854 research outputs found

    Performance in Print: Channeling Tƍmatsu Shƍmei’s NO.541

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    At 1 p.m. on 6 February 1971, eight “actors,” a reporter, and a cameraman entered a space at an undisclosed location with the intention of spending 24 hours together. They did not belong to a single artistic group and some of them had never met before. Tomatsu Shomei’s photographic record of this event appeared in the spring 1971 issue of the magazine Kikan shashin eizo accompanied by sections from a transcript of the tape recording. The images and the text – jointly titled NO.541 – offer fragmented glimpses into the situations and conversations unfolding in the room and also function with and against each other, as in a dialogue. We continue this dialogue in the writing up of major themes contextualizing the performing and recording of this work: the space, the magazine page, and the body. We imagine ourselves in NO.541 and enact this intermingling of space-times by reproducing not only some of Tomatsu’s photographs but also parts of the transcript in translation. Joining the conversation, we adopt some of the main strategies of the image-text, such as fragmentation, improvisation, and refusal of any singularity. Woman C and Man G take on the role of mediums, channeling, for instance, a possible future re-enactment instead of producing a conclusive account of the event

    Hawking radiation of unparticles

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    Unparticle degrees of freedom, no matter how weakly coupled to the standard model particles, must affect the evolution of a black hole, which thermally decays into all available degrees of freedom. We develop a method for calculating the grey-body factors for scalar unparticles for 3+1 and higher dimensional black holes. We find that the power emitted in unparticles may be quite different from the power emitted in ordinary particles. Depending on the parameters in the model, unparticles may become the dominant channel. This is of special interest for small primordial black holes and also in models with low scale quantum gravity where the experimental signature may significantly be affected. We also discuss the sensitivity of the results on the (currently unknown) unparticle normalization.Comment: Calculations for different normalization of unparticles included, discussion expanded, version published in Phys. Rev.

    Out of sight: surrealism and photography in 1930s Japan

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    "There is not a country in the world where the Surrealist voice found a faster response than Japan. From its origin (1924, date of the first Manifesto), until the war, there was no Surrealist activity in Europe that was not almost immediately reflected upon.", Breton, AndrĂ© ([1959] 2008). En guise de prĂ©face Ă  l’anthologie surrĂ©aliste de Tokyo. In: Breton, AndrĂ©; Hubert, Étienne-Alain (et al.), Ouvres completes IV: Écrits sur l’art et autres textes. Paris: Gallimard, p. 1155. Regardless of AndrĂ© Breton’s insistence on how there was no Surrealist activity that did not have a response in Japan, the knowledge of Surrealist photography practised in the country during the decade between 1930 and 1940 remains ‘out of sight’ of the existing scholarship until the present day. Therefore, this thesis brings to the fore the significance of this practice, encircled by the multifaceted relations between Surrealism, photography and 1930s Japan, asking how can its historical condition be altered and written into the existing field of knowledge. Emerging and developing at a time of political oppression and military campaigning that led Japan into the Pacific War in 1941, Surrealist photography of this decade is an important case study into how photography can perform a critical role in visualising new and different strands of thought and action. As this photography was practised outside of a single Surrealist group, it played such a role by equally remaining ‘out of sight’ of the state censorship and maintaining a position in the marginalised space of the illustrated press. Such a position outside of a formal Surrealist group and on the margins of Japanese society is affirmed in this thesis through the notion of minor literature, characteristic for its deterritorialised, collective and immanently political character. These three defining characteristics enable construction of a minor historical framework through which Surrealist photography in Japan of the 1930s can be considered as of significant relevance to the discursive fields of Surrealism and History of Japanese Art. To argue for such relevance, this thesis is based on archival research of over a hundred photographs and offers a close reading of the main texts published with regard to Surrealist photography in the decade. It shows how regardless of its unorthodox position, Surrealist photography in 1930s Japan mobilised an extensive number of practitioners around the country, in Tokyo, Osaka, Nagoya, and Fukuoka, and how they acted as a subversive force to the homogenised visual culture from within all the major categories of photographic practice developing in the decade

    A Vertex Correction in the Gap Equation for the High Temperature Superconductors

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    We show that the Migdal theorem is obviously violated in the high Tc cuprates and the vertex correction should be included, in particular, in the gap equation, in order to be consistent with the anomalously strong inelastic scattering in the ``hot spots'', which is observed from the various normal state experiments. The vertex correction is obtained by utilizing the generalized Ward identity, which is shown to hold in the important scattering channel for the pairing interaction in the high Tc cuprates. As a result, we find a strong enhancement of Tc from the vertex correction despite of the strong pair breaking effect due to the inelastic scattering.Comment: 5 pages, 2 figure

