Magnetic catalysis with massive dynamical flavours

TL;DR

This paper constructs a supergravity dual for a gauge theory with massive flavors under a magnetic field, revealing how magnetic catalysis is enhanced by internal flavor loops and analyzing the condensate behavior.

Contribution

It introduces a perturbative supergravity background with a hollow cavity to study magnetic catalysis in theories with massive flavors, including loop effects.

Findings

Magnetic catalysis effect is enhanced at next order.

Condensate contribution from internal loops grows logarithmically with cutoff.

The free energy and condensate match quenched results at leading order.

Abstract

Within gauge/gravity duality, we construct a backreacted supergravity background dual to SU(Nc) N=4 SYM coupled to Nf massive fundamental flavours in the presence of an external magnetic field. Our solution is perturbative in a parameter that counts the number of the internal flavour loops. The background has a hollow cavity in the bulk of the geometry, where it is similar to the supergravity dual of a non-commutative SYM. The radius of this cavity is related to the dynamically generated mass of the fundamental fields. We apply our construction to study the effect of magnetic catalysis and develop an appropriate renormalization scheme to compute the free energy and the fundamental condensate of the dual gauge theory as a function of the bare mass. While at leading order in the expansion of the perturbative parameter, the free energy and the fundamental condensate agree with the results obtained in the quenched approximation, at next order we show that the effect of magnetic catalysis is enhanced and the contribution to the condensate of the theory from internal fundamental loops runs logarithmically with the finite cutoff Lambda_UV.