Pure & Applied Mathematics (Scholarly Publications): Recent submissions

Now showing items 301-319 of 319

    • Effect of tree-level and mean-field improvement on the light-hadron spectrum in quenched QCD 

      RYAN, SINEAD MARIE (American Physical Society, 1997)
      We compute the light-hadron mass spectrum at b55.7 using the O(a)-improved Sheikholeslami-Wohlert fermion action with two choices of the clover coefficient: the classical value c51 and a mean-field or tadpole-improved ...

    • Soft covariant gauges on the lattice 

      RYAN, SINEAD MARIE (2008-10-08)
      We present an exploratory study of a one-parameter family of covariant, nonperturbative lattice gauge-fixing conditions that can be implemented through a simple Monte Carlo algorithm. We demonstrate that at the numerical ...

    • Radial and orbital excitations of static-light mesons 

      Ryan, Sinead; Peardon, Michael (2007)
      We present results for the spectrum of static-light mesons from Nf = 2 lattice QCD. These results were obtained using all-to-all light quark propagators on an anisotropic lattice, yielding an improved signal resolution ...

    • Octahedral and dodecahedral monopoles 

      HOUGHTON, CONOR JAMES (IOP, 1996)
      It is shown that there exists a charge five monopole with octahedral symmetry and a charge seven monopole with icosahedral symmetry. A numerical implementation of the ADHMN construction is used to calculate the energy ...

    • Tetrahedral and cubic monopoles 

      HOUGHTON, CONOR JAMES (Springer Science + Business Media, 1996)
      Using a numerical implementation of the ADHMN construction, we compute the fields and energy densities of a charge three monopole with tetrahedral symmetry and a charge four monopole with octahedral symmetry. We then ...

    • SU(N) monopoles and Platonic symmetry 

      HOUGHTON, CONOR JAMES (American Institute of Physics, 1997)
      We discuss the ADHMN construction for SU(N) monopoles and show that a particular simplification arises in studying charge N?1 monopoles with minimal symmetry breaking. Using this we construct families of tetrahedrally ...

    • New hyper-Kaehler manifolds by fixing monopoles 

      HOUGHTON, CONOR JAMES (American Physical Society, 1997)
      The construction of new hyper-Ka?hler manifolds by taking the infinite monopole mass limit of certain Bogomol?nyi-Prasad-Sommerfield monopole moduli spaces is considered. The one-parameter family of hyper- Ka?hler manifolds ...

    • Instanton vibrations of the 3-Skyrmion 

      HOUGHTON, CONOR JAMES (American Physical Society, 1999)
      The Atiyah-Drinfeld-Hitchin-Manin matrix corresponding to a tetrahedrally symmetric 3-instanton is calculated. Some small variations of the matrix correspond to vibrations of the instanton-generated 3-Skyrmion. These ...

    • On the constraints defining BPS monopoles 

      HOUGHTON, CONOR JAMES (Springer Science and Business Media, 2000)
      We discuss the explicit formulation of the transcendental constraints defining spectral curves of SU.2/ BPS monopoles in the twistor approach of Hitchin, following Ercolani and Sinha. We obtain an improved version of the ...

    • Nahm data and the mass of 1/4-BPS states 

      HOUGHTON, CONOR JAMES (American Physical Society, 2000)
      The mass of 1 / 4-BPS dyonic configurations in N=4 D=4 supersymmetric Yang-Mills theories is calculated within the Nahm formulation. The SU(3) example, with two massive monopoles and one massless monopole, is considered ...

    • Folding in the Skyrme model. 

      HOUGHTON, CONOR JAMES (American Institute of Physics, 2001)
      There are only three stable singularities of a differentiable map between three-dimensional manifolds, namely folds, cusps and swallowtails. A Skyrme configuration is a map from space to SU2, and its singularities correspond ...

    • Multicloud solutions with massless and massive monopoles. 

      HOUGHTON, CONOR JAMES (American Physical Society, 2002)
      Certain spontaneously broken gauge theories contain massless magnetic monopoles. These are realized classically as clouds of non-Abelian fields surrounding one or more massive monopoles. In order to gain a better understanding ...

    • Icosahedral Skyrmions 

      HOUGHTON, CONOR JAMES (American Institute of Physics, 2003)
      In this article we aim to determine the baryon numbers at which the minimal energy Skyrmion has icosahedral symmetry. By comparing polyhedra which arise as minimal energy Skyrmions with the dual of polyhedra that minimize ...

    • Inversion symmetric 3-monopoles and the Atiyah-Hitchin manifold 

      HOUGHTON, CONOR JAMES (IOP, 1996)
      We consider 3-monopoles symmetric under inversion symmetry. We show that the moduli space of these monopoles is an Atiyah?Hitchin submanifold of the 3-monopole moduli space. This allows what is known about 2-monopole ...

    • A zero-mode quantization of the Skyrmion 

      HOUGHTON, CONOR JAMES (Elsevier, 2006)
      In the semi-classical approach to the Skyrme model, nuclei are approximated by quantum mechanical states on a finite-dimensional space of field configurations; in zero-mode quantization this space is generated by rotations ...

    • Pulsation and precession of the resonant swinging spring 

      HOUGHTON, CONOR JAMES (Elsevier, 2004)
      When the frequencies of the elastic and pendular oscillations of an elastic pendulum or swinging spring are in the ratio 2:1, there is a regular exchange of energy between the two modes of oscillation. We refer to this ...

    • The effect of pion mass on Skyrme configurations 

      HOUGHTON, CONOR JAMES (2007)
      In the Skyrme model, atomic nuclei are identified with solitonic configurations. If the pion mass is set to zero, these configurations are spherical shells of energy with a fullerene-like appearance and are well approximated ...