18,697 research outputs found
Real-time evolution method and its application to 3 cluster system
A new theoretical method is proposed to describe the ground and excited
cluster states of atomic nuclei. The method utilizes the equation-of-motion of
the Gaussian wave packets to generate the basis wave functions having various
cluster configurations. The generated basis wave functions are superposed to
diagonalize the Hamiltonian. In other words, this method uses the real time as
the generator coordinate. The application to the system as a
benchmark shows that the new method works efficiently and yields the result
consistent with or better than the other cluster models. Brief discussion on
the structure of the excited and states is also made
Diurnal variations from muon data at Takeyama underground station
An underground station, Takeyama, is introduced, and some results of the solar diurnal and semi-diurnal variations for the period between 1967 and 1984 are presented. There are clear tendencies of double and single solar cycle variations in the daily variations which are in good accord with those detected by other underground and neutron monitor observations
Superconductivity in Pseudo-Binary Silicide SrNixSi2-x with AlB2-Type Structure
We demonstrate the emergence of superconductivity in pseudo-binary silicide
SrNixSi2-x. The compound exhibits a structural phase transition from the cubic
SrSi2-type structure (P4132) to the hexagonal AlB2-type structure (P6/mmm) upon
substituting Ni for Si at approximately x = 0.1. The hexagonal structure is
stabilized in the range of 0.1 < x < 0.7. The superconducting phase appears in
the vicinity of the structural phase boundary. Ni acts as a nonmagnetic dopant,
as confirmed by the Pauli paramagnetic behavior.Comment: 12 pages, 5 figure
Quark tensor and axial charges within the Schwinger-Dyson formalism
We calculate the tensor and axial charges of the quark in the Schwinger-Dyson
formalism of Landau gauge QCD. It is found that the dressed tensor and
isovector axial charges of the quark are suppressed against the bare quark
contribution, and the result agrees qualitatively with the experimental data.
We show that this is due to the superposition of the spin flip of the quark
arising from the successive emission of gluons which dress the vertex. For the
isoscalar quark axial charge, we have analyzed the Schwinger-Dyson equation by
including the leading unquenching quark-loop effect. It is found that the
suppression is more significant, due to the axial anomaly effect.Comment: 5 pages, 4 figures, Contribution of proceedings of XV International
Conference on Hadron Spectroscopy-Hadron 2013 (Hadron 2013
Generalized Landau-Pollak Uncertainty Relation
The Landau-Pollak uncertainty relation treats a pair of rank one projection
valued measures and imposes a restriction on their probability distributions.
It gives a nontrivial bound for summation of their maximum values. We give a
generalization of this bound (weak version of the Landau-Pollak uncertainty
relation). Our generalization covers a pair of positive operator valued
measures. A nontrivial but slightly weak inequality that can treat an arbitrary
number of positive operator valued measures is also presented.Comment: Simplified the proofs. To be published in Phys.Rev.
(63)Cu NQR Evidence for Spatial Variation of Hole Concentration in La(2-x)Sr(x)CuO(4)
We report experimental evidence for the spatial variation of hole
concentration x_(hole) in the high Tc superconductor La(2-x)Sr(x)CuO(4) (0.04
<= x <= 0.16) by using (63)Cu NQR for (63)Cu isotope enriched samples. We
demonstrate that the extent of the spatial variation of the local hole
concentration D(x)_(hole) is reflected on (63)1/T1 and deduce the temperature
dependence. D(x)_(hole) increases below 500 - 600K, and reaches values as large
as D(x)_(hole)/x ~ 0.5 below ~ 150K. We estimate the length scale of the
spatial variation in x_(hole) to be R_(hole) >~ 3nm from analysis of the NQR
spectrum.Comment: Accepted for publication in Physical Review Letter
What has NMR taught us about stripes and inhomogeneity?
The purpose of this brief invited paper is to summarize what we have (not)
learned from NMR on stripes and inhomogeneity in La{2-x}Sr{x}CuO{4}. We explain
that the reality is far more complicated than generally accepted.Comment: Accepted for publication in the Proceedings of the LT-23 Conference
(invited
Quark scalar, axial, and pseudoscalar charges in the Schwinger-Dyson formalism
We calculate the scalar, axial, and pseudoscalar charges of the quark in the
Schwinger-Dyson formalism of Landau gauge QCD. It is found that the dressed
quark scalar density of the valence quark is significantly enhanced against the
bare quark contribution, and the result explains qualitatively the
phenomenologically known value of the pion-nucleon sigma term and also that
given by lattice QCD. Moreover, we show that the Richardson's interquark
potential suppresses the quark scalar density in the Higashjima-Miransky
approximation. This fact suggests that the quark scalar density is an
observable that is sensitive to quark confinement. For the quark axial charge,
we find that it is suppressed due to the gluon dynamics. The result of the
quenched analysis agrees qualitatively with the experimental data of the
isovector axial coupling constant . We show that the suppression of the
quenched axial charge is due to a mechanism similar to that of the quark tensor
charge. In the Schwinger-Dyson equation with the leading unquenching quark-loop
contribution the quark axial charge is more suppressed, due to the anomaly
effect. The quark pseudoscalar density is found to be large, and is divergent
as the bare quark becomes massless. This result is in agreement with the
phenomenological current algebraic analysis, and explains well the dominance of
the pion-pole contribution.Comment: 28 pages, 22 figure
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