Thomas P. Sotiriou

Publications (60) View all

• Article: Absence of scalar hair in scalar-tensor gravity

  Valerio Faraoni, Thomas P. Sotiriou
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  ABSTRACT: Stationary, asymptotically flat black holes in scalar-tensor theories of gravity are studied. It is shown that such black holes have no scalar hair and are the same as in General Relativity.
  03/2013;
• Article: Apparent horizons in Clifton-Mota-Barrow inhomogeneous universe

  Vincenzo Vitagliano, Valerio Faraoni, Thomas P. Sotiriou, Stefano Liberati
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  ABSTRACT: We analyze the apparent horizon dynamics in the inhomogeneous Clifton-Mota-Barrow solution of Brans-Dicke theory. This solution models a central matter configuration embedded in a cosmological background. In certain regions of the parameter space we find solutions exhibiting dynamical creation or merging of two horizons.
  02/2013;
• Article: Horava-Lifshitz gravity with detailed balance

  Daniele Vernieri, Thomas P. Sotiriou
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  ABSTRACT: Horava-Lifshitz gravity with "detailed balance" but without the projectability assumption is discussed. It is shown that detailed balance is quite efficient in limiting the proliferation of couplings in Horava-Lifshitz gravity, and that its implementation without the projectability assumption leads to a theory with sensible dynamics. However, the (bare) cosmological constant is restricted to be large and negative.
  12/2012;
• Article: Slowly rotating black holes in Horava-Lifshitz gravity

  Enrico Barausse, Thomas P. Sotiriou
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  ABSTRACT: In a recent paper we claimed that there there are no slowly rotating, stationary, axisymmetric black holes in the infrared limit of Horava-Lifshitz gravity, provided that they are regular everywhere apart from the central singularity. Here we point out a subtlety in the equivalence between Einstein-aether theory and the infrared limit of Horava-Lifshitz gravity which was missed in our earlier derivation and drastically modifies our conclusion: our earlier calculations (which are otherwise technically correct) do not really imply that there are no slowly rotating black holes in Horava-Lifshitz gravity, but that there are no slowly rotating black holes in the latter that are also solutions of Einstein-aether theory and vice versa. That is, even though the two theories share the static, spherically symmetric solutions, there are no slowly rotating black holes that are solutions to both theories. We proceed to generate slowly rotating black hole solutions in the infrared limit of Horava-Lifshitz gravity, and we show that the configuration of the foliation-defining scalar remains the same as in spherical symmetry, thus these black holes are expected to posses a universal horizon.
  12/2012;
• Article: No-Go Theorem for Slowly Rotating Black Holes in Hořava-Lifshitz Gravity.

  Enrico Barausse, Thomas P Sotiriou
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  ABSTRACT: We consider slowly rotating, stationary, axisymmetric black holes in the infrared limit of Hořava-Lifshitz gravity. We show that such solutions do not exist, provided that they are regular everywhere apart from the central singularity. This has profound implications for the viability of the theory, considering the astrophysical evidence for the existence of black holes with nonzero spin.
  Physical Review Letters 11/2012; 109(18):181101. · 7.37 Impact Factor