35 research outputs found
de Sitter symmetry of Neveu-Schwarz spinors
We study the relations between Dirac fields living on the 2-dimensional
Lorentzian cylinder and the ones living on the double-covering of the
2-dimensional de Sitter manifold, here identified as a certain coset space of
the group . We show that there is an extended notion of de Sitter
covariance only for Dirac fields having the Neveu-Schwarz anti-periodicity and
construct the relevant cocycle. Finally, we show that the de Sitter symmetry is
naturally inherited by the Neveu-Schwarz massless Dirac field on the cylinder.Comment: 24 page
Exact vortex solutions in a CP^N Skyrme-Faddeev type model
We consider a four dimensional field theory with target space being CP^N
which constitutes a generalization of the usual Skyrme-Faddeev model defined on
CP^1. We show that it possesses an integrable sector presenting an infinite
number of local conservation laws, which are associated to the hidden
symmetries of the zero curvature representation of the theory in loop space. We
construct an infinite class of exact solutions for that integrable submodel
where the fields are meromorphic functions of the combinations (x^1+i x^2) and
(x^3+x^0) of the Cartesian coordinates of four dimensional Minkowski
space-time. Among those solutions we have static vortices and also vortices
with waves traveling along them with the speed of light. The energy per unity
of length of the vortices show an interesting and intricate interaction among
the vortices and waves.Comment: 21 pages, plain latex, no figure
The Worldvolume Action of Kink Solitons in AdS Spacetime
A formalism is presented for computing the higher-order corrections to the
worldvolume action of co-dimension one solitons. By modifying its potential, an
explicit "kink" solution of a real scalar field in AdS spacetime is found. The
formalism is then applied to explicitly compute the kink worldvolume action to
quadratic order in two expansion parameters--associated with the hypersurface
fluctuation length and the radius of AdS spacetime respectively. Two
alternative methods are given for doing this. The results are expressed in
terms of the trace of the extrinsic curvature and the intrinsic scalar
curvature. In addition to conformal Galileon interactions, we find a
non-Galileon term which is never sub-dominant. This method can be extended to
any conformally flat bulk spacetime.Comment: 32 pages, 3 figures, typos corrected and additional comments adde
Recurrent and de novo non-alcoholic steatohepatitis following orthotopic liver transplantation
Moduli space dynamics of noncommutative U(2) instantons
We consider the low energy dynamics of charge two instantons on noncommutative ℝ NC 2 × ℝ NC 2 in U(2) 5-dimensional super-Yang-Mills, using the Manton approximation for slow-moving instantons to calculate the moduli space metric. By employing the ADHM construction, we are able to understand some aspects of the geometry and topology of the system. We also consider the effect of adding a potential to the moduli space, giving scattering results for noncommutative dyonic instantons