Abstract
Recent advances in our understanding of the phase structure and the phase transitions of hadronic matter in strong magnetic fields and zero quark chemical potentials are reviewed in detail. Many aspects of QCD are described using low-energy effective theories and models such as the bag model, the hadron resonance gas model, chiral perturbation theory (), the Nambu–Jona-Lasinio (NJL) model, the quark-meson (QM) model, and Polyakov-loop extended versions of the NJL and QM models. Their properties and applications are critically examined. This includes mean-field calculations as well as approaches beyond the mean-field approximation such as the functional renormalization group. Renormalization issues are discussed and the influence of the vacuum fluctuations on the chiral phase transition is pointed out. At , model calculations and lattice simulations predict magnetic catalysis: The quark condensate increases as a function of the magnetic field. This is covered in detail. Recent lattice results for the thermodynamics of non-Abelian gauge theories with emphasis on and are also discussed. In particular, inverse magnetic catalysis around the transition temperature as a competition between contributions from valence quarks and sea quarks resulting in a decrease of as a function of is focused on. Finally, recent efforts to modify models in order to reproduce the behavior observed on the lattice are discussed.
41 More- Received 18 December 2014
DOI:https://doi.org/10.1103/RevModPhys.88.025001
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