330 research outputs found
Separation of Low Reynolds Number Flows Around a Corner
It was shown experimentally that low Reynolds number flows around a sharp corner do not separate at the corner, and separation points move downstream from the corner with decrease in Reynolds number. For the flow in a channel with a backward-facing step, the experimental results showed a good agreement with those of numerical calculation for the position of separation points and the length of standing vortices
Black holes in five-dimensional gauged supergravity with higher derivatives
We examine five-dimensional gauged supergravity including
terms up to four derivatives. These additional terms correspond to the
supersymmetric completion of , and were originally obtained in
hep-th/0611329 using conformal supergravity techniques. Here we integrate out
the auxiliary fields and obtain the on-shell action for minimal supergravity
with such corrections. We then construct -charged AdS black holes to linear
order in the four derivative terms and investigate the effect of these
corrections on their thermodynamical properties. Finally, we relate the
geometrical coefficients governing the four-derivative corrections to gauge
theory data using holographic anomaly matching. This enables us to obtain a
microscopic expression for the entropy of the solutions.Comment: 34 pages. Typos fixed, some comments and references adde
Development Of L-band High Power Rf Source For The Japanese hadron Project proton Linear Accelerator
correlations from the stopped reaction on He
We have investigated correlations of coincident pairs from the
stopped reaction on He, and clearly observed and
branches of the two-nucleon absorption process in the
invariant mass spectra. In addition, non-mesonic reaction channels, which
indicate possible exotic signals for the formation of strange multibaryon
states, have been identified.Comment: 5 pages, 3 figures, submitted to Physical Review Letter
Vortices, Q-balls and Domain Walls on Dielectric M2-branes
We study BPS solitons in N=6 U(N) \times U(N) Chern-Simons-matter theory
deformed by an F-term mass. The F-term mass generically breaks N=6
supersymmetry down to N=2. At vacua, M2-branes are polarized into a fuzzy S^3
forming a spherical M5-brane with topology \mathbf{R}^{1,2} \times S^3. The
polarization is interpreted as Myers' dielectric effect caused by an
anti-self-dual 4-form flux T_4 in the eleven-dimensional supergravity. Assuming
a polarized M2-brane configuration, the model effectively reduces to the
well-known abelian Chern-Simons-Higgs model studied in detail by
Jackiw-Lee-Weinberg. We find that the potential for the fuzzy S^3 radius agrees
with the one calculated from the M5-brane point of view at large N. This
effective model admits not only BPS topological vortex and domain wall
solutions but also non-topological solitons that keep 1/4 of the manifest N=2
supersymmetry. We also comment on the reduction of our configuration to ten
dimensions.Comment: references added, minor modification
Carrier concentrations in Bi_{2}Sr_{2-z}La_{z}CuO_{6+\delta} single crystals and their relation to Hall coefficient and thermopower
We measured the thermopower S and the Hall coefficients R_H of
Bi_{2}Sr_{2-z}La_{z}CuO_{6+\delta} (BSLCO) single crystals in a wide doping
range, in an effort to identify the actual hole concentrations per Cu, p, in
this system. It is found that the "universal" relation between the
room-temperature thermopower and T_c does not hold in the BSLCO system.
Instead, comparison of the temperature-dependent R_H data with other cuprate
systems is used as a tool to identify the actual p value. To justify this
approach, we compare normalized R_H(T) data of BSLCO, La_{2-x}Sr_{x}CuO_{4}
(LSCO), YBa_{2}Cu_{3}O_{y}, and Tl_{2}Ba_{2}CuO_{6+\delta}, and demonstrate
that the R_H(T) data of the LSCO system can be used as a template for the
estimation of p. The resulting phase diagram of p vs T_c for BSLCO suggests
that T_c is anomalously suppressed in the underdoped samples, becoming zero at
around p ~ 0.10, while the optimum T_c is achieved at p ~ 0.16 as expected.Comment: 4 pages including 5 figures, accepted for publication in Phys. Rev.
B, Rapid Communication
Higher derivative effects on eta/s at finite chemical potential
We examine the effects of higher derivative corrections on eta/s, the ratio
of shear viscosity to entropy density, in the case of a finite R-charge
chemical potential. In particular, we work in the framework of five-dimensional
N =2 gauged supergravity, and include terms up to four derivatives,
representing the supersymmetric completion of the Chern-Simons term A \wedge Tr
(R \wedge R). The addition of the four-derivative terms yields a correction
which is a 1/N effect, and in general gives rise to a violation of the eta/s
bound. Furthermore, we find that, once the bound is violated, turning on the
chemical potential only leads to an even larger violation of the bound.Comment: Typos fixed, references and comments on conventions adde
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