25,652 research outputs found
Observation of Conduction Band Satellite of Ni Metal by 3p-3d Resonant Inverse Photoemission Study
Resonant inverse photoemission spectra of Ni metal have been obtained across
the Ni 3 absorption edge. The intensity of Ni 3 band just above Fermi
edge shows asymmetric Fano-like resonance. Satellite structures are found at
about 2.5 and 4.2 eV above Fermi edge, which show resonant enhancement at the
absorption edge. The satellite structures are due to a many-body configuration
interaction and confirms the existence of 3 configuration in the ground
state of Ni metal.Comment: 4 pages, 3 figures, submitted to Physical Review Letter
Coulomb Drag of Massless Fermions in Graphene
Using a novel structure, consisting of two, independently contacted graphene
single layers separated by an ultra-thin dielectric, we experimentally measure
the Coulomb drag of massless fermions in graphene. At temperatures higher than
50 K, the Coulomb drag follows a temperature and carrier density dependence
consistent with the Fermi liquid regime. As the temperature is reduced, the
Coulomb drag exhibits giant fluctuations with an increasing amplitude, thanks
to the interplay between coherent transport in the graphene layer and
interaction between the two layers.Comment: 5 pages, 5 figure
Polarization Switching Dynamics Governed by Thermodynamic Nucleation Process in Ultrathin Ferroelectric Films
A long standing problem of domain switching process - how domains nucleate -
is examined in ultrathin ferroelectric films. We demonstrate that the large
depolarization fields in ultrathin films could significantly lower the
nucleation energy barrier (U*) to a level comparable to thermal energy (kBT),
resulting in power-law like polarization decay behaviors. The "Landauer's
paradox": U* is thermally insurmountable is not a critical issue in the
polarization switching of ultrathin ferroelectric films. We empirically find a
universal relation between the polarization decay behavior and U*/kBT.Comment: 5 pages, 4 figure
Three-loop HTL gluon thermodynamics at intermediate coupling
We calculate the thermodynamic functions of pure-glue QCD to three-loop order
using the hard-thermal-loop perturbation theory (HTLpt) reorganization of
finite temperature quantum field theory. We show that at three-loop order
hard-thermal-loop perturbation theory is compatible with lattice results for
the pressure, energy density, and entropy down to temperatures .
Our results suggest that HTLpt provides a systematic framework that can used to
calculate static and dynamic quantities for temperatures relevant at LHC.Comment: 24 pages, 13 figs. 2nd version: improved discussion and fixing typos.
Published in JHE
Time-Varying Priority Queuing Models for Human Dynamics
Queuing models provide insight into the temporal inhomogeneity of human
dynamics, characterized by the broad distribution of waiting times of
individuals performing tasks. We study the queuing model of an agent trying to
execute a task of interest, the priority of which may vary with time due to the
agent's "state of mind." However, its execution is disrupted by other tasks of
random priorities. By considering the priority of the task of interest either
decreasing or increasing algebraically in time, we analytically obtain and
numerically confirm the bimodal and unimodal waiting time distributions with
power-law decaying tails, respectively. These results are also compared to the
updating time distribution of papers in the arXiv.org and the processing time
distribution of papers in Physical Review journals. Our analysis helps to
understand human task execution in a more realistic scenario.Comment: 8 pages, 6 figure
Improving Monolithic Perovskite Silicon Tandem Solar Cells From an Optical Viewpoint
Perovskite silicon tandem solar cells are the most promising concept for a future photovoltaic technology. We report on recent progress from an optical viewpoint and disucss how we achieved more than 25 device efficienc
Enzyme-Loaded Nanoreactors Enable the Continuous Regeneration of Nicotinamide Adenine Dinucleotide in Artificial Metabolisms
Primary cerebral angitis of the central nervous
We report a case of a 28 year old female who presented with variedly progressive stroke like illness and raised intracranial pressure. Brain MRI scans revealed pericallosal and periventricular hyperintensities with oedema. Various medications like intravenous immunoglobulin, antibiotics, acyclovir, methyl prednisolone and management for raised intracranial pressure were instituted. She rapidly deteroriated and died on tenth hospital day. Only at autopsy was the diagnosis of primary angitis of central nervous system established. East African Medical Journla Vol. 85 (6) 2008: pp. 306-30
Direct Measurement of the Fermi Energy in Graphene Using a Double Layer Structure
We describe a technique which allows a direct measurement of the relative
Fermi energy in an electron system using a double layer structure, where
graphene is one of the two layers. We illustrate this method by probing the
Fermi energy as a function of density in a graphene monolayer, at zero and in
high magnetic fields. This technique allows us to determine the Fermi velocity,
Landau level spacing, and Landau level broadening in graphene. We find that the
N=0 Landau level broadening is larger by comparison to the broadening of upper
and lower Landau levels.Comment: 5 pages, 4 figure
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