    Vanishing Dimensions and Planar Events at the LHC

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    We propose that the effective dimensionality of the space we live in depends on the length scale we are probing. As the length scale increases, new dimensions open up. At short scales the space is lower dimensional; at the intermediate scales the space is three-dimensional; and at large scales, the space is effectively higher dimensional. This setup allows for some fundamental problems in cosmology, gravity, and particle physics to be attacked from a new perspective. The proposed framework, among the other things, offers a new approach to the cosmological constant problem and results in striking collider phenomenology and may explain elongated jets observed in cosmic-ray data.Comment: v1: 5 pages revtex, 1 eps figure; v2: includes extensive discussion on violation of Lorentz invariance, featured in a Nature editorial [Nature 466 (2010) 426] http://www.nature.com/news/2010/100720/full/466426a.html; v3: discussion expanded, matching journal versio

    Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy

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    Lower-dimensionality at higher energies has manifold theoretical advantages as recently pointed out. Moreover, it appears that experimental evidence may already exists for it - a statistically significant planar alignment of events with energies higher than TeV has been observed in some earlier cosmic ray experiments. We propose a robust and independent test for this new paradigm. Since (2+1)-dimensional spacetimes have no gravitational degrees of freedom, gravity waves cannot be produced in that epoch. This places a universal maximum frequency at which primordial waves can propagate, marked by the transition between dimensions. We show that this cut-off frequency may be accessible to future gravitational wave detectors such as LISA.Comment: Somewhat expanded version with discussions that could not fit into the PRL version; references adde

    Holes in the walls: primordial black holes as a solution to the cosmological domain wall problem

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    We propose a scenario in which the cosmological domain wall and monopole problems are solved without any fine tuning of the initial conditions or parameters in the Lagrangian of an underlying filed theory. In this scenario domain walls sweep out (unwind) the monopoles from the early universe, then the fast primordial black holes perforate the domain walls, change their topology and destroy them. We find further that the (old vacuum) energy density released from the domain walls could alleviate but not solve the cosmological flatness problem.Comment: References added; Published in Phys. Rev.

    Using quasars as standard clocks for measuring cosmological redshift

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    We report hitherto unnoticed patterns in quasar light curves. We characterize segments of quasars' light curves with the slopes of the straight lines fit through them. These slopes appear to be directly related to the quasars' redshifts. Alternatively, using only global shifts in time and flux, we are able to find significant overlaps between the light curves of different pairs of quasars by fitting the ratio of their redshifts. We are then able to reliably determine the redshift of one quasar from another. This implies that one can use quasars as standard clocks, as we explicitly demonstrate by constructing two independent methods of finding the redshift of a quasar from its light curve.Comment: References added, Published in Phys. Rev. Let

    Effect of FET geometry on charge ordering of transition metal oxides

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    We examine the effect of an FET geometry on the charge ordering phase diagram of transition metal oxides using numerical simulations of a semiclassical model including long-range Coulomb fields, resulting in nanoscale pattern formation. We find that the phase diagram is unchanged for insulating layers thicker than approximately twice the magnetic correlation length. For very thin insulating layers, the onset of a charge clump phase is shifted to lower values of the strength of the magnetic dipolar interaction, and intermediate diagonal stripe and geometric phases can be suppressed. Our results indicate that, for sufficiently thick insulating layers, charge injection in an FET geometry can be used to experimentally probe the intrinsic charge ordering phases in these materials.Comment: 4 pages, 4 postscript figure

    Geostationary payload concepts for personal satellite communications

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    This paper reviews candidate satellite payload architectures for systems providing world-wide communication services to mobile users equipped with hand-held terminals based on large geostationary satellites. There are a number of problems related to the payload architecture, on-board routing and beamforming, and the design of the S-band Tx and L-band Rx antenna and front ends. A number of solutions are outlined, based on trade-offs with respect to the most significant performance parameters such as capacity, G/T, flexibility of routing traffic to beams and re-configuration of the spot-beam coverage, and payload mass and power. Candidate antenna and front-end configurations were studied, in particular direct radiating arrays, arrays magnified by a reflector and active focused reflectors with overlapping feed clusters for both transmit (multimax) and receive (beam synthesis). Regarding the on-board routing and beamforming sub-systems, analog techniques based on banks of SAW filters, FET or CMOS switches and cross-bar fixed and variable beamforming are compared with a hybrid analog/digital approach based on Chirp Fourier Transform (CFT) demultiplexer combined with digital beamforming or a fully digital processor implementation, also based on CFT demultiplexing
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