5,895 research outputs found
Shintani functions, real spherical manifolds, and symmetry breaking operators
For a pair of reductive groups , we prove a geometric criterion
for the space of Shintani functions to be finite-dimensional
in the Archimedean case.
This criterion leads us to a complete classification of the symmetric pairs
having finite-dimensional Shintani spaces.
A geometric criterion for uniform boundedness of is
also obtained.
Furthermore, we prove that symmetry breaking operators of the restriction of
smooth admissible representations yield Shintani functions of moderate growth,
of which the dimension is determined for .Comment: to appear in Progress in Mathematics, Birkhause
Generic singularities of symplectic and quasi-symplectic immersions
For any k<2n we construct a complete system of invariants in the problem of
classifying singularities of immersed k-dimensional submanifolds of a
symplectic 2n-manifold at a generic double point.Comment: 12 page
Fermi Surface Study of Quasi-Two-Dimensional Organic Conductors by Magnetooptical Measurements
Magnetooptical measurements of several quasi-two-dimensional (q2D) organic
conductors, which have simple Fermi surface structure, have been performed by
using a cavity perturbation technique. Despite of the simple Fermi surface
structure, magnetooptical resonance results show a dramatic difference for each
sample. Cyclotron resonances (CR) were observed for q-(BEDT-TTF)2I3 and
(BEDT-TTF)3Br(pBIB), while periodic orbit resonances (POR) were observed for
(BEDT-TTF)2Br(DIA) and (BEDT-TTF)3Cl(DFBIB). The selection of the resonance
seems to correspond with the skin depth for each sample. The effective mass of
POR seems to have a mass enhancement due to the many-body effect, while
effective mass of CR is independent of the strength of the electron-electron
interaction. The scattering time deduced from each resonance's linewidth will
be also presented.Comment: 10 pages, 8 figures, to be published to J. Phys. Soc. Jpn Vol.72 No.1
(accepted
Electric Dipole Moments of Neutron-Odd Nuclei
The electric dipole moments (EDMs) of neutron-odd nuclei with even protons
are systematically evaluated. We first derive the relation between the EDM and
the magnetic moment operators by making use of the core polarization scheme.
This relation enables us to calculate the EDM of neutron-odd nuclei without any
free parameters. From this calculation, one may find the best atomic system
suitable for future EDM experiments.Comment: 4 page
How are Forbush decreases related to interplanetary magnetic field enhancements ?
Aims. Forbush decrease (FD) is a transient decrease followed by a gradual
recovery in the observed galactic cosmic ray intensity. We seek to understand
the relationship between the FDs and near-Earth interplanetary magnetic field
(IMF) enhancements associated with solar coronal mass ejections (CMEs).
Methods. We use muon data at cutoff rigidities ranging from 14 to 24 GV from
the GRAPES-3 tracking muon telescope to identify FD events. We select those FD
events that have a reasonably clean profile, and magnitude > 0.25%. We use IMF
data from ACE/WIND spacecrafts. We look for correlations between the FD profile
and that of the one hour averaged IMF. We ask if the diffusion of high energy
protons into the large scale magnetic field is the cause of the lag observed
between the FD and the IMF. Results. The enhancement of the IMF associated with
FDs occurs mainly in the shock-sheath region, and the turbulence level in the
magnetic field is also enhanced in this region. The observed FD profiles look
remarkably similar to the IMF enhancement profiles. The FDs typically lag the
IMF enhancement by a few hours. The lag corresponds to the time taken by high
energy protons to diffuse into the magnetic field enhancement via cross-field
diffusion. Conclusions. Our findings show that high rigidity FDs associated
with CMEs are caused primarily by the cumulative diffusion of protons across
the magnetic field enhancement in the turbulent sheath region between the shock
and the CME.Comment: accepted in A&
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