20,406 research outputs found
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
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
Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions
Unpolarized and beam-polarized fourfold cross sections (d(4)sigma / dQ(2)dx(B)dtd phi) for the ep - \u3e e\u27p\u27gamma reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 (Q(2), x (B), t) bins over the widest phase space ever explored in the valence-quark region. Several models of generalized parton distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD H, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton form factors, these results support the model predictions of a larger nucleon size at lower quark-momentum fraction x (B)
Orbital-dependent metamagnetic response in Sr4Ru3O10
We show that the metamagnetic transition in SrRuO bifurcates
into two transitions as the field is rotated away from the conducting planes.
This two-step process comprises partial or total alignment of moments in
ferromagnetic bands followed by an itinerant metamagnetic transition whose
critical field increases with rotation. Evidence for itinerant metamagnetism is
provided by the Shubnikov-de Hass effect which shows a non-trivial evolution of
the geometry of the Fermi surface and an enhancement of the quasiparticles
effective-mass across the transition. The metamagnetic response of
SrRuO is orbital-dependent and involves ferromagnetic and
metamagnetic bands.Comment: Physical Review B (in press
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