Browsing by Author "Takyi, Ishmael"

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    Chiral Soliton Models and Nucleon Structure Functions
    (Symmetry, 2021) Weigel, Herbert; Takyi, Ishmael; 0000-0002-1217-0889
    We outline and review the computations of polarized and unpolarized nucleon structure functions within the bosonized Nambu-Jona-Lasinio chiral soliton model. We focus on a consistent regularization prescription for the Dirac sea contribution and present numerical results from that formulation. We also reflect on previous calculations on quark distributions in chiral quark soliton models and attempt to put them into perspective.
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    Quantum corrections to solitons in the ϕ8 model
    (Physical Review D, 2020) Takyi, Ishmael; Matfunjwa, M. K.; Weigel, Herbert; 0000-0002-1217-0889
    We compute the vacuum polarization energy of kink solitons in the ϕ8 model in one space and one time dimensions. There are three possible field potentials that have eight powers of ϕ and that possess kink solitons. For these different field potentials we investigate whether the vacuum polarization destabilizes the solitons. This may particularly be the case for those potentials that have degenerate ground states with different curvatures in field space yielding different thresholds for the quantum fluctuations about the solitons at negative and positive spatial infinity. We find that destabilization occurs in some cases, but this is not purely a matter of the field potential but also depends on the realized soliton solution for that potential. One of the possible field potentials has solitons with different topological charges. In that case the classical mass approximately scales like the topological charge. Even though destabilization precludes robust statements, there are indications that the vacuum polarization energy does not scale as the topological charge
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    Scattering of kinks in noncanonical sine-Gor Scattering of kinks in noncanonical sine-Gordon Model don Model
    (Turkish Journal of Physics, 2022) Takyi, Ishmael; Barnes, Benedict; Tornyeviadzi, Hoese Michel; Ackora-Prah, Joseph; 0000-0002-1217-0889; 0000-0002-0580-5655; 0000-0001-9488-9610
    In this paper, we numerically study the scattering of kinks in the noncanonical sine-Gordon model using Fourier spectral methods. The model depends on two free parameters, which control the localized inner structure in the energy density and the characteristics of the scattering potential. It has been conjectured that the kink solutions in the noncanonical model possess inner structures in their energy density, and the presence of these yields bound states and resonance structures for some relative velocities between the kink and the antikink. In the numerical study, we observed that the classical kink mass decreases monotonically as the free parameters vary, and yields bion-formations and long-lived oscillations in the scattering of the kink-antikink system. :
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    Vacuum polarization energy of the kinks in the sinh-deformed models
    (Turkish Journal of Physics, 2021) Takyi, Ishmael; Barnes, Benedict; Ackora-Prah, Joseph; 0000-0002-1217-0889; 0000-0002-0580-5655; 0000-0001-9488-9610
    We compute the one-loop quantum corrections to the kink energies of the sinh-deformed 4 and 6 models in one space and one time dimensions. These models are constructed from the well-known polynomial 4 and 6 models by a deformation procedure. We also compute the vacuum polarization energy to the nonpolynomial function = 1 4 (1 − sinh2 .This potential approaches the model in the limit of small values of the scalar function. These energies are extracted from scattering data for fluctuations about the kink solutions. We show that for certain topological sectors with nonequivalent vacua the kink solutions of the sinh-deformed models are destabilized.