28,763 research outputs found

    The Goals of Antitrust: Welfare Trumps Choice

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    The mixing of banking and commerce: a conference summary

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    Acquisitions of industrial loan corporations by commercial firms have renewed the debate over the separation between banking and commerce in the U.S. On May 16–18, 2007, policymakers and academics weighed in on this debate during the Chicago Fed’s 43rd annual Conference on Bank Structure and Competition, titled The Mixing of Banking and Commerce.Banks and banking ; Banks and banking, American

    Effective 't Hooft-Polyakov monopoles from pure SU(3) gauge theory

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    The well known topological monopoles originally investigated by 't Hooft and Polyakov are known to arise in classical Yang-Mills-Higgs theory. With a pure gauge theory it is known that the classical Yang-Mills field equation do not have such finite energy configurations. Here we argue that such configurations may arise in a semi-quantized Yang-Mills theory, where the original gauge group, SU(3), is reduced to a smaller gauge group, SU(2), and with some combination of the coset fields of the SU(3) to SU(2) reduction acting as effective scalar fields. The procedure is called semi-quantized since some of the original gauge fields are treated as quantum degrees of freedom, while others are postulated to be effectively described as classical degrees of freedom. Some speculation is offer on a possible connection between these monopole configurations and the confinement problem, and the nucleon spin puzzle.Comment: one error is correcte

    Vacuum field energy and spontaneous emission in anomalously dispersive cavities

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    Anomalously dispersive cavities, particularly white light cavities, may have larger bandwidth to finesse ratios than their normally dispersive counterparts. Partly for this reason, their use has been proposed for use in LIGO-like gravity wave detectors and in ring-laser gyroscopes. In this paper we analyze the quantum noise associated with anomalously dispersive cavity modes. The vacuum field energy associated with a particular cavity mode is proportional to the cavity-averaged group velocity of that mode. For anomalously dispersive cavities with group index values between 1 and 0, this means that the total vacuum field energy associated with a particular cavity mode must exceed ℏω/2\hbar \omega/2. For white light cavities in particular, the group index approaches zero and the vacuum field energy of a particular spatial mode may be significantly enhanced. We predict enhanced spontaneous emission rates into anomalously dispersive cavity modes and broadened laser linewidths when the linewidth of intracavity emitters is broader than the cavity linewidth.Comment: 9 pages, 4 figure

    Discerning Differences between Producer Groups and Organic Adoption Barriers in Texas

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    The number of certified organic operations in Texas has remained relatively stagnant while nationally the organic food sector has experienced double-digit growth. To understand why this occurring, a survey was distributed to a random sample of 4,006 Texas producers. The results will assist in developing strategies to promote the growth of organic production in Texas.Crop Production/Industries,

    We haven't got a seat on the bus for you or All the seats are mine: Narratives and career transitions in professional golf

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    In this article we explore how the stories an athlete tells throughout life in sport affect her career transition experiences. We base our enquiry on a social constructionist conception of narrative theory which holds that storytelling is integral to the creation and maintenance of identity and sense of self. Life stories were gathered through interviews with two professional women golfers (Christiana and Kandy) over a six‐year period. Through a narrative analysis of structure and form we explored each participant’s stories of living in and withdrawing from professional golf. We suggest Christiana told monological performance‐oriented stories which, while aligning with the culture of elite sport, resulted in an exclusive athletic identity and foreclosure of alternative selves and roles. On withdrawal, Christiana experienced narrative wreckage, identity collapse, mental health difficulties and considerable psychological trauma. In contrast, Kandy told dialogical discovery‐oriented stories which, while being in tension with the dominant performance narrative, created and sustained a multidimensional identity and self. Her stories and identity remained intact, authentic and continuous on withdrawal from tournament golf and she experienced few psychological problems

    Reverse geometric engineering of singularities

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    One can geometrically engineer supersymmetric field theories theories by placing D-branes at or near singularities. The opposite process is described, where one can reconstruct the singularities from quiver theories. The description is in terms of a noncommutative quiver algebra which is constructed from the quiver diagram and the superpotential. The center of this noncommutative algebra is a commutative algebra, which is the ring of holomorphic functions on a variety V. If certain algebraic conditions are met, then the reverse geometric engineering produces V as the geometry that D-branes probe. It is also argued that the identification of V is invariant under Seiberg dualities.Comment: 17 pages, Latex. v2: updates reference

    Searching for Extra Dimensions in the Early Universe

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    We investigate extra spatial dimensions (D=3+Ï”D = 3+\epsilon) in the early universe using very high resolution molecular rotational spectroscopic data derived from a large molecular cloud containing moderately cold carbon monoxide gas at Z ≈6.42\approx 6.42. It turns out that the Ï”\epsilon-dependent quantum mechanical wavelength transitions are solvable for a linear molecule and we present the solution here. The CO microwave data allows a very precise determination of =−0.00000657±.10003032 = -0.00000657 \pm .10003032. The probability that ≠0 \neq 0 is one in 7794, only 850 million years (using the standard cosmology) after the Big Bang.Comment: 17 pages, 2 figure

    Quantum many-body models with cold atoms coupled to photonic crystals

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    Using cold atoms to simulate strongly interacting quantum systems represents an exciting frontier of physics. However, as atoms are nominally neutral point particles, this limits the types of interactions that can be produced. We propose to use the powerful new platform of cold atoms trapped near nanophotonic systems to extend these limits, enabling a novel quantum material in which atomic spin degrees of freedom, motion, and photons strongly couple over long distances. In this system, an atom trapped near a photonic crystal seeds a localized, tunable cavity mode around the atomic position. We find that this effective cavity facilitates interactions with other atoms within the cavity length, in a way that can be made robust against realistic imperfections. Finally, we show that such phenomena should be accessible using one-dimensional photonic crystal waveguides in which coupling to atoms has already been experimentally demonstrated
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