3,730 research outputs found
Developing Programmatic CDM Activities in Sri Lanka:A report on technical assistance submitted to Sri Lanka Carbon fund
Mission and Workshop report:A report on workshop and technical assistance submitted to Sri Lanka Carbon Fund
Exact Calculation of Ring Diagrams and the Off-shell Effect on the Equation of State
The partition function with ring diagrams at finite temperature is exactly
caluclated by using contour integrals in the complex energy plane. It contains
a pole part with temperature and momentum dependent mass and a phase shift part
induced by off-shell effect in hot medium. The thermodynamic potentials for
and interactions are calculated and compared with the
quasi-particle (pole) approximation. It is found that the off-shell effect on
the equation of state is remarkable.Comment: 7 pages, 11 figures, refereces added, final version to appear in PR
Leakage Effect on J/psi Pt Distributions in Different Centrality Bins for Pb-Pb Collisions at E/A=160 GeV
A transport approach including a leakage effect for J/psi's in the transverse
phase space is used to calculate the ratios between the J/psi transverse
momentum distributions in several centrality bins for Pb-Pb collisions at E/A =
160 GeV. From the comparison with the CERN-SPS data, where the centrality is
characterized by the transverse energy Et, the leakage effect is extremely
important in the region of high transverse momentum and high transverse energy,
and both the threshold and the comover models can describe the ratio well for
all centrality bins except the most central one (Et < 100 GeV), for which the
comover model calculation is considerably better than the threshold one.Comment: 4 pages, 2 figures, REVTEX3.1, accepted for publication in Phys. Rev.
Quantum Lifetime of Two-Dimensional Holes
The quantum lifetime of two-dimensional holes in a GaAs/AlGaAs double quantum
well is determined via tunneling spectroscopy. At low temperatures the lifetime
is limited by impurity scattering but at higher temperatures hole-hole Coulomb
scattering dominates. Our results are consistent with Fermi liquid theory, at
least up to r_s = 11. At the highest temperatures the measured width of the
hole spectral function becomes comparable to the Fermi energy. A new,
tunneling-spectroscopic, method for determining the in-plane effective mass of
the holes is also demonstrated.Comment: 5 pages, 4 figures. Published versio
Fast and Accurate Algorithm for Eye Localization for Gaze Tracking in Low Resolution Images
Iris centre localization in low-resolution visible images is a challenging
problem in computer vision community due to noise, shadows, occlusions, pose
variations, eye blinks, etc. This paper proposes an efficient method for
determining iris centre in low-resolution images in the visible spectrum. Even
low-cost consumer-grade webcams can be used for gaze tracking without any
additional hardware. A two-stage algorithm is proposed for iris centre
localization. The proposed method uses geometrical characteristics of the eye.
In the first stage, a fast convolution based approach is used for obtaining the
coarse location of iris centre (IC). The IC location is further refined in the
second stage using boundary tracing and ellipse fitting. The algorithm has been
evaluated in public databases like BioID, Gi4E and is found to outperform the
state of the art methods.Comment: 12 pages, 10 figures, IET Computer Vision, 201
On the Role of the Hot Feedback Mode in Active Galactic Nuclei Feedback in an Elliptical Galaxy
CP Test in J/Psi -> gamma phi phi Decay
We propose to test CP symmetry in the decay \jp\to \gamma \phi\phi, for
which large data sample exists at BESII, and a data sample of
's will be collected with BESIII and CLEO-C program. We suggest some CP
asymmetries in this decay mode for CP test. Assuming that CP violation is
introduced by the electric- and chromo-dipole moment of charm quark, these CP
asymmetries can be predicted by using valence quark models. Our work shows a
possible way to get information about the electric- and chromo-dipole moment of
charm quark, which is little known. Our results show that with the current data
sample of , electric- and chromo-dipole moment can be probed at order
of . In the near future with a data sample, these
moments can be probed at order of .Comment: Misprints corrected. To appear in Phys. Lett.
Connecting Berry's phase and the pumped charge in a Cooper pair pump
The properties of the tunnelling-charging Hamiltonian of a Cooper pair pump
are well understood in the regime of weak and intermediate Josephson coupling,
i.e. when . It is also known that
Berry's phase is related to the pumped charge induced by the adiabatical
variation of the eigenstates. We show explicitly that pumped charge in Cooper
pair pump can be understood as a partial derivative of Berry's phase with
respect to the phase difference across the array. The phase fluctuations
always present in real experiments can also be taken into account, although
only approximately. Thus the measurement of the pumped current gives reliable,
yet indirect, information on Berry's phase. As closing remarks, we give the
differential relation between Berry's phase and the pumped charge, and state
that the mathematical results are valid for any observable expressible as a
partial derivative of the Hamiltonian.Comment: 5 pages, 5 figures, RevTeX, Presentation has been clarifie
Layer charge instability in unbalanced bilayer systems in the quantum Hall regime
Measurements in GaAs hole bilayers with unequal layer densities reveal a
pronounced magneto-resistance hysteresis at the magnetic field positions where
either the majority or minority layer is at Landau level filling factor one. At
a fixed field in the hysteretic regions, the resistance exhibits an unusual
time dependence, consisting of random, bidirectional jumps followed by slow
relaxations. These anomalies are apparently caused by instabilities in the
charge distribution of the two layers.Comment: 4 pages, 4 figure
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