7,134 research outputs found
New Approach for Evaluating Incomplete and Complete Fusion Cross Sections with Continuum-Discretized Coupled-Channels Method
We propose a new method for evaluating incomplete and complete fusion cross
sections separately using the Continuum-Discretized Coupled-Channels method.
This method is applied to analysis of the deuteron induced reaction on a 7Li
target up to 50 MeV of the deuteron incident energy. Effects of deuteron
breakup on this reaction are explicitly taken into account. Results of the
method are compared with those of the Glauber model, and the difference between
the two is discussed. It is found that the energy dependence of the incomplete
fusion cross sections obtained by the present calculation is almost the same as
that obtained by the Glauber model, while for the complete fusion cross
section, the two models give markedly different energy dependence. We show also
that a prescription for evaluating incomplete fusion cross sections proposed in
a previous study gives much smaller result than an experimental value.Comment: 10 pages, 5 figure
Analysis of (K^-,K^+) inclusive spectrum with semiclassical distorted wave model
The inclusive K^+ momentum spectrum in the 12C(K^-,K^+) reaction is
calculated by the semiclassical distorted wave (SCDW) model, including the
transition to the \Xi^- bound state. The calculated spectra with the strength
of the \Xi^--nucleus potential -50, -20, and +10 MeV are compared with the
experimental data measured at KEK with p_{K^-}=1.65 GeV/c. The shape of the
spectrum is reproduced by the calculation. Though the inclusive spectrum
changes systematically depending on the potential strength, it is not possible
to obtain a constraint on the potential from the present data. The calculated
spectrum is found to have strong emission-angle dependence. We also investigate
the incident K^- momentum dependence of the spectrum to see the effect of the
Fermi motion of the target nucleons which is explicitly treated in the SCDW
method.Comment: 7 pages, 5 figure
Experimental band structure of the nearly half-metallic CuCrSe: An optical and magneto-optical study
Diagonal and off-diagonal optical conductivity spectra have been determined
form the measured reflectivity and magneto-optical Kerr effect (MOKE) over a
broad range of photon energy in the itinerant ferromagnetic phase of
CuCrSe at various temperatures down to T=10 K. Besides the low-energy
metallic contribution and the lower-lying charge transfer transition at
2 eV, a sharp and distinct optical transition was observed in the
mid-infrared region around 0.5 eV with huge magneto-optical activity.
This excitation is attributed to a parity allowed transition through the Se-Cr
hybridization-induced gap in the majority spin channel. The large off-diagonal
conductivity is explained by the high spin polarization in the vicinity of the
Fermi level and the strong spin-orbit interaction for the related charge
carriers. The results are discussed in connection with band structure
calculations
Experimental demonstration of four-party quantum secret sharing
Secret sharing is a multiparty cryptographic task in which some secret
information is splitted into several pieces which are distributed among the
participants such that only an authorized set of participants can reconstruct
the original secret. Similar to quantum key distribution, in quantum secret
sharing, the secrecy of the shared information relies not on computational
assumptions, but on laws of quantum physics. Here, we present an experimental
demonstration of four-party quantum secret sharing via the resource of
four-photon entanglement
On discrete constant principal curvature surfaces
Recently, it is discovered that a certain class of nanocarbon materials has
geometrical properties related to the discrete geometry, pre-constant discrete
principal curvature [9] based on the discrete surface theory proposed on
trivalent graphs by Kotani, Naito and Omori [10]. In this paper, with the aim
of an application to the nanocarbon materials, we will study discrete constant
principal curvature (CPC) surfaces. Firstly, we developed the discrete surface
theory on a full 3-ary oriented tree so that we define a discrete analogue of
principal directions on them to investigate it. We also construct some
interesting examples of discrete constant principal curvature surfaces,
including discrete CPC tori.Comment: 13 pages, 9 figure
Hierarchy of Temporal Responses of Multivariate Self-Excited Epidemic Processes
We present the first exact analysis of some of the temporal properties of
multivariate self-excited Hawkes conditional Poisson processes, which
constitute powerful representations of a large variety of systems with bursty
events, for which past activity triggers future activity. The term
"multivariate" refers to the property that events come in different types, with
possibly different intra- and inter-triggering abilities. We develop the
general formalism of the multivariate generating moment function for the
cumulative number of first-generation and of all generation events triggered by
a given mother event (the "shock") as a function of the current time . This
corresponds to studying the response function of the process. A variety of
different systems have been analyzed. In particular, for systems in which
triggering between events of different types proceeds through a one-dimension
directed or symmetric chain of influence in type space, we report a novel
hierarchy of intermediate asymptotic power law decays of the rate of triggered events as a function of the
distance of the events to the initial shock in the type space, where for the relevant long-memory processes characterizing many natural
and social systems. The richness of the generated time dynamics comes from the
cascades of intermediate events of possibly different kinds, unfolding via a
kind of inter-breeding genealogy.Comment: 40 pages, 8 figure
Spin-Gap Phase in the One-Dimensional t-J-J' Model
The spin-gap phase of the one-dimensional t-J-J' model is studied by the
level-crossing of the singlet and the triplet excitation spectra.
The phase boundary obtained between the Tomonaga-Luttinger and the spin-gap
phases is remarkably consistent with the analytical results at the
and the low-density limits discussed by Ogata et al.
The spin-gap phase has a single domain in the phase diagram even if the spin
gap opens at half-filling.
The phase boundary coincides with the line where the
Tomonaga-Luttinger liquid behaves as free electrons, in the low-density region.
The relation between our method and the solution of the two-electron problem
is also discussed.Comment: 4 pages(JPSJ.sty), 5 figures(EPS), to appear in J. Phys. Soc. Jpn.
67, No.3 (1998
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