59,847 research outputs found
Dirac Quasinormal Modes of New Type Black Holes in New Massive Gravity
We study new type black holes in three-dimensional New Massive Gravity and we
calculate analytically the quasinormal modes for fermionic perturbations for
some special cases. Then, we show that for these cases the new type black holes
are stable under fermionic field perturbations.Comment: improved version. arXiv admin note: text overlap with
arXiv:1306.5974, arXiv:1404.317
Meson-baryon threshold effects in the light-quark baryon spectrum
We argue that selected wave meson-baryon channels may play a key role to
match poor baryon mass predictions from quark models with data. The
identification of these channels with effective inelastic channels in data
analysis allows to derive a prescription which could improve the extraction and
identification of baryon resonances.Comment: 17 pages, 3 figures. Accepted for publication in Phys. Rev.
N electrons in a quantum dot: Two-point Pade approximants
We present analytic estimates for the energy levels of N electrons (N = 2 -
5) in a two-dimensional parabolic quantum dot. A magnetic field is applied
perpendicularly to the confinement plane. The relevant scaled energy is shown
to be a smooth function of the parameter \beta=(effective Rydberg/effective dot
energy)^{1/6}. Two-point Pade approximants are obtained from the series
expansions of the energy near the oscillator () and Wigner
() limits. The approximants are expected to work with an error
not greater than 2.5% in the entire interval .Comment: 27 pages. LaTeX. 6 figures not include
Motion of particles on a Four-Dimensional Asymptotically AdS Black Hole with Scalar Hair
Motivated by black hole solutions with matter fields outside their horizon,
we study the effect of these matter fields in the motion of massless and
massive particles. We consider as background a four-dimensional asymptotically
AdS black hole with scalar hair. The geodesics are studied numerically and we
discuss about the differences in the motion of particles between the
four-dimensional asymptotically AdS black holes with scalar hair and their
no-hair limit, that is, Schwarzschild AdS black holes. Mainly, we found that
there are bounded orbits like planetary orbits in this background. However, the
periods associated to circular orbits are modified by the presence of the
scalar hair. Besides, we found that some classical tests such as perihelion
precession, deflection of light and gravitational time delay have the standard
value of general relativity plus a correction term coming from the cosmological
constant and the scalar hair. Finally, we found a specific value of the
parameter associated to the scalar hair, in order to explain the discrepancy
between the theory and the observations, for the perihelion precession of
Mercury and light deflection.Comment: 20 pages and 9 figures. arXiv admin note: text overlap with
arXiv:1309.216
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