11 research outputs found
Spin-triplet superconducting pairing due to local (Hund's rule, Dirac) exchange
We discuss general implications of the local spin-triplet pairing among
fermions induced by local ferromagnetic exchange, example of which is the
Hund's rule coupling. The quasiparticle energy and their wave function are
determined for the three principal phases with the gap, which is momentum
independent. We utilize the Bogolyubov-Nambu-De Gennes approach, which in the
case of triplet pairing in the two-band case leads to the four-components wave
function. Both gapless modes and those with an isotropic gap appear in the
quasiparticle spectrum. A striking analogy with the Dirac equation is briefly
explored. This type of pairing is relevant to relativistic fermions as well,
since it reflects the fundamental discrete symmetry-particle interchange. A
comparison with the local interband spin-singlet pairing is also made.Comment: 16 pages, LaTex, submitted to Phys. Rev.
Magnetic Catalysis: A Review
We give an overview of the magnetic catalysis phenomenon. In the framework of
quantum field theory, magnetic catalysis is broadly defined as an enhancement
of dynamical symmetry breaking by an external magnetic field. We start from a
brief discussion of spontaneous symmetry breaking and the role of a magnetic
field in its a dynamics. This is followed by a detailed presentation of the
essential features of the phenomenon. In particular, we emphasize that the
dimensional reduction plays a profound role in the pairing dynamics in a
magnetic field. Using the general nature of underlying physics and its
robustness with respect to interaction types and model content, we argue that
magnetic catalysis is a universal and model-independent phenomenon. In support
of this claim, we show how magnetic catalysis is realized in various models
with short-range and long-range interactions. We argue that the general nature
of the phenomenon implies a wide range of potential applications: from certain
types of solid state systems to models in cosmology, particle and nuclear
physics. We finish the review with general remarks about magnetic catalysis and
an outlook for future research.Comment: 37 pages, to appear in Lect. Notes Phys. "Strongly interacting matter
in magnetic fields" (Springer), edited by D. Kharzeev, K. Landsteiner, A.
Schmitt, H.-U. Yee. Version 2: references adde
Quark Matter in a Strong Magnetic Background
In this chapter, we discuss several aspects of the theory of strong
interactions in presence of a strong magnetic background. In particular, we
summarize our results on the effect of the magnetic background on chiral
symmetry restoration and deconfinement at finite temperature. Moreover, we
compute the magnetic susceptibility of the chiral condensate and the quark
polarization at zero temperature. Our theoretical framework is given by chiral
models: the Nambu-Jona-Lasinio (NJL), the Polyakov improved NJL (or PNJL) and
the Quark-Meson (QM) models. We also compare our results with the ones obtained
by other groups.Comment: 34 pages, survey. To appear in Lect. Notes Phys. "Strongly
interacting matter in magnetic fields" (Springer), edited by D. Kharzeev, K.
Landsteiner, A. Schmitt, H.-U. Ye