Papers by Norma Graciela Sanchez
Gravitation & Cosmology, Apr 1, 2019
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Lecture Notes in Physics, 1986
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Nuclear Physics B, 1988
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Modern Physics Letters A, 1989
We discuss the constraints on the stronger sources of the cosmological gravitational waves backgr... more We discuss the constraints on the stronger sources of the cosmological gravitational waves background detectable by millisecond pulsars—upper bounds on the cosmic string parameter Gµ, on the anisotropy Δ of the QCD transition phase and, on the dimensionless gravity wave energy. We derive also upper limits on the string parameter from the future binary pulsar timings and confront them with those imposed by current elementary particle phenomenology. We wait for future observations and for new experiments which either detect or place significant constraints on the existence of strings and long wavelength gravity waves—millisecond pulsar plus binary pulsar and the COBE cosmic 3 K anisotropy experiment.
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International Journal of Modern Physics A, 1990
We study the effect of the charge in the scattering of ultra high energetic particles. The ultrar... more We study the effect of the charge in the scattering of ultra high energetic particles. The ultrarelativistic limit of the boosted Reissner-Nordstrom geometry is found. This is a shock wave space-time in the limit when v→c and the mass and charge vanish as m=γ−1p and e=γ−1/2pe respectively, with p and pe being constants. (γ=(1−ν2)−1/2). The kinetic (p) and electromagnetic (pe) momenta of the particle contribute with different ρ-dependence [Formula: see text]. For pe=0, it gives the known Aichelburg-Sexl geometry. We find the exact S-matrix describing the scattering of a neutral massive test particle with this geometry, which generalizes the pe=0 result. This is an infinite superposition of the S-matrices for pe=0 and exhibits poles in both positive and negative axis Gs=im/2, (m∈Z). This increases the number of poles of the uncharged case by a factor of four. The large and small (s, t) behaviors are computed. The scattering in which the two particles are charged is highly complicated ...
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International Journal of Modern Physics A, 2004
We provide a conceptual unified description of the quantum properties of black holes (BH), elemen... more We provide a conceptual unified description of the quantum properties of black holes (BH), elementary particles, de Sitter (dS) and Anti-de Sitter (AdS) string states.The conducting line of argument is the classical–quantum (de Broglie, Compton) duality here extended to the quantum gravity (string) regime (wave–particle–string duality). The semiclassical (QFT) and quantum (string) gravity regimes are respectively characterized and related: sizes, masses, accelerations and temperatures. The Hawking temperature, elementary particle and string temperatures are shown to be the same concept in different energy regimes and turn out the precise classical–quantum duals of each other; similarly, this result holds for the BH decay rate, heavy particle and string decay rates; BH evaporation ends as quantum string decay into pure (nonmixed) radiation. Microscopic density of states and entropies in the two (semiclassical and quantum) gravity regimes are derived and related, an unifying formula f...
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Modern Physics Letters A, May 30, 2007
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International Journal of Modern Physics, Apr 10, 2007
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Physical Review D, 2013
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Monthly Notices of the Royal Astronomical Society, 2014
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Physical Review D, 1990
We exactly quantize fundamental strings propagating in a straight cosmic-string space-time (conic... more We exactly quantize fundamental strings propagating in a straight cosmic-string space-time (conical space-time with deficit angle $8\ensuremath{\pi}G\ensuremath{\mu}$, $\ensuremath{\mu}$ being the cosmic-string tension). If the fundamental string collides with the cosmic string the scattering is inelastic since the internal modes of the fundamental string become excited. If there is no collision, the fundamental string only suffers a deflection of $\ifmmode\pm\else\textpm\fi{}4\ensuremath{\pi}G\ensuremath{\mu}$. If there is collision we find inelastic particle production from the interaction of the string with the (classical) geometry. The string oscillator modes only suffer a change of polarization (rotation) in the elastic case and a Bogoliubov transformation in the inelastic case. As a consequence, for a given initial state, the final particle may be in any state associated with the string oscillators. All transformations are explicitly calculated in closed form. Finally, the quantum scattering amplitude for the lowest scalar (tachyon) is computed exactly. In this calculation the vertex operator in the conical geometry and the oscillator linear transformations we find here are used thoroughly. The peculiar features of the string propagation in this topologically nontrivial space-time are discussed including the question whether string splitting can occur at the classical level.
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Physical Review D, 2006
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Physical Review D, 2006
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Physical Review D, 2005
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Physical Review D, 2007
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Physical Review D, 2006
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Physical Review D, 2008
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Physical Review D, 1993
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Papers by Norma Graciela Sanchez