No quantum friction between uniformly moving plates

The Casimir forces between two plates moving parallel to each other are found by calculating the vacuum electromagnetic stress tensor. The perpendicular force between the plates is modified by the motion but there is no lateral force on the plates. Electromagnetic vacuum fluctuations do not therefore give rise to "quantum friction" in this case, contrary to previous assertions. The result shows that the Casimir-Polder force on a particle moving at constant speed parallel to a plate also has no lateral component.Comment: 17 pages. Final, published versio

Fiber-optical analogue of the event horizon

The physics at the event horizon resembles the behavior of waves in moving media. Horizons are formed where the local speed of the medium exceeds the wave velocity. We use ultrashort pulses in microstructured optical fibers to demonstrate the formation of an artificial event horizon in optics. We observed a classical optical effect, the blue-shifting of light at a white-hole horizon. We also show by theoretical calculations that such a system is capable of probing the quantum effects of horizons, in particular Hawking radiation.Comment: MEDIA EMBARGO. This paper is subject to the media embargo of Scienc

Metamaterial "Multiverse"

Optical space in metamaterials may be engineered to mimic the landscape of a multidimensional Universe which has regions of different topology and different effective dimensionality. The "metamaterial landscape" may include regions in which one or two spatial dimensions are compactified. Nonlinear optics of metamaterials in these regions mimics either U(1) or SU(2) Kaluza-Klein theories having one or more kinds of effective charges. As a result, novel "photon blockade" nonlinear optical metamaterial devices may be realized. Topology-changing phase transitions in such metamaterials lead to considerable particle creation perceived as flashes of light, thus providing a toy model of birth of an individual physical Universe.Comment: 13 pages, 2 figures, this version is accepted for publication in the Journal of Optic

General Relativity in Electrical Engineering

In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. Given a desired device function, the theory describes the electromagnetic properties that turn this function into fact. We consider media that facilitate space-time transformations and include negative refraction. Our theory unifies the concepts operating behind the scenes of perfect invisibility devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic analogs of the event horizon, and may lead to further applications

Divergence of Casimir stress in inhomogeneous media

Copyright © 2013 American Physical SocietyWe examine the local behavior of the regularized stress tensor commonly used in calculations of the Casimir force for a dielectric medium inhomogeneous in one direction. It is shown that the usual expression for the stress tensor is not finite anywhere within the medium, whatever the temporal dispersion or index profile, and that this divergence is unlikely to be removed through a simple modification to the regularization procedure. Our analytic argument is illustrated numerically for a medium approximated as a series of homogeneous strips, as the width of these strips is taken to zero. The findings hold for all magnetodielectric media

Black hole lasers in Bose-Einstein condensates

We consider elongated condensates that cross twice the speed of sound. In the absence of periodic boundary conditions, the phonon spectrum possesses a discrete and finite set of complex frequency modes that induce a laser effect. This effect constitutes a dynamical instability and is due to the fact that the supersonic region acts as a resonant cavity. We numerically compute the complex frequencies and density-density correlation function. We obtain patterns with very specific signatures. In terms of the gravitational analogy, the flows we consider correspond to a pair of black hole and white hole horizons, and the laser effect can be conceived as a self-amplified Hawking radiation. This is verified by comparing the outgoing flux at early time with the standard black hole radiation.Comment: iopams, 37 pages, 14 figures, 1 table; for associated gif animations, see http://people.sissa.it/~finazzi/bec_bhlasers/movies/ or http://iopscience.iop.org/1367-2630/12/9/095015/media. Published on New. J. Phys. (http://iopscience.iop.org/1367-2630/12/9/095015/). V2: few new comments, modified figure

Reply to comment on 'No quantum friction between uniformly moving plates'

we reply to the comment on our paper made by Volokitin and Persson (2011 New J. Phys. 13 068001).Publisher PDFPeer reviewe

General relativity in electrical engineering - art. no. 658104

In electrical engineering metamaterials have been developed that offer unprecedented control over electromagnetic fields. Here we show that general relativity lends the theoretical tools for designing devices made of such versatile materials. We consider media that facilitate space-time transformations and include negative refraction. Our theory unifies the concepts operating behind the scenes of perfect invisibility devices, perfect lenses, the optical Aharonov-Bohm effect and electromagnetic analogs of the event horizon, and may lead to further applications.</p