5,279 research outputs found

    The quantum free particle on spherical and hyperbolic spaces: A curvature dependent approach

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    The quantum free particle on the sphere Sκ2S_\kappa^2 (κ>0\kappa>0) and on the hyperbolic plane Hκ2H_\kappa^2 (κ<0\kappa<0) is studied using a formalism that considers the curvature \k as a parameter. The first part is mainly concerned with the analysis of some geometric formalisms appropriate for the description of the dynamics on the spaces (Sκ2S_\kappa^2, \IR^2, Hκ2H_\kappa^2) and with the the transition from the classical κ\kappa-dependent system to the quantum one using the quantization of the Noether momenta. The Schr\"odinger separability and the quantum superintegrability are also discussed. The second part is devoted to the resolution of the κ\kappa-dependent Schr\"odinger equation. First the characterization of the κ\kappa-dependent `curved' plane waves is analyzed and then the specific properties of the spherical case are studied with great detail. It is proved that if κ>0\kappa>0 then a discrete spectrum is obtained. The wavefunctions, that are related with a κ\kappa-dependent family of orthogonal polynomials, are explicitly obtained

    Quantization of Hamiltonian systems with a position dependent mass: Killing vector fields and Noether momenta approach

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    The quantization of systems with a position dependent mass (PDM) is studied. We present a method that starts with the study of the existence of Killing vector fields for the PDM geodesic motion (Lagrangian with a PDM kinetic term but without any potential) and the construction of the associated Noether momenta. Then the method considers, as the appropriate Hilbert space, the space of functions that are square integrable with respect to a measure related with the PDM and, after that, it establishes the quantization, not of the canonical momenta pp, but of the Noether momenta PP instead. The quantum Hamiltonian, that depends on the Noether momenta, is obtained as an Hermitian operator defined on the PDM Hilbert space. In the second part several systems with position-dependent mass, most of them related with nonlinear oscillators, are quantized by making use of the method proposed in the first part.Comment: 21 pages, to appear in J.Phys. A:Math. Theo

    Study of the average vertical distribution of temperature in the martian atmosphere final report

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    Convective-radiative equilibrium model for computing temperature profile - vertical temperature distribution in Martian atmospher

    Relic density calculations beyond tree-level, exact calculations versus effective couplings: the ZZ final state

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    The inferred value of the relic density from cosmological observations has reached a precision that is akin to that of the LEP precision measurements. This level of precision calls for the evaluation of the annihilation cross sections of dark matter that goes beyond tree-level calculations as currently implemented in all codes for the computation of the relic density. In supersymmetry radiative corrections are known to be large and thus must be implemented. Full one-loop radiative corrections for many annihilation processes have been performed. It is important to investigate whether the bulk of these corrections can be parameterised through an improved Born approximation that can be implemented as a selection of form factors to a tree-level code. This paper is a second in a series that addresses this issue. After having provided these form factors for the annihilation of the neutralinos into fermions, which cover the case of a bino-like LSP (Lightest Supersymmetric Particle), we turn our attention here to a higgsino-like dark matter candidate through its annihilation into ZZZZ. We also investigate the cases of a mixed LSP. In all cases we compare the performance of the form factor approach with the result of a full one-loop correction. We also study the issue of the renormalisation scheme dependence. An illustration of the phenomenon of non decoupling of the heavy sfermions that takes place for the annihilation of the lightest neutralino into ZZZZ is also presented.Comment: 20
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