Now showing items 1-12 of 12

    • Black hole solutions and Euler equation in Rastall and generalized Rastall theories of gravity 

      Moradpour, H.; Heydarzade, Yaghoub; Corda, C.; Ziaie, A. H.; Ghaffari, S. (World Scientific Publishing, 2019)
      Focusing on the special case of generalized Rastall theory, as a subclass of the non-minimal curvature-matter coupling theories in which the field equations are mathematically similar to the Einstein field equations in the ...
    • Cosmological singularities in conformal Weyl gravity 

      Heydarzade, Yaghoub (Springer, 2019-11)
      In this work, we study the issue of the past and future cosmological singularities in the context of the fourth-order conformal Weyl gravity. In particular, we investigate the emergent universe scenario proposed by Ellis ...
    • D-bound and Bekenstein bound for McVittie solution surrounded by dark energy cosmological fields 

      Hadi, H.; Darabi, F.; Atazadeh, K.; Heydarzade, Yaghoub (Springer, 2020-07)
      The cosmological candidate fields for dark energy as quintessence, phantom and cosmological constant are studied in terms of an entropic hypothesis imposed on the McVittie solution surrounded by dark energy. We certify ...
    • D-bound and the Bekenstein bound for the surrounded Vaidya black hole 

      Hadi, H.; Darabi, F.; Atazadeh, K.; Heydarzade, Yaghoub (Springer Science and Business Media Deutschland GmbH, 2020-11)
      We study the Vaidya black hole surrounded by the exotic quintessence-like, phantom-like and cosmological constant-like fields by means of entropic considerations. Explicitly, we show that for this thermodynamical system, ...
    • Entropic considerations on the Universe and Universe-black hole systems 

      Hadi, H.; Darabi, F.; Heydarzade, Yaghoub (IOP Publishing Ltd, 2020-08)
      We study the entropic considerations on the Universe system and the Universe-black hole system, filled by cosmological constant or exotic quintessence-like and phantom-like fields having negative pressure, using their ...
    • FLRW-cosmology in generic gravity theories 

      Gürses, Metin; Heydarzade, Yaghoub (Springer Science and Business Media Deutschland GmbH, 2020-11)
      We prove that for the Friedmann–Lemaitre–Robertson–Walker metric, the field equations of any generic gravity theory in arbitrary dimensions are of the perfect fluid type. The cases of general Lovelock and F(R,G)F(R,G) ...
    • Kerr-Schild-Kundt metrics in generic Einstein-Maxwell theories 

      Gürses, Metin; Heydarzade, Yaghoub; Şentürk, Ç. (American Physical Society, 2022-02-03)
      We study the Kerr-Schild-Kundt class of metrics in generic gravity theories with Maxwell’s field. We prove that these metrics linearize and simplify the field equations of generic gravity theories with Maxwell’s field.
    • Kerr–Schild–Kundt metrics in generic gravity theories with modified Horndeski couplings 

      Gürses, Metin; Heydarzade, Yaghoub; Şentürk, Çetin (Springer, 2021-12-31)
      The Kerr–Schild–Kundt (KSK) metrics are known to be one of the universal metrics in general relativity, which means that they solve the vacuum field equations of any gravity theory constructed from the curvature tensor and ...
    • NAT black holes 

      Gürses, Metin; Heydarzade, Yaghoub; Şentürk, Ç. (Springer, 2019)
      We study some physical properties of black holes in Null Aether Theory (NAT) – a vector-tensor theory of gravity. We first review the black hole solutions in NAT and then derive the first law of black hole thermodynamics. ...
    • New classes of spherically symmetric, inhomogeneous cosmological models 

      Gürses, Metin; Heydarzade, Yaghoub (American Physical Society, 2019)
      We present two classes of inhomogeneous, spherically symmetric solutions of the Einstein-Maxwell-perfect fluid field equations with cosmological constant generalizing the Vaidya-Shah solution. Some special limits of our ...
    • On the initial singularity in Kantowski–Sachs spacetime 

      Ghorani, Elham; Heydarzade, Yaghoub (Springer, 2021-06-29)
      The emergent universe scenario is a proposal for resolving the Big Bang singularity problem in the standard Friedmann–Lemaitre–Robertson–Walker cosmology. In the context of this scenario, the Universe originates from a ...
    • Surrounded Bonnor-Vaidya solution by cosmological fields 

      Heydarzade, Yaghoub; Darabi, F. (Springer, 2018)
      In the present work, we generalize our previous work (Heydarzade and Darabi in arXiv:1710.04485, 2018 on the surrounded Vaidya solution by cosmological fields to the case of Bonnor-Vaidya charged solution. In this regard, ...