9,194 research outputs found
Energy Dependence of Jet Quenching and Life-time of the Dense Matter in High-energy Heavy-ion Collisions
Suppression of high hadron spectra in high-energy heavy-ion collisions
at different energies is studied within a pQCD parton model incorporating
medium induced parton energy loss. The dependence of the nuclear
modification factor is found to depend on both the energy
dependence of the parton energy loss and the power-law behavior of the initial
jet spectra. The high hadron suppression at GeV and its
centrality dependence are studied in detail. The overall values of the
modification factor are found to provide strong constraints on the lifetime of
the dense matter.Comment: 6 pages in RevTex with 3 postscript figure
A NLO analysis on fragility of dihadron tomography in high energy collisions
The dihadron spectra in high energy collisions are studied within the
NLO pQCD parton model with jet quenching taken into account. The high
dihadron spectra are found to be contributed not only by jet pairs close and
tangential to the surface of the dense matter but also by punching-through jets
survived at the center while the single hadron high spectra are only
dominated by surface emission. Consequently, the suppression factor of such
high- hadron pairs is found to be more sensitive to the initial gluon
density than the single hadron suppression factor.Comment: 4 pages, 4 figures, proceedings for the 19th international Conference
on ultra-relativistic nucleus-nucleus collisions (QM2006), Shanghai, China,
November 14-20, 200
Modification of conductive polymer for polymeric anodes of flexible organic light-emitting diodes
Author name used in this publication: Guang-Feng WangAuthor name used in this publication: Xiao-Ming TaoAuthor name used in this publication: John H. Xin2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
High Pt hadron-hadron correlations
We propose the formulation of a dihadron fragmentation function in terms of
parton matrix elements. Under the collinear factorization approximation and
facilitated by the cut-vertex technique, the two hadron inclusive cross section
at leading order (LO) in e+ e- annihilation is shown to factorize into a short
distance parton cross section and the long distance dihadron fragmentation
function. We also derive the DGLAP evolution equation of this function at
leading log. The evolution equation for the non-singlet and singlet quark
fragmentation function and the gluon fragmentation function are solved
numerically with the initial condition taken from event generators.
Modifications to the dihadron fragmentation function from higher twist
corrections in DIS off nuclei are computed. Results are presented for cases of
physical interest.Comment: 7 pages, 8 figures, Latex, Proceedings of Hot Quarks 2004, July
18-24, Taos, New Mexic
Counterdiabatic driving for pseudo- and antipseudo- Hermitian systems
In this work, we study the counterdiabatic driving scheme in pseudo- and
antipseudo- Hermitian systems. By discussing the adiabatic condition for
non-Hermitian system, we show that the adiabatic evolution of state can only be
realized in the non-Hermitian system which possesses real energy spectrum.
Therefore, the counterdiabatic driving scheme to reproduce an exact evolution
of an energy eigenstate needs either real energy spectrum or dropping its parts
of dynamic phase and Berry phase. In this sense, we derive the adiabatic
conditions and counterdiabatic driving Hamiltonians for the pseudo-Hermitian
Hamiltonian which possesses either real or complex energy spectrum and the
antipseudo-Hermitian Hamiltonian which possesses either imaginary or complex
energy spectrum. We also find the condition to get self-normalized energy
eigenstates in pseudo- and antipseudo- Hermitian system and derive the
well-defined population of bare states on this energy eigenstate. Our results
are illustrated by studying the counterdiabatic driving for a non-Hermitian
three level system, and a perfect population transfer with loss or gain is
realized.Comment: 9pages, 6figure
Adaptive conformal classification with noisy labels
This paper develops novel conformal prediction methods for classification
tasks that can automatically adapt to random label contamination in the
calibration sample, enabling more informative prediction sets with stronger
coverage guarantees compared to state-of-the-art approaches. This is made
possible by a precise theoretical characterization of the effective coverage
inflation (or deflation) suffered by standard conformal inferences in the
presence of label contamination, which is then made actionable through new
calibration algorithms. Our solution is flexible and can leverage different
modeling assumptions about the label contamination process, while requiring no
knowledge about the data distribution or the inner workings of the
machine-learning classifier. The advantages of the proposed methods are
demonstrated through extensive simulations and an application to object
classification with the CIFAR-10H image data set.Comment: 35 pages (98 pages including references and appendices
Doping dependance of the spin resonance peak in bilayer high- superconductors
Motivated by a recent experiment on the bilayer
YCaBaCuO superconductor and based on a bilayer
model, we calculate the spin susceptibility at different doping densities in
the even and odd channels in a bilayer system. It is found that the intensity
of the resonance peak in the even channel is much weaker than that in the odd
one, with the resonance position being at a higher frequency. While this
difference decreases as the doping increases, and both the position and
amplitude of the resonance peaks in the two channels are very similar in the
deeply overdoped sample. Moreover, the resonance frequency in the odd channel
is found to be linear with the critical temperature , while the resonance
frequency increases as doping decreases in the even channel and tends to
saturate at the underdoped sample. We elaborate the results based on the Fermi
surface topology and the d-wave superconductivity.Comment: 6 pages, 5 figure
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