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A modulation of refractive index can move at the speed of light. How it interacts with an electromagnetic wave? Does it reflect? We show that an incident electromagnetic wave, depending on its frequency either is totally transmitted with a…

Optics · Physics 2024-02-19 T. Z. Esirkepov , S. V. Bulanov

We examine the response of a plane wave incident on a flat surface of a medium characterized by simultaneously negative electric and magnetic susceptibilities by solving Maxwell's equations explicitly and without making any assumptions on…

Optics · Physics 2008-10-28 Antonia Chimonidou , E. C. G. Sudarshan

At present, the theory of light diffraction only has the simple wave-optical approach. In this paper, we study light diffraction with the approach of relativistic quantum theory. We find that the slit length, slit width, slit thickness and…

Contemporary observational and theoretical studies on the temporal nature of microscopic measurements renewed the discussion about the fundamental constants, leading to the possibility of light speed variation and superluminal pulse…

General Physics · Physics 2007-05-23 R Assumpcao

We study the influence of the space and time dispersion on the frequency dependence of the wave vectors of electromagnetic waves propagating in three-dimensional photonic crystals. Two types of structures are considered: media with weak…

Other Condensed Matter · Physics 2007-05-23 F. Bass , V. Freilikher , O. Shefranova

Propagation of electromagnetic plane waves in some directions in gravitationally affected vacuum over limited ranges of spacetime can be such that the phase velocity vector casts a negative projection on the time-averaged Poynting vector.…

Optics · Physics 2009-11-10 Akhlesh Lakhtakia , Tom G. Mackay

Space-time wave packets can propagate invariantly in free space with arbitrary group velocity thanks to the spatio-temporal correlation. Here it is proved that the space-time wave packets are stable in dispersive media as well and free from…

Optics · Physics 2022-07-27 Hao He , Cheng Guo , Meng Xiao

In two models it is shown that a light pulse propagates from a vacuum into certain media with velocity greater than that of a light in a vacuum (c). By numerical calculation the propagating properties of such a light are given.

Optics · Physics 2009-11-06 Xian-jian Zhou

By exploring the relationship between the propagation of electromagnetic waves in a gravitational field and the light propagation in a refractive medium, it is shown that, in the presence of a positive cosmological constant, the velocity of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 W. R. Esposito Miguel , J. G. Pereira

A new look at the so-called effect of an accelerating matter is presented. It was previously stated that the effect is optical in nature and consists in changing the frequency of the wave passing through a refractive sample moving with…

General Physics · Physics 2020-08-26 A. I. Frank

On speed of a photon in a dispersing medium Ogluzdin Valeriy E. Abstract Based on the author of the experimental results and their treatment, a model that demonstrates that the real dispersive medium in spectral regions where the refractive…

Optics · Physics 2015-06-03 Valeriy E. Ogluzdin

We extend Kramers-Kronig relations beyond the optical approximation to dielectric functions that depend not only on frequency but on the wave number as well. This implies extending the notion of causality commonly used in the theory of…

Classical Physics · Physics 2024-09-24 Josep Llosa , Francesc Salvat

Similar to the optical diffraction of light passing through a material grating, the Kapitza-Dirac effect occurs when an electron is diffracted by a standing light wave. In its original description the effect is time-independent. In the…

The effect of an external pressure disturbance, being displaced with a constant speed along the free surface of a viscous thin film, is studied theoretically in the lubrication approximation in one- and two-dimensional geometries. In the…

Fluid Dynamics · Physics 2016-03-24 René Ledesma-Alonso , Michael Benzaquen , Thomas Salez , Elie Raphaël

When a negative slope of the dispersion curve is encountered, the propagating light may be either 'fast light' or 'backward propagating'. We show that causality considerations select only one of which for each scenario, and demonstrate that…

Optics · Physics 2008-07-31 Eyal Feigenbaum , Noam Kaminski , Meir Orenstein

We discuss the density fluctuations of a fluid due to zero point motion. These can be regarded as density fluctuations in the phonon vacuum state. We assume a linear dispersion relation with a fixed speed of sound and calculate the density…

Quantum Physics · Physics 2010-04-22 L. H. Ford , N. F. Svaiter

The propagation of cosmic rays can be described as a diffusive motion in most galactic environments. High-energy gamma-rays measured by Fermi have allowed inference of a gradient in the cosmic-ray density and spectral energy behavior in the…

High Energy Astrophysical Phenomena · Physics 2021-10-14 J. Dörner , P. Reichherzer , L. Merten , J. Becker Tjus , H. Fichtner , M. J. Pueschel , E. G. Zweibel

In relativity and quantum field theory, the vacuum speed of light is assumed to be constant; the range of validity of general relativity is determined by the Planck length. However, there has been no convincing theory explaining the…

General Physics · Physics 2019-01-23 Christoph Köhn

The applied method of the amplitude envelopes give us the possibility to describe a new class of amplitude equations governing the propagation of optical pulses in media with dispersion, dispersionless media and vacuum. We normalized these…

Pattern Formation and Solitons · Physics 2007-05-23 Lubomir M. Kovachev

Interfering liquid surface waves are generated by electrically driven vertical oscillations of two or more equispaced pins immersed in a liquid (water). The corresponding intensity distribution, resulting from diffraction of monochromatic…

Optics · Physics 2009-11-10 Tarun Kr. Barik , Anushree Roy , Sayan Kar