African University of Science and Technology: Recent submissions

Now showing items 521-540 of 4824

  • The geometry and representation theory of superconformal quantum mechanics 

    Singleton, Andrew John (University of CambridgeDepartment of Applied Mathematics and Theoretical PhysicsJesus College, 2016-06-28)
    We study aspects of the quantum mechanics of nonlinear $\sigma$-models with superconformal invariance. The connection between the differential geometry of the target manifold and symmetries of the quantum mechanics is ...

  • First-order gradient regularisation methods for image restoration: reconstruction of tomographic images with thin structures and denoising piecewise affine images 

    Papoutsellis, Evangelos (University of CambridgeDepartment of Applied Mathematics and Theoretical PhysicsCentre for Mathematical SciencesJesus College, 2016-02-02)
    The focus of this thesis is variational image restoration techniques that involve novel non-smooth first-order gradient regularisers: Total Variation (TV) regularisation in image and data space for reconstruction of thin ...

  • Research Data Supporting "Preconditioned ADMM with nonlinear operator constraint" 

    Benning, Martin; Knoll, Florian; Schönlieb, Carola-Bibiana; Valkonen, Tuomo

  • Nonresonant optical control of a spinor polariton condensate 

    Askitopoulos, A; Kalinin, K; Liew, TCH; Cilibrizzi, P; Hatzopoulos, Z; Savvidis, PG; Berloff, Natalia G; Lagoudakis, PG (American Physical SocietyPhysical Review B, 2016)
    We investigate the spin dynamics of polariton condensates spatially separated from and effectively confined by the pumping exciton reservoir. We obtain a strong correlation between the ellipticity of the non-resonant optical ...

  • Secure quantum signatures using insecure quantum channels 

    Amiri, Ryan; Wallden, Petros; Kent, Adrian Patrick; Andersson, Erika (American Physical SocietyPhysical Review A, 2016-03-17)
    Digital signatures are widely used in modern communication to guarantee authenticity and transferability of messages. The security of currently used classical schemes relies on computational assumptions. We present a quantum ...

  • Electromagnetic transition strengths for light nuclei in the Skyrme model 

    Haberichter, M; Lau, PHC; Manton, Nicholas Stephen (American Physical SocietyPhysical Review C, 2016-03-07)
    We calculate reduced B(E2) electromagnetic transition strengths for light nuclei of mass numbers B = 8,12,16,20,24, and 32 within the Skyrme model. We find that the predicted transition strengths are of the correct order ...

  • Numerical study of the unitary Fermi gas across the superfluid transition 

    Goulko, Olga; Wingate, Matthew Bowen (American Physical SocietyPhysical Review A, 2016)
    We present results from Monte Carlo calculations investigating the properties of the homogeneous, spin-balanced unitary Fermi gas in three dimensions. The temperature is varied across the superfluid transition allowing us ...

  • Entropy power inequalities for qudits 

    Audenaert, Koenraad; Datta, Nilanjana; Ozols, Maris (American Institute of Physics PublishingJournal of Mathematical Physics, 2016-05-20)
    Shannon’s entropy power inequality (EPI) can be viewed as a statement of concavity of an entropic function of a continuous random variable under a scaled addition rule: f(√a X + √1 − a Y) ≥ a f(X) + (1 − a)f(Y) ∀ a ∈ [0, ...

  • Acoustic boundary conditions at an impedance lining in inviscid shear flow 

    Khamis, Doran; Brambley, Edward James (Cambridge University PressJournal of Fluid Mechanics, 2016)
    The accuracy of existing impedance boundary conditions is investigated, and new impedance boundary conditions are derived, for lined ducts with inviscid shear flow. The accuracy of the Ingard–Myers boundary condition is ...

  • Coordinated Beating of Algal Flagella is Mediated by Basal Coupling 

    Wan, Kirsty Y; Goldstein, Raymond Ethan (National Academy of SciencesProceedings of the National Academy of Sciences (PNAS), 2016)
    Cilia and flagella often exhibit synchronized behavior; this includes phase-locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and ...

