3,711 research outputs found

    Introduction: Analytic, Continental and the question of a bridge

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    This is the peer reviewed version of the following article: Introduction: Analytic, Continental and the question of a bridge, which has been published in final form at 10.1177/1474885115582078. This article may be used for non-commercial purposes in accordance with SAGE’s Terms and Conditions for Self-Archiving.In philosophy and political theory, divisions come and go, but some persist despite beingobviously problematic. The analytic and Continental divide is one such division. Inpolitical philosophy and political theory, the division has been particularly pronounced.Analytic and Continental thinkers are divided not only over substantial issues but also over the very nature of political theorising. In spite of this fundamental nature, theorists often seem to assume that, as a division, the analytic/Continental divide requires no explanation. We suggest that, as a central division within political theory, and despite being acknowledged as problematic for quite some time, it has persisted because it has not been adequately examined. Once examined, the division turns out to be operationally weaker than it once was. In recent years, there has been a growing interest in engaging thinkers from the other side. This has been accompanied by a corresponding tendency, among both analytic and Continental philosophers and political thinkers, to reflect on the nature of their own tradition and ‘philosophy’. Both traditions have entered a self-conscious period of meta-reflection. Such questioning indicates the possibility of transformation within both groups, in the absence of settled frameworks and divisions. However, it is also clear that such signs are the beginning of the possibility of a new relation rather than a sign of the eclipse of the division. The continued institutional separation and the space between their respective philosophical vocabularies suggest that, while the time is ripe for work here, there is still much to be done

    Universality and Critical Behavior at the Mott transition

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    We report conductivity measurements of Cr-doped V2O3 using a variable pressure technique. The critical behavior of the conductivity near the Mott-insulator to metal critical endpoint is investigated in detail as a function of pressure and temperature. The critical exponents are determined, as well as the scaling function associated with the equation of state. The universal properties of a liquid-gas transition are found. This is potentially a generic description of the Mott critical endpoint in correlated electron materials.Comment: 3 figure

    Chemical analysis by X-ray spectroscopy near phase transitions in the solid state

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    The methods discussed in this work show that the types of changes which may be observed, by precise XAS measurements of Absorbance A versus temperature, across a phase transition are: the changes in the relaxation time of the final states due to fluctuations near a phase transition; the detection of the anomalous Bragg condition coupled to phonon modes XAS enhancement that identifies the temperature interval where the phonon modes are active, the symmetry changes which introduce new allowed transitions to finite states below an element edge, near Tc indicate what symmetry changes occur, and the method of XTDAFST0 = XAFS(T) - XAFS(T0), allows the precise measurement of the progressive changes in the Debye-Waller factor versus T near a phase transition, and identify (when no other structural changes occur, except in the vibrational modes of a specific bond) the bond responsible for the transition. The methods have been applied to the superconducting transition in layer cuprates and the metal to insulator transition in NiS2-xSex

    Dynamic phenomena in superconducting oxides by ESR

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    Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1\u3e 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka =2.24 are identified with the presence of 5% Nd3+( 41912 ) in the Ba layer because the characteristic Cu2+ impurity hyperfine structure is absent and the ESR signal disappears several degrees below Te. Near Te the ESR absorption is reduced by two orders of magnitude. Proximity effects give rise to interference fringes with period r1 ( T) independent of the field B and the rate of sweep dBzldt. ESR is observed below Te because flux penetrates the superconductor. The temperature dependence of r1 leads to an activation energy for the flux motion E0 (1)/R ~ 16 K and Ea (111)/R ~3 K =Te /4. In the superconducting state a coherent flux expulsion response to a change in B. from 500 mT to zero is observed in times T, = 8 to 10 s. The inverse rate of noise spikes due to flux expulsion, when the samples are cooled through Te in a magnetic field, varies from Tnoise=3.5 s for III to 21 s for IV. The microwave absorption spectra identify three temperature regimes: (i) For 3.5 K \u3c T \u3c T m T* \u3c Teo superconducting behavior was confirmed by the energy loss near zero magnetic field and the kinetics of high-field noise due to flux expulsion. Near g =2.00 ESR absorption is observed for all materials. A broad absorption near 50 to 100 mT at 9.36 GHz has been attributed to AF resonance. (ii) T m T* ~ T ~ Te identifies the range where flux motion gives rise to interference fringes in the ESR absorption. (iii) ESR and AF resonance are observed immediately after warming above Tc

