2,179 research outputs found

    Education movies and the promotion of one dimensional thinking: a marcusean examination of films made between 2005 and 2017

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    This thesis examines how recent movies have depicted schools and teachers in the United Kingdom and the United States. Deploying methodological tools outlined by the Frankfurt School critical theorist Herbert Marcuse, it analyses the messages of twenty-first century film-making in the school genre, asking whether such films reinforce or challenge neoliberal perspectives of education. To address this, ten films are assessed against Marcuse’s most significant and well-known philosophical concept - ‘one-dimensionality’ - modes of thinking in ‘advanced capitalist societies’ where critical spaces and alternative ways of seeing the world are closed down. To analyse whether films contribute to a ‘one-dimensional’ perspective of education, key Marcusean constructs are utilised, concepts that Marcuse argued contributed to the death of critical thinking. The films are analysed through the main written method of the Frankfurt School – the dialectic. Through the combined dialectical analysis of ten films, literature in the field and through exploration of critical theory and Marcuse, this thesis argues that movies play an important role in the consolidation of neoliberal perspectives of education, and that awareness and examination of the impact of popular culture should remain a significant feature of any critical society. In so doing, the thesis also aims to critically contribute towards a recent ‘renaissance’ in the consideration and application of Marcuse’s scholarly output

    A homogenization theorem for Langevin systems with an application to Hamiltonian dynamics

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    This paper studies homogenization of stochastic differential systems. The standard example of this phenomenon is the small mass limit of Hamiltonian systems. We consider this case first from the heuristic point of view, stressing the role of detailed balance and presenting the heuristics based on a multiscale expansion. This is used to propose a physical interpretation of recent results by the authors, as well as to motivate a new theorem proven here. Its main content is a sufficient condition, expressed in terms of solvability of an associated partial differential equation ("the cell problem"), under which the homogenization limit of an SDE is calculated explicitly. The general theorem is applied to a class of systems, satisfying a generalized detailed balance condition with a position-dependent temperature.Comment: 32 page

    Massless and massive graviton spectra in anisotropic dilatonic braneworld cosmologies

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    We consider a braneworld model in which an anisotropic brane is embedded in a dilatonic background. We solve the background solutions and study the behavior of the perturbations when the universe evolves from an inflationary Kasner phase to a Minkowski phase. We calculate the massless mode spectrum, and find that it does not differ from what expected in standard four-dimensional cosmological models. We then evaluate the spectrum of both light (ultrarelativistic) and heavy (nonrelativistic) massive modes, and find that, at high energies, there can be a strong enhancement of the Kaluza-Klein spectral amplitude, which can become dominant in the total spectrum. The presence of the dilaton, on the contrary, decrease the relative importance of the massive modes.Comment: 18 pages, 4 figures, Typos correction

    Soliton Solutions to the Einstein Equations in Five Dimensions

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    We present a new class of solutions in odd dimensions to Einstein's equations containing either a positive or negative cosmological constant. These solutions resemble the even-dimensional Eguchi-Hanson--(anti)-de Sitter ((A)dS) metrics, with the added feature of having Lorentzian signatures. They provide an affirmative answer to the open question as to whether or not there exist solutions with negative cosmological constant that asymptotically approach AdS5/Γ_{5}/\Gamma, but have less energy than AdS5/Γ_{5}/\Gamma. We present evidence that these solutions are the lowest-energy states within their asymptotic class.Comment: 9 pages, Latex; Final version that appeared in Phys. Rev. Lett; title changed by journal from original title "Eguchi-Hanson Solitons

    Particle production and reheating in the inflationary universe

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    Thermal field theory is applied to particle production rates in inflationary models, leading to new results for catalysed, or two-stage decay, where massive fields act as decay channels for the production of light fields. A numerical investigation of the Bolztmann equation in an expanding universe shows that the particle distributions produced during small amplitude inflaton oscillations or alongside slowly moving inflaton fields can thermalise.Comment: 16 pages, 12 figures, LaTeX, extra references in v

