Spin Structure of the Proton

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton's spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global leading-order QCD fit to obtain the spin-dependent quark distributions, which could be used as input for analyzing lepton-hadron and hadron-hadron collisions.Comment: 13 pages, NCKU-HEP/94-0

Structural Aspects of the Proton in the Chiral Quark Model

We calculate with chiral symmetry the parton contents of the proton based on a two-component wave function. The calculation results give significant sea-quark contents and, especially, the intrinsic gluon polarization produced at a more fundamental level.Comment: 10 pages, LaTe

New product introduction and diffusion with costly search

Will the low search cost in the new economy help speed up new product introduction? The usual model of product market search suggests that a low search cost can turn out to have detrimental incentives on innovation and new product introduction as the low search cost erodes firms' market power, attenuating the profit from innovation. This usual model, however, misses the important dimension of product market search that how often it pays to search depends on the magnitude of the search cost. This paper studies a model of monopolistic competition with costly search, where the point of departure is that of a fixed cost of a shopping trip. With this fixed cost, the optimal search frequency is tied to the magnitude of the search cost. In this environment, a low search cost could turn out to be favorable to innovation. At a low search cost, consumers search more often, speeding up the diffusion of new products and possibly resulting in higher profits for firms, despite the erosion of market power.product market search, innovation, new product introduction

Deposit Insurance and the Composition of Bank Suspensions in Developing Economies: Lessons from the State Deposit Insurance Experiments of the 1920S

Eight states established deposit insurance systems between 1908 and 1917. All abandoned the systems between 1921 and 1930. Scholars debate the costs and benefits of these policy experiments. New data drawn from the archives of the Federal Reserve Board of Governors demonstrate that deposit insurance influenced the composition of bank suspensions in these states. In typical years, suspensions due to runs fell. Suspensions due to mismanagement rose. During the penultimate year of each system, the bank failure rate rose to an unsustainable height and the system ceased operations.

Quench Dynamics of Topological Maximally-Entangled States

We investigate the quench dynamics of the one-particle entanglement spectra (OPES) for systems with topologically nontrivial phases. By using dimerized chains as an example, it is demonstrated that the evolution of OPES for the quenched bi-partite systems is governed by an effective Hamiltonian which is characterized by a pseudo spin in a time-dependent pseudo magnetic field $\vec{S}(k,t)$. The existence and evolution of the topological maximally-entangled edge states are determined by the winding number of $\vec{S}(k,t)$ in the $k$-space. In particular, the maximally-entangled edge states survive only if nontrivial Berry phases are induced by the winding of $\vec{S}(k,t)$. In the infinite time limit the equilibrium OPES can be determined by an effective time-independent pseudo magnetic field \vec{S}_{\mb{eff}}(k). Furthermore, when maximally-entangled edge states are unstable, they are destroyed by quasiparticles within a characteristic timescale in proportional to the system size.Comment: 5 pages, 3 figure