  • Lecture notes: Astrophysical fluid dynamics 

    Ogilvie, Gordon I. (Cambridge University PressJournal of Plasma Physics, 2016)
    These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, ...

  • The formation and evolution of reconnection-driven, slow-mode shocks in a partially ionised plasma 

    Hillier, Andrew Stephen; Takasao, S; Nakamura, N (EDP SciencesAstronomy & Astrophysics, 2016)
    The role of slow-mode magnetohydrodynamic (MHD) shocks in magnetic reconnection is of great importance for energy conversion and transport, but in many astrophysical plasmas the plasma is not fully ionised. In this paper, ...

  • The fluxes and behaviour of plumes inferred from measurements of coherent structures within images of the bulk flow 

    Burridge, Henry Charles; Partridge, JL; Linden, Paul Frederick (Taylor & FrancisAtmosphere - Ocean, 2016-06-01)
    This paper describes how measurements of the movement of identifiable features at the edge of a turbulent plume can be interpreted to determine the properties of the mean flow and consequently, using plume theory, can be ...

  • Asymptotic Analysis of Asymmetric Thin Sheet Rolling 

    Minton, Jeremy; Cawthorn, CJ; Brambley, Edward James (ElsevierInternational Journal of Mechanical Sciences, 2016-04-22)
    An analytical model for asymmetric rolling is presented, which includes asymmetry in roll friction, roll size and roll speed, for a rigid, perfectly-plastic thin sheet deformed with Coulomb friction. This model is solved ...

  • Consequences of tidal interaction between disks and orbiting protoplanets for the evolution of multi-planet systems with architecture resembling that of Kepler 444 

    Papaloizou, John Christopher (SpringerCelestial Mechanics and Dynamical Astronomy, 2016)
    We study orbital evolution of multi-planet systems with masses in the terrestrial planet regime induced through tidal interaction with a protoplanetary disk assuming that this is the dominant mechanism for producing orbital ...

  • Bivariate spatial point patterns in the retina: a reproducible review 

    Eglen, Stephen J. (Societe Française de StatistiqueJournal de la Société Française de Statistique, 2016-04-08)
    In this article I present a reproducible review of recent research to investigate the spatial positioning of neurons in the nervous system. In particular, I focus on the relative spatial positioning of pairs of cell types ...

  • Entrainment by turbulent fountains 

    Burridge, H. C.; Hunt, G. R. (Cambridge University PressJournal of Fluid Mechanics, 2016-02-04)
    Experimental measurements of entrainment by turbulent fountains from circular sources in quiescent uniform environments are presented. Our results span almost four orders of magnitude in the source Froude number (0.004 ≤ ...

  • Atomic Processes for Astrophysical Plasmas 

    Badnell, NR; del, Giulio; Fernandez-Menchero, L; Giunta, AS; Liang, GY; Mason, Helen Elizabeth; Storey, PJ (Institute of PhysicsJournal of Physics B: Atomic, Molecular and Optical Physics, 2016)
    In this review we summarize the recent calculations and improvements of atomic data that we have carried out for the analysis of astrophysical spectroscopy within the Atomic Processes for Astrophysical Plasmas (APAP) ...

  • The Complexity of Divisibility 

    Bausch, Johannes; Cubitt, Toby (ElsevierLinear Algebra and its Applications, 2016-04-08)
    We address two sets of long-standing open questions in linear algebra and probability theory, from a computational complexity perspective: stochastic matrix divisibility, and divisibility and decomposability of probability ...

  • Spontaneous scalarization with massive fields 

    Ramazanoğlu, Fethi M; Pretorius, Frans (American Physical SocietyPhysical Review D, 2016-03-03)
    We study the effect of a mass term in the spontaneous scalarization of neutron stars, for a wide range of scalar field parameters and neutron star equations of state. Even though massless scalars have been the focus of ...