10,743 research outputs found
Analyses of multiplicity distributions by means of the Modified Negative Binomial Distribution and its KNO scaling function
We analyze various data of multiplicity distributions by means of the
Modified Negative Binomial Distribution (MNBD) and its KNO scaling function,
since this MNBD explains the oscillating behavior of the cumulant moment
observed in e^+e^- annihilations, h-h collisions and e-p collisions. In the
present analyses, we find that the MNBD(discrete distributions) describes the
data of charged particles in e^+e^- annihilations much better than the Negative
Binomial Distribution (NBD). To investigate stochastic property of the MNBD, we
derive the KNO scaling function from the discrete distribution by using a
straightforward method and the Poisson transform. It is a new KNO function
expressed by the Laguerre polynomials. In analyses of the data by using the KNO
scaling function, we find that the MNBD describes the data better than the
gamma function.Thus, it can be said that the MNBD is one of useful formulas as
well as NBD.Comment: 12 pages, latex, 3 figure
SU(3) lattice QCD study for octet and decuplet baryon spectra
The spectra of octet and decuplet baryons are studied using SU(3) lattice QCD
at the quenched level. As an implementation to reduce the statistical
fluctuation, we employ the anisotropic lattice with improved quark
action. In relation to , we measure also the mass of the SU(3)
flavor-singlet negative-parity baryon, which is described as a three quark
state in the quenched lattice QCD, and its lowest mass is measured about 1.6
GeV. Since the experimentally observed negative-parity baryon
is much lighter than 1.6 GeV, may include a large component of
a bound state rather than the three quark state. The mass splitting
between the octet and the decuplet baryons are also discussed in terms of the
current quark mass.Comment: 8 pages, 3 figures, proceeding of "International Symposium on Hadron
and Nuclei" at Yonsei Univ., Seoul, Korea 20-22 Feb. 200
Combinatorial realizations of crystals via torus actions on quiver varieties
Consider Kashiwara's crystal associated to a highest weight representation of
a symmetric Kac-Moody algebra. There is a geometric realization of this object
using Nakajima's quiver varieties, but in many particular cases it can also be
realized by elementary combinatorial methods. Here we propose a framework for
extracting combinatorial realizations from the geometric picture: We construct
certain torus actions on the quiver varieties and use Morse theory to index the
irreducible components by connected components of the subvariety of torus fixed
points. We then discuss the case of affine sl(n). There the fixed point
components are just points, and are naturally indexed by multi-partitions.
There is some choice in our construction, leading to a family of combinatorial
models for each highest weight crystal. Applying this construction to the
crystal of the fundamental representation recovers a family of combinatorial
realizations recently constructed by Fayers. This gives a more conceptual proof
of Fayers' result as well as a generalization to higher level. We also discuss
a relationship with Nakajima's monomial crystal.Comment: 23 pages, v2: added Section 8 on monomial crystals and some
references; v3: many small correction
The Gauge-Bethe Correspondence and Geometric Representation Theory
The Gauge/Bethe correspondence of Nekrasov and Shatashvili relates the
spectrum of integrable spin chains to the ground states of supersymmetric gauge
theories. Up to now, this correspondence has been an observation; the
underlying reason for its existence remaining elusive. We argue here that
geometrical representation theory is the mathematical foundation of the
Gauge/Bethe correspondence, and it provides a framework to study families of
gauge theories in a unified way.Comment: 8 page
Negative-Parity Baryons in Quenched Anisotropic Lattice QCD
We study negative-parity baryon spectra in quenched anisotropic lattice QCD.
The negative-parity baryons are measured as the parity partner of the
ground-state baryons. In addition to the flavor octet and decuplet baryons, we
pay much attention to the flavor-singlet negative-parity baryon as a
three-quark state and compare it with the Lambda(1405) baryon. Numerical
results of the flavor octet and decuplet negative-parity baryon masses are
close to experimental values of lowest-lying negative-parity baryons, while the
flavor-singlet baryon is much heavier than Lambda(1405). This indicates that
the Lambda(1405) would be a multi-quark state such as the N-Kbar molecule
rather than the flavor-singlet 3 quark state.Comment: 4 pages, 4 figs. Talk given at 16th International Conference on
Particles and Nuclei (PANIC 02), Osaka, Japan, 30 Sep - 4 Oct 200
Quantum Coherence and Correlations of optical radiation by atomic ensembles interacting with a two-level atom in microwave cavity
We examine quantum statistics of optical photons emitted from atomic
ensembles which are classically driven and simultaneously coupled to a
two-level atom via microwave photon exchange. Quantum statistics and
correlations are analyzed by calculating second order coherence degree, von
Neumann entropy, spin squeezing for multi-particle entanglement, as well as
genuine two and three-mode entanglement parameters for steady state and
non-equilibrium situations. Coherent transfer of population between the
radiation modes and quantum state mapping between the two-level atom and the
optical modes are discussed. A potential experimental realization of the
theoretical results in a superconducting coplanar waveguide resonator
containing diamond crystals with Nitrogen-Vacancy color centers and a
superconducting artificial two-level atom is discussed.Comment: 15 pages, 17 figures, submitted to Phys. Rev.
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