Coherence revivals in two-photon frequency combs

We describe and theoretically analyze the self-imaging Talbot effect of entangled photon pairs in the time domain. Rich phenomena are observed in coherence propagation along dispersive media of mode-locked two- photon states with frequency entanglement exhibiting a comblike correlation function. Our results can be used to remotely transfer frequency standards through optical fiber networks with two-photon light, avoiding the requirement of dispersion compensation

Ghost interference with classical partially coherent light pulses

The two-photon temporal coincidence detection amplitude obeys a pair of equations identical to those of classical partially coherent plane-wave pulses propagating in linearly dispersive media. These equations are also the same as the paraxial Wolf equations, for both the two-photon spatial probability amplitude and the cross-spectral density function. Therefore, a fourfold analogy between space and time, as well as between quantum entanglement and partial coherence, arises. In accordance to this, we predict nonlocal interference structures in a fourth-order interferometric configuration with classical partially coherent pulses under the assumption of Gaussian statistics. As an example, we present the classical temporal counterpart of the ghost diffraction phenomenon. Our work suggests that some time-domain entanglement phenomena that hitherto were considered as uniquely quantum can be mimicked by conventional partially coherent light pulse

Resolution-enhanced optical coherence tomography based on classical intensity interferometry

We propose a fourth-order interference scheme for optical coherence tomography operating with broadband incoherent (or quasi-incoherent) light. It is shown that using this proposal, an axial resolution improvement by a factor of 2 and a better sensitivity for weakly reflecting samples are obtained than with the standard second-order correlation scheme. From a practical perspective, we suggest the use of broadband Q-switched pulses and performing ultrafast intensity correlation with a nonlinear crystal. The global performance of our proposal is illustrated by means of numerical simulation

Rattle Em Bones / music by Fred Rose; words by Fred Rose

https://egrove.olemiss.edu/sharris_e/1000/thumbnail.jp

Gwine to Heaben Some Day / music by Vernon Richner; words by Speed Langworthy

Description reads: Negro Spiritual with Male Quartet; Publisher: T. S. Denison and Company (Chicago)https://egrove.olemiss.edu/sharris_d/1101/thumbnail.jp

Tidal and rotational effects in the perturbations of hierarchical triple stellar systems. II. Eccentric systems - the case of AS Camelopardalis

We study the perturbations of a relatively close third star on a tidally distorted eccentric eclipsing binary. We consider both the observational consequences of the variations of the orbital elements and the interactions of the stellar rotation with the orbital revolution in the presence of dissipation. We concentrate mainly on the effect of a hypothetical third companion on both the real, and the observed apsidal motion period. We investigate how the observed period derived mainly from some variants of the O-C relates to the real apsidal motion period. We carried out both analytical and numerical investigations and give the time variations of the orbital elements of the binary both in the dynamical and the observational reference frames. We give the direct analytical form of an eclipsing O-C affected simultaneously by the mutual tidal forces and the gravitational interactions with a tertiary. We also integrated numerically simultaneously the orbital and rotational equations for the possible hierarchical triple stellar system AS Camelopardalis. We find that there is a significant domain of the possible hierarchical triple system configurations, where both the dynamical and the observational effects tend to measure longer apsidal advance rate than is expected theoretically. This happens when the mutual inclination of the close and the wide orbits is large, and the orbital plane of the tertiary almost coincides with the plane of the sky. We also obtain new numerical results on the interaction of the orbital evolution and stellar rotation in such triplets. The most important fact is that resonances might occur as the stellar rotational rate varies during the dissipation-driven synchronization process...Comment: 33 pages, 12 figures (reduced quality!), accepted for publication for Astronomy and Astrophysic

Star-galaxy separation in the AKARI NEP Deep Field

Context: It is crucial to develop a method for classifying objects detected in deep surveys at infrared wavelengths. We specifically need a method to separate galaxies from stars using only the infrared information to study the properties of galaxies, e.g., to estimate the angular correlation function, without introducing any additional bias. Aims. We aim to separate stars and galaxies in the data from the AKARI North Ecliptic Pole (NEP) Deep survey collected in nine AKARI / IRC bands from 2 to 24 {\mu}m that cover the near- and mid-infrared wavelengths (hereafter NIR and MIR). We plan to estimate the correlation function for NIR and MIR galaxies from a sample selected according to our criteria in future research. Methods: We used support vector machines (SVM) to study the distribution of stars and galaxies in the AKARIs multicolor space. We defined the training samples of these objects by calculating their infrared stellarity parameter (sgc). We created the most efficient classifier and then tested it on the whole sample. We confirmed the developed separation with auxiliary optical data obtained by the Subaru telescope and by creating Euclidean normalized number count plots. Results: We obtain a 90% accuracy in pinpointing galaxies and 98% accuracy for stars in infrared multicolor space with the infrared SVM classifier. The source counts and comparison with the optical data (with a consistency of 65% for selecting stars and 96% for galaxies) confirm that our star/galaxy separation methods are reliable. Conclusions: The infrared classifier derived with the SVM method based on infrared sgc- selected training samples proves to be very efficient and accurate in selecting stars and galaxies in deep surveys at infrared wavelengths carried out without any previous target object selection.Comment: 8 pages, 8 figure

Lower Cretaceous (Hauterivian-Albian) ammonite biostratigraphy in the Maestrat Basin (E Spain)

Peer reviewedPublisher PD

Modeling Micro-Porous Surfaces for Secondary Electron Emission Control to Suppress Multipactor

This work seeks to understand how the topography of a surface can be engineered to control secondary electron emission (SEE) for multipactor suppression. Two unique, semi-empirical models for the secondary electron yield (SEY) of a micro-porous surface are derived and compared. The first model is based on a two-dimensional (2D) pore geometry. The second model is based on a three-dimensional (3D) pore geometry. The SEY of both models is shown to depend on two categories of surface parameters: chemistry and topography. An important parameter in these models is the probability of electron emissions to escape the surface pores. This probability is shown by both models to depend exclusively on the aspect ratio of the pore (the ratio of the pore height to the pore diameter). The increased accuracy of the 3D model (compared to the 2D model) results in lower electron escape probabilities with the greatest reductions occurring for aspect ratios less than two. In order to validate these models, a variety of micro-porous gold surfaces were designed and fabricated using photolithography and electroplating processes. The use of an additive metal-deposition process (instead of the more commonly used subtractive metal-etch process) provided geometrically ideal pores which were necessary to accurately assess the 2D and 3D models. Comparison of the experimentally measured SEY data with model predictions from both the 2D and 3D models illustrates the improved accuracy of the 3D model. For a micro-porous gold surface consisting of pores with aspect ratios of two and a 50% pore density, the 3D model predicts that the maximum total SEY will be one. This provides optimal engineered surface design objectives to pursue for multipactor suppression using gold surfaces

De Wes\u27 Wind Blows from de Wes\u27 / music by Larry E. Johnson; words by Larry E. Johnson

Cover: description reads exclusive novelty numbers for musical comedies, minstrels, vaudeville, revues and specialties; Publisher: T. S. Denison and Company (Chicago)https://egrove.olemiss.edu/sharris_d/1056/thumbnail.jp