13,913 research outputs found

    "It's the real thing": performance and murder in Sweden.

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    The article investigates contemporary experimental theatre in Sweden. It sums up and probes the implications of Sju tre (1999), the most controversial theatre production in Sweden in modern times. Lars Nor'n, the playwright and director, staged a dialogue involving three real convicts, of whom two were outspoken Nazis. The article explores the uncertain boundaries between aesthetic, ethical, and political issues with ramifications regarding the wider public opinion in Sweden, on racism and crime. It is methodologically motivated by reception research, performativity and idealogical discourse. By virtue of its performative impact, the theatrical event proved to be directly linked with critical questions of democracy, although conceivably at the expense of the artistic integrity of the director and the theatre as creator of public opinion. The article points to a paradox of democracy whereby hate speech is at once allowed and unjustified in the theatre as national arena. The actors are described and analysed as parasites in a societal body, that in Sju tre, becomes politically epitomised

    Considerations for ultrafast photomagnetism in manganese(III)-based single-molecule magnets

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    Manipulation of magnetic materials is a cornerstone of digital data storage technologies. Recently, it has been shown that femtosecond laser pulses are capable of switching the magnetization in a material between two stable configurations faster than ever before. One stateof-the-art method is to use laser pulses to control the magnetic anisotropy by photoexciting crystal-field transitions. The photoinduced change in anisotropy applies a torque to the magnetic moment, which reorientates it in a different direction. So far, research has focused solely on condensed matter materials. However, there is a huge variety of molecule-based magnetic materials that have been and continue to be developed. In particular, single-molecule magnets (SMMs) provide a highly tunable platform and have the added advantage of operating on nanometer length scales. This review discusses recent research in the area of ultrafast magnetism in SMMs, with a focus on manganese(III)-based transition metal complexes. Experimental data are reviewed, showing that control of the strength of the photoinduced anisotropy, the lifetime of excited states, and the dephasing times are possible and can be used to develop some design criteria for the bestoptically controllable SMMs

    Crystal-field effects in the first-order valence transition in YbInCu4 induced by an external magnetic field

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    As it was shown earlier [Dzero, Gor'kov, and Zvezdin, J. Phys.:Condens. Matter 12, L711 (2000)] the properties of the first-order valence phase transition in YbInCu4 in the wide range of magnetic fields and temperatures are perfectly described in terms of a simple entropy transition for free Yb ions. Within this approach, the crystal field effects have been taken into account and we show that the phase diagram in the B−TB-T plane acquires some anisotropy with respect to the direction of an external magnetic field.Comment: 4 pages, 3 eps figures; minor changes; to be piblished in J. of Physics: Cond. Ma

    Internally Electrodynamic Particle Model: Its Experimental Basis and Its Predictions

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    The internally electrodynamic (IED) particle model was derived based on overall experimental observations, with the IED process itself being built directly on three experimental facts, a) electric charges present with all material particles, b) an accelerated charge generates electromagnetic waves according to Maxwell's equations and Planck energy equation and c) source motion produces Doppler effect. A set of well-known basic particle equations and properties become predictable based on first principles solutions for the IED process; several key solutions achieved are outlined, including the de Broglie phase wave, de Broglie relations, Schr\"odinger equation, mass, Einstein mass-energy relation, Newton's law of gravity, single particle self interference, and electromagnetic radiation and absorption; these equations and properties have long been broadly experimentally validated or demonstrated. A specific solution also predicts the Doebner-Goldin equation which emerges to represent a form of long-sought quantum wave equation including gravity. A critical review of the key experiments is given which suggests that the IED process underlies the basic particle equations and properties not just sufficiently but also necessarily.Comment: Presentation at the 27th Int Colloq on Group Theo Meth in Phys, 200

