Lasse Robroek

We present a theoretical analysis of the behavior of the anomalous dimension of the scalar glueball operator γ at the non-trivial infrared fixed point inside the conformal window of a non-Abelian gauge theory. By virtue of the non-renormalizability of the energy-momentum tensor, γ is determined by the derivative of the gauge coupling beta function at the fixed point. We therefore predict from the perturbative beta-function to 2, 3, 4 loops, and show that its flavor number (Nf) dependence along… Meer weergeven

We present a theoretical analysis of the behavior of the anomalous dimension of the scalar glueball operator γ at the non-trivial infrared fixed point inside the conformal window of a non-Abelian gauge theory. By virtue of the non-renormalizability of the energy-momentum tensor, γ is determined by the derivative of the gauge coupling beta function at the fixed point. We therefore predict from the perturbative beta-function to 2, 3, 4 loops, and show that its flavor number (Nf) dependence along the infrared fixed-point line is opposite to that implied by an ultravioletinfrared fixed-point merging mechanism at the lower edge of the conformal window. A nonperturbative determination of γ can thus establish the mechanism for the loss of conformality and the fate of the preconformal phase. We also discuss large-N massless QCD in the Veneziano limit in this context. Minder weergeven

We study the symmetry restoring zero-temperature (bulk) and finite-temperature (thermal) phase transitions that are known to exist for theories inside the conformal window and QCD respectively. We use probes of chiral symmetry breaking and confinement in combination with lattice simulations to locate the lower edge of the conformal window between Nf = 6 and Nf = 8. Furthermore we show that the anomalous dimension of the scalar glueball operator can be useful as a novel probe of the
mechanism… Meer weergeven

We study the symmetry restoring zero-temperature (bulk) and finite-temperature (thermal) phase transitions that are known to exist for theories inside the conformal window and QCD respectively. We use probes of chiral symmetry breaking and confinement in combination with lattice simulations to locate the lower edge of the conformal window between Nf = 6 and Nf = 8. Furthermore we show that the anomalous dimension of the scalar glueball operator can be useful as a novel probe of the
mechanism underlying the emergence of the conformal window. In particular it may confirm a UVIR fixed point merging scenario in favor of predictions made by perturbation theory and large-Nc approximations, or vice versa. Finally we introduce lattice upscaling as new technique to reduce
computational costs of lattice simulations. Minder weergeven

The main focus of my research was to find a description of electrodynamics using the framework of non-commutative geometry (from now: NCG).

We present a lattice study of the zero-temperature line of chiral symmetry breaking phase transitions in the conformal window of QCD for varying number of flavors. We argue that it is consistent with a lower edge of the conformal window between Nf=8 and Nf=6, and remarkably in agreement with perturbation theory and recent large-N arguments. We add a theoretical analysis of the anomalous dimension of the scalar glueball operator and show that its agreement with perturbation theory and large-N… Meer weergeven

We present a lattice study of the zero-temperature line of chiral symmetry breaking phase transitions in the conformal window of QCD for varying number of flavors. We argue that it is consistent with a lower edge of the conformal window between Nf=8 and Nf=6, and remarkably in agreement with perturbation theory and recent large-N arguments. We add a theoretical analysis of the anomalous dimension of the scalar glueball operator and show that its agreement with perturbation theory and large-N arguments would be sufficient to exclude an ultraviolet-infrared fixed-point merging as a mechanism for the loss of conformality. Minder weergeven