26,352 research outputs found
dimensional Dirac equation with non Hermitian interaction
We study dimensional Dirac equation with non Hermitian interactions,
but real energies. In particular, we analyze the pseudoscalar and scalar
interactions in detail, illustrating our observations with some examples. We
also show that the relevant hidden symmetry of the Dirac equation with such an
interaction is pseudo supersymmetry.Comment: 9 page
Book Review: The Impact of Ancient Indian Thought on Christianity
A review of The Impact on Ancient Indian Thought on Christianity by Braj M. Sinha
Angular Distribution and CP Asymmetries in the Decays B->K^-pi^+e^-e^+ and B->pi^-pi^+e^-e^+
The short-distance Hamiltonian describing b->s(d)e^-e^+ in the standard model
is used to obtain the decay spectrum of \bar{B}->K^-pi^+e^-e^+ and
\bar{B}->pi^-pi^+e^-e^+, assuming the Kpi and pipi systems to be the decay
products of K^* and rho respectively. Specific features calculated are (i)
angular distribution of K^- (or pi^-) in the K^-pi^+ (or pi^-pi^+)
centre-of-mass (c.m.) frame; (ii) angular distribution of e^- in the e^-e^+
c.m. frame; and (iii) the correlation between the meson and lepton planes. We
also derive CP-violating observables obtained by combining the above decays
with the conjugate processes B->K^+pi^-e^-e^+ and B->pi^-pi^+e^-e^+.Comment: 19 pages, REVTeX, no figures. Equations (2.19a), (2.19b), (5.5)-(5.7)
have been corrected; all results remain unchanged. These changes will appear
in an Erratum submitted to Phys. Rev.
Octet baryon magnetic moments from QCD sum rules
A comprehensive study is made for the magnetic moments of octet baryons in
the method of QCD sum rules. A complete set of QCD sum rules is derived using
the external field method and generalized interpolating fields. For each
member, three sum rules are constructed from three independent tensor
structures. They are analyzed in conjunction with the corresponding mass sum
rules. The performance of each of the sum rules is examined using the criteria
of OPE convergence and ground-state dominance, along with the role of the
transitions in intermediate states. Individual contributions from the u, d and
s quarks are isolated and their implications in the underlying dynamics are
explored. Valid sum rules are identified and their predictions are obtained.
The results are compared with experiment and previous calculations.Comment: 21 pages, 11 figures, 6 figures; added a reference, minor change in
tex
Motion sequence analysis in the presence of figural cues
Published in final edited form as: Neurocomputing. 2015 January 5, 147: 485–491The perception of 3-D structure in dynamic sequences is believed to be subserved primarily through the use of motion cues. However, real-world sequences contain many figural shape cues besides the dynamic ones. We hypothesize that if figural cues are perceptually significant during sequence analysis, then inconsistencies in these cues over time would lead to percepts of non-rigidity in sequences showing physically rigid objects in motion. We develop an experimental paradigm to test this hypothesis and present results with two patients with impairments in motion perception due to focal neurological damage, as well as two control subjects. Consistent with our hypothesis, the data suggest that figural cues strongly influence the perception of structure in motion sequences, even to the extent of inducing non-rigid percepts in sequences where motion information alone would yield rigid structures. Beyond helping to probe the issue of shape perception, our experimental paradigm might also serve as a possible perceptual assessment tool in a clinical setting.The authors wish to thank all observers who participated in the experiments reported here. This research and the preparation of this manuscript was supported by the National Institutes of Health RO1 NS064100 grant to LMV. (RO1 NS064100 - National Institutes of Health)Accepted manuscrip
Dynamic Transitions in Small World Networks: Approach to Equilibrium
We study the transition to phase synchronization in a model for the spread of
infection defined on a small world network. It was shown (Phys. Rev. Lett. {\bf
86} (2001) 2909) that the transition occurs at a finite degree of disorder ,
unlike equilibrium models where systems behave as random networks even at
infinitesimal in the infinite size limit. We examine this system under
variation of a parameter determining the driving rate, and show that the
transition point decreases as we drive the system more slowly. Thus it appears
that the transition moves to in the very slow driving limit, just as in
the equilibrium case.Comment: 8 pages, 2 figure
Robust Emergent Activity in Dynamical Networks
We study the evolution of a random weighted network with complex nonlinear
dynamics at each node, whose activity may cease as a result of interactions
with other nodes. Starting from a knowledge of the micro-level behaviour at
each node, we develop a macroscopic description of the system in terms of the
statistical features of the subnetwork of active nodes. We find the asymptotic
characteristics of this subnetwork to be remarkably robust: the size of the
active set is independent of the total number of nodes in the network, and the
average degree of the active nodes is independent of both the network size and
its connectivity. These results suggest that very different networks evolve to
active subnetworks with the same characteristic features. This has strong
implications for dynamical networks observed in the natural world, notably the
existence of a characteristic range of links per species across ecological
systems.Comment: 4 pages, 5 figure
Hadronic components of EAS by rigorous saddle point method in the energy range between 10(5) and 10(8) GeV
The study of hadronic components in the high energy range between 10 to the 5 and 10 to the 8 Gev exhibits by far the strongest mass sensitivity since the primary energy spectrum as discussed by Linsley and measured by many air shower experimental groups indicates a change of slope from -1.7 to 2.0 in this energy range. This change of slope may be due to several reasons such as a genuine spectral feature of astrophysical origin, a confinement effect of galactic component or a rather rapid change of mass, a problem which we have attempted to study here in detail
- …