161,984 research outputs found
Analysis on the minimal representation of O(p,q) -- I. Realization via conformal geometry
This is the first in a series of papers devoted to an analogue of the
metaplectic representation, namely, the minimal unitary representation of an
indefinite orthogonal group; this representation corresponds to the minimal
nilpotent coadjoint orbit in the philosophy of Kirillov-Kostant.
We begin by applying methods from conformal geometry of pseudo-Riemannian
manifolds to a general construction of an infinite-dimensional representation
of the conformal group on the solution space of the Yamabe equation. By
functoriality of the constructions, we obtain different models of the unitary
representation, as well as giving new proofs of unitarity and irreducibility.
The results in this paper play a basic role in the subsequent papers, where
we give explicit branching formulae, and prove unitarization in the various
models
Parity criterion and Dehn twists for unstabilized Heegaard splittings
We give a parity condition of a Heegaard diagram to show that it is
unstabilized. This improves the result of [5]. As an application, we construct
unstabilized Heegaard splittings by Dehn twists on any given Heegaard
splitting.Comment: 10 pages, 6 figure
The magnetic behavior of Li2MO3 (M=Mn, Ru and Ir) and Li2(Mn1-xRux)O3
The present study summerizes magnetic and Mossbauer measurements on ceramic
Li2MO3 M= Mn, Ru and Ir and the mixed Li2(Mn1-xRux)O3 materials, which show
many of the features reflecting to antiferromagnetic ordering or to existence
of paramagnetic states. Li2IrO3 and Li2RuO3 are paramagnetic down to 5 K.
Li2(Mn1-xRux)O3 compounds are antiferromagnetically ordered at TN = 48 K for
x=0. TN decreases as the Ru content increases and, for x=0.8, TN =34 K.Comment: accepted to Physica
Heterotic string backgrounds and CP violation
In the framework of orbifolds, we discuss effects of heterotic string
backgrounds including discrete Wilson lines on the Yukawa matrices and their
connection to CP violation.Comment: 12 pages, latex, no figur
Quark masses and mixing angles in heterotic orbifold models
We study systematically the possibility for realizing realistic values of
quark mass ratios and and the mixing angle by
using only renormalizable Yukawa couplings derived from heterotic orbifold
models. We assume one pair of up and down sector Higgs fields. We show
realistic examples including hierarchical and democratic forms of Yukawa
matrices.Comment: 16 pages, late
Finite multiplicity theorems for induction and restriction
We find upper and lower bounds of the multiplicities of irreducible
admissible representations of a semisimple Lie group occurring in the
induced representations from irreducible representations
of a closed subgroup .
As corollaries, we establish geometric criteria for finiteness of the
dimension of (induction) and of
(restriction) by means of the real flag variety , and discover that
uniform boundedness property of these multiplicities is independent of real
forms and characterized by means of the complex flag variety.Comment: to appear in Advances in Mathematic
Entropy Burst from Parabolic Potentials
The change of the energy of ground state is investigated in a thermodynamical
process by using the model described by one-dimensional harmonic oscillator +
two-dimensional isotropic parabolic potential barrier such as
. In the process where two
independent many-particle systems suddenly touch with each other, it is shown
that the lowest energy after the interaction can possibly be smaller than that
before the interaction and then the entropy burst can occur.Comment: 6 pages, AmS-LaTeX, 1 figur
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