66,260 research outputs found
Ferromagnetic one dimensional Ti atomic chain
Using the full potential linearized augmented plane wave (FLAPW) method, we
have explored the magnetic properties of one dimensional (1D) Ti atomic chain.
Astonishingly, we for the first time observed that the 1D Ti atomic chain has
ferromagnetic ground state even on NiAl(110) surface although the Ti has no
magnetic moment in bulk or macroscopic state. It was found that the physical
property of direct exchange interaction among Ti atoms occurred in free
standing state is well preserved on NiAl(110) surface and this feature has an
essential role in ferromagnetism of 1D Ti atomic chain. It was shown that the
m= state has the largest contribution to the magnetic moment of Ti atom
grown on NiAl(110) surface. In addition, we found that the magnetic dipole
interaction is a key factor in the study of magnetic anisotropy, not the
magnetocrystalline anisotropy arising from spin-orbit interaction
Pseudoscalar or vector meson production in non-leptonic decays of heavy hadrons
We have addressed the study of non-leptonic weak decays of heavy hadrons
( and ), with external and internal emission to
give two final hadrons, taking into account the spin-angular momentum structure
of the mesons and baryons produced.
A detailed angular momentum formulation is developed which leads to easy
final formulas. By means of them we have made predictions for a large amount of
reactions, up to a global factor, common to many of them, that we take from
some particular data. Comparing the theoretical predictions with the
experimental data, the agreement found is quite good in general and the
discrepancies should give valuable information on intrinsic form factors,
independent of the spin structure studied here. The formulas obtained are also
useful in order to evaluate meson-meson or meson-baryon loops, for instance of
decays, in which one has PP, PV, VP or VV intermediate states, with P for
pseudoscalar mesons and V for vector meson and lay the grounds for studies of
decays into three final particles.Comment: 54 pages, 7 figures, 13 tables; v2: 60 pages, 9 figures, 14 tables,
discussion added, references added, version to appear in Eur.Phys.J.
Irregular and multi--channel sampling of operators
The classical sampling theorem for bandlimited functions has recently been
generalized to apply to so-called bandlimited operators, that is, to operators
with band-limited Kohn-Nirenberg symbols. Here, we discuss operator sampling
versions of two of the most central extensions to the classical sampling
theorem. In irregular operator sampling, the sampling set is not periodic with
uniform distance. In multi-channel operator sampling, we obtain complete
information on an operator by multiple operator sampling outputs
Theoretical description of the , and reactions
We have made a study of the (with
being and ) and assuming
the axial vector mesons to be dynamically generated from the
pseudoscalar-vector meson interaction. We have taken the needed input from
previous studies of the reactions.
We obtain fair agreement with experimental data and provide an explanation on
why the recent experiment on observed in the mode observes the peak of the
at a higher energy than its nominal mass.Comment: 21 pages, 6 figure
Baryon states with hidden charm in the extended local hidden gauge approach
The s-wave interaction of and , is studied within a unitary coupled channels scheme
with the extended local hidden gauge approach. In addition to the
Weinberg-Tomozawa term, several additional diagrams via the pion-exchange are
also taken into account as box potentials. Furthermore, in order to implement
the full coupled channels calculation, some of the box potentials which mix the
vector-baryon and pseudoscalar-baryon sectors are extended to construct the
effective transition potentials. As a result, we have observed six possible
states in several angular momenta. Four of them correspond to two pairs of
admixture states, two of - with , and two of - with . Moreover, we find a resonance which couples to
the channel and one spin degenerated bound state of
with .Comment: 24 pages, 6 figure
Small-scale Effects of Thermal Inflation on Halo Abundance at High-, Galaxy Substructure Abundance and 21-cm Power Spectrum
We study the impact of thermal inflation on the formation of cosmological
structures and present astrophysical observables which can be used to constrain
and possibly probe the thermal inflation scenario. These are dark matter halo
abundance at high redshifts, satellite galaxy abundance in the Milky Way, and
fluctuation in the 21-cm radiation background before the epoch of reionization.
The thermal inflation scenario leaves a characteristic signature on the matter
power spectrum by boosting the amplitude at a specific wavenumber determined by
the number of e-foldings during thermal inflation (), and strongly
suppressing the amplitude for modes at smaller scales. For a reasonable range
of parameter space, one of the consequences is the suppression of minihalo
formation at high redshifts and that of satellite galaxies in the Milky Way.
While this effect is substantial, it is degenerate with other cosmological or
astrophysical effects. The power spectrum of the 21-cm background probes this
impact more directly, and its observation may be the best way to constrain the
thermal inflation scenario due to the characteristic signature in the power
spectrum. The Square Kilometre Array (SKA) in phase 1 (SKA1) has sensitivity
large enough to achieve this goal for models with if a
10000-hr observation is performed. The final phase SKA, with anticipated
sensitivity about an order of magnitude higher, seems more promising and will
cover a wider parameter space.Comment: 28 pages, 8 figure
Wilson-t'Hooft Loops in Finite-Temperature Non-commutative Dipole Field Theory from Dual Supergravity
We first study the temporal Wilson loop in the finite-temperature
non-commutative dipole field theory from the string/gauge correspondence. The
associated dual supergravity background is constructed from the near-horizon
geometry of near-extremal D-branes, after applying T-duality and smeared twist.
We investigate the string configuration therein and find that while the
temperature produces a maximum distance in the interquark distance
the dipole in there could produce a minimum distance . The quark
boundary pair therefore could be found only if their distance is between
and . We also show that, beyond a critical temperature the
quark pair becomes totally free due to screening by thermal bath. We next study
the spatial Wilson loop and find the confining nature in the zero temperature
3D and 4D non-supersymmetry dipole gauge theory. The string tension of the
linear confinement potential is obtained and found to be a decreasing function
of the dipole field. We also investigate the associated t'Hooft loop and
determine the corresponding monopole anti-monopole potential. The conventional
screening of magnetic charge which indicates the confinement of the electric
charge is replaced by a strong repulsive however. Finally, we show that the
dual string which is rotating along the dipole deformed will behave as a
static one without dipole field, which has no minimum distance and has larger
energy than a static one with dipole field. We discuss the phase transition
between these string solutions.Comment: Latex, 22 pages, 8 figures, add several comment
Finite-size scaling in complex networks
A finite-size-scaling (FSS) theory is proposed for various models in complex
networks. In particular, we focus on the FSS exponent, which plays a crucial
role in analyzing numerical data for finite-size systems. Based on the
droplet-excitation (hyperscaling) argument, we conjecture the values of the FSS
exponents for the Ising model, the susceptible-infected-susceptible model, and
the contact process, all of which are confirmed reasonably well in numerical
simulations
Price Determination in the Bottled Water Industry: A Case Study of Poland Spring
This paper analyzes the price of a single brand in the bottled water industry. We find that the brand's price is negatively related to its own share. We also find that price is positively related to the four firm concentration ratio in the carbonated segment, but unrelated in the noncarbonated segment.Demand and Price Analysis,
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