    SAURON's Challenge for the Major Merger Scenario of Elliptical Galaxy Formation

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    The intrinsic anisotropy delta and flattening epsilon of simulated merger remnants is compared with elliptical galaxies that have been observed by the SAURON collaboration, and that were analysed using axisymmetric Schwarzschild models. Collisionless binary mergers of stellar disks and disk mergers with an additional isothermal gas component, neglecting star formation cannot reproduce the observed trend delta = 0.55 epsilon (SAURON relationship). An excellent fit of the SAURON relationship for flattened ellipticals with epsilon >= 0.25 is however found for merger simulations of disks with gas fractions >= 20%, including star formation and stellar energy feedback. Massive black hole feedback does not strongly affect this result. Subsequent dry merging of merger remnants however does not generate the slowly-rotating SAURON ellipticals which are characterized by low ellipticities epsilon < 0.25 and low anisotropies. This indicates that at least some ellipticals on the red galaxy sequence did not form by binary mergers of disks or early-type galaxies. We show that stellar spheroids resulting from multiple, hierarchical mergers of star-bursting subunits in a cosmological context are in excellent agreement with the low ellipticities and anisotropies of the slowly rotating SAURON ellipticals and their observed trend of delta with epsilon. The numerical simulations indicate that the SAURON relation might be a result of strong violent relaxation and phase mixing of multiple, kinematically cold stellar subunits with the angular momentum of the system determining its location on the relation.Comment: 13 pages, 3 figures, submitted to Ap

    The FERRUM project: Transition probabilities for forbidden lines in [FeII] and experimental metastable lifetimes

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    Accurate transition probabilities for forbidden lines are important diagnostic parameters for low-density astrophysical plasmas. In this paper we present experimental atomic data for forbidden [FeII] transitions that are observed as strong features in astrophysical spectra. Aims: To measure lifetimes for the 3d^6(^3G)4s a ^4G_{11/2} and 3d^6(^3D)4s b ^4D_{1/2} metastable levels in FeII and experimental transition probabilities for the forbidden transitions 3d^7 a ^4F_{7/2,9/2}- 3d^6(^3G)4s a ^4G_{11/2}. Methods: The lifetimes were measured at the ion storage ring facility CRYRING using a laser probing technique. Astrophysical branching fractions were obtained from spectra of Eta Carinae, obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. The lifetimes and branching fractions were combined to yield absolute transition probabilities. Results: The lifetimes of the a ^4G_{11/2} and the b ^4D_{1/2} levels have been measured and have the following values, 0.75(10) s and 0.54(3) s respectively. Furthermore, we have determined the transition probabilities for two forbidden transitions of a ^4F_{7/2,9/2}- a ^4G_{11/2} at 4243.97 and 4346.85 A. Both the lifetimes and the transition probabilities are compared to calculated values in the literature.Comment: 5 pages, accepted for publication in A&

    Observation of Buried Phosphorus Dopants near Clean Si(100)-(2x1) with Scanning Tunneling Microscopy

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    We have used scanning tunneling microscopy to identify individual phosphorus dopant atoms near the clean silicon (100)-(2x1) reconstructed surface. The charge-induced band bending signature associated with the dopants shows up as an enhancement in both filled and empty states and is consistent with the appearance of n-type dopants on compound semiconductor surfaces and passivated Si(100)-(2x1). We observe dopants at different depths and see a strong dependence of the signature on the magnitude of the sample voltage. Our results suggest that, on this clean surface, the antibonding surface state band acts as an extension of the bulk conduction band into the gap. The positively charged dimer vacancies that have been observed previously appear as depressions in the filled states, as opposed to enhancements, because they disrupt these surface bands.Comment: 4 pages, 3 figures. TeX for OSX from Wierde

    Coherent current transport in wide ballistic Josephson junctions

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    We present an experimental and theoretical investigation of coherent current transport in wide ballistic superconductor-two dimensional electron gas-superconductor junctions. It is found experimentally that upon increasing the junction length, the subharmonic gap structure in the current-voltage characteristics is shifted to lower voltages, and the excess current at voltages much larger than the superconducting gap decreases. Applying a theory of coherent multiple Andreev reflection, we show that these observations can be explained in terms of transport through Andreev resonances.Comment: 4 pages, 4 figure

    Proof-Pattern Recognition and Lemma Discovery in ACL2

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    We present a novel technique for combining statistical machine learning for proof-pattern recognition with symbolic methods for lemma discovery. The resulting tool, ACL2(ml), gathers proof statistics and uses statistical pattern-recognition to pre-processes data from libraries, and then suggests auxiliary lemmas in new proofs by analogy with already seen examples. This paper presents the implementation of ACL2(ml) alongside theoretical descriptions of the proof-pattern recognition and lemma discovery methods involved in it
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