2,262 research outputs found
Pressure effects on the superconducting thin film BaKFeAs
We report electrical resistivity measurements on a high-quality
BaKFeAs thin film () under pressure. The
superconducting transition temperature (=39.95 K) of the optimally-doped thin
film shows a dome shape with pressure, reaching a maximal value 40.8 K at 11.8
kbar. The unusually high superconducting transition temperature and its
anomalous pressure dependence are ascribed to a lattice mismatch between the
LaAlO substrate and the thin film. The local temperature exponent of the
resistivity () shows a funnel shape around
the optimal pressure, suggesting that fluctuations associated with the
anomalous normal state are responsible for high-temperature superconductivity.Comment: To appear in Appl. Phys. Let
Probing Smearing Effect by Point-Like Graviton in Plane-Wave Matrix Model
We investigate the interaction between flat membrane and point-like graviton
in the plane-wave matrix model. The one-loop effective potential in the large
distance limit is computed and is shown to be of r^{-3} type where r is the
distance between two objects. This type of interaction has been interpreted as
the one incorporating the smearing effect due to the configuration of flat
membrane in plane-wave background. Our result supports this interpretation and
provides one more evidence about it.Comment: 22 pages, LaTeX2
Dynamics of false vacuum bubbles with nonminimal coupling
We study the dynamics of false vacuum bubbles. A nonminimally coupled scalar
field gives rise to the effect of negative tension. The mass of a false vacuum
bubble from outside observer's point of view can be positive, zero, or
negative. The interior false vacuum has de Sitter geometry, while the exterior
true vacuum background can have geometry depending on the vacuum energy. We
show that there exist expanding false vacuum bubbles without the initial
singularity in the past.Comment: 17 pages, 13 figure
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