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Oct 25, 2014
10/14

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Koodaryan, Roodabeh; Rafighi, Ali; Hafezeqoran, Ali

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This article is from Journal of Dental Research, Dental Clinics, Dental Prospects , volume 3 . Abstract Background and aims: Class III malocclusions are considered complex and difficult orthodontic problems to diagnose and treat. The purpose of this study was to investigate the morphologic characteristics of the craniofacial complex of adults with Class III malocclusion in an Iranian population. Materials and methods: Lateral cephalometric radiographs of 50 patients with Class III malocclusion...

Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3517198

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Oct 29, 2014
10/14

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Smith, J; Baer, L; Blank, S; Dilawari, A; Carapetyan, K; Alvear, M; Utate, M; Curtin, J; Muggia, F

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This article is from ecancermedicalscience , volume 3 . Abstract Introduction: We describe a screening and prevention programme primarily targeting under-served minority women at high risk of breast and/or ovarian cancer. Women attending this Bellevue Hospital Center (BHC) Clinic were either self-referred from a variety of special outreach programmes or referred internally by medical professionals caring for relatives or friends. Our objective was to delineate referral sources and preliminary...

Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3224011

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Oct 24, 2014
10/14

by
Minaev, Boris; Lindgren, Mikael

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This article is from Sensors (Basel, Switzerland) , volume 9 . Abstract Bis-MPA dendron-coated free-base tetraphenylporphyrin and zinc-tetraphenyl-porphyrin (TPPH2 and TPPZn) were studied in comparison with simple porphyrins (H2P, ZnP) by theoretical simulation of their infrared, Raman and electronic absorption spectra, as well as fluorescense emission. Infrared and fluorescence spectra of the dendrimers were measured and interpreted along with time-resolved measurements of the fluorescence....

Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3345821

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Oct 28, 2014
10/14

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Razi, Tahmine; Moslemzade, Seyed Hosein; Razi, Sedighe

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This article is from Journal of Dental Research, Dental Clinics, Dental Prospects , volume 3 . Abstract Background and aims: Panoramic radiography is a method widely used because of low absorbed dose in patients (ap-proximately 10 times less than that in the full mouth survey), reasonable cost and time. Disadvantages of this radiography technique are magnification and distortion as a result of unequal magnification, which can influence dimensional and angular measurements used in clinical...

Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3517203

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Sep 23, 2013
09/13

by
Vincent Beck

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Let $\Ascr,\Bscr$ be exact categories with $\Ascr$ karoubian and $M$ be an exact functor. Under suitable adjonction hypotheses for $M$, we are able to show that the direct factors of the objects of $\Ascr$ of the form $MY$ with $Y \in \Bscr$ make up a Frobenius category which allow us to define an $M$-stable category for $\Ascr$ only by quotienting. In addition, we propose a construction of an $M$-stable category for $\Ascr,\Bscr$ triangulated categories and $M$ a triangulated functor. We...

Source: http://arxiv.org/abs/0903.2868v1

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Sep 23, 2013
09/13

by
J. P. May

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Infinite loop space theory, both additive and multiplicative, arose largely from two basic motivations. One was to solve calculational questions in geometric topology. The other was to better understand algebraic K-theory. The Adams conjecture is intrinsic to the first motivation, and Quillen's proof of that led directly to his original, calculationally accessible, definition of algebraic K-theory. In turn, the infinite loop understanding of algebraic K-theory feeds back into the calculational...

Source: http://arxiv.org/abs/0903.2819v1

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Sep 23, 2013
09/13

by
Sergio Lopez-Permouth; Steve Szabo

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Repeated root Cyclic and Negacyclic codes over Galois rings have been studied much less than their simple root counterparts. This situation is beginning to change. For example, repeated root codes of length $p^s$, where $p$ is the characteristic of the alphabet ring, have been studied under some additional hypotheses. In each one of those cases, the ambient space for the codes has turned out to be a chain ring. In this paper, all remaining cases of cyclic and negacyclic codes of length $p^s$...

