Trans-Planckian problem of inflationary cosmology

By Jérôme Martin, Robert Brandenberger. 2000

605 citations recorded by the source corpus.

In most current models of inflation based on a weakly self-coupled scalar matter field minimally coupled to gravity, the period of inflation lasts so long that, at the beginning of the inflationary period, the physical wavelengths of comoving scales which correspond to the present large-scale structure of the Universe were smaller than the Planck length. Thus, the usual computations of the spectrum of fluctuations in these models involve extrapolating low-energy physics (both in the matter and gravitational sector) into regions where this physics is not applicable. In this article we study the dependence of the usual predictions of inflation for the spectrum of cosmological fluctuations on the hidden assumptions about super-Planck scale physics. We introduce a class of modified dispersion relations to mimic possible effects of super-Planck scale physics, and find that, given an initial state determined by minimizing the energy density, for dispersions relations introduced by Unruh the spectrum is unchanged, whereas for a class of dispersion relations similar to those used by Corley and Jacobson (which involve a more radical departure from the usual linear relation) important deviations from the usual predictions of inflation can be obtained. Some implications of this result for the unification of fundamental physicsmore » and early Universe cosmology are discussed.« less

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/f2d101fe3efebe7f2318f3e89aa9dfe258373c4d

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Citations in the corpus

Quantum-Spacetime Phenomenology (2008, background): “Inflation works in such a way that some of the scales that are presently of cosmological interest should have been trans-Planckian scales at the beginning of inflation, and, therefore, cannot be handled satisfactorily without (the correct) quantum gravity [134, 393, 197].”
Trans-Planckian censorship and inflationary cosmology (2019, background): “In [8] (see also [9]) it was realized that if the inflationary phase lasts somewhat longer than the minimal period, then the length scales we observe today originate from modes that are smaller than the Planck length dur-”
Information loss problem and a ‘black hole’ model with a closed apparent horizon (2014, background): “Let us notice that this phenomenon has common features with a well known transplanckian problem in black holes [36] and in the inflating universe [37].”
Islands outside the horizon (2019, background): “[41, 42, 43]) that quantum gravity implies that we cannot have an approximately de Sitter universe for more than this time.”
Effective theories of single field inflation when heavy fields matter (2012, background): “Trans-Planckian concerns notwithstanding [19], in many circumstances, from the perspective of the parent theory we are forced to account for the”
Analogue Gravity (2005, background): “We expect that these analogue models provide us with new insights as to how their inherent modified dispersion relations affect cosmological process such as the generation of a primordial spectrum of perturbations (see for example [250, 251, 46, 42, 41, 107, 209, 229, 230, 249, 275, 275, 274, 43, 47”
Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “[57] J.”
Exploring bouncing cosmologies with cosmological surveys (2014, background): “[53] J.”