QCD in magnetic fields: from Hofstadter's butterfly to the phase diagram
Abstract
I revisit the problem of a charged particle on a two-dimensional lattice immersed in a constant (electro)magnetic field, and discuss the energy spectrum - Hofstadter's butterfly - from a new, quantum field theoretical perspective. In particular, I point out that there is an intricate interplay between a) the structure of the butterfly at low magnetic flux, b) the absence of asymptotic freedom in QED and c) the enhancement of the quark condensate by a magnetic field at zero temperature. I proceed to discuss the response of the QCD condensate to the magnetic field at nonzero temperatures in four space-time dimensions, present the resulting phase diagram and compare it to low-energy model predictions.
Keywords
Cite
@article{arxiv.1410.8028,
title = {QCD in magnetic fields: from Hofstadter's butterfly to the phase diagram},
author = {G. Endrodi},
journal= {arXiv preprint arXiv:1410.8028},
year = {2014}
}
Comments
15 pages, 12 figures, plenary talk at the 32nd International Symposium on Lattice Field Theory (23-28 June 2014, Columbia University, New York, NY, USA)