1 / 20

Energy extraction from black holes

Energy extraction from black holes. BHs2011 19-20 Dec 2011 | Aveiro, Portugal. Credit : ESO/MPE (2010). Vitor Cardoso (CENTRA/IST & Olemiss ) . Credit : ESO/MPE/ M.Schartmann (2011). Orbital energy : slingshot effect. Rotational energy: tidal acceleration .

majed
Download Presentation

Energy extraction from black holes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Energyextractionfromblackholes BHs2011 19-20 Dec 2011 | Aveiro, Portugal Credit: ESO/MPE (2010) Vitor Cardoso (CENTRA/IST & Olemiss)

  2. Credit: ESO/MPE/M.Schartmann (2011)

  3. Orbital energy: slingshoteffect

  4. Rotational energy: tidal acceleration

  5. Tidalaccelerationisin general impossible for BHs! Press & Teukolsky, Nature (1973)

  6. Ergo-region: asymptotictime-translationKiling vector isspace-like Penrose process • Superradiance • Hawking radiation

  7. Insert a mirroraroundthe BH anti-de Sitter Make a “bomb”! (Zel’dovich, 1971; Press & Teukolsky 1973) SmallKerr-AdSBHs are unstable (Cardoso & Dias ‘04; Kodama ’07; Uchikata, Yoshida & Futamase ’09)

  8. (Witeketal, ‘10)

  9. Horizonless geometries? Theorem(Friedman, 1978): Everystationary, AF, horizonlessspacetimewithanergoregionisunstable (Intuition: negative-energystates are amplified, no horizon to absorbthem) Gravastars(Mazur & Mottola ‘01) BosonStars(Kaup ’68; Ruffini & Bonazzola ‘69) Wormholes(Morris & Thorne ‘88) Superspinars(Gimon & Horava ‘09) Ergoregioninstability rules out “all” of these! (Cardoso etal, ’08; Panietal ‘10;)

  10. Resonant excitation of BH modes? Resonant tides? MasslessmodesofBHs are localizedaroundthelightring... ...andthenullgeodesicliesinsidethe ISCO

  11. (massive) scalar fields Interesting as effective description Proxy for more complex interactions Arise as interesting alternatives of GR Brans-Dicke or generic scalar-tensor theories; quadratic f(R) GW spectrum encodes the gravity theory Axiverse scenarios (moduli and coupling constants in QCD, Peccei-Quinn mechanism QCD, etc)

  12. Massivefields MassivefieldsaroundKerr are unstable (Damouretal ‘76; Detweiler, ’80; Cardoso & Yoshida ’05; Dolan ‘07)

  13. Floatingorbits Cardoso et al, PRL107:241101, 2011

  14. Tidalaccelerationisequivalent to superradiancein BH physics •  • Inabsenceofotherdissipationmechanisms, tidaldissipationleads to floatingorbits •  • Floating orbits can be instrumental to constrain or prove existence of massive scalars coupled to matter... stilla lot to do

  15. Thank you Cardoso, Chakrabarti, Pani, Berti, Gualtieri, PRL107: 241101 (2011) Yunes, Pani, Cardoso, arXiv:1112.3351 • Cardoso, Pani, in progress (2012) ____________________________ ____________________________ 

More Related