Counting similarities between tetraquark and mesonic/gluonic operators

After the study of the preclusion of exotic meson states in large-$N_c$ limit QCD, combining Weinberg's opposite proposal, we get different counting orders for a tetraquark operator to create or destroy an one-tetraquark state. Meanwhile, by comparing tetraquark operator with the mesonic and gluonic operators, we find that tetraquark operators are similar with mesonic and gluonic operators in the counting. Furthermore, we find a mixing of different kinds of operators.Comment: 4 page

Estimating the Stochastic Sickness Effect on Employment, Worktime and Saving Decisions

This paper aims to study labor supply and saving decisions as a result of health uncertainty. O’Donnell (1995) suggested a theoretical positive relationship between working hours (or saving rate) and the perceived health uncertainty. That is, for risk-averse individuals, there exists a precaution motion to work harder and save more when facing the uncertainty for the health condition. We test this hypothetical relationship by applying the 2003-2005 data from the Panel Study of Family Dynamics (PSFD) in Taiwan. Following Hughes and Maguire’s approach (2003), our estimation result indicates that a stochastic sickness has positive effects on the decisions of working time and saving rate.Health, Uncertainty, Labor Supply, Saving

Rashba Spin Interferometer

A spin interferometer utilizing the Rashba effect is proposed. The novel design is composed of a one-dimensional (1D) straight wire and a 1D half-ring. By calculating the norm of the superposed wave function, we derive analytical expressions to describe the spin interference spectrum as a function of the Rashba coupling strength. Presented spin interference results are identified to include (i) the quantum-mechanical 4pi rotation effect, (ii) geometric effect, and (iii) Shubnikov-de Haas-like beating effect.Comment: 3 pages, 3 figures, appears in the proceedings of the 10th Joint MMM/Intermag Conferenc

Quantum World-line Monte Carlo Method with Non-binary Loops and Its Application

A quantum world-line Monte Carlo method for high-symmetrical quantum models is proposed. Firstly, based on a representation of a partition function using the Matsubara formula, the principle of quantum world-line Monte Carlo methods is briefly outlined and a new algorithm using non-binary loops is given for quantum models with high symmetry as SU(N). The algorithm is called non-binary loop algorithm because of non-binary loop updatings. Secondary, one example of our numerical studies using the non-binary loop updating is shown. It is the problem of the ground state of two-dimensional SU(N) anti-ferromagnets. Our numerical study confirms that the ground state in the small N <= 4 case is a magnetic ordered Neel state, but the one in the large N >= 5 case has no magnetic order, and it becomes a dimer state.Comment: 14 pages, 5 figures, Invited talk at the 18th Annual Workshop on Recent Developments of Computer Simulation Studies in Condensed Matter Physics, Athens, 7-11 March, 200

Mining progressive user behavior for e-commerce using virtual reality technique

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on March 21, 2008)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2007.Dissertations, Academic -- University of Missouri--Columbia -- Computer science.In the past decade, the virtual reality (VR) technique has been becoming a popular marketing tool on e-commerce websites, where the consumers are allowed to interact with the products and have a vivid shopping experience simulated to the real world. Despite of the advantages, VR shopping is still at its early stage due to some difficulties, namely, 1) complex communication among VR components, backend relational databases, and web services, 2) meaningful interpretation of mined patterns into the user behavior through VR tools, and 3) vast amount of information to mine and efficient summarization of the results to guide user's navigation. To overcome these obstacles, several techniques from the fields of Information Retrieval and Data Mining & Knowledge Discovery have been adopted and extended for the development of our system that is able to recommend products computationally according to the user's preference. These techniques include ranking in a Vector-Space Model to profile user's behavior based on their demographic information and mining Association Rules to analyze user's choices as well as real-time navigational behavior. This system can adapt itself to meet each individual's interest progressively. It is our ultimate goal to provide a general framework that can be applied to any web-based e-commerce applications where customers can find the most fitting products efficiently and effectively under a virtual reality environment