Source: http://arxiv.org/abs/0903.2791v1

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Sep 18, 2013
09/13

by
Josef Ludescher; Ralf Hofmann

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Based on the postulate that photon propagation is governed by an SU(2) gauge principle we numerically compute the one-loop dispersion for thermalized photon propagation on the radiatively induced mass shell. Formerly, the dispersion was addressed by assuming $p^2=0$. While this approximation turns out to be excellent for temperatures $\le 2 T_{\tiny{CMB}}$ the exact result exhibits a much faster (power-like) shrinking of the gap in the black-body spectral intensity with rising temperature. Our...

Source: http://arxiv.org/abs/0806.0972v2

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Sep 23, 2013
09/13

by
Satyan L. Devadoss; Rahul Shah; Xuancheng Shao; Ezra Winston

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The associahedron is a convex polytope whose face poset is based on nonintersecting diagonals of a convex polygon. In this paper, given an arbitrary simple polygon P, we construct a polytopal complex analogous to the associahedron based on convex diagonalizations of P. We describe topological properties of this complex and provide realizations based on secondary polytopes. Moreover, using the visibility graph of P, a deformation space of polygons is created which encapsulates substructures of...

Source: http://arxiv.org/abs/0903.2848v1

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Sep 23, 2013
09/13

by
Najib Mahdou; Mohammed Tamekkante; Siamak Yassemi

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We compute the Gorenstein weak dimension of a coherent power series rings over a commutative rings and we show that, in general, $\gwd(R) \leq 1$ does not imply that $R$ is an arithmetical ring.

Source: http://arxiv.org/abs/0903.2779v1

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Sep 22, 2013
09/13

by
L. Qian; M. A. Abramowicz; P. C. Fragile; J. Horak; M. Machida; O. Straub

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We construct a new family of analytic models of black hole accretion disks in dynamical equilibria. Our construction is based on assuming distributions of angular momentum and entropy. For a particular choice of the distribution of angular momentum, we calculate the shapes of equipressure surfaces. The equipressure surfaces we find are similar to those in thick, slim and thin disks, and to those in ADAFs.

Source: http://arxiv.org/abs/0812.2467v2

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Jul 20, 2013
07/13

by
L. Herrera; A. Di Prisco; E. Fuenmayor; O. Troconis

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The Misner and Sharp approach to the study of gravitational collapse is extended to the viscous dissipative case in, both, the streaming out and the diffusion approximations. The dynamical equation is then coupled to causal transport equations for the heat flux, the shear and the bulk viscosity, in the context of Israel--Stewart theory, without excluding the thermodynamics viscous/heat coupling coefficients. The result is compared with previous works where these later coefficients were...

Source: http://arxiv.org/abs/0804.3584v2

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Sep 23, 2013
09/13

by
Chris Orum; Cliff A Joslyn

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We extend the definitions of upper and lower valuations on partially ordered sets, and consider the metrics they induce, in particular the metrics available (or not) based on the logarithms of such valuations. Motivating applications in computational linguistics and computational biology are indicated.

Source: http://arxiv.org/abs/0903.2679v1

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Sep 23, 2013
09/13

by
T. T. Heikkila; F. Giazotto

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We study the role of the superconducting proximity effect on the electron-phonon energy exchange in diffusive normal metals (N) attached to superconductors (S). The proximity effect modifies the spectral response of the normal metal, in particular the local density of states. This leads to a weakening of the electron-phonon energy relaxation. We show that the effect is easily observable with modern thermometry methods, and predict that it can be tuned in structures connected to multiple...

Source: http://arxiv.org/abs/0810.4843v2

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Sep 21, 2013
09/13

by
Fabio Riccioni; Peter West

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We give a method of deriving the field-strengths of all massless and massive maximal supergravity theories in any dimension starting from the Kac-Moody algebra $E_{11}$. Considering the subalgebra of $E_{11}$ that acts on the fields in the non-linear realisation as a global symmetry, we show how this is promoted to a gauge symmetry enlarging the algebra by the inclusion of additional generators. We show how this works in eleven dimensions, and we call the resulting enlarged algebra...

