Cosmological fluids with logarithmic equation of state

Odintsov, Sergei D.; Oikonomou, V. K.; Тимошкин, А. В.; Saridakis, Emmanuel N.; Myrzakulov, Ratbay

doi:10.1016/j.aop.2018.09.015

Cited by 66 publications

(35 citation statements)

References 141 publications

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“…The Anton-Schmidt scenario has been introduced in the cosmological context to unify dark matter and dark energy into a single fluid [24,40]. Analogously to the Chaplygin gas [41], it is possible to consider the cosmic fluid made of matter characterized by a non-vanishing equation of state, which would account for the accelerated expansion observed at late epochs of the universe evolution.…”

Section: A the Tolman-oppenheimer-volkoff Approachmentioning

confidence: 99%

Black holes and naked singularities from Anton–Schmidt’s fluids

Capozziello

D’Agostino

Gregoris

2020

Physics of the Dark Universe

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Adopting the Tolman-Oppenheimer-Volkoff formalism, we propose a new analytical solution for a static and spherically symmetric black hole where the cosmological constant is generalized to a nonisotropic Anton-Schmidt fluid acting as a unified dark energy -dark matter source. Our novel result can describe a black hole in energetic equilibrium with the surrounding universe. We thus investigate the interplay between the mass of the black hole and the parameters of the Anton-Schmidt equation of state, and physically interpret the solution as a family of space-time metrics that may describe both Schwarzschild-de Sitter black holes and naked singularities. The result opens a new window for further constraining the physical properties of the cosmic fluid using the Event Horizon Telescope results, which complement the analysis relying on classical cosmological observations.

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Section: A the Tolman-oppenheimer-volkoff Approachmentioning

confidence: 99%

Black holes and naked singularities from Anton–Schmidt’s fluids

Capozziello

D’Agostino

Gregoris

2020

Physics of the Dark Universe

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“…• Find all possible truncations of the function f (x) in Eq. (26). A dominant truncation controls the evolution of the dynamical system near finite-time singularities, which we denote asf (x), hence the dynamical system becomes,ẋ =f (x) .…”

Section: The Classical Cosmology Framework and Interacting Dark Ementioning

confidence: 99%

Classical and loop quantum cosmology phase space of interacting dark energy and superfluid dark matter

Oikonomou¹

2019

Phys. Rev. D

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In this paper we study in detail the phase space of a cosmological system consisting of two coupled fluids, namely a dark energy fluid coupled with a superfluid dark matter fluid. The dark matter fluid is assumed to have a superfluid equation of state, hence it is not pressureless and our aim is to find the impact of this non-trivial equation of state on the phase space of the coupled system. We shall use two theoretical contexts, namely that of classical cosmology and that of loop quantum cosmology. In the classical case, we investigated the existence and stability of fixed points, and as we will show, no de Sitter fixed points occur, however matter and radiation domination fixed points occur, which are hyperbolic and unstable. We also show that there exist limited sets of initial conditions for which singular solutions occur in the phase space. With regard to the loop quantum cosmology case, we demonstrate that stable de Sitter fixed points exist, for some values of the free parameters of the theory, and interestingly enough, for the same values, singular solutions corresponding to general sets of initial conditions occur. To our knowledge this feature does not occur so frequently in loop quantum cosmological frameworks. We also demonstrate that non-singular solutions corresponding to a general set of initial conditions occur, however these occur when the dark matter superfluid has negative pressure, so it is a rather physically unappealing situation.PACS numbers:

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“…Some other models consider a proper dark energy fluid with viscosity [9][10][11]. Such possibility may lead to a fluid with a negative pressure that may even cross the phantom barrier [9,10,[12][13][14][15]. In addition, the viscosity terms may play an essential role during the early time inflationary stage [2,16].…”

Section: Introductionmentioning

confidence: 99%

“…The second model is inspired in Anton-Schmidt's equation of state for crystalline solids ( [17]), which includes a logarithmic-corrected power-law fluid and the the same viscous term as above ζ(H) ∼ H 2β−1 , leading to the following EoS [14]:…”

Section: Introductionmentioning

confidence: 99%

Testing the equation of state for viscous dark energy

2020

Self Cite

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Some cosmological scenarios with bulk viscosity for the dark energy fluid are considered. Based on some considerations related to hydrodynamics, two different equations of state for dark energy are assumed, leading to power-law and logarithmic effective corrections to the pressure. The models are tested with the latest astronomical data from Type Ia supernovae (Pantheon sample), measurements of the Hubble parameter H(z), Baryon Acoustic Oscillations and Cosmic Microwave Background radiation. In comparison with ΛCDM model, some different results are obtained and their viability is discussed. The power-law model shows some modest results, achieved under negative values of bulk viscosity, while the logarithmic scenario provide good fits in comparison to ΛCDM model.

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Cosmological fluids with logarithmic equation of state

Cited by 66 publications

References 141 publications

Black holes and naked singularities from Anton–Schmidt’s fluids

Black holes and naked singularities from Anton–Schmidt’s fluids

Classical and loop quantum cosmology phase space of interacting dark energy and superfluid dark matter

Testing the equation of state for viscous dark energy

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