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Spatial coherence singularities and incoherent vortex solitons  [PDF]
Kristian Motzek,Yuri S. Kivshar,Ming-Feng Shih,Grover A. Swartzlander Jr
Physics , 2004, DOI: 10.1364/JOSAB.22.001437
Abstract: We study spatially localized optical vortices created by self-trapping of partially incoherent light with a phase dislocation in a biased photorefractive crystal. In a contrast to the decay of coherent self-trapped vortex beams due to the azimuthal instability, the incoherent vortices are stabilized when the spatial incoherence of light exceeds a certain threshold. We analyze the spatial coherence properties of the incoherent optical vortices and reveal the existence of ring-like singularities in the spatial coherence function of a vortex field that can characterize the stable propagation of vortices through nonlinear media.
Coherent and Incoherent Multiple Scattering  [PDF]
Julien Chabe,Mohamed-Taha Rouabah,Louis Bellando,Tom Bienaime,Nicola Piovella,Romain Bachelard,Robin Kaiser
Physics , 2012, DOI: 10.1103/PhysRevA.89.043833
Abstract: We compare two different models of transport of light in a disordered system with a spherical Gaussian distribution of scatterers. A coupled dipole model, keeping into account all interference effects, is compared to an incoherent model, using a random walk of particles. Besides the well known coherent backscattering effect and a well pronounced forward lobe, the incoherent model reproduces extremely well all scattering features. In an experiment with cold atoms, we use the momentum recoil imparted on the center of mass of the sample as a partial probe of the light scattering properties. We find that the force acting on the center of mass of the atoms is not well suited to exhibit the coherence effects in light propagation under multiple scattering conditions.
Incoherent vector vortex-mode solitons in self-focusing nonlinear media  [PDF]
Kristian Motzek,Friedemann Kaiser,José R. Salgueiro,Yuri S. Kivshar,Cornelia Denz
Physics , 2004, DOI: 10.1364/OL.29.002285
Abstract: We suggest a novel type of composite spatial optical soliton created by a coherent vortex beam guiding a partially incoherent light beam in a self-focusing nonlinear medium. We show that the incoherence of the guided mode may enhance, rather than suppress, the vortex azimuthal instability, and also demonstrate strong destabilization of dipole-mode solitons by partially incoherent light.
Coherent and incoherent contents of correlations  [PDF]
Kavan Modi,Mile Gu
Physics , 2009, DOI: 10.1142/S0217979213450276
Abstract: We examine bipartite and multipartite correlations within the construct of unitary orbits. We show that the set of product states is a very small subset of set of all possible states, while all unitary orbits contain classically correlated states. Using this we give meaning to degeneration of quantum correlations due to a unitary interactions, which we call coherent correlations. The remaining classical correlations are called incoherent correlations and quantified in terms of the distance of the joint probability distributions to its marginals. Finally, we look at how entanglement looks in this picture for the two-qubit case.
Conditional vorticity budget of coherent and incoherent flow contributions in fully developed homogeneous isotropic turbulence  [PDF]
Michael Wilczek,Benjamin Kadoch,Kai Schneider,Rudolf Friedrich,Marie Farge
Physics , 2012, DOI: 10.1063/1.3694807
Abstract: We investigate the conditional vorticity budget of fully developed three-dimensional homogeneous isotropic turbulence with respect to coherent and incoherent flow contributions. The Coherent Vorticity Extraction based on orthogonal wavelets allows to decompose the vorticity field into coherent and incoherent contributions, of which the latter are noise-like. The impact of the vortex structures observed in fully developed turbulence on statistical balance equations is quantified considering the conditional vorticity budget. The connection between the basic structures present in the flow and their statistical implications is thereby assessed. The results are compared to those obtained for large- and small-scale contributions using a Fourier decomposition, which reveals pronounced differences.
Spatial Interference: From Coherent To Incoherent  [PDF]
Su-Heng Zhang,Lu Gao,Jun Xiong,Li-Juan Feng,De-Zhong Cao,Kaige Wang
Physics , 2008, DOI: 10.1103/PhysRevLett.102.073904
Abstract: It is well known that direct observation of interference and diffraction pattern in the intensity distribution requires a spatially coherent source. Optical waves emitted from portions beyond the coherence area possess statistically independent phases, and will degrade the interference pattern. In this paper we show an optical interference experiment, which seems contrary to our common knowledge, that the formation of the interference pattern is related to a spatially incoherent light source. Our experimental scheme is very similar to Gabor's original proposal of holography[1], just with an incoherent source replacing the coherent one. In the statistical ensemble of the incoherent source, each sample field produces a sample interference pattern between object wave and reference wave. These patterns completely differ from each other due to the fluctuation of the source field distribution. Surprisingly, the sum of a great number of sample patterns exhibits explicitly an interference pattern, which contains all the information of the object and is equivalent to a hologram in the coherent light case. In this sense our approach would be valuable in holography and other interference techniques for the case where coherent source is unavailable, such as x-ray and electron sources.