Source: http://arxiv.org/abs/0902.4678v2

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Sep 23, 2013
09/13

by
Jean-Francois Clément; Jean-Philippe Brantut; Martin Robert De Saint Vincent; Robert A. Nyman; A. Aspect; Thomas Bourdel; Philippe Bouyer

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We demonstrate runaway evaporative cooling directly with a tightly confining optical dipole trap and achieve fast production of condensates of 1.5x10^5 87Rb atoms. Our scheme is characterized by an independent control of the optical trap confinement and depth, permitting forced evaporative cooling without reducing the trap stiffness. Although our configuration is particularly well suited to the case of 87Rb atoms in a 1565nm optical trap, where an efficient initial loading is possible, our...

Source: http://arxiv.org/abs/0903.2745v1

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Sep 23, 2013
09/13

by
V. F. Krotov

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Here the probability density of relativistic particles coordinates, satisfying the formal conditions of the quantum mechanics and the special relativity, is determined (under textbooks view, such density does not exist). It is specified for the boson, neutral and charged, scalar and vector, including the photon, the electron. Uniqueness of this design has been proved. This is a relativistic invariant, describing the probability of the particle observation in points of space-time. The time is...

Source: http://arxiv.org/abs/0903.2725v1

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Sep 23, 2013
09/13

by
Hichem Hajaiej

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We prove the uniqueness of the maximizers of a Hardy-Littlewood type functional under constraints. We also establish a quantitative stability estimate. Introduction

Source: http://arxiv.org/abs/0903.2826v1

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Sep 23, 2013
09/13

by
P. Di Matteo; A. Pipino; M. D. Lehnert; F. Combes; B. Semelin

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Using a large suite of galaxies with a variety of concentrations and metallicity gradients, we study the evolution of non-dissipative ("dry") equal mass mergers. Our purpose in generating these simulations is to explore how the metallicity gradient in dry mergers depends on the structure and metallicity gradients of the galaxies involved in the merger. Specifically, we would like to answer: Could dry mergers lead to metallicity gradients as observed in elliptical galaxies in the local...

Source: http://arxiv.org/abs/0903.2846v1

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Sep 23, 2013
09/13

by
J. P. May

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The construction of E infinity ring spaces and thus E infinity ring spectra from bipermutative categories gives the most highly structured way of obtaining the K-theory commutative ring spectra. The original construction dates from around 1980 and has never been superseded, but the original details are difficult, obscure, and slightly wrong. We rework the construction in a much more elementary fashion.

Source: http://arxiv.org/abs/0903.2818v1

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Sep 23, 2013
09/13

by
Brent C. Melot; Brian Paden; Ram Seshadri; Ambesh Dixit; Gavin Lawes; Emmanuelle Suard

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CoSe$_2$O$_5$ has a crystal structure consisting of zig-zag chains of edge shared CoO$_6$ octahedra running along the c axis, with the chains separated by Se$_2$O$_5^{2-}$ units. Magnetic susceptibility measurements indicate a transition at 8.5 K to an ordered state. We investigate here the nature of this magnetic ordering using magnetization and specific heat measurements in addition to powder neuttron diffraction. A transition to long-range antiferromagnetic order is found below $T_N$ = 8.5 K...

Source: http://arxiv.org/abs/0903.2513v1

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Sep 23, 2013
09/13

by
Sarah E. Ragan; Edwin A. Bergin; Robert A. Gutermuth

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We have conducted a survey of a sample of infrared-dark clouds (IRDCs) with the Spitzer Space Telescope in order to explore their mass distribution. We present a method for tracing mass using dust absorption against the bright Galactic background at 8 microns. The IRDCs in this sample are comprised of tens of clumps, ranging in sizes from 0.02 to 0.3 pc in diameter and masses from 0.5 to a few 10 Msun, the broadest dynamic range in any clump mass spectrum study to date. Structure with this...

