No Escape

The initial idea for the film came from an inspiring performance of Chaplin's Easy Street (1917) accompanied by Donald MacKenzie, resident organist at the Odeon Leicester Square, which led me into researches of early cinema (c1895-1907), a period described by Tom Gunning as the ‘cinema of attractions’. James Lastra points out that during this time competition between cinemas was based on the success of various sound strategies all emphasising the ‘liveness’ of the film experience and films were made to motivate particular types of sound accompaniment. Particularly intriguing was the use of live sound effects performed by a skilled troupe from behind the film screen to produce ‘realistic’ sound effects. This is translated in No Escape into the manipulation of on-screen diegetic sound, also inspired by Pierre Schaeffer's musique concrète and his notions of the sound object and reduced listening. The interaction between the live piano and the onscreen sound is crucial to No Escape as is that of the piano and images, which exist alone together for long stretches. The visual content and structure of the film draws on the city symphonies of Walter Ruttman and especially Dziga Vertov whose formal experimentation, startling juxtaposition of images and very rapid editing is important to No Escape’s non-narrative and at times complex montage of British rural and urban vistas. Vertov’s Man with a Movie Camera (1929) is by and partially about the man with the camera as is No Escape, the title of which refers to the idea that though we may travel to get away from something, there is no escape from the inner life. This is represented by the piano music, which varies but within fairly restricted limits. It does respond or drive image choice and editing but the overall sense should be that one cannot escape and these responses are temporary and fleeting Extrapolating from Tom Gunning's cinema of attractions, James Beattie's concept of ‘documentary display’ - a poetic, sensual and subjective approach which encourages listening and looking rather than cognitive understanding - underpins the aesthetic of No Escape, as is a belief in the supremacy of sound and of film as a performative event

Fractional topological phase for entangled qudits

We investigate the topological structure of entangled qudits under unitary local operations. Different sectors are identified in the evolution, and their geometrical and topological aspects are analyzed. The geometric phase is explicitly calculated in terms of the concurrence. As a main result, we predict a fractional topological phase for cyclic evolutions in the multiply connected space of maximally entangled states.Comment: REVTex, 4 page

Fading Gravity and Self-Inflation

We study the cosmology of a toy modified theory of gravity in which gravity shuts off at short distances, as in the fat graviton scenario of Sundrum. In the weak-field limit, the theory is perturbatively local, ghost-free and unitary, although likely suffers from non-perturbative instabilities. We derive novel self-inflationary solutions from the vacuum equations of the theory, without invoking scalar fields or other forms of stress energy. The modified perturbation equation expressed in terms of the Newtonian potential closely resembles its counterpart for inflaton fluctuations. The resulting scalar spectrum is therefore slightly red, akin to the simplest scalar-driven inflationary models. A key difference, however, is that the gravitational wave spectrum is generically not scale invariant. In particular the tensor spectrum can have a blue tilt, a distinguishing feature from standard inflation.Comment: 35 pages, 4 figures. v3: version to appear in Phys. Rev.

Symmetron Fields: Screening Long-Range Forces Through Local Symmetry Restoration

We present a screening mechanism that allows a scalar field to mediate a long range (~Mpc) force of gravitational strength in the cosmos while satisfying local tests of gravity. The mechanism hinges on local symmetry restoration in the presence of matter. In regions of sufficiently high matter density, the field is drawn towards \phi = 0 where its coupling to matter vanishes and the \phi-> -\phi symmetry is restored. In regions of low density, however, the symmetry is spontaneously broken, and the field couples to matter with gravitational strength. We predict deviations from general relativity in the solar system that are within reach of next-generation experiments, as well as astrophysically observable violations of the equivalence principle. The model can be distinguished experimentally from Brans-Dicke gravity, chameleon theories and brane-world modifications of gravity.Comment: 4 pages. v3: version appearing in PR

String creation in cosmologies with a varying dilaton

FRW solutions of the string theory low-energy effective actions are described, yielding a dilaton which first decreases and then increases. We study string creation in these backgrounds and find an exponential divergence due to an initial space-like singularity. We conjecture that this singularity may be removed by the effects of back-reaction, leading to a solution which at early times is de Sitter space.Comment: 15 pages, latex, one figur

No-Go Theorems for Generalized Chameleon Field Theories

The chameleon, or generalizations thereof, is a light scalar that couple to matter with gravitational strength, but whose manifestation depends on the ambient matter density. A key feature is that the screening mechanism suppressing its effects in high-density environments is determined by the local scalar field value. Under very general conditions, we prove two theorems limiting its cosmological impact: i) the Compton wavelength of such a scalar can be at most Mpc at present cosmic density, which restricts its impact to non-linear scales; ii) the conformal factor relating Einstein- and Jordan-frame scale factors is essentially constant over the last Hubble time, which precludes the possibility of self-acceleration. These results imply that chameleon-like scalar fields have a negligible effect on the linear-scale growth history; theories that invoke a chameleon-like scalar to explain cosmic acceleration rely on a form of dark energy rather than a genuine modified gravity effect. Our analysis applies to a broad class of chameleon, symmetron and dilaton theories.Comment: 4 page

Multiphoton path entanglement by non-local bunching

Multiphoton path entanglement is created without applying post-selection, by manipulating the state of stimulated parametric down-conversion. A specific measurement on one of the two output spatial modes leads to the non-local bunching of the photons of the other mode, forming the desired multiphoton path entangled state. We present experimental results for the case of a heralded two-photon path entangled state and show how to extend this scheme to higher photon numbers.Comment: 4 pages, 5 figures, published versio