    Population bound effects on bosonic correlations in non-inertial frames

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    We analyse the effect of bounding the occupation number of bosonic field modes on the correlations among all the different spatial-temporal regions in a setting in which we have a space-time with a horizon along with an inertial observer. We show that the entanglement between A (inertial observer) and R (uniformly accelerated observer) depends on the bound N, contrary to the fermionic case. Whether or not decoherence increases with N depends on the value of the acceleration a. Concerning the bipartition A-antiR (Alice with an observer in Rindler's region IV), we show that no entanglement is created whatever the value of N and a. Furthermore, AR entanglement is very quickly lost for finite N and for infinite N. We will study in detail the mutual information conservation law found for bosons and fermions. By means of the boundary effects associated to N finiteness, we will show that for bosons this law stems from classical correlations while for fermions it has a quantum origin. Finally, we will present the strong N dependence of the entanglement in R-antiR bipartition and compare the fermionic cases with their finite N bosonic analogs. We will also show the anti-intuitive dependence of this entanglement on statistics since more entanglement is created for bosons than for their fermion counterparts.Comment: revtex 4, 12 pages, 10 figures. Added Journal ref

    Conformal invariance and apparent universality of semiclassical gravity

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    In a recent work, it has been pointed out that certain observables of the massless scalar field theory in a static spherically symmetric background exhibit a universal behavior at large distances. More precisely, it was shown that, unlike what happens in the case the coupling to the curvature \xi is generic, for the special cases \xi=0 and \xi = 1/6 the large distance behavior of the expectation value turns out to be independent of the internal structure of the gravitational source. Here, we address a higher dimensional generalization of this result: We first compute the difference between a black hole and a static spherically symmetric star for the observables and in the far field limit. Thus, we show that the conformally invariant massless scalar field theory in a static spherically symmetric background exhibits such universality phenomenon in D\geq 4 dimensions. Also, using the one-loop effective action, we compute for a weakly gravitating object. These results lead to the explicit expression of the expectation value for a Schwarzschild-Tangherlini black hole in the far field limit. As an application, we obtain quantum corrections to the gravitational potential in D dimensions, which for D=4 are shown to agree with the one-loop correction to the graviton propagator previously found in the literature.Comment: 11 page

    Hawking radiation from "phase horizons" in laser filaments?

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    Belgiorno et al have reported on experiments aiming at the detection of (the analogue of) Hawking radiation using laser filaments [F. Belgiorno et al, Phys. Rev. Lett. 105, 203901 (2010)]. They sent intense focused Bessel pulses into a non-linear dielectric medium in order to change its refractive index via the Kerr effect and saw creation of photons orthogonal to the direction of travel of the pluses. Since the refractive index change in the pulse generated a "phase horizon" (where the phase velocity of these photons equals the pulse speed), they concluded that they observed the analogue of Hawking radiation. We study this scenario in a model with a phase horizon and a phase velocity very similar to that of their experiment and find that the effective metric does not quite correspond to a black hole. The photons created in this model are not due to the analogue of black hole evaporation but have more similarities to cosmological particle creation. Nevertheless, even this effect cannot explain the observations -- unless the pulse has significant small scale structure in both the longitudinal and transverse dimensions.Comment: 13 pages RevTeX, 2 figure

    Hawking Radiation from Fluctuating Black Holes

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    Classically, black Holes have the rigid event horizon. However, quantum mechanically, the event horizon of black holes becomes fuzzy due to quantum fluctuations. We study Hawking radiation of a real scalar field from a fluctuating black hole. To quantize metric perturbations, we derive the quadratic action for those in the black hole background. Then, we calculate the cubic interaction terms in the action for the scalar field. Using these results, we obtain the spectrum of Hawking radiation in the presence of interaction between the scalar field and the metric. It turns out that the spectrum deviates from the Planck spectrum due to quantum fluctuations of the metric.Comment: 35pages, 4 figure

    Detecting many-body entanglements in noninteracting ultracold atomic fermi gases

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    We explore the possibility of detecting many-body entanglement using time-of-flight (TOF) momentum correlations in ultracold atomic fermi gases. In analogy to the vacuum correlations responsible for Bekenstein-Hawking black hole entropy, a partitioned atomic gas will exhibit particle-hole correlations responsible for entanglement entropy. The signature of these momentum correlations might be detected by a sensitive TOF type experiment.Comment: 5 pages, 5 figures, fixed axes labels on figs. 3 and 5, added reference
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