Source: http://arxiv.org/abs/0903.2771v1

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Sep 21, 2013
09/13

by
M. Cinal

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It is found that, in closed-$l$-subshell atoms, the exact local exchange potential of the density functional theory is very well represented, within the region of every atomic shell, by each of the suitably shifted potentials obtained with the non-local Fock exchange operator acting on the Hartree-Fock (HF) orbitals that belong to this shell. This explains the outstanding proximity of Kohn-Sham and HF orbitals and the high quality of the Krieger-Li-Iafrate and localized HF (or, equivalently,...

Source: http://arxiv.org/abs/0808.0173v4

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Sep 23, 2013
09/13

by
J. M. Hoff da Silva; Roldao da Rocha

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A fundamental action, representing a mass dimension-transmuting operator between Dirac and ELKO spinor fields, is performed on the Dirac Lagrangian, in order to lead it into the ELKO Lagrangian. Such a dynamical transformation can be seen as a natural extension of the Standard Model that incorporates dark matter fields. The action of the mass dimension-transmuting operator on a Dirac spinor field, that defines and introduces such a mapping, is shown to be a composition of the Dirac operator and...

Source: http://arxiv.org/abs/0903.2815v1

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Sep 23, 2013
09/13

by
Sergey Smirnov; Dario Bercioux; Milena Grifoni; Klaus Richter

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Traditionally the charge ratchet effect is considered as a consequence of the extrinsic spatial asymmetry engineered by external asymmetric periodic potentials. Here we demonstrate that electrically and magnetically driven dissipative systems with spin-orbit interactions represent an exception from this standard idea. The charge and spin ratchet currents appear just due to the coexistence of quantum dissipation with the intrinsic spatial asymmetry of the spin-orbit coupling. The extrinsic...

Source: http://arxiv.org/abs/0903.2765v1

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Sep 23, 2013
09/13

by
Abedelaziz Mohaisen; Dowon Hong; DaeHun Nyang

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Location based services (LBS) are one of the most promising and innovative directions of convergence technologies resulting of emergence of several fields including database systems, mobile communication, Internet technology, and positioning systems. Although being initiated as early as middle of 1990's, it is only recently that the LBS received a systematic profound research interest due to its commercial and technological impact. As the LBS is related to the user's location which can be used...

Source: http://arxiv.org/abs/0903.2682v1

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Sep 23, 2013
09/13

by
Daniele Colosi

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We quantize a real massive Klein-Gordon field in curved spacetimes within the general boundary formulation. The vacuum wave function is given by a Gaussian in the Schr\"odinger representation and we study the general structure of the operator appearing in the Gaussian. We show that it obeys a Riccati equation and we provide the general solution.

Source: http://arxiv.org/abs/0903.2476v1

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Sep 23, 2013
09/13

by
Ties Behnke; Klaus Dehmelt; Takeshi Matsuda; Peter Schade

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The use of a TPC in future collider experiments needs significant research and development. Within the EUDET program an infrastructure has been designed and built to allow the efficient testing of TPC prototypes under realistic conditions. The infrastructure consists of a test beam facility, located at DESY Hamburg, and a multi-purpose TPC field cage.

Source: http://arxiv.org/abs/0903.2803v1

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Jul 22, 2013
07/13

by
James S. Bolton; S. Peng Oh; Steven R. Furlanetto

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We use a combination of analytic and numerical arguments to consider the impact of quasar photo-heating during HeII reionisation on the thermal evolution of the intergalactic medium (IGM). We demonstrate that rapid (\Delta z < 0.1-0.2), strong (\Delta T > 10^4 K) photo-heating is difficult to achieve across the entire IGM unless quasar spectra are significantly harder than implied by current observational constraints. Although filtering of intrinsic quasar radiation through dense regions...