Coherent and Incoherent Thermal Transport in Nanomeshes  [PDF]
Navaneetha K. Ravichandran,Austin J. Minnich
Physics , 2014, DOI: 10.1103/PhysRevB.89.205432
Abstract: Coherent thermal transport in nanopatterned structures is a topic of considerable interest, but whether it occurs in certain structures remains unclear due to poor understanding of which phonons conduct heat. Here, we perform the first fully three-dimensional, frequency-dependent simulations of thermal transport in nanomeshes by solving the Boltzmann transport equation with a novel, efficient Monte Carlo method. From the spectral information in our simulations, we show that thermal transport in nanostructures that can be created with available lithographic techniques is dominated by incoherent boundary scattering at room temperature. Our result provides important insights into the conditions required for coherent thermal transport to occur in artificial structures.
Coherent and Incoherent Neutral Current Scattering for Supernova Detection  [PDF]
P. C. Divari
Advances in High Energy Physics , 2012, DOI: 10.1155/2012/379460
Abstract: The total cross sections as well as the neutrino event rates are calculated in the neutral current neutrino scattering off 40Ar and 132Xe isotopes at neutrino energies ( ?MeV). The individual contribution coming from coherent and incoherent channels is taking into account. An enhancement of the neutral current component is achieved via the coherent ( ) channel which is dominant with respect to incoherent ( ) one. The response of the above isotopes as a supernova neutrino detection has been considered, assuming a two parameter Fermi-Dirac distribution for the supernova neutrino energy spectra. The calculated total cross sections are tested on a gaseous spherical TPC detector dedicated for supernova neutrino detection. 1. Introduction It is well known that neutrinos and their interactions with nuclei have attracted a great deal of attention, since they play a fundamental role in nuclear physics, cosmology, and in various astrophysical processes, especially in the dynamics of core-collapse supernova-nucleosynthesis [1–11]. Moreover, neutrinos proved to be interesting tools for testing weak interaction properties, by examining nuclear structure and for exploring the limits of the standard model [12]. In spite of the important role the neutrinos play in many phenomena in nature, numerous questions concerning their properties, oscillation characteristics, their role in star evolutions and in the dark matter of the universe, and so forth remain still unanswered. The main goal of experimental [13–17] and theoretical studies [18–27] is to shed light on the above open problems to which neutrinos are absolutely crucial. Among the probes which involve neutrinos, the neutrino-nucleus interaction possess a prominent position [28–34]. Thus, the study of neutrino scattering with nuclei is a good way to detect or distinguish neutrinos of different flavor and explore the basic structure of the weak interactions. Also, specific neutrino-induced transitions between discrete nuclear states with good quantum numbers of spin, isospin, and parity allows us to study the structure of the weak hadronic currents. Furthermore, terrestrial experiments performed to detect astrophysical neutrinos, as well as neutrino-induced nucleosynthesis interpreted through several neutrino-nucleus interaction theories, constitute good sources of explanation for neutrino properties. There are four categories of neutrino-nucleus processes: the two types of charged-current (CC) reactions of neutrinos and antineutrinos and the two types of neutral-current (NC) ones. In the charged-current reactions a
Rhodopsin Photoisomerization: Coherent vs. Incoherent Excitation  [PDF]
Kunihito Hoki,Paul Brumer
Physics , 2009,
Abstract: A uniform minimal model of rhodopsin photoisomerization induced by either coherent laser light or low level incoherent light (e.g. moonlight) is provided. Realistic timescales for both processes, which differ by ten orders of magnitude, are obtained. Further, a kinetic scheme involving rates for both coherent and incoherent light excitation is introduced, placing all timescales into a uniform framework.
Intermittency for coherent and incoherent current ensemble model  [PDF]
B. Ziaja
Physics , 1995, DOI: 10.1007/BF02907025
Abstract: We investigate the origin of intermittency for multiparticle distribution in momentum space, following the idea that there is a kind of power law distribution of the space-time region of hadron emission. Using the formalism of current ensamble model to describe boson sources we discuss intermittency exponents for the coherent and incoherent ( chaotic) particle production scheme.
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