Superfluid Motion of Light

Superfluidity, the ability of a fluid to move without dissipation, is one of the most spectacular manifestations of the quantum nature of matter. We explore here the possibility of superfluid motion of light. Controlling the speed of a light packet with respect to a defect, we demonstrate the presence of superfluidity and, above a critical velocity, its breakdown through the onset of a dissipative phase. We describe a possible experimental realization based on the transverse motion through an array of waveguides. These results open new perspectives in transport optimization.Comment: 4 pages, 3 figure

Propagation of relativistic charged particles in ultracold atomic gases with Bose-Einstein condensates

We study theoretically some effects produced by a propagation of the charged particles in dilute gases of alkali-metal atoms in the state with Bose-Einstein condensates. The energy change of the high-speed (relativistic) particle that corresponds to the Cherenkov effect in the condensate is investigated. We show that in the studied cases the particle can both loose and receive the energy from a gas. We find the necessary conditions for the particle acceleration in the multi-component condensate. It is shown that the Cherenkov effect in Bose-Einstein condensates can be used also for defining the spectral characteristics of atoms.Comment: 6 pages, 3 figure

Dynamics of platicons due to third-order dispersion

Dynamics of platicons caused by the third-order dispersion is studied. It is shown that under the influence of the third-order dispersion platicons obtain angular velocity depending both on dispersion and on detuning value. A method of tuning of platicon associated optical frequency comb repetition rate is proposed.Comment: 11 pages, 5 figure

Spatial distribution of Cherenkov radiation in periodic dielectric media

The nontrivial dispersion relation of a periodic medium affects both the spectral and the spatial distribution of Cherenkov radiation. We present a theory of the spatial distribution of Cherenkov radiation in the far-field zone inside arbitrary three- and two-dimensional dielectric media. Simple analytical expressions for the far-field are obtained in terms of the Bloch mode expansion. Numerical examples of the Cherenkov radiation in a two-dimensional photonic crystal is presented. The developed analytical theory demonstrates good agreement with numerically rigorous finite-difference time-domain calculations.Comment: 14 pages, 5 figures, Journal of Optics A (in press

Mapping local optical densities of states in silicon photonic structures with nanoscale electron spectroscopy

Relativistic electrons in a structured medium generate radiative losses such as Cherenkov and transition radiation that act as a virtual light source, coupling to the photonic densities of states. The effect is most pronounced when the imaginary part of the dielectric function is zero, a regime where in a non-retarded treatment no loss or coupling can occur. Maps of the resultant energy losses as a sub-5nm electron probe scans across finite waveguide structures reveal spatial distributions of optical modes in a spectral domain ranging from near-infrared to far ultraviolet.Comment: 18 pages, 4 figure

Prototype 9.7 m Schwarzschild-Couder telescope for the Cherenkov Telescope Array: status of the optical system

The Cherenkov Telescope Array (CTA) is an international project for a next-generation ground-based gamma ray observatory, aiming to improve on the sensitivity of current-generation experiments by an order of magnitude and provide energy coverage from 30 GeV to more than 300 TeV. The 9.7m Schwarzschild-Couder (SC) candidate medium-size telescope for CTA exploits a novel aplanatic two-mirror optical design that provides a large field of view of 8 degrees and substantially improves the off-axis performance giving better angular resolution across all of the field of view with respect to single-mirror telescopes. The realization of the SC optical design implies the challenging production of large aspherical mirrors accompanied by a submillimeter-precision custom alignment system. In this contribution we report on the status of the implementation of the optical system on a prototype 9.7 m SC telescope located at the Fred Lawrence Whipple Observatory in southern Arizona.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan, Korea. All CTA contributions at arXiv:1709.0348

Theoretical analysis of electromagnetic field electric tension distribution in the seeds of cereals

In this paper, based on the developed model of seeds, theoretical research are performed concerning the distribution of the electric intensity within low-energy (information) electromagnetic field of millimeter range wave lengths (frequency, power flow density, exposure, amplitude modulation), which may affect the biophysical processes in seed

Cherenkov Radiation from e+e−e^+e^- Pairs and Its Effect on νe\nu_e Induced Showers

We calculate the Cherenkov radiation from an $e^+e^-$ pair at small separations, as occurs shortly after a pair conversion. The radiation is reduced (compared to that from two independent particles) when the pair separation is smaller than the wavelength of the emitted light. We estimate the reduction in light in large electromagnetic showers, and discuss the implications for detectors that observe Cherenkov radiation from showers in the Earth's atmosphere, as well as in oceans and Antarctic ice.Comment: Final version, with minor changes, to appear in PRD. 5 pages with 4 figure