Exact solution of the Falicov-Kimball model with dynamical mean-field theory

The Falicov-Kimball model was introduced in 1969 as a statistical model for metal-insulator transitions; it includes itinerant and localized electrons that mutually interact with a local Coulomb interaction and is the simplest model of electron correlations. It can be solved exactly with dynamical mean-field theory in the limit of large spatial dimensions which provides an interesting benchmark for the physics of locally correlated systems. In this review, we develop the formalism for solving the Falicov-Kimball model from a path-integral perspective, and provide a number of expressions for single and two-particle properties. We examine many important theoretical results that show the absence of fermi-liquid features and provide a detailed description of the static and dynamic correlation functions and of transport properties. The parameter space is rich and one finds a variety of many-body features like metal-insulator transitions, classical valence fluctuating transitions, metamagnetic transitions, charge density wave order-disorder transitions, and phase separation. At the same time, a number of experimental systems have been discovered that show anomalies related to Falicov-Kimball physics [including YbInCu4, EuNi2(Si[1-x]Gex)2, NiI2 and TaxN].Comment: 51 pages, 40 figures, submitted to Reviews of Modern Physic

Ideology, Political Discourse, and Political Struggle in Early America

The paper employs ethnomethodology and discourse analysis to examine political struggles during three periods in the early history of the United States: the struggle between the British and American colonial revolutionaries in the period directly preceding the American revolution; the struggle between Federalists and Republicans in the period between the adoption of the constitution and the inauguration of Thomas Jefferson; and the struggle between commitment to the constitution and opposition to slavery faced by Northern Americans directly preceding the Civil War. The paper examines the use of ideological categories as linguistic tools employed in social practices by different actors in different situations to achieve widely different ends. When applied in concrete situations the variability of such categories is at least as striking as any consistency. Ideologies are flexible enough to allow social actors to a categorize people or events in one way on one occasion and in a different way on another. This is not just understandable it is necessary because social categorization is fundamental to the way we make sense of social structure and because it provide coherence to our social worlds

Evolutionary Narratives: A Cautionary Tale

Abstrac

Bourdieu\u27s Habitus and Cognitive Sudies

Bourdieu\u27s habitus is designed to overcome some of the major dichotomies is social analysis: structure and agency, subject and object, self and society, culture and personality. Bourdieu\u27s habitus is a feel for the game, a personal disposition as corporeal as it is cognitive, an individual\u27s history of games played, a store of strategies ready to be deployed in the appropriate situations. Because an individual\u27s history is the history of games played and positions occupied, the social categories which one has occupied come into place as well. One\u27s gender, class, ethnicity, race and help structure the positions one occupies in social space. In Bourdieu\u27s formulation, social actors are active and knowing agents endowed with a practical sense, that is, an acquired system of preferences, of principles of vision and division, (what is usually called taste) and also a system of durable cognitive structures (which are essentially the product of the internalization of objective structures) and of schemes of action which orient the perception of the situation and the appropriate response Bourdieu tells us that the habitus is the product of individual history and that individual history is in part the embodiment of social forces. What he doesn\u27t tell us is how this happens. This paper will review recent work on memory, perception, language, cognition, neuro-psychology and human action and link Bourdieu\u27s habitus with the mechanisms in which social experiences are formed and manifested in human social action