15,400 research outputs found
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
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
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
Measuring the Economic Impact of Civil War
Civil wars impose substantial costs on the domestic economy. We empirically measure the economic impact of such internal wars. The paper contributes to the existing literature both theoretically and methodologically. First, it explores the economic channels through which civil war affects growth. Previous studies have shown the negative growth effects of civil wars. We go a step further by identifying the channels through which war strips a country of its growth potential. Our argument is that civil war negatively impacts private investment through the process of portfolio substitution. Methodologically, the paper improves on both the data and statistical models used in the existing literature. Our data set includes better measurements of the intensity and scope of civil war as well as new economic and political data for the 1990s. Moreover, using a multiple imputation technique, we minimize the estimation bias due to missing data. Finally, to improve the model, we apply fixed and random effects models to the panel data. The evidence gives strong support to our argument indicating that the driving force behind the negative effects of civil war on economic growth is a decrease in private investment.civil war, instability, economic growth, investment, fiscal balance
(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 tensor charge and electric dipole moment within the Schwinger-Dyson formalism
We calculate the tensor charge of the quark in the QCD-like theory in the
Landau gauge using the Schwinger-Dyson formalism. It is found that the dressed
tensor charge of the quark is significantly suppressed against the bare quark
contribution, and the result agrees qualitatively with the analyses in the
collinear factorization approach and lattice QCD. We also analyze the quark
confinement effect with the phenomenological strong coupling given by
Richardson, and find that this contribution is small. We show that the
suppression of the quark tensor charge is due to the superposition of the spin
flip of the quark arising from the successive emission of gluons which dress
the tensor vertex. We also consider the relation between the quark and the
nucleon electric dipole moments by combining with the simple constituent quark
model.Comment: 16 pages, 11 figures. arXiv admin note: text overlap with
arXiv:1401.285
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