2,592 research outputs found

    Eco-aesthetic dimensions: Herbert Marcuse, ecollogy and art

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    In his last book, The Aesthetic Dimension (1978), Marcuse argued that a concern for aesthetics is justified when political change is unlikely. But the relation between aesthetics and politics is oblique: “Art cannot change the world, but it can contribute to changing the consciousness … of the men and women who could change the world.” (p. 33). Marcuse also linked his critique of capitalism to environmentalism in the early 1970s: “the violation of the Earth is a vital aspect of the counterrevolution.” (Ecology and Revolution, in The New Left and the 1960s, Collected Papers 3, 2005, p. 173). This article revisits Marcuse’s ideas on aesthetics and ecology, and reviews two recent art projects which engage their audiences in ecological issues: The Jetty Project (2014) by Wolfgang Weileder—which used recycled material and community participation to construct a temporary monument within a wider conservation project on the Tyne, N-E England—and Fracking Futures by HeHe (Helen Evans and Heiko Hansen)—which turned the interior of the gallery at FACT, Liverpool, into what appeared to be a fracking site. The aim is not to evaluate the projects, nor to test the efficacy of Marcuse’s ideas, more to ask again whether art has a role in a shift of attitude which might contribute to dealing with the political and economic causes of climate change

    Theory of disorder-induced multiple coherent scattering in photonic crystal waveguides

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    We introduce a theoretical formalism to describe disorder-induced extrinsic scattering in slow-light photonic crystal waveguides. This work details and extends the optical scattering theory used in a recent \emph{Physical Review Letter} [M. Patterson \emph{et al.}, \emph{Phys. Rev. Lett.} \textbf{102}, 103901 (2009)] to describe coherent scattering phenomena and successfully explain complex experimental measurements. Our presented theory, that combines Green function and coupled mode methods, allows one to self-consistently account for arbitrary multiple scattering for the propagating electric field and recover experimental features such as resonances near the band edge. The technique is fully three-dimensional and can calculate the effects of disorder on the propagating field over thousands of unit cells. As an application of this theory, we explore various sample lengths and disordered instances, and demonstrate the profound effect of multiple scattering in the waveguide transmission. The spectra yield rich features associated with disorder-induced localization and multiple scattering, which are shown to be exasperated in the slow light propagation regime

    Scarring in a driven system with wave chaos

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    We consider acoustic wave propagation in a model of a deep ocean acoustic waveguide with a periodic range-dependence. Formally, the wave field is described by the Schrodinger equation with a time-dependent Hamiltonian. Using methods borrowed from the quantum chaos theory it is shown that in the driven system under consideration there exists a "scarring" effect similar to that observed in autonomous quantum systems.Comment: 5 pages, 7 figure

    Classical simulation of Quantum Entanglement using Optical Transverse Modes in Multimode Waveguides

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    We discuss mode-entangled states based on the optical transverse modes of the optical field propagating in multi-mode waveguides, which are classical analogs of the quantum entangled states. The analogs are discussed in detail, including the violation of the Bell inequality and the correlation properties of optical pulses' group delays. The research on these analogs may be important, for it not only provides useful insights into fundamental features of quantum entanglement, but also yields new insights into quantum computation and quantum communication.Comment: RevTeX v4, 17 pages and 4 figure

    Atom trapping and guiding with a subwavelength-diameter optical fiber

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    We suggest using an evanescent wave around a thin fiber to trap atoms. We show that the gradient force of a red-detuned evanescent-wave field in the fundamental mode of a silica fiber can balance the centrifugal force when the fiber diameter is about two times smaller than the wavelength of the light and the component of the angular momentum of the atoms along the fiber axis is in an appropriate range. As an example, the system should be realizable for Cesium atoms at a temperature of less than 0.29 mK using a silica fiber with a radius of 0.2 μ\mum and a 1.3-μ\mum-wavelength light with a power of about 27 mW.Comment: 5 pages, 5 figure

    Unified theory for Goos-H\"{a}nchen and Imbert-Fedorov effects

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    A unified theory is advanced to describe both the lateral Goos-H\"{a}nchen (GH) effect and the transverse Imbert-Fedorov (IF) effect, through representing the vector angular spectrum of a 3-dimensional light beam in terms of a 2-form angular spectrum consisting of its 2 orthogonal polarized components. From this theory, the quantization characteristics of the GH and IF displacements are obtained, and the Artmann formula for the GH displacement is derived. It is found that the eigenstates of the GH displacement are the 2 orthogonal linear polarizations in this 2-form representation, and the eigenstates of the IF displacement are the 2 orthogonal circular polarizations. The theoretical predictions are found to be in agreement with recent experimental results.Comment: 15 pages, 3 figure

    Comparison of Quantum and Classical Local-field Effects on Two-Level Atoms in a Dielectric

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    The macroscopic quantum theory of the electromagnetic field in a dielectric medium interacting with a dense collection of embedded two-level atoms fails to reproduce a result that is obtained from an application of the classical Lorentz local-field condition. Specifically, macroscopic quantum electrodynamics predicts that the Lorentz redshift of the resonance frequency of the atoms will be enhanced by a factor of the refractive index n of the host medium. However, an enhancement factor of (n*n+2)/3 is derived using the Bloembergen procedure in which the classical Lorentz local-field condition is applied to the optical Bloch equations. Both derivations are short and uncomplicated and are based on well-established physical theories, yet lead to contradictory results. Microscopic quantum electrodynamics confirms the classical local-field-based results. Then the application of macroscopic quantum electrodynamic theory to embedded atoms is proved false by a specific example in which both the correspondence principle and microscopic theory of quantum electrodynamics are violated.Comment: Published version with rewritten abstract and introductio

    Comment on "Measuring the Orbital Angular Momentum of a Single Photon"

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    Optical modes with different orbital angular momentums (OAMs) per photon may be sorted by Mach-Zehnder interferometers incorporated with beam rotators, without resorting to OAM mode converters.Comment: 1 page, 1 figur

    Intensity Distribution of Modes in Surface Corrugated Waveguides

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    Exact calculations of transmission and reflection coefficients in surface randomly corrugated optical waveguides are presented. As the length of the corrugated part of the waveguide increases, there is a strong preference to forward coupling through the lowest mode. An oscillating behavior of the enhanced backscattering as a function of the wavelength is predicted. Although the transport is strongly non isotropic, the analysis of the probability distributions of the transmitted waves confirms in this configuration distributions predicted by Random Matrix Theory for volume disorder

    Entropic uncertainty relations for electromagnetic beams

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    The symplectic tomograms of 2D Hermite--Gauss beams are found and expressed in terms of the Hermite polynomials squared. It is shown that measurements of optical-field intensities may be used to determine the tomograms of electromagnetic-radiation modes. Furthermore, entropic uncertainty relations associated with these tomograms are found and applied to establish the compatibility conditions of the the field profile properties with Hermite--Gauss beam description. Numerical evaluations for some Hermite--Gauss modes illustrating the corresponding entropic uncertainty relations are finally given.Comment: Invited talk at the XV Central European Workshop on Quantum Optics (Belgrade, Serbia, 30 May -- 3 June 2008), to appear in Physica Scripta
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