Inverse Magnetic Catalysis in Holographic QCD

Typically one expects that the chiral condensate increases with magnetic field in QCD and other field theories. This phenomenon is called "magnetic catalysis". Therefore it came as a surprise when lattice simulations found the opposite behavior near the chiral and deconfinement transition temperatures of QCD. After a brief introduction to holography at finite magnetic field, I demonstrate that this "inverse magnetic catalysis" is found in a bottom-up holographic model, which includes the backreaction of the flavors to the glue dynamics. The model agrees well with lattice results for the condensate and related observables. It also predicts the extent of inverse catalysis at finite chemical potential, where no lattice data is currently available. A detailed analysis of the effect suggests that it arises due to the anisotropy caused by the magnetic field rather than the magnetic field directly.