3,053 research outputs found
Electronic Phase Diagram of High-T_c Cuprate Superconductors from a Mapping of the In-Plane Resistivity Curvature
We propose that Resistivity Curvature Mapping (RCM) based on the in-plane
resistivity data is a useful way to objectively draw an electronic phase
diagrams of high-T_c cuprates, where various crossovers are important. In
particular, the pseudogap crossover line can be conveniently determined by RCM.
We show experimental phase diagrams obtained by RCM for
Bi_{2}Sr_{2-z}La_{z}CuO_{6+\delta}, La_{2-x}Sr_{x}CuO_{4}, and
YBa_{2}Cu_{3}O_{y}, and demonstrate the universal nature of the pseudogap
crossover. Intriguingly, the electronic crossover near optimum doping depicted
by RCM appears to occur rather abruptly, suggesting that the quantum critical
regime, if exists, must be very narrow.Comment: 4 pages, 3 color figures, final version accepted for publication in
Phys. Rev. Let
Evolution of the Hall Coefficient and the Peculiar Electronic Structure of the Cuprate Superconductors
Although the Hall coefficient R_H is an informative transport property of
metals and semiconductors, its meaning in the cuprate superconductors has been
ambiguous because of its unusual characteristics. Here we show that a
systematic study of R_H in La_{2-x}Sr_{x}CuO_{4} single crystals over a wide
doping range establishes a qualitative understanding of its peculiar evolution,
which turns out to reflect a two-component nature of the electronic structure
caused by an unusual development of the Fermi surface recently uncovered by
photoemission experiments.Comment: 4 pages, 5 figures, final version appeared in Phys. Rev. Let
Naked singularity resolution in cylindrical collapse
In this paper, we study the gravitational collapse of null dust in the
cylindrically symmetric spacetime. The naked singularity necessarily forms at
the symmetry axis. We consider the situation in which null dust is emitted
again from the naked singularity formed by the collapsed null dust and
investigate the back-reaction by this emission for the naked singularity. We
show a very peculiar but physically important case in which the same amount of
null dust as that of the collapsed one is emitted from the naked singularity as
soon as the ingoing null dust hits the symmetry axis and forms the naked
singularity. In this case, although this naked singularity satisfies the strong
curvature condition by Kr\'{o}lak (limiting focusing condition), geodesics
which hit the singularity can be extended uniquely across the singularity.
Therefore we may say that the collapsing null dust passes through the
singularity formed by itself and then leaves for infinity. Finally the
singularity completely disappears and the flat spacetime remains.Comment: 17 pages, no figur
Quasinormal Ringing for Acoustic Black Holes at Low Temperature
We investigate a condensed matter ``black hole'' analogue, taking the
Gross-Pitaevskii (GP) equation as a starting point. The linearized GP equation
corresponds to a wave equation on a black hole background, giving quasinormal
modes under some appropriate conditions. We suggest that we can know the
detailed characters and corresponding geometrical information about the
acoustic black hole by observing quasinormal ringdown waves in the low
temperature condensed matters.Comment: 9 pages, 3 figures, PRD accepted versio
Thermodynamics of Squashed Kaluza-Klein Black Holes and Black Strings -- A Comparison of Reference Backgrounds --
We investigate thermodynamics constructed on different background reference
spacetimes for squashed Kaluza-Klein (SqKK) black hole and electrically charged
black string in five-dimensional Einstein-Maxwell system. Two spacetimes are
possible to be reference spacetimes giving finite gravitational classical
actions: one is four-dimensional Minkowski times a circle and the other is the
KK monopole. The boundary of the SqKK black hole can not be matched perfectly
to that of the former reference spacetime because of the difference in
topology. However, the resultant classical action coincides with that
calculated by the counterterm subtraction scheme. The boundary of the KK
monopole has the same topology with that of the SqKK black hole and can be
matched to the boundary of the black hole perfectly. The resultant action takes
different value from the result given by using the former reference spacetime.
After a brief review of thermodynamic quantities of the black hole solutions,
we calculate thermodynamic potentials relevant for several thermodynamic
environments. The most stable state is different for each environment: For
example, the KK monopole is the most stable state in isothermal environment
with fixed gravitational tension. On the other hand, when the size of the
extra-dimension is fixed, the Minkowski times a circle is the most stable. It
is shown that these two spacetimes can be reference spacetimes of the
five-dimensional black string.Comment: 28 pages; references added, typo corrected;version accepted for
publication in Class. Quantum Gra
"Spin-Flop" Transition and Anisotropic Magnetoresistance in Pr_{1.3-x}La_{0.7}Ce_{x}CuO_{4}: Unexpectedly Strong Spin-Charge Coupling in Electron-Doped Cuprates
We use transport and neutron-scattering measurements to show that a
magnetic-field-induced transition from noncollinear to collinear spin
arrangement in adjacent CuO_{2} planes of lightly electron-doped
Pr_{1.3-x}La_{0.7}Ce_{x}CuO_{4} (x=0.01) crystals affects significantly both
the in-plane and out-of-plane resistivity. In the high-field collinear state,
the magnetoresistance (MR) does not saturate, but exhibits an intriguing
four-fold-symmetric angular dependence, oscillating from being positive at
B//[100] to being negative at B//[110]. The observed MR of more than 30% at low
temperatures induced by a modest modification of the spin structure indicates
an unexpectedly strong spin-charge coupling in electron-doped cuprates.Comment: 4 pages, 5 figures, accepted for publication in Phys. Rev. Let
Comparison of imaging follow-up between joints with arthroscopic surgery (Lysis and lavage) and those with nonsurgical treatment
ArticleJournal of Oral and Maxillofacial Surgery. 65(7):1309-1314 (2007)journal articl
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