    Zener double exchange from local valence fluctuations in magnetite

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    Magnetite (Fe3_{3}O4_{4}) is a mixed valent system where electronic conductivity occurs on the B-site (octahedral) iron sublattice of the spinel structure. Below TV=122T_{V}=122 K, a metal-insulator transition occurs which is argued to arise from the charge ordering of 2+ and 3+ iron valences on the B-sites (Verwey transition). Inelastic neutron scattering measurements show that optical spin waves propagating on the B-site sublattice (\sim80 meV) are shifted upwards in energy above TVT_{V} due to the occurrence of B-B ferromagnetic double exchange in the mixed valent metallic phase. The double exchange interaction affects only spin waves of Δ5\Delta_{5} symmetry, not all modes, indicating that valence fluctuations are slow and the double exchange is constrained by electron correlations above TVT_{V}.Comment: 4 pages, 5 figure

    Structural dichroism in the antiferromagnetic insulating phase of V_2O_3

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    We performed near-edge x-ray absorption spectroscopy (XANES) at V K edge in the antiferromagnetic insulating (AFI) phase of a 2.8% Cr-doped V_2O_3 single crystal. Linear dichroism of several percent is measured in the hexagonal plane and found to be in good agreement with ab-initio calculations based on multiple scattering theory. This experiment definitively proves the structural origin of the signal and therefore solves a controversy raised by previous interpretations of the same dichroism as non-reciprocal. It also calls for a further investigation of the role of the magnetoelectric annealing procedure in cooling to the AFI phase.Comment: 4 pages 3 figures. To be published in Phys. Rev. B (2005

    Characterization of nanometer-sized, mechanically exfoliated graphene on the H-passivated Si(100) surface using scanning tunnelling microscopy

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    We have developed a method for depositing graphene monolayers and bilayers with minimum lateral dimensions of 2-10 nm by the mechanical exfoliation of graphite onto the Si(100)-2x1:H surface. Room temperature, ultra-high vacuum (UHV) tunnelling spectroscopy measurements of nanometer-sized single-layer graphene reveal a size dependent energy gap ranging from 0.1-1 eV. Furthermore, the number of graphene layers can be directly determined from scanning tunnelling microscopy (STM) topographic contours. This atomistic study provides an experimental basis for probing the electronic structure of nanometer-sized graphene which can assist the development of graphene-based nanoelectronics.Comment: Accepted for publication in Nanotechnolog

    Modus Vivendi Beyond the Social Contract: Peace, Justice, and Survival in Realist Political Theory

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    This essay examines the promise of the notion of modus vivendi for realist political theory. I interpret recent theories of modus vivendi as affirming the priority of peace over justice, and explore several ways of making sense of this idea. I proceed to identify two key problems for modus vivendi theory, so conceived. Normatively speaking, it remains unclear how this approach can sustain a realist critique of Rawlsian theorizing about justice while avoiding a Hobbesian endorsement of absolutism. And conceptually, the theory remains wedded to a key feature of social contract theory: political order is conceived as based on agreement. This construes the horizontal tensions among individual or group agents in society as prior to the vertical, authoritative relations between authorities and their subjects. Political authority thereby appears from the start as a solution to societal conflict, rather than a problem in itself. I argue that this way of framing the issue abstracts from political experience. Instead I attempt to rethink the notion of modus vivendi from within the lived experience of political conflict, as oriented not primarily toward peace, but political survival. With this shift of perspective, the idea of modus vivendi shows us, pace Bernard Williams, that the “first political question” is not how to achieve order and stability, but rather: what can I live with

    Mass enhancement and magnetic order at the Mott-Hubbard transition

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    We study the evolution with pressure P and band filling y of the heat capacity, Hall coefficient, and resistivity at the approach to the T→0 Mott-Hubbard metal-insulator transition (MIT) in highly correlated V_(2-y)O_3. Under P, the electronic effective mass m* diverges at the MIT with a negligible change in carrier concentration n away from half-filling. Conversely, in the doped system m* actually decreases as the MIT is approached, while n increases linearly with y. The low-T magnetic order in the metal helps us deconvolute contributions from charge correlations and spin fluctuations
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