scholarly journals Constraining variations in the fine structure constant in the presence of early dark energy

2011 ◽  
Vol 84 (2) ◽  
Author(s):  
Erminia Calabrese ◽  
Eloisa Menegoni ◽  
C. J. A. P. Martins ◽  
Alessandro Melchiorri ◽  
Graca Rocha
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Structure Constant ◽  
Fine Structure Constant

scholarly journals Dark energy and equivalence principle constraints from astrophysical tests of the stability of the fine-structure constant

2015 ◽  
Vol 2015 (08) ◽  
pp. 047-047 ◽  
Author(s):  
C.J.A.P. Martins ◽  
A.M.M. Pinho ◽  
R.F.C. Alves ◽  
M. Pino ◽  
C.I.S.A. Rocha ◽  
...  
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Equivalence Principle ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
The Stability

scholarly journals CONSTRAINTS ON THAWING SCALAR FIELD MODELS FROM FUNDAMENTAL CONSTANTS

2013 ◽  
Vol 22 (07) ◽  
pp. 1350035 ◽  
Author(s):  
QING GAO ◽  
YUNGUI GONG
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Scalar Field ◽  
Observational Data ◽  
Dark Energy Model ◽  
Structure Constant ◽  
Energy Model ◽  
Fine Structure Constant ◽  
Density Parameter ◽  
Scalar Field Models

We consider a dark energy model with a relation between the equation of state parameter w and the energy density parameter Ωϕ derived from thawing scalar field models. Assuming the variation of the fine structure constant is caused by dark energy, we use the observational data of the variation of the fine structure constant to constrain the current value of w0 and Ωϕ0 for the dark energy model. At the 1σ level, the observational data excluded some areas around w0 = –1, which explains the positive detection of the variation of the fine structure constant at the 1σ level, but ΛCDM model is consistent with the data at the 2σ level.

NEW LIMITS ON THE FUNDAMENTAL CONSTANTS FROM THE CMB DATA

2013 ◽  
Vol 23 ◽  
pp. 391-399
Author(s):  
ELOISA MENEGONI ◽  
ALESSANDRO MELCHIORRI ◽  
ERMINIA CALABRESE ◽  
SILVIA GALLI
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Structure Constant ◽  
Theoretical Models ◽  
Big Bang ◽  
Current Data ◽  
Fine Structure Constant ◽  
Microwave Background ◽  
Satellite Mission ◽  
Cosmological Data

The Cosmic Microwave Background anisotropies provide a unique opportunity to constrain simultaneous variations of the fine-structure constant α and Newton's gravitational constant G. Those correlated variations are possible in a wide class of theoretical models. In this brief paper we show that the current data, assuming that particle masses are constant, gives no clear indication for such variations, but already prefers that any relative variations in α should be of the same sign of those of G for variations of ≈ 1%. We also show that a cosmic complementarity is present with Big Bang Nucleosynthesis, and that a combination of current CMB and BBN data strongly constraints simultaneous variations in α and G. We finally discuss the future bounds achievable by the Planck satellite mission. We discuss present and future cosmological constraints on variations of the fine structure constant α induced by an early dark energy component having the simplest allowed (linear) coupling to electromagnetism. We find that current cosmological data show no variation of the fine structure constant at recombination respect to the present-day value, with α/α0 = 0.975 ± 0.020 at 95% c.l., constraining the energy density in early dark energy to Ωe < 0.060 at 95% c.l.

CONSTRAINTS ON THE DARK ENERGY EQUATION OF STATE IN PRESENCE OF A VARYING FINE STRUCTURE CONSTANT

2010 ◽  
Vol 19 (04) ◽  
pp. 507-512 ◽  
Author(s):  
E. MENEGONI ◽  
S. PANDOLFI ◽  
S. GALLI ◽  
M. LATTANZI ◽  
A. MELCHIORRI
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Constant ◽  
Energy Equation ◽  
Structure Constant ◽  
Hubble Constant ◽  
Fine Structure Constant ◽  
Cosmological Constraints ◽  
Energy Models

We discuss the cosmological constraints on the dark energy equation of state in the presence of primordial variations in the fine structure constant. We find that the constraints from CMB data alone on w and the Hubble constant are much weaker when variations in the fine structure constant are permitted. Vice versa, constraints on the fine structure constant are relaxed by more than 50% when dark energy models different from a cosmological constant are considered.

scholarly journals Fine-structure constant constraints on dark energy. II. Extending the parameter space

2016 ◽  
Vol 93 (2) ◽  
Author(s):  
C. J. A. P. Martins ◽  
A. M. M. Pinho ◽  
P. Carreira ◽  
A. Gusart ◽  
J. López ◽  
...  
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Parameter Space ◽  
Structure Constant ◽  
Fine Structure Constant

LIMIT ON THE TIME VARIATION OF THE FINE STRUCTURE CONSTANT DRIVEN BY QUINTESSENCE

2004 ◽  
Vol 19 (13n16) ◽  
pp. 1089-1092 ◽  
Author(s):  
WOLUNG LEE ◽  
KIN-WANG NG ◽  
DA-SHIN LEE
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Scalar Field ◽  
Time Variation ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Fifth Force

We study the time variation of the fine structure constant driven by quintessential dark energy which is coupled to electromagnetism. By employing phenomenological quintessential models which provide the scalar field with maximal dynamics and satisfy the constraints from SNIa observations and the WMAP, we show that the fifth force experiments restrict the variation of the value of α at the decoupling epoch with respect to the present-day value from being less than about 0.1%.

scholarly journals Distinguishing freezing and thawing dark energy models through measurements of the fine-structure constant

2020 ◽  
Vol 635 ◽  
pp. A80
Author(s):  
J. M. A. Vilas Boas ◽  
D. M. N. Magano ◽  
C. J. A. P. Martins ◽  
A. Barbecho ◽  
C. Serrano
Keyword(s):  
Fine Structure ◽  
Dark Energy ◽  
Equation Of State ◽  
Parameter Space ◽  
Energy Equation ◽  
Structure Constant ◽  
Fine Structure Constant ◽  
Freezing And Thawing ◽  
Energy Models ◽  
Dynamical Dark Energy

Mapping the behaviour of dark energy is a pressing task for observational cosmology. Phenomenological classification divides dynamical dark energy models into freezing and thawing, depending on whether the dark energy equation of state is approaching or moving away from w = p/ρ = −1. Moreover, in realistic dynamical dark energy models the dynamical degree of freedom is expected to couple to the electromagnetic sector, leading to variations of the fine-structure constant α. We discuss the feasibility of distinguishing between the freezing and thawing classes of models with current and forthcoming observational facilities and using a parametrisation of the dark energy equation of state, which can have either behaviour, introduced by Mukhanov as fiducial paradigm. We illustrate how freezing and thawing models lead to different redshift dependencies of α, and use a combination of current astrophysical observations and local experiments to constrain this class of models, improving the constraints on the key coupling parameter by more than a factor of two, despite considering a more extended parameter space than the one used in previous studies. We also briefly discuss the improvements expected from future facilities and comment on the practical limitations of this class of parametrisations. In particular, we show that sufficiently sensitive data can distinguish between freezing and thawing models, at least if one assumes that the relevant parameter space does not include phantom dark energy models.

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