2,592 research outputs found
Eco-aesthetic dimensions: Herbert Marcuse, ecollogy and art
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
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
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
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
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 m and a 1.3-m-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
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
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"
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
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
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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