4,799 research outputs found
Tensor product theorem for Hitchin pairs -An algebraic approach
We give an algebraic approach to the study of Hitchin pairs and prove the
tensor product theorem for Higgs semistable Hitchin pairs over smooth
projective curves defined over algebraically closed fields of
characteristic and characteristic , with satisfying some natural
bounds. We also prove the corresponding theorem for polystable bundles.Comment: To appear in Annales de l'Institut Fourier, Volume 61 (2011
An analogue of the Narasimhan-Seshadri theorem and some applications
We prove an analogue in higher dimensions of the classical
Narasimhan-Seshadri theorem for strongly stable vector bundles of degree 0 on a
smooth projective variety with a fixed ample line bundle . As
applications, over fields of characteristic zero, we give a new proof of the
main theorem in a recent paper of Balaji and Koll\'ar and derive an effective
version of this theorem; over uncountable fields of positive characteristics,
if is a simple and simply connected algebraic group and the characteristic
of the field is bigger than the Coxeter index of , we prove the existence of
strongly stable principal bundles on smooth projective surfaces whose
holonomy group is the whole of .Comment: 42 pages. Theorem 3 of this version is new. Typos have been
corrected. To appear in Journal of Topolog
Single Field Baryogenesis
We propose a new variant of the Affleck-Dine baryogenesis mechanism in which
a rolling scalar field couples directly to left- and right-handed neutrinos,
generating a Dirac mass term through neutrino Yukawa interactions. In this
setup, there are no explicitly CP violating couplings in the Lagrangian. The
rolling scalar field is also taken to be uncharged under the quantum
numbers. During the phase of rolling, scalar field decays generate a
non-vanishing number density of left-handed neutrinos, which then induce a net
baryon number density via electroweak sphaleron transitions.Comment: 4 pages, LaTe
Semistable principal bundles-II (positive characteristics)
Let H be a semisimple algebraic group and let X be a smooth projective curve defined over an algebraically closed field k. The principal aim of this paper is to prove the existence and projectivity of the moduli spaces of principal H-bundles on X for fields of characteristic p, p > Ψ, where Ψ is a certain representation-theoretic index associated to H. The projectivity is a consequence of the semistable reduction theorem for principal H-bundles
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