Spin Squeezing with Coherent Light via Entanglement Swapping

We analyze theoretically a scheme that produces spin squeezing via the continuous swapping of atom-photon entanglement into atom-atom entanglement, and propose an explicit experimental system where the necessary atom-field coupling can be realized. This scheme is found to be robust against perturbations due to other atom-field coupling channels.Comment: 6 pages, 10 figure

Superradiance induced topological vortex phase in a Bose-Einstein condensate

We investigate theoretically a topological vortex phase transition induced by a superradiant phase transition in an atomic Bose-Einstein condensate driven by a Laguerre-Gaussian optical mode. We show that superradiant radiation can either carry zero angular momentum, or be in a rotating Laguerre-Gaussian mode with angular momentum. The conditions leading to these two regimes are determined in terms of the width for the pump laser and the condensate size for the limiting cases where the recoil energy is both much smaller and larger than the atomic interaction energy.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Photonic Band Gap in the Triangular Lattice of BEC vortices

We investigate the photonic bands of an atomic Bose-Einstein condensate with a triangular vortex lattice. Index contrast between the vortex cores and the bulk of the condensate is achieved through the enhancement of the index via atomic coherence. Frequency dependent dielectric function is used in the calculations of the bands, resulting in photonic band gap widths of a few MHz.Comment: 8 pages, 6 figure

Research of thermal performance investigation of stator winding solder region in hydroelectric power plants

Hydroelectric power plants are the most widely used renewable energy sources all over the world. In these plants, many studies have been conducted in order to produce energy continuously and efficiently. Among these studies, predictive maintenance methods, efforts to increase power by improving cooling conditions, and improving efficiency by improving the turbine wheel. In this paper, soldering at the junctions of the stator windings in the central generators has been investigated. Traditional solder (Cu-Zn) materials and silver alloy solders (Ag-Cu-Zn) have been investigated in terms of thermal and metallographic. Silver alloy soldering has been found to have lower electrical conductivity than conventional soldering. The winding temperatures measured on the generating generator show that silver alloy soldering is more efficient. Reducing the stator winding temperature in hydroelectric power plants allows more energy production and also reduces costs by preventing winding failures

Fano Resonances in the Linear and Nonlinear Plasmonic Response

Fano resonances manifest novel phenomena both in linear and nonlinear response of plasmonic nanomaterials. They can extend the lifetime of plasmonic excitations, enabling the operation of nanolasers, or they can increase the fluorescence of quantum emitters. They also provide control over nonlinear optical processes such as second harmonic generation and surface enhanced Raman scattering. Fano resonances can both enhance and suppress nonlinear response. Interference of two or more absorption/conversion paths is responsible for the appearance of these effects. In this Chapter, we demonstrate explicitly—on a single equation—how path interference takes part in linear and nonlinear Fano resonances