Finding the conformal window on the lattice

by Jarno Rantaharju (Helsinki University)

Monday 10 Oct 2011, 11:00 → 12:00 Europe/Zurich

TH Theory Conference Room (CERN)

There has recently been interest in quantum field theories with a non-trivial infrared fixed point. In these theories the coupling flows to a constant value at large distances and to zero at small distances. They have applications in beyond the standard model phenomenology, such as technicolor models and unparticles. It is also interesting from a purely theoretical standpoint to understand the phase structure of Yang-Mills theories in the space of the number of colors and fermion flavors. I present lattice studies of the running coupling of SU(2) gauge theories with fermions in the fundamental and adjoint representations. The results using unimproved lattice actions show large discretization errors and we have used improved lattice actions to reduce these errors. Using the improved actions we produce significantly different results.