Local electric current correlation function in an exponentially decaying magnetic field

The effect of an exponentially decaying magnetic field on the dynamics of Dirac fermions in 3+1 dimensions is explored. The spatially decaying magnetic field is assumed to be aligned in the third direction, and is defined by {\mathbf{B}}(x)=B(x){\mathbf{e}}_{z}, with B(x)=B_{0}e^{-\xi\ x/\ell_{B}}. Here, \xi\ is a dimensionless damping factor and \ell_{B}=(eB_{0})^{-1/2} is the magnetic length. As it turns out, the energy spectrum of fermions in this inhomogeneous magnetic field can be analytically determined using the Ritus method. Assuming the magnetic field to be strong, the chiral condensate and the \textit{local} electric current correlation function are computed in the lowest Landau level (LLL) approximation and the results are compared with those arising from a strong homogeneous magnetic field. Although the constant magnetic field B_{0} can be reproduced by taking the limit of \xi-> 0 and/or x-> 0 from B(x), these limits turn out to be singular once the quantum corrections are taken into account.Comment: V1: 16 pages, 7 figures, 2 tables; V2: Section II improved, references added. Version accepted for publication in PR

Gravitational catalysis of chiral and color symmetry breaking of quark matter in hyperbolic space

We study the dynamical breaking of chiral and color symmetries of dense quark matter in the ultrastatic hyperbolic spacetime $R\otimes H^3$ in the framework of an extended Nambu--Jona-Lasinio model. On the basis of analytical expressions for chiral and color condensates as functions of curvature and temperature, the phenomenon of dimensional reduction and gravitational catalysis of symmetry breaking in strong gravitational field is demonstrated in the regime of weak coupling constants. In the case of strong couplings it is shown that curvature leads to small corrections to the flat-space values of condensate and thus enhances the symmetry breaking effects. Finally, using numerical calculations phase transitions under the influence of chemical potential and negative curvature are considered and the phase portrait of the system is constructed.Comment: 14 pages, 5 figure

Chiral dynamics in QED and QCD in a magnetic background and nonlocal noncommutative field theories

We study the connection of the chiral dynamics in QED and QCD in a strong magnetic field with noncommutative field theories (NCFT). It is shown that these dynamics determine complicated nonlocal NCFT. In particular, although the interaction vertices for electrically neutral composites in these gauge models can be represented in the space with noncommutative spatial coordinates, there is no field transformation that could put the vertices in the conventional form considered in the literature. It is unlike the Nambu-Jona-Lasinio (NJL) model in a magnetic field where such a field transformation can be found, with a cost of introducing an exponentially damping form factor in field propagators. The crucial distinction between these two types of models is in the characters of their interactions, being short-range in the NJL-like models and long-range in gauge theories. The relevance of the NCFT connected with the gauge models for the description of the quantum Hall effect in condensed matter systems with long-range interactions is briefly discussed.Comment: 19 pages, REVTeX4, v2: clarifications added, v3: to match PRD versio

Color superconductivity in the static Einstein Universe

We study the behavior of quark and diquark condensates in dense quark matter under the influence of a gravitational field adopting as a simple model the static $D-$dimensional Einstein Universe. Calculations are performed in the framework of the extended Nambu--Jona-Lasinio model at finite temperature and quark density on the basis of the thermodynamic potential and the gap equations. Quark and diquark condensates as functions of the chemical potential and temperature at different values of the curvature have been studied. Phase portraits of the system have been constructed

Phase diagram of hot magnetized two-flavor color superconducting quark matter

A two-flavor color superconducting (2SC) Nambu--Jona-Lasinio (NJL) model is introduced at finite temperature T, chemical potential mu and in the presence of a constant magnetic field eB. The effect of (T,mu,eB) on the formation of chiral and color symmetry breaking condensates is studied. The complete phase portrait of the model in T-mu, mu-eB, and T-eB phase spaces for various fixed eB, T, and mu is explored. A threshold magnetic field eB_t~ 0.5 GeV^2 is found above which the dynamics of the system is solely dominated by the lowest Landau level (LLL) and the effects of T and mu are partly compensated by eB.Comment: V1: 29 pages, 15 figures, 3 tables. V2: Discussions improved. Version accepted for publication in PR

Plasmonic nanoparticle monomers and dimers: From nano-antennas to chiral metamaterials

We review the basic physics behind light interaction with plasmonic nanoparticles. The theoretical foundations of light scattering on one metallic particle (a plasmonic monomer) and two interacting particles (a plasmonic dimer) are systematically investigated. Expressions for effective particle susceptibility (polarizability) are derived, and applications of these results to plasmonic nanoantennas are outlined. In the long-wavelength limit, the effective macroscopic parameters of an array of plasmonic dimers are calculated. These parameters are attributable to an effective medium corresponding to a dilute arrangement of nanoparticles, i.e., a metamaterial where plasmonic monomers or dimers have the function of "meta-atoms". It is shown that planar dimers consisting of rod-like particles generally possess elliptical dichroism and function as atoms for planar chiral metamaterials. The fabricational simplicity of the proposed rod-dimer geometry can be used in the design of more cost-effective chiral metamaterials in the optical domain.Comment: submitted to Appl. Phys.