1,032 research outputs found
Twisted Link Theory
We introduce stable equivalence classes of oriented links in orientable
three-manifolds that are orientation -bundles over closed but not
necessarily orientable surfaces. We call these twisted links, and show that
they subsume the virtual knots introduced by L. Kauffman, and the projective
links introduced by Yu. Drobotukhina. We show that these links have unique
minimal genus three-manifolds. We use link diagrams to define an extension of
the Jones polynomial for these links, and show that this polynomial fails to
distinguish two-colorable links over non-orientable surfaces from
non-two-colorable virtual links.Comment: 33 pages and 35 figure
Faddeev calculations of break-up reactions with realistic experimental constraints
We present a method to integrate predictions from a theoretical model of a
reaction with three bodies in the final state over the region of phase space
covered by a given experiment. The method takes into account the true
experimental acceptance, as well as variations of detector efficiency, and
eliminates the need for a Monte-Carlo simulation of the detector setup. The
method is applicable to kinematically complete experiments. Examples for the
use of this method include several polarization observables in dp break-up at
270 MeV. The calculations are carried out in the Faddeev framework with the CD
Bonn nucleon-nucleon interaction, with or without the inclusion of an
additional three-nucleon force.Comment: 18 pages, 9 figure
Megabits secure key rate quantum key distribution
Quantum cryptography (QC) can provide unconditional secure communication
between two authorized parties based on the basic principles of quantum
mechanics. However, imperfect practical conditions limit its transmission
distance and communication speed. Here we implemented the differential phase
shift (DPS) quantum key distribution (QKD) with up-conversion assisted hybrid
photon detector (HPD) and achieved 1.3 M bits per second secure key rate over a
10-km fiber, which is tolerant against the photon number splitting (PNS)
attack, general collective attacks on individual photons, and any other known
sequential unambiguous state discrimination (USD) attacks.Comment: 14 pages, 4 figure
The alpha-particle based on modern nuclear forces
The Faddeev-Yakubovsky equations for the alpha-particle are solved. Accurate
results are obtained for several modern NN interaction models, which include
charge-symmetry breaking effects in the NN force, nucleon mass dependences as
well as the Coulomb interaction. These models are augmented by three-nucleon
forces of different types and adjusted to the 3N binding energy. Our results
are close to the experimental binding energy with a slight overbinding. Thus
there is only little room left for the contribution of possible 4N interactions
to the alpha-particle binding energy. We also discuss model dependences of the
binding energies and the wave functions.Comment: 22 pages REVTeX 4, 12 figures, table with TM parameters added, typos
corrected, version as published in PR
Experimental search for evidence of the three-nucleon force and a new analysis method
A research program with the aim of investigating the spin dependence of the
three-nucleon continuum in pd collisions at intermediate energies was carried
out at IUCF using the Polarized INternal Target EXperiments (PINTEX) facility.
In the elastic scattering experiment at 135 and 200 MeV proton beam energies a
total of 15 independent spin observables were obtained. The breakup experiment
was done with a vector and tensor polarized deuteron beam of 270 MeV and an
internal polarized hydrogen gas target. We developed a novel technique for the
analysis of the breakup observables, the sampling method. The new approach
takes into account acceptance and non-uniformities of detection efficiencies
and is suitable for any kinematically complete experiment with three particles
in the final state.Comment: Contribution to the 19th European Few-Body Conference, Groningen Aug.
23-27, 200
Time-resolved spectroscopy of multi-excitonic decay in an InAs quantum dot
The multi-excitonic decay process in a single InAs quantum dot is studied
through high-resolution time-resolved spectroscopy. A cascaded emission
sequence involving three spectral lines is seen that is described well over a
wide range of pump powers by a simple model. The measured biexcitonic decay
rate is about 1.5 times the single-exciton decay rate. This ratio suggests the
presence of selection rules, as well as a significant effect of the Coulomb
interaction on the biexcitonic wavefunction.Comment: one typo fixe
Inclusive Scattering of Polarized Electrons on Polarized 3He Effects of Final State Interaction and the Magnetic Form Factor of the Neutron
Effects of final state interaction on asymmetries in inclusive scattering of
polarized electrons on polarized 3He are investigated using consistent 3He
bound state wave function and 3N continuum scattering states. Significant
effects are found, which influence the extraction of the magnetic neutron form
factor from A_T'. The enhancement found experimentally for A_TL' near the 3N
breakup threshold, which could not be explained in calculations carried through
in plane wave impulse approximation up to now, occurs now also in theory if the
full final state interaction is included.Comment: 29 pages, 5 figure
Isoscalar off-shell effects in threshold pion production from pd collisions
We test the presence of pion-nucleon isoscalar off-shell effects in the
reaction around the threshold region. We find that these
effects significantly modify the production cross section and that they may
provide the missing strength needed to reproduce the data at threshold.Comment: 6 pages, REVTeX, twocolumn, including 3 figures (Postscript), uses
psfig, updated and extended versio
The three-nucleon bound state using realistic potential models
The bound states of H and He have been calculated using the Argonne
plus the Urbana three-nucleon potential. The isospin state
have been included in the calculations as well as the - mass difference.
The H-He mass difference has been evaluated through the charge
dependent terms explicitly included in the two-body potential. The calculations
have been performed using two different methods: the solution of the Faddeev
equations in momentum space and the expansion on the correlated hyperspherical
harmonic basis. The results are in agreement within 0.1% and can be used as
benchmark tests. Results for the CD-Bonn interaction are also presented. It is
shown that the H and He binding energy difference can be predicted
model independently.Comment: 5 pages REVTeX 4, 1 figures, 6 table
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