Related papers: Has superluminal light propagation been observed?
Redshifts of several galaxies thought to be associated with NGC 326 are determined. The results confirm the presence of a cluster and find a mean redshift of z = 0.0477 +/- 0.0007 and a line-of-sight velocity dispersion sigma_{z} = 599…
In this paper, we investigate the propagation of the light pulse reflected from the layer system with a graphene layer. We show a tunable transition between positive and negative group delay of the optical pulse reflection in such a layered…
In this paper the fields generated by an electric dipole and a gravitational quadrapole are shown to propagate superluminally in the nearfield of the source and reduce to the speed of light as the fields propagate into the farfield. A…
A critical review of experimental studies of the so-called 'slow light' arising due to anomalously high steepness of the refractive index dispersion under conditions of electromagnetically induced transparency or coherent population…
We examine the propagation of a weak probe light through a coherently driven $Y$-type system. Under the condition that the excited atomic levels decay via same vacuum modes, the effects of quantum interference in decay channels are…
We report ultraslow group velocities of light in a solid. Light speeds as slow as 45 m/s were observed, corresponding to a group delay of 66 ms in a 3-mm thick crystal. Reduction of the group velocity is accomplished by using a sharp…
We examine properties and propagation of the energy-density and photon-probability centroids of electromagnetic wavepackets in free space. In the second-order paraxial approximation, both of these centroids propagate with the same…
Pulse propagation is considered in an inhomogeneously broadened medium of three-level atoms in a V-configuration, dressed by a counter-propagating pump pulse. A significant signal slowdown is demonstrated in this of the three frequency…
We consider the effect of radiative corrections on the maximum velocity of propagation of neutral scalar fields in a uniform electromagnetic field. The propagator of neutral scalar fields interacting with charged fields depends on the…
We investigate the dispersion and the absorption properties of a weak probe field in a three-level Lambda-type atomic system. We use just an incoherent field for controlling the group velocity of light. It is shown that the slope of…
Velocity bias offers a single parameter ($b_v$) description of the likely segregation of mass and light in a galaxy cluster. The relation between the projected mass profile and the light profile, normalized by the virial $M/L$, is presented…
Hubble's Law, v=HD (recession velocity is proportional to distance), is a theoretical result derived from the Friedmann-Robertson-Walker metric. v=HD applies at least as far as the particle horizon and in principle for all distances. Thus,…
We analyse a system in which, due to entanglement between the spin and spatial degrees of freedom, the reduced transmitted state has the shape of the freely propagating pulse translated in the complex co-ordinate plane. In the case an…
It is a striking result the one found by Wang, Kuzmich & Dogariu 1 (see also 2) experimentally last year, that a pulse of light, entered into an atomic caesium (Cs) vapour cell, appeared at the exit before its entrance (!) by 62…
We investigate theoretically the formation of two-component light with superluminal group velocity in a medium controlled by four Raman pump fields. In such an optical scheme only a particular combination of the probe fields is coupled to…
Experiments have shown that individual photons penetrate an optical tunnel barrier with an effective group velocity considerably greater than the vacuum speed of light. The experiments were conducted with a two-photon parametric…
We show theoretically the presence of electromagnetically induced transparency (EIT) like feature in a {\Lambda}-type atom-molecule coupled system. We demonstrate that EIT in such a systems has a sharp dispersion characteristic which is…
Though many experiments appear to have confirmed the light speed invariance postulate of special relativity theory, this postulate is actually unverified. This paper resolves this issue by first showing the manner in which an illusion of…
We study distances of propagation and the group velocities of the muon neutrinos in the presence of mixing and oscillations assuming that Lorentz invariance holds. Oscillations lead to distortion of the $\nu_\mu$ wave packet which, in turn,…
The two outer triangular caustics (regions of infinite magnification) of a close binary microlens move much faster than the components of the binary themselves, and can even exceed the speed of light. When $\epsilon > 1$, where $\epsilon c$…