Source: http://arxiv.org/abs/0807.2447v3

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Sep 23, 2013
09/13

by
S. Gandolfi; A. Yu. Illarionov; K. E. Schmidt; F. Pederiva; S. Fantoni

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We calculate the equation of state of neutron matter at zero temperature by means of the auxiliary field diffusion Monte Carlo method (AFDMC) combined with a fixed-phase approximation. The calculation of the energy is carried out by simulating up to 114 neutrons in a periodic box. Special attention was made to reduce finite size effects at the energy evaluation by adding to the interaction the effect due to the truncation of the simulation box, and by performing several simulations using...

Source: http://arxiv.org/abs/0903.2610v1

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Sep 23, 2013
09/13

by
C. V. Chianca; J. S. S. Martins; P. M. C. de Oliveira

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We perform a computational study of a variant of the ``train'' model for earthquakes [PRA 46, 6288 (1992)], where we assume a static friction that is a stochastic function of position rather than being velocity dependent. The model consists of an array of blocks coupled by springs, with the forces between neighbouring blocks balanced by static friction. We calculate the probability, P(s), of the occurrence of avalanches with a size s or greater, finding that our results are consistent with the...

Source: http://arxiv.org/abs/0903.2787v1

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Sep 22, 2013
09/13

by
Ayse Arslanargin; Ali Kaya

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We consider early time cosmic evolution in string gas cosmology dominated by open strings attached to D-branes. After reviewing statistical properties of open strings in D-brane backgrounds, we use dilaton-gravity equations to determine the string frame fields. Although, there are distinctions in the Hagedorn regime thermodynamics and dilaton coupling as compared to closed strings, it seems difficult to avoid Jeans instability and assume thermal equilibrium simultaneously, which is already a...

Source: http://arxiv.org/abs/0901.4608v2

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Sep 22, 2013
09/13

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Evgeny Epelbaum; Hermann Krebs; Dean Lee; Ulf-G. Meißner

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We present lattice calculations for the ground state energy of dilute neutron matter at next-to-leading order in chiral effective field theory. This study follows a series of recent papers on low-energy nuclear physics using chiral effective field theory on the lattice. In this work we introduce an improved spin- and isospin-projected leading-order action which allows for a perturbative treatment of corrections at next-to-leading order and smaller estimated errors. Using auxiliary fields and...

Source: http://arxiv.org/abs/0812.3653v2

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Sep 19, 2013
09/13

by
Matthias Kuenzer

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We show by an example that in a Verdier triangulated category, there may exist two mutually nonisomorphic Verdier octahedra containing the same commutative triangle.

Source: http://arxiv.org/abs/0708.0151v4

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Sep 21, 2013
09/13

by
C. Bogdanos; A. Dimitriadis; K. Tamvakis

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We consider 5D braneworld models of quasi-localized gravity in which 4D gravity is reproduced at intermediate scales while the extra dimension opens up at both the very short and the very long distances, where the geometry is flat. Our main interest is the interplay between the zero mode of these models, whenever a normalizable zero mode exists, and the effects of zero energy graviton resonant modes coming from the contributions of massive KK modes. We first consider a compactified version of...

Source: http://arxiv.org/abs/0706.1015v2

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Sep 20, 2013
09/13

by
Laszlo Erdos; Benjamin Schlein; Horng-Tzer Yau

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Consider a system of $N$ bosons in three dimensions interacting via a repulsive short range pair potential $N^2V(N(x_i-x_j))$, where $\bx=(x_1, >..., x_N)$ denotes the positions of the particles. Let $H_N$ denote the Hamiltonian of the system and let $\psi_{N,t}$ be the solution to the Schr\"odinger equation. Suppose that the initial data $\psi_{N,0}$ satisfies the energy condition \[ < \psi_{N,0}, H_N \psi_{N,0} > \leq C N >. \] and that the one-particle density matrix...

