Screening of cosmological constant for De Sitter Universe in non-local gravity, phantom-divide crossing and finite-time future singularities

Abstract

We investigate de Sitter solutions in non-local gravity as well as in non-local gravity with Lagrange constraint multiplier. We examine a condition to avoid a ghost and discuss a screening scenario for a cosmological constant in de Sitter solutions. Furthermore, we explicitly demonstrate that three types of the finite-time future singularities can occur in non-local gravity and explore their properties. In addition, we evaluate the effective equation of state for the universe and show that the late-time accelerating universe may be effectively the quintessence, cosmological constant or phantom-like phases. In particular, it is found that there is a case in which a crossing of the phantom divide from the non-phantom (quintessence) phase to the phantom one can be realized when a finite-time future singularity occurs. Moreover, it is demonstrated that the addition of an $R^2$ term can cure the finite-time future singularities in non-local gravity. It is also suggested that in the framework of non-local gravity, adding an $R^2$ term leads to possible unification of the early-time inflation with the late-time cosmic acceleration.

42 pages, no figure, version accepted for publication in General Relativity and Gravitation

References in corpus (39)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Quantum Gravity at a Lifshitz Point
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Phantom scalar dark energy as modified gravity: understanding the origin of the Big Rip singularity
• Modified non-local-F(R) gravity as the key for the inflation and dark energy
• The future evolution and finite-time singularities in $F(R)$-gravity unifying the inflation and cosmic acceleration
• Towards a Resolution of the Cosmological Singularity in Non-local Higher Derivative Theories of Gravity
• Relativistic stars in f(R) gravity, and absence thereof
• Dynamics of Nonlocal Cosmology
• Accelerating cosmologies from non-local higher-derivative gravity
• Quantum phantom cosmology
• Avoidance of future singularities in loop quantum cosmology
• Phantom and non-phantom dark energy: The cosmological relevance of non-locally corrected gravity
• Localization of nonlocal theories
• Classifying and avoiding singularities in the alternative gravity dark energy models
• Reconstructing the Distortion Function for Nonlocal Cosmology
• Time-dependent matter instability and star singularity in $F(R)$ gravity
• Newtonian limit of nonlocal cosmology
• Avoidance of Big Rip In Phantom Cosmology by Gravitational Back Reaction
• Can higher curvature corrections cure the singularity problem in f(R) gravity?
• Nonlocal gravity and the diffusion equation
• Screening of cosmological constant in non-local gravity
• Delicate f(R) gravity models with disappearing cosmological constant and observational constraints on the model parameters
• Dynamics in Nonlocal Cosmological Models Derived from String Field Theory
• Classical Stability of Sudden and Big Rip Singularities
• Screening of cosmological constant in non-local cosmology
• Viscous Dark Cosmology with Account of Quantum Effects
• Strings at future singularities
• Singular fate of the universe in modified theories of gravity
• Explosive phenomena in modified gravity
• One-loop effective action for non-local modified Gauss-Bonnet gravity in de Sitter space
• Astronomical bounds on future big freeze singularity
• Newton's constant in f(R,R_{μν}R^{μν},\Box R) theories of gravity and constraints from BBN
• Constraints on a variable dark energy model with recent observations
• Generic feature of future crossing of phantom divide in viable $f(R)$ gravity models
• Tackling Higher Derivative Ghosts with the Euclidean Path Integral
• Inflation with a Weyl term, or ghosts at work

Cited by in corpus (40)

• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Inflationary cosmology in modified gravity theories
• Cosmological perturbations and structure formation in nonlocal infrared modifications of general relativity
• Non-local gravity and dark energy
• A non-local theory of massive gravity
• Finite-time Cosmological Singularities and the Possible Fate of the Universe
• Non-local gravity and comparison with observational datasets
• Cosmological dynamics and dark energy from non-local infrared modifications of gravity
• Connecting early and late universe by $f(R)$ gravity
• Apparent ghosts and spurious degrees of freedom in non-local theories
• Spherically symmetric static solutions in a non-local infrared modification of General Relativity
• Non-local gravity and comparison with observational datasets. II. Updated results and Bayesian model comparison with $\Lambda$CDM
• Tolman-Oppenheimer-Volkoff equations in non-local $f(R)$ gravity
• Reconstruction Procedure in Nonlocal Cosmological Models
• Cosmological Solutions of a Nonlocal Model with a Perfect Fluid
• Acausality in Nonlocal Gravity Theory
• Nonlocal Metric Realizations of MOND
• Stability analysis and future singularity of the $m^{2}R{\square }^{-2}R$ model of non-local gravity
• Revival of the Deser-Woodard nonlocal gravity model: Comparison of the original nonlocal form and a localized formulation
• A Caveat on Building Nonlocal Models of Cosmology
• Non-local $F(R)$-mimetic gravity
• Energy Conditions in Non-local Gravity
• Nonlocal Gravitational Models and Exact Solutions
• Modelling of a compact anisotropic star as an anisotropic fluid sphere in $f(T)$ gravity
• On the covariant formalism of the effective field theory of gravity and its cosmological implications
• De Sitter and Power-law Solutions in Non-local Gauss-Bonnet Gravity
• The fate of bound systems through Sudden Future Singularities
• Phase Space description of Nonlocal Teleparallel Gravity
• Noether symmetry in a nonlocal f(T) Gravity
• Can nonlocal gravity really explain dark energy?
• Unitarization and Causalization of Non-local quantum field theories by Classicalization
• Periodic Cosmological Evolutions of Equation of State for Dark Energy
• Ghosts in classes of non-local gravity
• Non-local scalar fields inflationary mechanism in light of Planck $2013$
• An Improved Cosmological Model
• Sudden Future Singularities in Quintessence and Scalar-Tensor Quintessence Models
• Does nonlocal gravity yield divergent gravitational energy-momentum fluxes?
• Uncertainty Principles and Non-local Black Holes
• Stability of the de-Sitter universe: One-loop nonlocal $f(R)$ gravity
• The stability of the de-Sitter universe in nonlocal gravity