Garay Elizondo, Luis Javier

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First Name
Luis Javier
Last Name
Garay Elizondo
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Física Teórica
Física Teórica
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Now showing 1 - 2 of 2
  • Publication
    Stability analysis of sonic horizons in Bose-Einstein condensates
    (Amer Physical Soc, 2006-07) Barceló, C.; Cano, A.; Garay Elizondo, Luis Javier; Jannes, G.
    We examine the linear stability of various configurations in Bose-Einstein condensates with steplike sonic horizons. These configurations are chosen in analogy with gravitational systems with a black hole horizon, a white hole horizon, and a combination of both. We discuss the role of different boundary conditions in this stability analysis, paying special attention to their meaning in gravitational terms. We highlight that the stability of a given configuration, not only depends on its specific geometry, but especially on these boundary conditions. Under boundary conditions directly extrapolated from those in standard general relativity, black hole configurations, white hole configurations, and the combination of both into a black hole-white hole configuration are shown to be stable. However, we show that under other (less stringent) boundary conditions, configurations with a single black hole horizon remain stable, whereas white hole and black hole-white hole configurations develop instabilities associated to the presence of the sonic horizons.
  • Publication
    Sensitivity of Hawking radiation to superluminal dispersion relations
    (Amer Physical Soc, 2009-01) Barceló, C.; Garay Elizondo, Luis Javier; Jannes, G.
    We analyze the Hawking radiation process due to collapsing configurations in the presence of superluminal modifications of the dispersion relation. With such superluminal dispersion relations, the horizon effectively becomes a frequency-dependent concept. In particular, at every moment of the collapse, there is a critical frequency above which no horizon is experienced. We show that, as a consequence, the late-time radiation suffers strong modifications, both quantitative and qualitative, compared to the standard Hawking picture. Concretely, we show that the radiation spectrum becomes dependent on the measuring time, on the surface gravities associated with different frequencies, and on the critical frequency. Even if the critical frequency is well above the Planck scale, important modifications still show up.