58,167 research outputs found
Formation of \eta'(958)-mesic nuclei and axial U_A(1) anomaly at finite density
We discuss the possibility to produce the bound states of the
meson in nuclei theoretically. We calculate the formation cross sections of the
bound states with the Green function method for (,p) reaction
and discuss the experimental feasibility at photon facilities like SPring-8. We
conclude that we can expect to observe resonance peaks in (,p) spectra
for the formation of bound states and we can deduce new information on
properties at finite density. These observations are believed to be
essential to know the possible mass shift of and deduce new information
of the effective restoration of the chiral anomaly in the nuclear
medium.Comment: 4 pages, 3 figure
Determination of polarized parton distribution functions
We study parametrization of polarized parton distribution functions in the
\alpha_s leading order (LO) and in the next-to-leading order (NLO). From \chi^2
fitting to the experimental data on A_1, optimum polarized distribution
functions are determined. The quark spin content \Delta\Sigma is very sensitive
to the small-x behavior of antiquark distributions which suggests that small-x
data are needed for precise determination of \Delta\Sigma. We propose three
sets of distributions and also provide FORTRAN library for our distributions.Comment: 1+5 pages, LATEX, aipproc.sty, 4 eps figures. Talk given at the 14th
International Spin Physics Symposium, Osaka, Japan, October 16-21, 200
Quantum network coding for quantum repeaters
This paper considers quantum network coding, which is a recent technique that
enables quantum information to be sent on complex networks at higher rates than
by using straightforward routing strategies. Kobayashi et al. have recently
showed the potential of this technique by demonstrating how any classical
network coding protocol gives rise to a quantum network coding protocol. They
nevertheless primarily focused on an abstract model, in which quantum resource
such as quantum registers can be freely introduced at each node. In this work,
we present a protocol for quantum network coding under weaker (and more
practical) assumptions: our new protocol works even for quantum networks where
adjacent nodes initially share one EPR-pair but cannot add any quantum
registers or send any quantum information. A typically example of networks
satisfying this assumption is {\emph{quantum repeater networks}}, which are
promising candidates for the implementation of large scale quantum networks.
Our results thus show, for the first time, that quantum network coding
techniques can increase the transmission rate in such quantum networks as well.Comment: 9 pages, 11figure
A tight analysis of Kierstead-Trotter algorithm for online unit interval coloring
Kierstead and Trotter (Congressus Numerantium 33, 1981) proved that their
algorithm is an optimal online algorithm for the online interval coloring
problem. In this paper, for online unit interval coloring, we show that the
number of colors used by the Kierstead-Trotter algorithm is at most , where is the size of the maximum clique in a given
graph , and it is the best possible.Comment: 4 page
The Nature of Support from Adult Sansei (Third Generation) Children to Older Nisei (Second Generation) Parents in Japanese Canadian Families
Given the growing ethnocultural diversity of Canada's aging population and the increased research focus on the role of the family in the social support of older persons, it is important to explore the ways in which adult ethnic minority children provide assistance to older parents within the context of the family. The current study contributes to research on intergenerational support systems in later life in Japanese Canadian families by examining the factors, particularly the cultural value of oya koh koh (filial obligation), affecting the nature of support from adult children to older parents. Using data gathered from interviews with 100 older nisei (second generation) parents and 100 adult sansei (third generation) children in British Columbia, the study focuses on the frequency, quality and provision of three types of support: emotional, service, and financial. Results of logistic regression analyses indicate that oya koh koh has a significant effect on children's provision of emotional support, but no effect on financial or service support. Parent's health and socioeconomic status are found to have significant effects on children's provision of financial and service support. Child's availability is also a major determinant of financial support. Further, ordinary least squares (OLS) regression analyses results suggest that oya koh koh has a significant effect on the quality of emotional support provided by children to their parents. Findings are discussed in terms of the North American Asian "ideal" family myth and directions for future research.family support; filial obligation, intergenerational relations; Japanese Canadian; model minority myth
Global analysis by hidden symmetry
Hidden symmetry of a G'-space X is defined by an extension of the G'-action
on X to that of a group G containing G' as a subgroup. In this setting, we
study the relationship between the three objects:
(A) global analysis on X by using representations of G (hidden symmetry);
(B) global analysis on X by using representations of G';
(C) branching laws of representations of G when restricted to the subgroup
G'.
We explain a trick which transfers results for finite-dimensional
representations in the compact setting to those for infinite-dimensional
representations in the noncompact setting when is -spherical.
Applications to branching problems of unitary representations, and to spectral
analysis on pseudo-Riemannian locally symmetric spaces are also discussed.Comment: Special volume in honor of Roger Howe on the occasion of his 70th
birthda
Quantum States from Tangent Vectors
We argue that tangent vectors to classical phase space give rise to quantum
states of the corresponding quantum mechanics. This is established for the case
of complex, finite-dimensional, compact, classical phase spaces C, by
explicitly constructing Hilbert-space vector bundles over C. We find that these
vector bundles split as the direct sum of two holomorphic vector bundles: the
holomorphic tangent bundle T(C), plus a complex line bundle N(C). Quantum
states (except the vacuum) appear as tangent vectors to C. The vacuum state
appears as the fibrewise generator of N(C). Holomorphic line bundles N(C) are
classified by the elements of Pic(C), the Picard group of C. In this way Pic(C)
appears as the parameter space for nonequivalent vacua. Our analysis is
modelled on, but not limited to, the case when C is complex projective space.Comment: Refs. update
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