17,409 research outputs found
Lax forms of the -Painlev\'e equations
All -Painlev\'e equations which are obtained from the -analog of the
sixth Painlev\'e equation are expressed in a Lax formalism. They are
characterized by the data of the associated linear -difference equations.
The degeneration pattern from the -Painlev\'e equation of type is also
presented.Comment: 24 page
Current-induced persistent magnetization in a relaxorlike manganite
A single crystal of 7% Fe-doped
(LaPr)CaMnO shows up as a typical relaxor
ferromagnet, where ferromagnetic metallic and charge-orbital-ordered insulating
clusters coexist with controllable volume fraction by external stimuli. There,
the persistent ferromagnetic metallic state can be produced by an
electric-current excitation as the filamentary region, the magnetization in
which is increased by ~0.4 per Mn. A clear distinction from the
current heating effect in a magnetic field, which conversely leads to a
decrease in ferromagnetic fraction, enables us to bi-directionally switch both
the magnetization and resistance by applying the voltages with different
magnitudes.Comment: 4 pages, 3 figure
CFT approach to the -Painlev\'e VI equation
Iorgov, Lisovyy, and Teschner established a connection between isomonodromic
deformation of linear differential equations and Liouville conformal field
theory at . In this paper we present a analog of their construction.
We show that the general solution of the -Painlev\'e VI equation is a ratio
of four tau functions, each of which is given by a combinatorial series arising
in the AGT correspondence. We also propose conjectural bilinear equations for
the tau functions.Comment: 26 page
Unified Analysis of Spin Isospin Responses of Nuclei
We investigated the Gamow-Teller (GT) strength distribution, especially the
quenching with respect to the GT sum rule, and the enhancement of the pionic
responses in the quasielasic scattering region, in the same theoretical
framework. That is the continuum random phase approximation with the pi+rho+g'
model interaction, incorporated with distorted wave impulse approximation and
two-step calculations. From this analysis we searched the Landau-Migdal
parameters, g'NN and g'ND, through the comparison with the experimental data of
the GT strength distribution obtained at 300 MeV and the spin-longitudinal
(pionic) cross sections IDq of (p,n) at 350 and 500 MeV. This comprehensive and
sophisticated study gave a common set of g'NN=0.6-0.7 and g'ND=0.2-0.4, for
both low and high momentum transfers.Comment: 11 pages, 4 figures, submitted to Phys. Rev.
Peculiar Velocities of Nonlinear Structure: Voids in McVittie Spacetime
As a study of peculiar velocities of nonlinear structure, we analyze the
model of a relativistic thin-shell void in the expanding universe. (1) Adopting
McVittie (MV) spacetime as a background universe, we investigate the dynamics
of an uncompensated void with negative MV mass. Although the motion itself is
quite different from that of a compensated void, as shown by Haines & Harris
(1993), the present peculiar velocities are not affected by MV mass. (2) We
discuss how precisely the formula in the linear perturbation theory applies to
nonlinear relativistic voids, using the results in (1) as well as the previous
results for the homogeneous background (Sakai, Maeda, & Sato 1993). (3) We
re-examine the effect of the cosmic microwave background radiation. Contrary to
the results of Pim & Lake (1986, 1988), we find that the effect is negligible.
We show that their results are due to inappropriate initial conditions. Our
results (1)-(3) suggest that the formula in the linear perturbation theory is
approximately valid even for nonlinear voids.Comment: 12 pages, aastex, 4 ps figures separate, Fig.2 added, to appear in
Ap
Single domain YBCO/Ag bulk superconductors fabricated by seeded infiltration and growth
We have applied the seeded infiltration and growth (IG) technique to the processing of samples containing Ag in an attempt to fabricate Ag-doped Y-Ba-Cu-O (YBCO) bulk superconductors with enhanced mechanical properties. The IG technique has been used successfully to grow bulk Ag-doped YBCO superconductors of up to 25 mm in diameter in the form of single grains. The distribution of Ag in the parent Y-123 matrix fabricated by the IG technique is observed to be at least as uniform as that in samples grown by conventional top seeded melt growth (TSMG). Fine Y-211 particles were observed to be embedded within the Y-123 matrix for the IG processed samples, leading to a high critical current density, Jc, of over 70 kA/cm2 at 77.3 K in self-field. The distribution of Y-211 in the IG sample microstructure, however, is inhomogeneous, which leads to a variation in the spatial distribution of Jc throughout the bulk matrix. A maximum-trapped field of around 0.43 T at 1.2 mm above the sample surface (i.e. including 0.7 mm for the sensor mould thickness) is observed at liquid nitrogen temperature, despite the relatively small grain size of the sample (20 mm diameter Ă— 7 mm thickness)
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