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Ultra-high sensitive strain sensor based on post-processed optical fiber Bragg grating
An ultra-high sensitive strain sensor is proposed. The sensing head, based on the post-processing of a fiber Bragg grating, is used to perform passive and active strain measurements. Both wavelength and full width half maximum dependences with the applied strain are studied for the passive sensor, where maximum sensitivities of 104.1 pm/με and 61.6 pm/με are respectively obtained. When combining the high performance of this sensor with a ring laser cavity configuration, the Bragg grating will act as a filter and high resolution measurements can be performed. With the proposed sensor, a resolution of 700 nε is achieved
Supersymmetry for Fermion Masses
It is proposed that supersymmetry (SUSY) maybe used to understand fermion
mass hierarchies. A family symmetry Z_{3L} is introduced, which is the cyclic
symmetry among the three generation SU(2) doublets. SUSY breaks at a high
energy scale ~ 10^{11} GeV. The electroweak energy scale ~ 100 GeV is
unnaturally small. No additional global symmetry, like the R-parity, is
imposed. The Yukawa couplings and R-parity violating couplings all take their
natural values which are about (10^0-10^{-2}). Under the family symmetry, only
the third generation charged fermions get their masses. This family symmetry is
broken in the soft SUSY breaking terms which result in a hierarchical pattern
of the fermion masses. It turns out that for the charged leptons, the tau mass
is from the Higgs vacuum expectation value (VEV) and the sneutrino VEVs, the
muon mass is due to the sneutrino VEVs, and the electron gains its mass due to
both Z_{3L} and SUSY breaking. The large neutrino mixing are produced with
neutralinos playing the partial role of right-handed neutrinos. |V_{e3}| which
is for nu_e-nu_{tau} mixing is expected to be about 0.1. For the quarks, the
third generation masses are from the Higgs VEVs, the second generation masses
are from quantum corrections, and the down quark mass due to the sneutrino
VEVs. It explains m_c/m_s, m_s/m_e, m_d > m_u and so on. Other aspects of the
model are discussed.Comment: 25 pages, 3 figures, revtex4; neutrino oscillation and many
discussions added, smallness of the electron mass due to supersymmetry
pointed out; v3: numerical errors correcte
Which phase is measured in the mesoscopic Aharonov-Bohm interferometer?
Mesoscopic solid state Aharonov-Bohm interferometers have been used to
measure the "intrinsic" phase, , of the resonant quantum
transmission amplitude through a quantum dot (QD). For a two-terminal "closed"
interferometer, which conserves the electron current, Onsager's relations
require that the measured phase shift only "jumps" between 0 and .
Additional terminals open the interferometer but then depends on the
details of the opening. Using a theoretical model, we present quantitative
criteria (which can be tested experimentally) for to be equal to the
desired : the "lossy" channels near the QD should have both a
small transmission and a small reflection
Localization of gravity in brane world with arbitrary extra dimensions
We study the induced 4-dimensional linearized Einstein field equations in an
m-dimensional bulk space by means of a confining potential. It is shown that in
this approach the mass of graviton is quantized. The cosmological constant
problem is also addressed within the context of this approach. We show that the
difference between the values of the cosmological constant in particle physics
and cosmology stems from our measurements in two different scales, small and
large.Comment: 8 pages. arXiv admin note: substantial text overlap with
arXiv:gr-qc/0408004, arXiv:gr-qc/0607067, arXiv:0704.1035, arXiv:0707.3558,
arXiv:0710.266
Un système d'acquisition de données pour l'analyse en ligne des photographies de grandes chambres à bulles
Ce travail présente le système d'analyse des clichés de grandes chambres à bulles telles que Gargamelle et BEBC, réalisé au Groupe de Chambre à Bulles à Liquide Lourd à l'aide d'appareils de projection mis en ligne sur ordinateur CDC 1700. Ce travail présente les caractéristiques générales de ces appareils ainsi que celles de l'ordinateur et développe la conception et les fonctions des programmes d'analyse des photographies : prémesures, mesures et gestion des données. L'ensemble du système d'acquisition de données fonctionne dans un contexte de multiprogrammation en temps réel
Mesoscopic Fano Effect in a Quantum Dot Embedded in an Aharonov-Bohm Ring
The Fano effect, which occurs through the quantum-mechanical cooperation
between resonance and interference, can be observed in electron transport
through a hybrid system of a quantum dot and an Aharonov-Bohm ring. While a
clear correlation appears between the height of the Coulomb peak and the real
asymmetric parameter for the corresponding Fano lineshape, we need to
introduce a complex to describe the variation of the lineshape by the
magnetic and electrostatic fields. The present analysis demonstrates that the
Fano effect with complex asymmetric parameters provides a good probe to detect
a quantum-mechanical phase of traversing electrons.Comment: REVTEX, 9 pages including 8 figure
Measuring the Spectra of High Energy Neutrinos with a Kilometer-Scale Neutrino Telescope
We investigate the potential of a future kilometer-scale neutrino telescope
such as the proposed IceCube detector in the South Pole, to measure and
disentangle the yet unknown components of the cosmic neutrino flux, the prompt
atmospheric neutrinos coming from the decay of charmed particles and the
extra-galactic neutrinos, in the 10 TeV to 1 EeV energy range.
