Radiative Neutrino Mass in Type III Seesaw Model

The simplest type III seesaw model as originally proposed introduces one lepton triplet. It thus contains four active neutrinos, two massive and two massless at tree level. We determine the radiative masses that the latter receive first at two loops. The masses are generally so tiny that they are definitely excluded by the oscillation data, if the heavy leptons are not very heavy, say, within the reach of LHC. To accommodate the data on masses, the seesaw scale must be as large as the scale of grand unification. This indicates that the most economical type III model would entail no new physics at low energies beyond the tiny neutrino masses.Comment: 21 pages, 1 figure; v2: added 3 sentences in sec 4 for clarifications, version published on 7 Apr 2009 in PR D79, 073003 (2009

Spectra of Baryons Containing Two Heavy Quarks in Potential Model

In this work, we employ the effective vertices for interaction between diquarks (scalar or axial-vector) and gluon where the form factors are derived in terms of the B-S equation, to obtain the potential for baryons including a light quark and a heavy diquark. The concerned phenomenological parameters are obtained by fitting data of $B^{(*)}-$mesons instead of the heavy quarkonia. The operator ordering problem in quantum mechanics is discussed. Our numerical results indicate that the mass splitting between $B_{3/2}(V), B_{1/2}(V)$ and $B_{1/2}(S)$ is very small and it is consistent with the heavy quark effective theory (HQET).Comment: 16 page

Nonequilibrium thermal entanglement in three-qubit XXXX model

Making use of the master equation and effective Hamiltonian approach, we investigate the steady state entanglement in a three-qubit $XX$ model. Both symmetric and nonsymmetric qubit-qubit couplings are considered. The system (the three qubits) is coupled to two bosonic baths at different temperatures. We calculate the steady state by the effective Hamiltonian approach and discuss the dependence of the steady state entanglement on the temperatures and couplings. The results show that for symmetric qubit-qubit couplings, the entanglements between the nearest neighbor are equal, independent of the temperatures of the two baths. The maximum of the entanglement arrives at $T_L=T_R$. For nonsymmetric qubit-qubit couplings, however, the situation is totally different. The baths at different temperatures would benefit the entanglement and the entanglements between the nearest neighbors are no longer equal. By examining the probability distribution of each eigenstate in the steady state, we present an explanation for these observations. These results suggest that the steady entanglement can be controlled by the temperature of the two baths.Comment: Comments are welcom

Decoy State Quantum Key Distribution With Modified Coherent State

To beat PNS attack, decoy state quantum key distribution (QKD) based on coherent state has been studied widely. We present a decoy state QKD protocol with modified coherent state (MCS). By destruction quantum interference, MCS with fewer multi-photon events can be get, which may improve key bit rate and security distance of QKD. Through numerical simulation, we show about 2-dB increment on security distance for BB84 protocol.Comment: 4 pages, 4 figure

Technological Support for a Learning Oriented Knowledge Management System

Knowledge management is quickly becoming a requirement for today’s complex organizations. Creating and managing existing knowledge has been linked to successful innovation and to sustainable competitive advantage. However, systems specifically designed to manage knowledge, support knowledge creation, and verify existing knowledge are in their infancy. This article follows the framework for a Learning-Oriented Knowledge Management System, and shows how such a complex system can be supported by an equally complex technology – that is, a multi-agent system. We define single agents and multi-agent systems and subsystems in the context of knowledge management systems in general, and the Learning-Oriented Knowledge Management System (LOKMS) specifically. We show how a multi-agent system can be conceived to fully support the LOKMS, describe some necessary agents and agent subsystems, and demonstrate prototypically a multi-agent system designed and built to support the integrity-checking component of the LOKMS. This system begins the process of LOKMS design and development

Quantum theory of light diffraction

At present, the theory of light diffraction only has the simple wave-optical approach. In this paper, we study light diffraction with the approach of relativistic quantum theory. We find that the slit length, slit width, slit thickness and wave-length of light have affected to the diffraction intensity and form of diffraction pattern. However, the effect of slit thickness on the diffraction pattern can not be explained by wave-optical approach, and it can be explained in quantum theory. We compare the theoretical results with single and multiple slits experiment data, and find the theoretical results are accordance with the experiment data. Otherwise, we give some theory prediction. We think all the new prediction will be tested by the light diffraction experiment.Comment: 10 page

The Effects of Flow on Learning Outcomes in an Online Information Management Cou

As online courses and programs expand in business schools, it becomes increasingly important to understand the link between students\u27 experiences in these courses and learning outcomes. The study reported here investigates the relationship between students\u27 experiences of flow, a psychological state generally associated with improved task performance, and learning outcomes in an online information management course taught in an MBA program. Four learning outcomes (objective learning performance, perceived learning of the subject matter, perceived skill development, and student satisfaction) are predicted to be affected by an overall flow score, four dimensions of flow, and three characteristics of flow activities. Support is found for a relationship between flow and students\u27 perceived learning of the subject matter, students\u27 perceived skill development, and student satisfaction. The findings of the study have implications for the design and instruction of online courses offered in business schools