Antigravity and the big crunch/big bang transition

  title={Antigravity and the big crunch/big bang transition},
  author={Itzhak Bars and Shih-Hung Chen and Paul J. Steinhardt and Neil Turok},
  journal={Physics Letters B},
Abstract We point out a new phenomenon which seems to be generic in 4d effective theories of scalar fields coupled to Einstein gravity, when applied to cosmology. A lift of such theories to a Weyl-invariant extension allows one to define classical evolution through cosmological singularities unambiguously, and hence construct geodesically complete background spacetimes. An attractor mechanism ensures that, at the level of the effective theory, generic solutions undergo a big crunch/big bang… Expand

Figures from this paper

Traversing Cosmological Singularities, Complete Journeys Through Spacetime Including Antigravity
A unique description of the Big Crunch-Big Bang transition is given at the classical gravity level, along with a complete set of homogeneous, isotropic, analytic solutions in scalar-tensor cosmology,Expand
Through the Big Bang in inflationary cosmology
  • F. Mercati
  • Physics
  • Journal of Cosmology and Astroparticle Physics
  • 2019
Singularities in General Relativity are regions where the description of spacetime in terms of a pseudo-Riemannian geometry breaks down. The theory seems unable to predict the evolution of theExpand
Journeys through antigravity?
A bstractA possibility of journeys through antigravity has recently been proposed, with the suggestion that Weyl-invariant extension of scalars coupled to Einstein gravity allows for an unambiguousExpand
Mini-superspace universality and no-scale quantum cosmology
Abstract We prove that, at the mini superspace level, and for an arbitrary Brans-Dicke parameter, one cannot tell traditional Einstein-Hilbert gravity from local scale invariant Weyl-Dirac gravity.Expand
Local conformal symmetry in physics and cosmology
We show how to lift a generic non-scale invariant action in Einstein frame into a locally conformally-invariant (or Weyl-invariant) theory and present a new general form for Lagrangians consistentExpand
Conformal inflation from the Higgs
A bstractWe modify the conformal inflation set-up of [1], with a local Weyl invariance, a dynamical Planck scale and an SO(1, 1) invariance at high energies, in order to be able to identify theExpand
Conflation: a new type of accelerated expansion
In the framework of scalar-tensor theories of gravity, we construct a new kind of cosmological model that conflates inflation and ekpyrosis. During a phase of conflation, the universe undergoesExpand
Bouncing cosmology in an extended theory of gravity
We have investigated some bouncing models in the framework of an extended gravity theory where the usual Ricci scalar in the gravitational action is replaced by a sum of the Ricci scalar and a termExpand
Cyclic cosmology, conformal symmetry and the metastability of the Higgs
Recent measurements at the LHC suggest that the current Higgs vacuum could be metastable with a modest barrier (height (10^(10–12) GeV)^4) separating it from a ground state with negative vacuumExpand
Singularity Crossing, Transformation of Matter Properties and the Problem of Parametrization in Field Theories
We investigate particular cosmological models, based either on tachyon fields or on perfect fluids, for which soft future singularities arise in a natural way. Our main result is the description of aExpand


Solution of a braneworld big crunch/big bang cosmology
We solve for the cosmological perturbations in a five-dimensional background consisting of two separating or colliding boundary branes, as an expansion in the collision speed V divided by the speedExpand
The Ekpyrotic universe: Colliding branes and the origin of the hot big bang
We propose a cosmological scenario in which the hot big bang universe is produced by the collision of a brane in the bulk space with a bounding orbifold plane, beginning from an otherwise cold,Expand
Kasner and mixmaster behavior in universes with equation of state w >= 1
We consider cosmological models with a scalar field with equation of state $w\ge 1$ that contract towards a big crunch singularity, as in recent cyclic and ekpyrotic scenarios. We show that chaoticExpand
Inflationary universe: A possible solution to the horizon and flatness problems
The standard model of hot big-bang cosmology requires initial conditions which are problematic in two ways: (1) The early universe is assumed to be highly homogeneous, in spite of the fact thatExpand
Quiescent Cosmological Singularities
Abstract: The most detailed existing proposal for the structure of spacetime singularities originates in the work of Belinskii, Khalatnikov and Lifshitz. We show rigorously the correctness of thisExpand
New Ekpyrotic Cosmology
In this paper, we present a new scenario of the early universe that contains a pre-big bang ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energyExpand
Geometry and symmetry structures in two-time gravity
Two-time (2T) gravity in d+2 dimensions predicts 1T general relativity in d dimensions, augmented with a local scale symmetry known as the Weyl symmetry in 1T field theory. The emerging generalExpand
Quantum Fields in Curved Space
This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black holeExpand
Cosmology for Grand Unified Theories with Radiatively Induced Symmetry Breaking
The treatment of first-order phase transitions for standard grand unified theories is shown to break down for models with radiatively induced spontaneous symmetry breaking. It is argued that properExpand
A Cyclic Model of the Universe
A cosmological model in which the universe undergoes an endless sequence of cosmic epochs that begin with a "bang" and end in a “crunch" is proposed, which produces the homogeneity, flatness, and energy needed to begin the next cycle. Expand