Assuming a power law type spectra,
, we quantify the discriminating
power of the IceCube detector and discuss how well we can determine magnitude
() as well as slope () of these two components of the high
energy neutrino spectrum, taking into account the background coming from the
conventional atmospheric neutrinos.Comment: 21 pages, 7 figure
Advances in multispectral and hyperspectral imaging for archaeology and art conservation
Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed
Discovery of the Binary Pulsar PSR B1259-63 in Very-High-Energy Gamma Rays around Periastron with H.E.S.S
We report the discovery of very-high-energy (VHE) gamma-ray emission of the
binary system PSR B1259-63/SS 2883 of a radio pulsar orbiting a massive,
luminous Be star in a highly eccentric orbit. The observations around the 2004
periastron passage of the pulsar were performed with the four 13 m Cherenkov
telescopes of the H.E.S.S. experiment, recently installed in Namibia and in
full operation since December 2003. Between February and June 2004, a gamma-ray
signal from the binary system was detected with a total significance above 13
sigma. The flux was found to vary significantly on timescales of days which
makes PSR B1259-63 the first variable galactic source of VHE gamma-rays
observed so far. Strong emission signals were observed in pre- and
post-periastron phases with a flux minimum around periastron, followed by a
gradual flux decrease in the months after. The measured time-averaged energy
spectrum above a mean threshold energy of 380 GeV can be fitted by a simple
power law F_0(E/1 TeV)^-Gamma with a photon index Gamma =
2.7+-0.2_stat+-0.2_sys and flux normalisation F_0 = (1.3+-0.1_stat+-0.3_sys)
10^-12 TeV^-1 cm^-2 s^-1. This detection of VHE gamma-rays provides unambiguous
evidence for particle acceleration to multi-TeV energies in the binary system.
In combination with coeval observations of the X-ray synchrotron emission by
the RXTE and INTEGRAL instruments, and assuming the VHE gamma-ray emission to
be produced by the inverse Compton mechanism, the magnetic field strength can
be directly estimated to be of the order of 1 G.Comment: 10 pages, 8 figures, accepted in Astronomy and Astrophysics on 2 June
2005, replace: document unchanged, replaced author field in astro-ph entry -
authors are all members of the H.E.S.S. collaboration and three additional
authors (99+3, see document
Power-spectrum analysis of Super-Kamiokande solar neutrino data, taking into account asymmetry in the error estimates
The purpose of this article is to carry out a power-spectrum analysis (based
on likelihood methods) of the Super-Kamiokande 5-day dataset that takes account
of the asymmetry in the error estimates. Whereas the likelihood analysis
involves a linear optimization procedure for symmetrical error estimates, it
involves a nonlinear optimization procedure for asymmetrical error estimates.
We find that for most frequencies there is little difference between the
power spectra derived from analyses of symmetrized error estimates and from
asymmetrical error estimates. However, this proves not to be the case for the
principal peak in the power spectra, which is found at 9.43 yr-1. A likelihood
analysis which allows for a "floating offset" and takes account of the start
time and end time of each bin and of the flux estimate and the symmetrized
error estimate leads to a power of 11.24 for this peak. A Monte Carlo analysis
shows that there is a chance of only 1% of finding a peak this big or bigger in
the frequency band 1 - 36 yr-1 (the widest band that avoids artificial peaks).
On the other hand, an analysis that takes account of the error asymmetry leads
to a peak with power 13.24 at that frequency. A Monte Carlo analysis shows that
there is a chance of only 0.1% of finding a peak this big or bigger in that
frequency band 1 - 36 yr-1. From this perspective, power spectrum analysis that
takes account of asymmetry of the error estimates gives evidence for
variability that is significant at the 99.9% level.
We comment briefly on an apparent discrepancy between power spectrum analyses
of the Super-Kamiokande and SNO solar neutrino experiments.Comment: 13 pages, 2 tables, 6 figure
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