82 research outputs found

    Talbot Oscillations and Periodic Focusing in a One-Dimensional Condensate

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    An exact theory for the density of a one-dimensional Bose-Einstein condensate with hard core particle interactions is developed in second quantization and applied to the scattering of the condensate by a spatially periodic impulse potential. The boson problem is mapped onto a system of free fermions obeying the Pauli exclusion principle to facilitate the calculation. The density exhibits a spatial focusing of the probability density as well as a periodic self-imaging in time, or Talbot effect. Furthermore, the transition from single particle to many body effects can be measured by observing the decay of the modulated condensate density pattern in time. The connection of these results to classical and atom optical phase gratings is made explicit

    Renormalized kinetic theory of classical fluids in and out of equilibrium

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    We present a theory for the construction of renormalized kinetic equations to describe the dynamics of classical systems of particles in or out of equilibrium. A closed, self-consistent set of evolution equations is derived for the single-particle phase-space distribution function ff, the correlation function C=C=, the retarded and advanced density response functions χR,A=δf/δϕ\chi^{R,A}=\delta f/\delta\phi to an external potential ϕ\phi, and the associated memory functions ΣR,A,C\Sigma^{R,A,C}. The basis of the theory is an effective action functional Ω\Omega of external potentials ϕ\phi that contains all information about the dynamical properties of the system. In particular, its functional derivatives generate successively the single-particle phase-space density ff and all the correlation and density response functions, which are coupled through an infinite hierarchy of evolution equations. Traditional renormalization techniques are then used to perform the closure of the hierarchy through memory functions. The latter satisfy functional equations that can be used to devise systematic approximations. The present formulation can be equally regarded as (i) a generalization to dynamical problems of the density functional theory of fluids in equilibrium and (ii) as the classical mechanical counterpart of the theory of non-equilibrium Green's functions in quantum field theory. It unifies and encompasses previous results for classical Hamiltonian systems with any initial conditions. For equilibrium states, the theory reduces to the equilibrium memory function approach. For non-equilibrium fluids, popular closures (e.g. Landau, Boltzmann, Lenard-Balescu) are simply recovered and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.and we discuss the correspondence with the seminal approaches of Martin-Siggia-Rose and of Rose.Comment: 63 pages, 10 figure

    Once upon a time the cell membranes: 175 years of cell boundary research

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    Peace and Justice through a Feminist Lens: Gender Justice and the Women’s Court for the Former Yugoslavia

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    Post-conflict interventions to ‘deal with’ violent pasts have moved from exception to global norm. Early efforts to achieve peace and justice were critiqued as ‘gender-blind’—for failing to address sexual and gender-based violence, and neglecting the gender-specific interests and needs of women in transitional settings. The advent of UN Security Council resolutions on ‘Women, Peace and Security’ provided a key policy framework for integrating both women and gender issues into transitional justice processes and mechanisms. Despite this, gender justice and equality in (post-)conflict settings remain largely unachieved. This article explores efforts to attain gender-just peace in post-conflict Bosnia and Herzegovina (BiH). It critically examines the significance of a recent ‘bottom-up’ truth-telling project—the Women’s Court for the former Yugoslavia—as a locally engaged approach to achieving justice and redress for women impacted by armed conflict. Drawing on participant observation, documentary analysis, and interviews with women activists, the article evaluates the successes and shortcomings of responding to gendered forms of wartime violence through truth-telling. Extending Nancy Fraser’s tripartite model of justice to peacebuilding contexts, the article advances notions of recognition, redistribution and representation as crucial components of gender-just peace. It argues that recognizing women as victims and survivors of conflict, achieving a gender-equitable distribution of material and symbolic resources, and enabling women to participate as agents of transitional justice processes are all essential for transforming the structural inequalities that enable gender violence and discrimination to materialize before, during, and after conflict

    Administrative Development in \u27Low-Intensity\u27 Democracies: Governance, Rule-of-Law and Corruption in the Western Balkans (SWP 5)

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    Although the Western Balkan states achieved considerable progress in pluralist development during the post-2000 period, weakness in both state-building and democracy-building continues to trouble the region. This article explores the dimensions of the “weak state syndrome”, particularly the interaction between democratic consolidation and deficiencies in administrative capacity (including limited professionalization and the politicization of the public service, patterns of corruption, and problems of judicial development and decentralization). Afflicted as well by the global economic crisis that began in 2008, most of the Western Balkan states remain trapped in an intermediate zone; clearly no longer repressive authoritarian systems, but not yet consolidated or strong democracies. This situation will delay EU entry for most states in the region, and influence their post-accession development.&nbsp

    Communist Systems in Comparative Perspective

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    Outdoor advertising, obesity, and soda consumption: a cross-sectional study

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    Abstract Background: Recent research has shown that neighborhood characteristics are associated with obesity prevalence. While food advertising in periodicals and television has been linked to overweight and obesity, it is unknown whether outdoor advertising is related to obesity. Methods: To test the association between outdoor food advertising and obesity, we analyzed telephone survey data on adults, aged 18-98, collected from 220 census tracts in Los Angeles and Louisiana. We linked self-reported information on BMI and soda consumption with a database of directly observed outdoor advertisements. Results: The higher the percentage of outdoor advertisements promoting food or non-alcoholic beverages within a census tract, the greater the odds of obesity among its residents, controlling for age, race and educational status. For every 10% increase in food advertising, there was a 1.05 (95% CI 1.003 -1.093, p<0.03) greater odds of being overweight or obese, controlling for other factors. Given these predictions, compared to an individual living in an area with no food ads, those living in areas in which 30% of ads were for food would have a 2.6% increase in the probability of being obese. Conclusions: There is a relationship between the percentage of outdoor food advertising and overweight/obesity
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