Holography and the scale invariance of density fluctuations

@article{Magueijo2006HolographyAT,
  title={Holography and the scale invariance of density fluctuations},
  author={Jo{\~a}o Magueijo and Lee Smolin and Carlo R. Contaldi},
  journal={Classical and Quantum Gravity},
  year={2006},
  volume={24},
  pages={3691 - 3699}
}
We study a scenario for the very early universe in which there is a fast phase transition from a non-geometric, high temperature phase to a low temperature, geometric phase described by a classical solution to the Einstein equations. In spite of the absence of a classical metric, the thermodynamics of the high temperature phase may be described by making use of the holographic principle. The thermal spectrum of fluctuations in the high temperature phase manifests itself after the phase… 

Quantum gravity at Hubble scales determines the cosmological constant and the amplitude of primordial perturbations

Gravity controls the amount of information that is accessible to any specific observer. We quantify the notion of cosmic information (‘CosmIn’) for the case of an eternal observer in the universe.

Early Universe Cosmology in Internal Relativity

We present a new approach to early universe cosmology. Inflation is replaced by a phase transition in which both matter and geometry are created simultaneously. We calculate the spectrum of metric

Inhomogeneous universe from group field theory condensate

  • Steffen Gielen
  • Physics
    Journal of Cosmology and Astroparticle Physics
  • 2019
One of the fundamental challenges for quantum cosmology is to explain the emergence of our macroscopic Universe from physics at the Planck scale. In the group field theory (GFT) approach to quantum

Quantum Graphity

We introduce a new model of background independent physics in which the degrees of freedom live on a complete graph and the physics is invariant under the permutations of all the points. We argue

Big Bang as a Critical Point

This article addresses the issue of possible gravitational phase transitions in the early universe. We suggest that a second-order phase transition observed in the Causal Dynamical Triangulations

Towards a Cosmological GFT Condensate Scenario : Gauge-Invariant Perturbations 16 IV

One of the fundamental challenges for quantum cosmology is to explain the emergence of our macroscopic Universe from physics at the Planck scale. In the group field theory (GFT) approach to quantum

Disordered locality as an explanation for the dark energy

We discuss a novel explanation of the dark energy as a manifestation of macroscopic nonlocality coming from quantum gravity, as proposed by Markopoulou [F. Markopoulou (private communication)]. It

References

SHOWING 1-10 OF 43 REFERENCES

SUPERLUMINARY UNIVERSE: A POSSIBLE SOLUTION TO THE INITIAL VALUE PROBLEM IN COSMOLOGY

The spontaneous breaking of local Lorentz invariance in the early Universe, associated with a first order phase transition at a critical time tc, generates a large increase in the speed of light and

Could thermal fluctuations seed cosmic structure

We examine the possibility that thermal, rather than quantum, fluctuations are responsible for seeding the structure of our universe. We find that while the thermalization condition leads to nearly

Producing a scale-invariant spectrum of perturbations in a Hagedorn phase of string cosmology.

In this cosmological scenario, the early Hagedorn phase of string gas cosmology goes over smoothly into the radiation-dominated phase of standard cosmology, without having a period ofcosmological inflation.

The world as a hologram

According to ’t Hooft the combination of quantum mechanics and gravity requires the three‐dimensional world to be an image of data that can be stored on a two‐dimensional projection much like a

A Time varying speed of light as a solution to cosmological puzzles

We consider the cosmological implications of light travelling faster in the early Universe. We propose a prescription for deriving corrections to the cosmological evolution equations while the speed

Origin of the large scale structures of the universe

We revise the statistical properties of the primordial cosmological density anisotropies that, at the time of matter-radiation equality, seeded the gravitational development of large scale structures

More on the spectrum of perturbations in string gas cosmology

String gas cosmology is rewritten in the Einstein frame. In an effective theory in which a gas of closed strings is coupled to a dilaton gravity background without any potential for the dilaton, the

New varying speed of light theories

We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying-c, dispelling the myth that the constancy of c is a matter of

Black hole evaporation without information loss

An approach to black hole quantization is proposed wherein it is assumed that quantum coherence is preserved. After giving our motivations for such a quantization procedure we formulate the