Electromagnetic Form Factors of Nucleons with QCD Constraints Sytematic Study of the Space and Time-like Regions

Elastic electromagnetic form factors of nucleons are investigated both for the time-like and the space-like momentums under the condition that the QCD constraints are satisfied asymptotically. The unsubtracted dispersion relation with the superconvergence conditions are used as a realization of the QCD conditions. The experimental data are analyzed by using the dispersion formula and it is shown that the calculated form factors reproduce the experimental data reasonably well.Comment: 14 page

Comparative evaluation of catalyst materials using a binary choice model

Advances in algorithms and hardware have enabled computers to design new materials atom-by-atom. However, in order for these computer-generated materials to truly address problems of societal importance, such as clean energy generation, it is not enough for them to have superior physical properties. It is also important for them to be adopted by as many users as possible. In this paper, we present a simple binary choice model for comparing catalyst materials on the basis of consumer preferences. This model considers a population of utility maximisers who select one of two materials by comparing catalytic turnover rates with sales prices. Through a mixture of numerical simulation and analytic theorems, we characterise the predictions of the model in a variety of regimes of consumer behavior. We also show how the model can be used as a guide for crafting policies for lowering catalyst prices in order to improve their market shares. This work represents a first step towards understanding how material properties should be balanced against production costs and consumer demand when designing new materials, an intellectual advance which may facilitate the spread of green materials in society.Comment: 23 pages, 6 figures, 1 table. Re-write and expansion of a previous versio

Distribution of the spacing between two adjacent avoided crossings

We consider the frequency at which avoided crossings appear in an energy level structure when an external field is applied to a quantum chaotic system. The distribution of the spacing in the parameter between two adjacent avoided crossings is investigated. Using a random matrix model, we find that the distribution of these spacings is well fitted by a power-law distribution for small spacings. The powers are 2 and 3 for the Gaussian orthogonal ensemble and Gaussian unitary ensemble, respectively. We also find that the distributions decay exponentially for large spacings. The distributions in concrete quantum chaotic systems agree with those of the random matrix model.Comment: 11 page

Chaotic Transport in the Symmetry Crossover Regime with a Spin-orbit Interaction

We study a chaotic quantum transport in the presence of a weak spin-orbit interaction. Our theory covers the whole symmetry crossover regime between time-reversal invariant systems with and without a spin-orbit interaction. This situation is experimentally realizable when the spin-orbit interaction is controlled in a conductor by applying an electric field. We utilize a semiclassical approach which has recently been developed. In this approach, the non-Abelian nature of the spin diffusion along a classical trajectory plays a crucial role. New analytical expressions with one crossover parameter are semiclassically derived for the average conductance, conductance variance and shot noise. Moreover numerical results on a random matrix model describing the crossover from the GOE (Gaussian Orthogonal Ensemble) to the GSE (Gaussian Symplectic Ensemble) are compared with the semiclassical expressions.Comment: 13 pages, 7 figure

NMR C-NOT gate through Aharanov-Anandan's phase shift

Recently, it is proposed to do quantum computation through the Berry's phase(adiabatic cyclic geometric phase) shift with NMR (Jones et al, Nature, 403, 869(2000)). This geometric quantum gate is hopefully to be fault tolerant to certain types of errors because of the geometric property of the Berry phase. Here we give a scheme to realize the NMR C-NOT gate through Aharonov-Anandan's phase(non-adiabatic cyclic phase) shift on the dynamic phase free evolution loop. In our scheme, the gate is run non-adiabatically, thus it is less affected by the decoherence. And, in the scheme we have chosen the the zero dynamic phase time evolution loop in obtaining the gepmetric phase shift, we need not take any extra operation to cancel the dynamic phase.Comment: 5 pages, 1 figur

Entanglement Cost of Antisymmetric States and Additivity of Capacity of Some Quantum Channel

We study the entanglement cost of the states in the contragredient space, which consists of $(d-1)$ $d$-dimensional systems. The cost is always $\log_2 (d-1)$ ebits when the state is divided into bipartite \C^d \otimes (\C^d)^{d-2}. Combined with the arguments in \cite{Matsumoto02}, additivity of channel capacity of some quantum channels is also shown.Comment: revtex 4 pages, no figures, small changes in title and author's affiliation and some typo are correcte