16,424 research outputs found

    Remarks on the Aharonov-Casher dynamics in a CPT-odd Lorentz-violating background

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    The Aharonov-Casher problem in the presence of a Lorentz-violating background nonminimally coupled to a spinor and a gauge field is examined. Using an approach based on the self-adjoint extension method, an expression for the bound state energies is obtained in terms of the physics of the problem by determining the self-adjoint extension parameter.Comment: Matches published versio

    Effects of spin on the dynamics of the 2D Dirac oscillator in the magnetic cosmic string background

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    In this work the dynamics of a 2D Dirac oscillator in the spacetime of a magnetic cosmic string is considered. It is shown that earlier approaches to this problem have neglected a δ\delta function contribution to the full Hamiltonian, which comes from the Zeeman interaction. The inclusion of spin effects leads to results which confirm a modified dynamics. Based on the self-adjoint extension method, we determined the most relevant physical quantities, such as energy spectrum, wave functions and the self-adjoint extension parameter by applying boundary conditions allowed by the system.Comment: 9 pages, 2 figures, published versio

    Remarks on the Dirac oscillator in (2+1)(2+1) dimensions

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    In this work the Dirac oscillator in (2+1)(2+1) dimensions is considered. We solve the problem in polar coordinates and discuss the dependence of the energy spectrum on the spin parameter ss and angular momentum quantum number mm. Contrary to earlier attempts, we show that the degeneracy of the energy spectrum can occur for all possible values of smsm. In an additional analysis, we also show that an isolated bound state solution, excluded from Sturm-Liouville problem, exists.Comment: 5 pages, 2 figures, minor corrections, published versio

    On the necessity to include event-by-event fluctuations in experimental evaluation of elliptical flow

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    Elliptic flow at RHIC is computed event-by-event with NeXSPheRIO. We show that when symmetry of the particle distribution in relation to the reaction plane is assumed, as usually done in the experimental extraction of elliptic flow, there is a disagreement between the true and reconstructed elliptic flows (15-30% for η\eta=0, 30% for pp_\perp=0.5 GeV). We suggest a possible way to take into account the asymmetry and get good agreement between these elliptic flows

    Nonrelativistic quantum dynamics on a cone with and without a constraining potential

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    In this paper we investigate the bound state problem of nonrelativistic quantum particles on a conical surface. This kind of surface appears as a topological defect in ordinary semiconductors as well as in graphene sheets. Specifically, we compare and discuss the results stemming from two different approaches. In the first one, it is assumed that the charge carriers are bound to the surface by a constraining potential, while the second one is based on the Klein-Gordon type equation on surfaces, without the constraining potential. The main difference between both theories is the presence/absence of a potential which contains the mean curvature of a given surface. This fact changes the dependence of the bound states on the angular momentum ll. Moreover, there are bound states that are absent in the Klein-Gordon theory, which instead appear in the Schr\"{o}dinger one.Comment: Accepted for publication in Journal of Mathematical Physics, 14 pages, 1 figur
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