Two Particle States in a Box and the ss-Matrix in Multi-Channel Scattering

Using a quantum mechanical model, the exact energy eigenstates for two-particle two-channel scattering are studied in a cubic box with periodic boundary conditions. A relation between the exact energy eigenvalue in the box and the two-channel $S$-matrix elements in the continuum is obtained. This result can be viewed as a generalization of the well-known L\"uscher's formula which establishes a similar relation in elastic scattering.Comment: 4 pages, typeset with ws-ijmpa.cls. Talk presented at International Conference on QCD and Hadronic Physics, June 16-20, 2005, Beijing, China. One reference adde

Massive Overlap Fermions on Anisotropic Lattices

We formulate the massive overlap fermions on anisotropic lattices. We find that the dispersion relation for the overlap fermion resembles the continuum form in the low-momentum region once the bare parameters are properly tuned. The quark self-energy and the quark field renormalization constants are calculated to one-loop in bare lattice perturbation theory. We argue that massive domain wall quarks might be helpful in lattice QCD studies on heavy-light hadron spectroscopy.Comment: 21 pages, 5 figures, one reference added compared with v.

Regulations on Biotechnological Research and Biologically Modified Products

The developments in biotechnology have brought not only benefits but also harms to society. On the one hand, the biotechnologically modified products has rapidly changed our lifestyle, but on the other hand, they could also endanger the ecosystem due to their reproduction and novel characteristics, and raise sharp debate over social values, including moral and religious values, and ethical standards. These rapid developments and problems of biotechnology posed a significant challenge to policymakers. E.g., are current regulations enough? Or do we need more regulations for biotechnological experiments and the development of genetically modified products because of their potential negative impacts? After comparing the advantages (such as the avoidance of the negative and special influences of biotechnology, and the solution of market failure and social injustice) and disadvantages (such as economic loss, government failure, and violation of social justice and freedom of scientific experiments), this research addressed that more and specified regulations are necessary. However, the scope of regulations ¡V or how much control the government should have in scientific development ¡V should be reasonably limited to give consideration to the independence of scientific fields, and economic developments. First, the regulations of biotechnological experiments should be looser than those of genetically modified products because of the different substantial impacts on consumers, and the respect of the freedom of speech (or research). Second, more participation of the general public will help to avoid the professionals¡¦ and governments¡¦ arbitrary decisions. Third, the regulations of ¡§Physical Risks¡¨ and ¡§Social Risks and Ethical Considerations¡¨ should be different because their influences are varified

Scaling of geometric phase versus band structure in cluster-Ising models

We study the phase diagram of a class of models in which a generalized cluster interaction can be quenched by Ising exchange interaction and external magnetic field. We characterize the various phases through winding numbers. They may be ordinary phases with local order parameter or exotic ones, known as symmetry protected topologically ordered phases. Quantum phase transitions with dynamical critical exponents z = 1 or z = 2 are found. Quantum phase transitions are analyzed through finite-size scaling of the geometric phase accumulated when the spins of the lattice perform an adiabatic precession. In particular, we quantify the scaling behavior of the geometric phase in relation with the topology and low energy properties of the band structure of the system