Slater screening constants in atomic and molecular orbitals

Slater screening constants in atomic and molecular orbital

An interesting example for spectral invariants

In "Illinois J. of Math. {\bf 38} (1994) 653--678", the heat operator of a Bismut superconnection for a family of generalized Dirac operators is defined along the leaves of a foliation with Hausdorff groupoid. The Novikov-Shubin invariants of the Dirac operators were assumed greater than three times the codimension of the foliation. It was then showed that the associated heat operator converges to the Chern character of the index bundle of the operator. In "J. K-Theory {\bf 1} (2008) 305--356", we improved this result by reducing the requirement on the Novikov-Shubin invariants to one half of the codimension. In this paper, we construct examples which show that this is the best possible result.Comment: Third author added. Some typos corrected and some material added. Appeared in Journal of K Theory, Volume 13, in 2014, pages 305 to 31

Fermionic Projected Entangled Pair States and Local U(1) Gauge Theories

Tensor networks, and in particular Projected Entangled Pair States (PEPS), are a powerful tool for the study of quantum many body physics, thanks to both their built-in ability of classifying and studying symmetries, and the efficient numerical calculations they allow. In this work, we introduce a way to extend the set of symmetric PEPS in order to include local gauge invariance and investigate lattice gauge theories with fermionic matter. To this purpose, we provide as a case study and first example, the construction of a fermionic PEPS, based on Gaussian schemes, invariant under both global and local U(1) gauge transformations. The obtained states correspond to a truncated U(1) lattice gauge theory in 2 + 1 dimensions, involving both the gauge field and fermionic matter. For the global symmetry (pure fermionic) case, these PEPS can be studied in terms of spinless fermions subject to a p-wave superconducting pairing. For the local symmetry (fermions and gauge fields) case, we find confined and deconfined phases in the pure gauge limit, and we discuss the screening properties of the phases arising in the presence of dynamical matter

Segmentation of Retail Food Store Formats in Qingdao, China

This study empirically estimates a multivariate binary choice model for four categories of food shopping store formats. The results indicate that in the Qingdao market, traditional counter parts such as wet markets and small grocery stores have been dominated by supermarkets and hypermarkets. At the same time, the rapid growth of hypermarkets in Qingdao is significantly challenging current supermarkets in this city, but they do not compete extensively with wet markets and small grocery stores. Further development of various categories of the food shopping store format is linked to store owned characteristics, potential interrelations among existing retail formats, as well as consumers' demographics and shopping habits.Food retail store format, consumer choice, multivariate probit model, China, Agribusiness,

Electronic Hong-Ou-Mandel interferometry in two-dimensional topological insulators

The edge states of a two-dimensional topological insulator are characterized by their helicity, a very remarkable property which is related to the time-reversal symmetry and the topology of the underlying system. We theoretically investigate a Hong-Ou-Mandel like setup as a tool to probe it. Collisions of two electrons with the same spin show a Pauli dip, analogous to the one obtained in the integer quantum Hall case. Moreover, the collisions between electrons of opposite spin also lead to a dip, known as $\mathbb{Z}_{2}$ dip, which is a direct consequence of the constraints imposed by time-reversal symmetry. In contrast to the integer quantum Hall case, the visibility of these dips is reduced by the presence of the additional edge channels, and crucially depends on the properties of the quantum point contact. As a unique feature of this system, we show the possibility of three-electron interference, which leads to a total suppression of the noise independently of the point contact configuration. This is assured by the peculiar interplay between Fermi statistics and topology. This work intends to extend the domain of applicability of electron quantum optics.Comment: 12 pages, 7 figure

Functional Foods in the Marketplace: Willingness to Pay for Apples Enriched with Antioxidants

The attention on so-called functional foods has been growing as consumers become more concerned with diet and nutrition. This article aims to measure consumers response to apples with naturally enriched antioxidant coatings. Surveys were conducted in grocery stores in Seattle, Washington and Spokane, Washington. The results suggest that consumers have a somewhat positive attitude towards functional foods in general and with apples enriched with antioxidants in particular. A contingent valuation technique was used to assess factors affecting consumers willingness to pay for the apples with antioxidant coatings. Consumers in the Spokane grocery stores are more likely to pay a premium for the new type of apples than consumers in Seattle. Consumers who look for a wide variety of product in choosing where to shop for food are more likely to pay a premium for apples enriched with antioxidants. Also, it is estimated that consumers, on average, are willing to pay from 4% to 8% premium for these apples.functional food, willingness to pay, antioxidants, Demand and Price Analysis, Health Economics and Policy,

IMPLICATIONS OF THE CONSUMER RESPONSE TO EMERGING TECHNOLOGIES AND DISEASES FOR INTERNATIONAL TRADE: THE CASE OF JAPAN

International Relations/Trade,

Hartree-Fock calculations for the ground and first excited states of H2

Hartree-Fock calculation for ground and first excited state of H

Fluid milk consumption in urban Qingdao, China

This study relates the social-demographic characteristics of urban Chinese consumers to their consumption of fluid milk. A Tobit model is estimated drawing on individual consumer survey data collected in urban Qingdao in China in 2005. The major results of this study indicate that fluid milk consumption in urban Qingdao is much higher compared to China’s national level. The effect of increased income on milk consumption is positive, as expected. The expansion of modern food retailers also appears to play a positive role by facilitating consumers’ fluid milk consumption and influencing their food shopping patterns. The young and old consume significantly more fluid milk than the middle-aged. Health consciousness of the elderly and the openness of youth to new foods appear to be fuelling these consumption patterns. If the findings of this study apply to other urban regions in China, then as urbanisation continues so also will the trend of increasing fluid milk consumption in China.China, fluid milk consumption, market participation, Qingdao, Food Consumption/Nutrition/Food Safety,