.

2 recordsLinked to original sources

arXiv2026

Non-perturbative renormalization of the energy momentum tensor in the 2d O(3) nonlinear sigma model

The two-dimensional O(3) nonlinear sigma model is a well known toy model for studying non-perturbative phenomena in quantum field theory. A central challenge is the renormalization of the energy-momentum tensor, which is complicated by the nonlinear realization of the $O(3)$ symmetry leading to non-trivial operator mixing patterns, and by large discretization artifacts affecting the determination of renormalization constants. We present results for the renormalization constants in the non-singlet sector, employing a modified lattice action with shifted boundary conditions and defining the renormalized coupling through the gradient flow. With this we obtain a precise determination of the renormalization constants $z_T$ and $Z_T$

hep-lat↗

arXiv2025

Energy-momentum tensor in the 2d $O(3)$ non-linear sigma model on the lattice

The long-term goal of this project is the non-perturbative renormalization of the energy-momentum tensor in the 2d $O(3)$ non-linear sigma model using different methods which have been developed for QCD applications. As a first step, we have identified all operators that mix with the energy-momentum tensor once a lattice discretization is employed, that is all which are compatible with power counting and with the symmetries of the theory. Since these operators are constrained by non-linear Ward identities arising from the non-linear realization of the $O(3)$ symmetry, this is not entirely straightforward on the technical level. We have also outlined the basics of ongoing numerical simulations with shifted boundary conditions and an optimized constraint action to minimize lattice artifacts.

hep-lat↗