63 research outputs found
Geometrically induced magnetic catalysis and critical dimensions
We discuss the combined effect of magnetic fields and geometry in interacting
fermionic systems. At leading order in the heat-kernel expansion, the infrared
singularity (that in flat space leads to the magnetic catalysis) is regulated
by the chiral gap effect, and the catalysis is deactivated by the effect of the
scalar curvature. We discover that an infrared singularity is found in
higher-order terms that mix the magnetic field with curvature, and these lead
to a novel form of geometrically induced magnetic catalysis. The dynamical mass
squared is then modified not only due to the chiral gap effect by an amount
proportional to the curvature, but also by a magnetic shift ,
where represents the number of space-time dimensions. We argue that
is a critical dimension across which the behavior of the magnetic shift changes
qualitatively.Comment: 5 pages; minor change
Chiral Phase Transitions around Black Holes
In this paper we discuss the possibility that chiral phase transitions,
analogous to those of QCD, occur in the vicinity of a black hole. If the black
hole is surrounded by a gas of strongly interacting particles, an inhomogeneous
condensate will form. We demonstrate this by explicitly constructing
self-consistent solutions.Comment: 4 pages; 3 figure
Fermion vacuum energies in brane world models
The fermion representations and boundary conditions in five dimensional anti
de Sitter space are described in detail. In each case the one loop effective
action is calculated for massless fermions. The possibility of topological or
Wilson loop symmetry breaking is discussed.Comment: 6 pages, no figures, one correctio
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