Source: http://arxiv.org/abs/0802.3877v3

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Sep 23, 2013
09/13

by
Paul Kessenich

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Global existence for a system of nonlinear partial differential equations (PDE) modeling an isotropic incompressible viscoelastic material is proved. The structure of the PDE is derived through constitutive assumptions on the material. Restriction on the size of the initial displacement and velocity for the model is specified independent of the size of the viscosity of the material. The proof of global existence combines use of vector fields, local energy decay estimates, generalized Sobolev...

Source: http://arxiv.org/abs/0903.2824v1

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Sep 23, 2013
09/13

by
Tadeusz Iwaniec; Leonid V. Kovalev; Jani Onninen

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As long ago as 1962 Nitsche conjectured that a harmonic homeomorphism $h \colon A(r,R) \to A(r_*, R_*)$ between planar annuli exists if and only if $\frac{R_*}{r_*} \ge {1/2} (\frac{R}{r} + \frac{r}{R})$. We prove this conjecture when the domain annulus is not too wide; explicitly, when $\log \frac{R}{r} \le {3/2}$. For general $A(r,R)$ the conjecture is proved under additional assumption that either $h$ or its normal derivative have vanishing average on the inner boundary circle. This is the...

Source: http://arxiv.org/abs/0903.2665v1

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Sep 22, 2013
09/13

by
L. Ferroni; V. Koch

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We formulate a simple model for a gas of extended hadrons at zero chemical potential by taking inspiration from the compressible bag model. We show that a crossover transition qualitatively similar to lattice QCD can be reproduced by such a system by including some appropriate additional dynamics. Under certain conditions, at high temperature, the system consist of a finite number of infinitely extended bags, which occupy the entire space. In this situation the system behaves as an ideal gas of...

Source: http://arxiv.org/abs/0812.1044v2

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Sep 22, 2013
09/13

by
Armin Lühr; Alejandro Saenz

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The stopping power of antiprotons in atomic and molecular hydrogen as well as helium was calculated in an impact-energy range from 1 keV to 6.4 MeV. In the case of H2 and He the targets were described with a single-active electron model centered on the target. The collision process was treated with the close-coupling formulation of the impact-parameter method. An extensive comparison of the present results with theoretical and experimental literature data was performed in order to evaluate...

Source: http://arxiv.org/abs/0812.5058v2

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Sep 23, 2013
09/13

by
Frédéric Faure

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We consider a simple model of partially expanding map on the torus. We study the spectrum of the Ruelle transfer operator and show that in the limit of high frequencies in the neutral direction (this is a semiclassical limit), the spectrum develops a spectral gap, for a generic map. This result has already been obtained by M. Tsujii (05). The novelty here is that we use semiclassical analysis which provides a different and quite natural description. We show that the transfer operator is a...

Source: http://arxiv.org/abs/0903.2747v1

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Sep 23, 2013
09/13

by
Jose A. Diaz-Garcia; R. Gutierrez-Jaimez

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Several matrix variate hypergeometric type distributions are derived. The compound distributions of left-spherical matrix variate elliptical distributions and inverted hypergeometric type distributions with matrix arguments are then proposed. The scale mixture of left-spherical matrix variate elliptical distributions and univariate inverted hypergeometric type distributions is also derived as a particular case of the compound distribution approach.

Source: http://arxiv.org/abs/0903.2875v1

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Sep 23, 2013
09/13

by
Xavier Caicedo; Ricardo Oscar Rodriguez

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In this paper we consider an approach where both propositions and the accessibility relation are infinitely many-valued over G\"{o}del algebras. In particular, we consider separately the $\Box $-fragment and the $\Diamond $-fragment of our G\"{o}del modal logic and prove that both logics are complete with respect to the class of models with values in the linear Hetying algebra [0,1]. In addition, we show that the first fragment is uniquely determined by the class of models having...

