Dark Energy: Investigation and Modeling

Tsujikawa, Shinji

doi:10.1007/978-90-481-8685-3_8

Cited by 94 publications

(104 citation statements)

References 646 publications

(859 reference statements)

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“…This test was performed mainly using Supernovae, but also using Baryonic Acoustic Oscillations and the CMB so as to fix the background history of the Universe [162, 217, 221, 286, 391, 23, 405, 481, 304, 382, 462]. Current observations seem to slightly disfavor the additional term in the Friedmann equation of DGP, even in the normal branch where the late-time acceleration of the Universe is due to a cosmological constant as in ΛCDM.…”

Section: The Dvali-gabadadze-porrati Modelmentioning

confidence: 99%

Massive Gravity

Rham

2014

Living Rev. Relativ.

1,013

1,062

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We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

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Section: The Dvali-gabadadze-porrati Modelmentioning

confidence: 99%

Massive Gravity

Rham

2014

Living Rev. Relativ.

1,013

1,062

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“…The ΛCDM model shows an excellent guidance with current data [35][36][37][38][39][40][41][42][43][44] but it is severely plagued by the coincidence and fine tuning problems [45,46]. These issues do not enable concluding that the ΛCDM model represents the final paradigm to describe the universe dynamics (in particular, the measures of cosmological constant and matter magnitudes are extremely close to each other, i.e., Ω Λ /Ω ∼ 2.7, at our time [38,[47][48][49], whereas the predicted and observed cosmological constant values differ for about 123 orders of magnitude [50]). As a natural consequence, a wide amount of cosmological models has been introduced to extend the concordance model in 2 Advances in High Energy Physics order to get possible alternatives to dark energy derived from prime principles (see, e.g., [51][52][53][54][55][56][57][58][59] and references therein).…”

Section: Introductionmentioning

confidence: 84%

A Thermodynamic Approach to Holographic Dark Energy

Luongo

2017

Advances in High Energy Physics

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We propose a method to relate the holographic minimal information density to de Broglie's wavelength at a given universe temperature . To figure this out, we assume that the thermal length of massive and massless constituents represents the cutoff scale of the holographic principle. To perform our analysis, we suppose two plausible universe volumes, that is, the adiabatic and the horizon volumes, that is, ∝ 3 and ∝ −3 , respectively, assuming zero spatial curvature. With these choices in mind, we evaluate the thermal lengths for massive and massless particles and we thus find two cosmological models associated with late and early cosmological epochs. We demonstrate that both models depend upon a free term which enters the temperature parametrization in terms of the redshift . For the two treatments, we show evolving dark energy terms which can be compared with the CDM quintessence paradigm when the barotropic factor takes the formal values 0 = −(1/3)(2 + ) and 0 = −(1/3)(1 + 2 ), respectively, for late and early eras. From our analyses, we nominate the two models as viable alternatives to dark energy determined from thermodynamics in the field of the holographic principle.

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“…On the other hand, we have considered that the different components are conserved separately, therefore by replacing Equation (5) …”

Section: The Model and The Lsbr Induced Abrupt Eventmentioning

confidence: 99%

“…The exponentials have an imaginary argument, so the solutions are bounded and the DeWitt boundary condition is satisfied 5 . In the case of a positive value of E k , the solutions of the gravitational part read…”

Section: Wdw Equation With a Scalar Fieldmentioning

confidence: 99%

The Avoidance of the Little Sibling of the Big Rip Abrupt Event by a Quantum Approach

et al. 2018

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Abstract:We address the quantisation of a model that induces the Little Sibling of the Big Rip (LSBR) abrupt event, where the dark energy content is described by means of a phantom-like fluid or a phantom scalar field. The quantisation is done in the framework of the Wheeler-DeWitt (WDW) equation and imposing the DeWitt boundary condition; i.e., the wave function vanishes close to the abrupt event. We analyse the WDW equation within two descriptions: First, when the dark energy content is described with a perfect fluid. This leaves the problem with the scale factor as the single degree of freedom. Second, when the dark energy content is described with a phantom scalar field in such a way that an additional degree of freedom is incorporated. Here, we have applied the Born-Oppenheimer (BO) approximation in order to simplify the WDW equation. In all cases, the obtained wave function vanishes when the LSBR takes place, thus fulfilling the DeWitt boundary condition.

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Dark Energy: Investigation and Modeling

Cited by 94 publications

References 646 publications

Massive Gravity

Massive Gravity

A Thermodynamic Approach to Holographic Dark Energy

The Avoidance of the Little Sibling of the Big Rip Abrupt Event by a Quantum Approach

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