125 research outputs found
Composite vortex model of the electrodynamics of high- superconductor
We propose a phenomenological model of vortex dynamics in which the vortex is
taken as a composite object made of two components: the vortex current which is
massless and driven by the Lorentz force, and the vortex core which is massive
and driven by the Magnus force. By combining the characteristics of the
Gittleman-Rosenblum model (Phys. Rev. Lett. {\bf 16}, 734 (1966)) and Hsu's
theory of vortex dynamics (Physica {\bf C 213},305 (1993)), the model provides
a good description of recent far infrared measurements of the
magneto-conductivity tensor of superconducting YBaCuO
films from 5 cm to 200 cm.Comment: LaTex file (12 pages) + 3 Postscript figures, uuencoded. More
information on this paper, please check
http://www.wam.umd.edu/~lihn/newmodel
Measurement of the Far Infrared Magneto-Conductivity Tensor of Superconducting YBaCuO Thin Films
We report measurements of the far infrared transmission of superconducting
YBaCuO thin films from 5 cm to 200 cm in
fields up to 14. A Kramers-Kronig analysis of the magneto-transmission
spectrum yields the magneto-conductivity tensor. The result shows that the
magneto-conductivity of YBaCuO is dominated by three
terms: a London term, a low frequency Lorentzian ( 3 cm) of width 10 cm and a finite frequency Lorentzian of
width 17 cm at 24 cm in the hole
cyclotron resonance active mode of circular polarization.\\Comment: Revised LaTex file (12 pages) + 4 Postscript figures, uuencoded. In
response to referees' comments, we refined the paper a lot; we encourage you
to download this revised versio
Electrodynamics of a Clean Vortex Lattice
We report on a microscopic evaluation of electrodynamic response for the
vortex lattice state of a model s-wave superconductor. Our calculation accounts
self-consistently for both quasiparticle and order parameter response and
establishes the collective nature of linear response in the clean limit. We
discuss the effects of homogeneous and inhomogeneous pinning on the optical
conductivity and the penetration depth, and comment on the relationship between
macroscopic and local penetration depths. We find unexpected relationships
between pinning arrangements and conductivity due to the strongly non-local
response.Comment: 4 pages, 2 figure
Sum rule for the optical Hall angle
We consider the optical Hall conductivity of a general electronic medium and
prove that the optical Hall angle obeys a new sum rule. This sum rule governs
the response of an electronic fluid to a Lorentz electric field and can thought
of as the transverse counterpart to the f-sum rule in optical conductivity. The
physical meaning of this sum rule is discussed, giving a number of examples of
its application to a variety of of electronic media.Comment: Four pages. Latex file with two postscript figure
Grain Boundary Induced Magneto-Far Infrared Resonances in Superconducting YBaCuO Thin Films
Spectral features induced by 45 in-plane misoriented grains have
been observed in the far infrared magneto-transmission of YBaCuO thin films. Two strong dispersive features are found at 80 and
160 and a weaker one at 116 . The data can be well
represented by Lorentzian oscillator contributions to the conductivity. Several
possible interpretations are discussed. We conclude that the resonances are due
to vortex core excitations.Comment: Latex file (14 pages) + 4 Postscript figures, uuencode
Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor
In the presence of an external magnetic field, the low lying elementary
excitations of a d-wave superconductor have quantized energy and their momenta
are locked near the node direction. It is argued that these discrete states can
most likely be detected by a local probe, such as a scanning tunneling
microscope. The low temperature local tunneling conductance on the Wigner-Seitz
cell boundaries of the vortex lattice is predicted to show peaks spaced as . The peak is anomalous, and it is present only
if the superconducting order parameter changes sign at certain points on the
Fermi surface. Away from the cell boundary, where the superfluid velocity is
nonzero, each peak splits, in general, into four peaks, corresponding to the
number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included
Optimizing patient care and outcomes through the congenital heart center of the 21st century
Pediatric cardiovascular services are responding to the dynamic changes in the medical environment, including the business of medicine. The opportunity to advance our pediatric cardiology field through collaboration is now realized, permitting us to define meaningful quality metrics and establish national benchmarks through multicenter efforts. In March 2016, the American College of Cardiology hosted the first Adult Congenital/Pediatric Cardiology Section Congenital Heart Community Day. This was an open participation meeting for clinicians, administrators, patients/parents to propose metrics that optimize patient care and outcomes for a stateâ ofâ theâ art congenital heart center of the 21st century. Care center collaboration helps overcome the barrier of relative small volumes at any given program. Patients and families have become active collaborative partners with care centers in the definition of acute and longitudinal outcomes and our quality metrics. Understanding programmatic metrics that create an environment to provide outstanding congenital heart care will allow centers to improve their structure, processes and ultimately outcomes, leading to an increasing number of centers that provide excellent care. This manuscript provides background, as well listing of proposed specialty domain quality metrics for centers, and thus serves as an updated baseline for the ongoing dynamic process of optimizing care and realizing patient value.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143653/1/chd12575_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143653/2/chd12575.pd
Vector electromagnetic theory of transition and diffraction radiation with application to the measurement of longitudinal bunch size
We have developed a novel method based on vector electromagnetic theory and
Schellkunoff's principles to calculate the spectral and angular distributions
of transtion radiation (TR) and diffraction radiation (DR) produced by a
charged particle interacting with an arbitrary target. The vector method
predicts the polarization and spectral angular distributions of the radiation
at an arbitrary distance form the source, i.e. in both the near and far fields,
and in any direction of observation. The radiation fields of TR and DR
calculated with the commonly used scalar Huygens model are shown to be limiting
forms of those predicted by the vector theory and the regime of validity of the
scalar theory is explicitly shown. Calculations of TR and DR done using the
vector model are compared to results available in the literature for various
limiting cases and for cases of more general interest. Our theory has important
applications in the design of TR and DR diagnostics particularly those that
utilize coherent TR or DR to infer the longitudinal bunch size and shape. A new
technique to determine the bunch length using the angular distribution of
coherent TR or DR is proposed.Comment: 47 pages, 16 figures, accepted for publication in Phys. Rev. ST.
Accel. and Beam
AMP-Activated Protein Kinase–Deficient Mice Are Resistant to the Metabolic Effects of Resveratrol
Adipokines and the insulin resistance syndrome in familial partial lipodystrophy caused by a mutation in lamin A/C
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