Source: http://arxiv.org/abs/0903.2767v1

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Sep 23, 2013
09/13

by
Susmit Jha; Sanjit A. Seshia; Rhishikesh Limaye

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Satisfiability solvers are increasingly playing a key role in software verification, with particularly effective use in the analysis of security vulnerabilities. String processing is a key part of many software applications, such as browsers and web servers. These applications are susceptible to attacks through malicious data received over network. Automated tools for analyzing the security of such applications, thus need to reason about strings. For efficiency reasons, it is desirable to have...

Source: http://arxiv.org/abs/0903.2825v1

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Sep 23, 2013
09/13

by
Catalin D. Spataru; Mark S. Hybertsen; Steven G. Louie; Andrew J. Millis

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The Anderson model for a single impurity coupled to two leads is studied using the $GW$ approximation in the strong electron-electron interaction regime as a function of the alignment of the impurity level relative to the chemical potentials in the leads. We employ a non-equilibrium Green's function technique to calculate the electron self-energy, the spin density and the current as a function of bias across the junction. In addition we develop an expression for the change in the expectation...

Source: http://arxiv.org/abs/0903.2683v1

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Sep 23, 2013
09/13

by
Carlos Hernandez-Monteagudo; Shirley Ho

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The peculiar motion of ionized baryons is known to introduce temperature anisotropies in the CMB by means of the kinetic Sunyaev-Zel'dovich effect (kSZ). In this work, we present an all sky computation of angular power spectrum of the temperature anisotropies introduced by kSZ momentum of all baryons in the Universe during and after reionization. In an attempt to study the bulk flows of the missing baryons not yet detected, we address separately the contribution from all baryons in the IGM and...

Source: http://arxiv.org/abs/0903.2814v1

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Sep 23, 2013
09/13

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N. N. Nikolaev; V. R. Zoller

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One of the well known effects of the asymptotic freedom is splitting of the leading-$\log$ BFKL pomeron into a series of isolated poles in complex angular momentum plane. Following our earlier works we explore the phenomenological consequences of the emerging BFKL-Regge factorized expansion for the small-$x$ charm ($F_2^c$) and beauty ($F_{2}^{b}$) structure functions of the proton. As we found earlier,the color dipole approach to the BFKL dynamics predicts uniquely decoupling of subleading...

Source: http://arxiv.org/abs/0903.2729v1

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Sep 23, 2013
09/13

by
Brendon W. Lovett; Ahsan Nazir

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Coherence is a familiar concept in physics: It is the driving force behind wavelike phenomena such as the diffraction of light. Moreover, wave-particle duality implies that all quantum objects can exhibit coherence, and this quantum coherence is crucial to understanding the behaviour of a plethora of systems. In this article, which is written at an undergraduate level, we shall briefly introduce what is meant by coherence in a well-known classical setting, before going on to describe its...

Source: http://arxiv.org/abs/0903.2746v1

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28

Sep 23, 2013
09/13

by
Garry W. Angus; Antonaldo Diaferio

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We re-investigate the old problem of the survival of the five globular clusters orbiting the Fornax dwarf galaxy in both standard and modified Newtonian dynamics. For the first time in the history of the topic, we use accurate mass models for the Fornax dwarf, obtained through Jeans modelling of the recently published line of sight velocity dispersion data, and we are also not resigned to circular orbits for the globular clusters. Previously conceived problems stem from fixing the starting...

Source: http://arxiv.org/abs/0903.2874v1

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Sep 23, 2013
09/13

by
Charles P. Meaney; Tim Duty; Ross H. McKenzie; Gerard J. Milburn

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We consider the steady states of a harmonic oscillator coupled so strongly to a two-level system (a qubit) that the rotating wave approximation cannot be made. The Hamiltonian version of this model is known as the $E\otimes\beta$ Jahn-Teller model. The semiclassical version of this system exhibits a fixed point bifurcation, which in the quantum model leads to a ground state with substantial entanglement between the oscillator and the qubit. We show that the dynamical bifurcation survives in a...

Source: http://arxiv.org/abs/0903.2681v1