3,619 research outputs found

    Media interventions and new social imaginaries

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    Recent re-articulations of the “social imaginary" (Castoriadis 1987) have emerged due to the proliferation and dispersion of new technologies in everyday life. What effect can enacting imaginative narratives for the near future have on present conditions? By reflecting upon two case studies in Serbia (2006) and Montenegro (2009), this paper considers the construction of narrative and spectacle as crafting of social imaginaries. Drawing on participatory, ethnographic and practice-based research methods, these interventions navigate economic and social change by connecting location-based situations with global media networks

    The Role of Splayed Disorder and Channel Flow on the Dynamics of Driven 3D Vortices

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    We present the results of three-dimensional molecular dynamics simulations of vortices which indicate that, for B greater than the matching field, the enhanced pinning effectiveness of splayed columnar defects relative to vertical columnar defects can be explained in terms of the existence or absence of channels through which the vortices can flow without encountering defects.Comment: 2 Pages, 3 Figures, Proceedings from Houston M2S-HTSC-VI References altered, minor correction

    Role of Symmetry in Raman Spectroscopy of Unconventional Superconductors

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    The role of symmetry of the inelastic light scattering amplitude, the superconducting energy gap, and the underlying Fermi surface manifold on the Raman spectra of unconventional superconductors is discussed in detail. Particular emphasis is placed on both single and bi-layer superconductors. It is found that the B1gB_{1g} channel may be the most sensitive to doping due to the role of the Van Hove singularity. Lastly the effects of both disorder and spin fluctuations are considered. The theory imposes strong constraints on both the magnitude and symmetry of the energy gap for the bi-layer cuprates, indicating that a nearly identical energy gap of dx2−y2d_{x^{2}-y^{2}} symmetry provides a best fit to the data.Comment: 12 pages, 4 postscript files, 1 tabl

    Unconventional electronic Raman spectra of borocarbide superconductors

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    Borocarbide superconductors, which are thought to be conventional BCS-type superconductors, are not so conventional in several electronic Raman properties. Anisotropic gap-like features and finite scattering strength below the gap were observed for the RRNi2_2B2_2C (RR = Lu, Y) systems in our previous study. The effects of Co-doping on the 2Δ\Delta gap-like features and the finite scattering strength below and above the gap are studied in RR = Lu (B = B11^{11}) system. In superconducting states, Co-doping strongly suppresses the 2Δ\Delta peak in both B2g_{2g} and B1g_{1g} symmetries. Raman cross-section calculation which includes inelastic scattering shows a relatively good fit to the features above the 2Δ\Delta peak, while it does not fully account for the features below the peak.Comment: 2 pages, 1 figur

    Collective Spin Fluctuation Mode and Raman Scattering in Superconducting Cuprates

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    Although the low frequency electronic Raman response in the superconducting state of the cuprates can be largely understood in terms of a d-wave energy gap, a long standing problem has been an explanation for the spectra observed in the A1gA_{1g} polarization orientations. We present calculations which suggest that the peak position of the observed A1gA_{1g} spectra is due to a collective spin fluctuation mode.Comment: 4 pages, 5 eps figure

    Symmetry dependence of phonon lineshapes in superconductors with anisotropic gaps

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    The temperature dependence below TcT_{c} of the lineshape of optical phonons of different symmetry as seen in Raman scattering is investigated for superconductors with anisotropic energy gaps. It is shown that the symmetry of the electron-phonon vertex produces non-trivial couplings to an anisotropic energy gap which leads to unique changes in the phonon lineshape for phonons of different symmetry. The phonon lineshape is calculated in detail for B1gB_{1g} and A1gA_{1g} phonons in a superconductor with dx2−y2d_{x^{2}-y^{2}} pairing symmetry. The role of satellite peaks generated by the electron-phonon coupling are also addressed. The theory accounts for the substantial phonon narrowing of the B1gB_{1g} phonon, while narrowing of the A1gA_{1g} phonon which is indistinguishable from the normal state is shown, in agreement with recent measurements on BSCCO.Comment: 15 pages (3 Figures available upon request), Revtex, 1

    Raman Scattering in Cuprate Superconductors

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    A theory for electronic Raman scattering in the cuprate superconductors is presented with a specific emphasis on the polarization dependence of the spectra which can infer the symmetry of the energy gap. Signatures of the effects of disorder on the low frequency and low temperature behavior of the Raman spectra for different symmetry channels provide detailed information about the magnitude and the phase of the energy gap. Properties of the theory for finite T are discussed and compared to recent data concerning the doping dependence of the Raman spectra in cuprate superconductors, and remaining questions are addressed.Comment: 27 pages, 11 figures, style file include
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