10,976 research outputs found
N-body Efimov states from two-particle noise
The ground state energies of universal N-body clusters tied to Efimov
trimers, for N even, are shown to be encapsulated in the statistical
distribution of two particles interacting with a background auxiliary field at
large Euclidean time when the interaction is tuned to the unitary point.
Numerical evidence that this distribution is log-normal is presented, allowing
one to predict the ground-state energies of the N-body system.Comment: Extended discussion of results; published versio
SVM-based texture classification in optical coherence tomography
This paper describes a new method for automated texture classification for glaucoma detection using high resolution retinal Optical Coherence Tomography (OCT). OCT is a non-invasive technique that produces cross-sectional imagery of ocular tissue. Here, we exploit information from OCT im-ages, specifically the inner retinal layer thickness and speckle patterns, to detect glaucoma. The proposed method relies on support vector machines (SVM), while principal component analysis (PCA) is also employed to improve classification performance. Results show that texture features can improve classification accuracy over what is achieved using only layer thickness as existing methods currently do. Index Terms — classification, support vector machine, optical coherence tomography, texture 1
High Angular Resolution Stellar Imaging with Occultations from the Cassini Spacecraft II: Kronocyclic Tomography
We present an advance in the use of Cassini observations of stellar
occultations by the rings of Saturn for stellar studies. Stewart et al. (2013)
demonstrated the potential use of such observations for measuring stellar
angular diameters. Here, we use these same observations, and tomographic
imaging reconstruction techniques, to produce two dimensional images of complex
stellar systems. We detail the determination of the basic observational
reference frame. A technique for recovering model-independent brightness
profiles for data from each occulting edge is discussed, along with the
tomographic combination of these profiles to build an image of the source star.
Finally we demonstrate the technique with recovered images of the {\alpha}
Centauri binary system and the circumstellar environment of the evolved
late-type giant star, Mira.Comment: 8 pages, 8 figures, Accepted by MNRA
Sign problems, noise, and chiral symmetry breaking in a QCD-like theory
The Nambu-Jona-Lasinio model reduced to 2+1 dimensions has two different path
integral formulations: at finite chemical potential one formulation has a
severe sign problem similar to that found in QCD, while the other does not. At
large N, where N is the number of flavors, one can compute the probability
distributions of fermion correlators analytically in both formulations. In the
former case one finds a broad distribution with small mean; in the latter one
finds a heavy tailed positive distribution amenable to the cumulant expansion
techniques developed in earlier work. We speculate on the implications of this
model for QCD.Comment: 16 pages, 5 figures; Published version with minor changes from the
origina
Two-stream instability in quasi-one-dimensional Bose-Einstein condensates
We apply a kinetic model to predict the existence of an instability mechanism in elongated Bose-Einstein condensates. Our kinetic description, based on the Wigner formalism, is employed to highlight the existence of unstable Bogoliubov waves that may be excited in the counterpropagation configuration. We identify a dimensionless parameter, the Mach number at T=0, that tunes different regimes of stability. We also estimate the magnitude of the main parameters at which two-stream instability is expected to be observed under typical experimental conditions
SSRI use and bone mineral density in women with a history of depression : Geelong Osteoporosis Study (GOS)
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