29,011 research outputs found
Certain homotopy properties related to
For given spaces and , let and be the
unbased and based mapping spaces from to , equipped with compact-open
topology respectively. Then let and be the path
component of containing and containing ,
respectively. In this paper, we compute cohomotopy groups of suspended complex
plane for . Using these results, we
classify path components of the spaces up to
homotopy equivalent. We also determine the generalized Gottlieb groups
. Finally, we compute homotopy groups of mapping
spaces for all generators of
, and Gottlieb groups of mapping components
containing constant map
Understanding the Complex Position in a PT-symmetric Oscillator
We study how to understand the complex coordinates involved in the
non-Hermitian but PT-symmetric systems. We explore a PT-symmetric oscillator
model to show that the entire information on the complex position is
attainable. Its real part is from the observation while its imaginary part is
from the non-Hermiticity parameter. We also propose a new complex extension of
P-transformation and T-transformation (the `parity' and `time reflection'
respectively). Particularly, the P-transformation realizes the left-right
reflection in the complex plane.Comment: 4 pages with 1 figure, uses revtex4-1.cl
AdS_3 Black Hole Entropy and the Spectral Flow on the Horizon
We consider the entropy problem of AdS_3 black holes using the conformal
field theory at the horizon. We observe that the supersymmetry is enhanced at
the horizon of massless AdS_3 black hole. This allows us to determine the
vacuum of the modular invariant conformal field theory to be the NS-ground
state (which corresponds to AdS_3 spacetime). This is smoothly related to the
R-ground state (corresponding to massless black hole) by a spectral flow, which
can be understood as a superconformal transformation.Comment: 14 pages using REVTeX macr
Beam dynamics at the main LEBT of RAON accelerator
The high-intensity rare-isotope accelerator (RAON) of the Rare Isotope
Science Project (RISP) in Daejeon, Korea, has been designed to accelerate
multiple-charge-state beams. The ion beams, which are generated by Electron
Cyclotron Resonance Ion Source (ECR-IS), will be transported through the main
Low Energy Beam Transport (LEBT) system to the Radio Frequency Quadrupole
(RFQ). While passing the beams through LEBT, we should keep the transverse beam
size and longitudinal emittance small. Furthermore, the matching of required
twiss parameter at the RFQ entrance will be performed by using electro-static
quadrupoles at the main LEBT matching section which is from the multi-harmonic
buncher (MHB) to the entrance of RFQ. We will briefly review the new aspects of
main LEBT lattice and the beam matching at the main LEBT matching section will
be presented. In addition, the effects of various errors on the beam orbit and
the correction of distorted orbit will be discussed
Mutation invariance of the arc index for some Montesinos knots
For the alternating knots or links, mutations do not change the arc index. In
the case of nonalternating knots, some semi-alternating knots or links have
this property. We mainly focus on the problem of mutation invariance of the arc
index for nonalternating knots which are not semi-alternating. In this paper,
we found families of infinitely many mutant pairs/triples of Montesinos knots
with the same arc index.Comment: 19 pages, 24 figures, 1 tabl
Rotating Supertubes
We study the rotating tubular D2-brane as a time dependent supersymmetric
solution of type-IIA string theory. We show that the Poynting angular momentum
of the supertube can be replaced by the mechanical angular momentum without
disturbing the 8 supersymmetries. Unlike the non-rotating supertube, whose
cross section can take an arbitrary shape, the rotating supertube admits only
the circular cross section. When there is no electric field on the world
volume, the supersymmetry dictates the angular velocity of the tubular D2-brane
to be inversely proportional to the magnetic field. This rotating supertube can
be considered as the `blown-up' configuration of an array of spinning
D0-particles and is T-dual to the spiraling D-helix whose pitch moves at the
speed of light.Comment: V2. added one more figure, comments on the reparametrization
symmetry, and a referenc
Living Near de Sitter Bubble Walls
We study various bubble solutions in string/M theories obtained by double
Wick rotations of (non-)extremal brane configurations. Typically, the geometry
interpolates de Sitter space-time times non-compact extra-dimensional space in
the near-bubble wall region and the asymptotic flat Minkowski space-time. These
bubble solutions provide nice background geometries reconciling string/M
theories with de Sitter space-time. For the application of these solutions to
cosmology, we consider multi-bubble solutions and find landscapes of varying
cosmological constant. Double Wick rotation in string/M theories, used in this
paper, introduces imaginary higher-form fields. Rather than regard these fields
as classical pathologies, we interpret them as semi-classical decay processes
of de Sitter vacuum via the production of spherical branes. We speculate on the
possibility of solving the cosmological constant problem making use of the
condensation of the spherical membranes.Comment: 51 pages, 8 figures, additional sections on the ghosts and on the
wave function of the Univese, and additonal reference
Lifting graph automorphisms along solvable regular covers
A {\em solvable} cover of a graph is a regular cover whose covering
transformation group is solvable. In this paper, we show that a solvable cover
of a graph can be decomposed into layers of abelian covers, and also, a lift of
a given automorphism of the base graph of a solvable cover can be decomposed
into layers of lifts of the automorphism in the layers of the abelian covers.
This procedure is applied to classify metacyclic covers of the tetrahedron
branched at face-centers.Comment: 23 pages, 1 figure
Certain maps preserving self-homotopy equivalences
Let be the group of homotopy classes of self homotopy
equivalences for a connected CW complex . We observe two classes of maps
-maps and co--maps. They are defined as the maps
that induce the homomorphisms and
, respectively. We give some rationalized
examples related to spheres, Lie groups and homogeneous spaces by using
Sullivan models. Furthermore, we introduce an -equivalence
relation between rationalized spaces and as a
geometric realization of an isomorphism
Start-to-end simulation with rare isotope beam for post accelerator of the RAON accelerator
The RAON accelerator of the Rare Isotope Science Project (RISP) has been
developed to create and accelerate various kinds of stable heavy ion beams and
rare isotope beams for a wide range of the science applications. In the RAON
accelerator, the rare isotope beams generated by the Isotope Separation On-Line
(ISOL) system will be transported through the post accelerator, namely, from
the post Low Energy Beam Transport (LEBT) system and the post Radio Frequency
Quadrupole (RFQ) to the superconducting linac (SCL3). The accelerated beams
will be put to use in the low energy experimental hall or accelerated again by
the superconducting linac (SCL2) in order to be used in the high energy
experimental hall. In this paper, we will describe the results of the
start-to-end simulations with the rare isotope beams generated by the ISOL
system in the post accelerator of the RAON accelerator. In addition, the error
analysis and correction at the superconducting linac SCL3 will be presented
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