69,232 research outputs found
The definability criterions for convex projective polyhedral reflection groups
Following Vinberg, we find the criterions for a subgroup generated by
reflections \Gamma \subset \SL^{\pm}(n+1,\mathbb{R}) and its finite-index
subgroups to be definable over where is an integrally
closed Noetherian ring in the field . We apply the criterions for
groups generated by reflections that act cocompactly on irreducible properly
convex open subdomains of the -dimensional projective sphere. This gives a
method for constructing injective group homomorphisms from such Coxeter groups
to \SL^{\pm}(n+1,\mathbb{Z}). Finally we provide some examples of
\SL^{\pm}(n+1,\mathbb{Z})-representations of such Coxeter groups. In
particular, we consider simplicial reflection groups that are isomorphic to
hyperbolic simplicial groups and classify all the conjugacy classes of the
reflection subgroups in \SL^{\pm}(n+1,\mathbb{R}) that are definable over
. These were known by Goldman, Benoist, and so on previously.Comment: 31 pages, 8 figure
Comment about pion electro-production and the axial form factors
The claim by Haberzettl (Phys.Rev.Lett.85 (2000) 3576) that the axial form
factor of the nucleon cannot be accessed through threshold pion
electroproduction is unfounded
The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC
We compute the rates for pp annihilation into chargino-pairs via Drell-Yan
process taking into account the effects of supersymmetric soft phases, at
proton-proton collider. In particular, the phase of the mu parameter gains
direct accessibility via the production of dissimilar charginos. The phases of
the trilinear soft masses do not have a significant effect on the cross
sections.Comment: 24 pages, 7 figure
Controlling quasiparticle excitations in a trapped Bose-Einstein condensate
We describe an approach to quantum control of the quasiparticle excitations
in a trapped Bose-Einstein condensate based on adiabatic and diabatic changes
in the trap anisotropy. We describe our approach in the context of Landau-Zener
transition at the avoided crossings in the quasiparticle excitation spectrum.
We show that there can be population oscillation between different modes at the
specific aspect ratios of the trapping potential at which the mode energies are
almost degenerate. These effects may have implications in the expansion of an
excited condensate as well as the dynamics of a moving condensate in an atomic
wave guide with a varying width
Se and Cu NMR studies of the electronic correlations in CuTiSe ()
We report Se and Cu nuclear magnetic resonance (NMR)
investigation on the charge-density-wave (CDW) superconductor CuTiSe
( and 0.07). At high magnetic fields where superconductivity is
suppressed, the temperature dependence of Se and Cu spin-lattice
relaxation rates 1/T_{1}^{77}1/T_{1}$
vs \emph{T} increases with the Cu doping. This can be described by a modified
Korringa relation which suggests the significance of electronic correlations
and the Se 4\emph{p}- and Ti 3\emph{d}-band contribution to the density of
states at the Fermi level in the studied compounds.Comment: Revised manuscript. Submitted to Journal of Physics: Condensed Matte
Quantum Phase Transitions in Josephson Junction Chains
We investigate the quantum phase transition in a one-dimensional chain of
ultra-small superconducting grains, considering both the self- and junction
capacitances. At zero temperature, the system is transformed into a
two-dimensional system of classical vortices, where the junction capacitance
introduces anisotropy in the interaction between vortices. This leads to the
superconductor-insulator transition of the Berezinskii-Kosterlitz-Thouless
type, as the ratios of the Josephson coupling energy to the charging energies
are varied. It is found that the junction capacitance plays a role similar to
that of dissipation and tends to suppress quantum fluctuations; nevertheless
the insulator region survives even for arbitrarily large values of the junction
capacitance.Comment: REVTeX+5 EPS figures, To appear in PRB Rapid
Spectrum of TeV Particles in Warped Supersymmetric Grand Unification
In warped supersymmetric grand unification, XY gauge particles appear near
the TeV scale along with Kaluza-Klein towers of the standard model gauge
fields. In spite of this exotic low-energy physics, MSSM gauge coupling
unification is preserved and proton decay is naturally suppressed. In this
paper we study in detail the low-lying mass spectrum of superparticles and GUT
particles in this theory, taking supersymmetry breaking to be localized to the
TeV brane. The masses of the MSSM particles, Kaluza-Klein modes, and XY states
are all determined by two parameters, one which fixes the strength of the
supersymmetry breaking and the other which sets the scale of the infrared
brane. A particularly interesting result is that for relatively strong
supersymmetry breaking, the XY gauginos and the lowest Kaluza-Klein excitations
of the MSSM gauginos may both lie within reach of the LHC, providing the
possibility that the underlying unified gauge symmetry and the enhanced N=2
supersymmetry of the theory will both be revealed.Comment: 29 pages, 5 figure
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