Spring 2009, IA Alumna discovers fascinating world of food culture and production through Italian graduate program

Jacqueline Lewin graduated from UNH in 2005 with a dual major in international affairs and French. Her interest in the Slow Food movement has led her to a masters program at the University of Gastronomic Sciences in Colorno, Italy

Renormalization of Dirac's Polarized Vacuum

We review recent results on a mean-field model for relativistic electrons in atoms and molecules, which allows to describe at the same time the self-consistent behavior of the polarized Dirac sea. We quickly derive this model from Quantum Electrodynamics and state the existence of solutions, imposing an ultraviolet cut-off $\Lambda$. We then discuss the limit $\Lambda\to\infty$ in detail, by resorting to charge renormalization.Comment: Proceedings of the Conference QMath 11 held in Hradec Kr\'alov\'e (Czechia) in September 201

Semi-classical limit of the Levy-Lieb functional in Density Functional Theory

In a recent work, Bindini and De Pascale have introduced a regularization of $N$-particle symmetric probabilities which preserves their one-particle marginals. In this short note, we extend their construction to mixed quantum fermionic states. This enables us to prove the convergence of the Levy-Lieb functional in Density Functional Theory , to the corresponding multi-marginal optimal transport in the semi-classical limit. Our result holds for mixed states of any particle number $N$, with or without spin.Comment: Final version to appear in Comptes rendus de l'Acad{\'e}mie des Sciences, Math{\'e}matique

Digital decoder for phase-delay coded data

Coded or modulated digital data converts to nonreturn to zero /NRZ/ data. Technique includes logic implementation and pertinent timing diagrams. Demodulation to NRZ facilitates digital logic operations on incoming data. Phase-delay modulation has advantage of inherent self-timing not present in NRZ modulation

Geometric methods for nonlinear many-body quantum systems

Geometric techniques have played an important role in the seventies, for the study of the spectrum of many-body Schr\"odinger operators. In this paper we provide a formalism which also allows to study nonlinear systems. We start by defining a weak topology on many-body states, which appropriately describes the physical behavior of the system in the case of lack of compactness, that is when some particles are lost at infinity. We provide several important properties of this topology and use them to provide a simple proof of the famous HVZ theorem in the repulsive case. In a second step we recall the method of geometric localization in Fock space as proposed by Derezi\'nski and G\'erard, and we relate this tool to our weak topology. We then provide several applications. We start by studying the so-called finite-rank approximation which consists in imposing that the many-body wavefunction can be expanded using finitely many one-body functions. We thereby emphasize geometric properties of Hartree-Fock states and prove nonlinear versions of the HVZ theorem, in the spirit of works of Friesecke. In the last section we study translation-invariant many-body systems comprising a nonlinear term, which effectively describes the interactions with a second system. As an example, we prove the existence of the multi-polaron in the Pekar-Tomasevich approximation, for certain values of the coupling constant.Comment: Final version to appear in Journal of Functional Analysi

A dilogarithmic integral arising in quantum field theory

Recently, an interesting dilogarithmic integral arising in quantum field theory has been closed-form evaluated in terms of the Clausen function $\text{Cl}_2(\theta)$ by Coffey [J. Math. Phys.} 49 (2008), 093508]. It represents the volume of an ideal tetrahedron in hyperbolic space and is involved in two intriguing equivalent conjectures of Borwein and Broadhurst. It is shown here, by simple and direct arguments, that this integral can be expressed by the triplet of the Clausen function values which are involved in one of the two above-mentioned conjectures.Comment: 6 page

Expanded access to secondary schooling in Sub-Saharan Africa: key planning and finance issues

This paper makes the case for managed expansion of secondary schooling in Sub-Saharan Africa. The great majority of secondary age African children remain excluded from access to good quality secondary schooling. Increasing numbers are graduating from primary schools where enrolments are rapidly growing as a result of successful Education for All programmes. The knowledge and skill that secondary schools can provide is central to closing the gap between Sub Saharan Africa and the rest of the world in the capabilities in the labour force that can sustain growth. The analyses undertaken for the Secondary Education in Africa (SEIA) programme of the World Bank have explored many dimensions of the challenges ahead. This paper complements this work and offers new insights into necessary reforms of policy and practice. It outlines the current status and structure of secondary provision, and the demographic issues that will influence expanded access. It then elaborates some of the key issues facing governments and development partners, and reviews the resources that would be needed to reach different levels of participation. It offers a set of policy options and strategies that can be used to shape managed growth within sustainable financial frameworks. The analysis indicates that budget shares between educational levels and overall spending on secondary education need to be revisited if higher participation is to be achieved. More than 3.0% of gross national product (GNP) would be needed to achieve gross enrolment rates of 60% at lower secondary and 30% at upper secondary in low enrolment countries with existing cost structures. The costs per pupil have to fall if expanded access is to be sustainable. No countries with ratios of secondary to primary unit costs of more than 3:1 succeed in universalising access to secondary schooling but many countries remain above these levels. New balances will have to struck between rates of expansion towards enrolment targets at primary, lower and upper secondary levels. Structural changes are needed that can facilitate higher secondary enrolment rates at affordable costs and diminish gender inequities. Better management of the flow of pupils could increase completion rates and lower costs per successful completer. Improved teacher deployment will be critical to successful expansion. Much more access could be provided if norms for pupil-teacher ratios (e.g. 35:1 at lower secondary, and 25:1 at upper secondary) could be applied and if class teacher ratios at secondary level fell from 3:1 to less than 2:1. Trained teachers will be critical to secondary expansion. Where demand is greatest, and initial training lengthy and expensive, alternative methods will have to be considered which lower costs of training and increase supply. So also will be changes in school management that can provide some incentives to manage human and physical resources efficiently. Secondary expansion without curriculum reform risks irrelevance and wastage. New populations of school children require curricula that address their needs, respond to changing social and economic circumstances, and recognise resource constraints. Alongside this physical capacity needs planned expansion in ways that optimise increased access. Expanded secondary access will benefit greatly from successful mechanisms to generate support from the communities that schools serve. There are many possible methods of cost-sharing and cost-recovery that can and should be facilitated. These need to be linked to the capacity of households to support fees and contributions so that they do not become exclusionary. Partnerships with non-government providers can make some contribution to expanded access. However, they are most likely to play a complementary role since they are unlikely to be the providers of last resort to those otherwise excluded by location, household income, or low achievement