18,628 research outputs found
p-p' System with B Field and Projection Operator Noncommutative Solitons
We study the system of the Dp'-brane with Dp-brane (p<p') inside, in the case
where B_{ij} field is a nonvanishing constant. In order to understand how the
Dp-brane is viewed from the Dp'-brane worldvolume theory, we investigate the
process in which the Dp-brane is probed with p'-p' open string. We calculate
the scattering amplitudes among p-p' open strings and p'-p' open strings and
show that not only the Weyl transform of the projection operator onto the
ground state but also those onto higher excited states emerge as multiplicative
factors of the amplitudes.Comment: 22 pages, LaTeX2
Talk about Rice: A Discursive Approach to Studying Culture.
The paper examines the ways in which people talk about others of different culture or ethnic origin. I analyse interview talk of the British W.W.II veterans about their experiences at the prisoners of war camp in Japan and recent activities of reconciliation. Proposed is a discursive approach to the study of culture and cross-cultural communication, in comparison to work in cultural anthropology and ethnographic conversation analysis. The discussion is guided by two analytic concepts—membership categorisation and ethnification processes. The paper concludes that the ways in which cultural knowledge is constructed, established and shared are discursive accomplishments of a social action of accounting for the war-time past
Fractional Flux Periodicity in Doped Carbon Nanotubes
An anomalous magnetic flux periodicity of the ground state is predicted in
two-dimensional cylindrical surface composed of square and honeycomb lattice.
The ground state and persistent currents exhibit an approximate fractional
period of the flux quantum for a specific Fermi energy. The period depends on
the aspect ratio of the cylinder and on the lattice structure around the axis.
We discuss possibility of this nontrivial periodicity in a heavily doped
armchair carbon nanotube.Comment: 5 pages, 4 figure
Stabilization mechanism of edge states in graphene
It has been known that edge states of a graphite ribbon are zero-energy,
localized eigen-states. We show that next nearest-neighbor hopping process
decreases the energy of the edge states at zigzag edge with respect to the
Fermi energy. The energy reduction of the edge states is calculated
analytically by first-order perturbation theory and numerically. The resultant
model is consistent with the peak of recent scanning tunneling spectroscopy
measurements.Comment: 4 pages, 2 figures, final version to appear in Applied Physics
Letter
The solar wind effect on cosmic rays and solar activity
The relation of cosmic ray intensity to solar wind velocity is investigated, using neutron monitor data from Kiel and Deep River. The analysis shows that the regression coefficient of the average intensity for a time interval to the corresponding average velocity is negative and that the absolute effect increases monotonously with the interval of averaging, tau, that is, from -0.5% per 100km/s for tau = 1 day to -1.1% per 100km/s for tau = 27 days. For tau 27 days the coefficient becomes almost constant independently of the value of tau. The analysis also shows that this tau-dependence of the regression coefficiently is varying with the solar activity
Electron impact on K+: mechanisms for extreme ultraviolet submission
A series of R-matrix calculations on K+ is used to derive electron excitation and ionization cross sections. The excitation cross section to the 4s and 3d levels leading to the K+ 60.1, 60.8 and 61.3nm emission lines shows poor agreement with the cross beam experiment of Zapesochny et al (1986, Zh. Eksp. Teor. Fiz. 90 1972 [Sov. Phys. JETP 63 1155]). Cross sections are also presented for exciting the 4p, 5s and 4d levels, the autoionizing 3s open-shell levels, and for ionization. It is shown how pseudoresonances in the calculated cross section can be eliminated by increasing the target
basis.</p
Yang-Mills theory constructed from Cho--Faddeev--Niemi decomposition
We give a new way of looking at the Cho--Faddeev--Niemi (CFN) decomposition
of the Yang-Mills theory to answer how the enlarged local gauge symmetry
respected by the CFN variables is restricted to obtain another Yang-Mills
theory with the same local and global gauge symmetries as the original
Yang-Mills theory. This may shed new light on the fundamental issue of the
discrepancy between two theories for independent degrees of freedom and the
role of the Maximal Abelian gauge in Yang-Mills theory. As a byproduct, this
consideration gives new insight into the meaning of the gauge invariance and
the observables, e.g., a gauge-invariant mass term and vacuum condensates of
mass dimension two. We point out the implications for the Skyrme--Faddeev
model.Comment: 17pages, 1 figure; English improved; a version appeared in Prog.
Theor. Phy
The sidereal anisotropy of cosmic rays around 3 x 10 (15) eV observed at a middle north latitude
The sidereal time variation of cosmic rays (median primary energy : 3 10 to the 15th power eV) is investigated with air shower observations at Akeno, Japan (900 m a.s.l.) which started in September 1981. Air showers are detected by a coincidence requirement on several muon detectors. The result obtained for three years is suggestive of a big semi-diurnal variation (0.37 % in amplitude). On the other hand, the diurnal variation is rather small than the semi-diurnal one. The feature of the sidereal anisotropy supposed from the present result looks quite different from that below 10 to the 14th power eV
Altitude variations of cosmic-ray soft and hard components observed by airborne detectors
The altitude variations of cosmic-ray total and hard components were measured up to 12,000 m on board a jet liner over Japan island on December, 1981. Observed results together with soft component are presented comparing with the model calculations through the atmosphere by applying the hadronic cascade
- …