scholarly journals COSMOLOGICAL SYMMETRY BREAKING, PSEUDO-SCALE INVARIANCE, DARK ENERGY AND THE STANDARD MODEL

2007 ◽  
Vol 22 (22) ◽  
pp. 1651-1661 ◽  
Author(s):  
PANKAJ JAIN ◽  
SUBHADIP MITRA
Keyword(s):  
Field Theory ◽  
Dark Energy ◽  
Scalar Field ◽  
Symmetry Breaking ◽  
Scale Invariance ◽  
Quantum Theories ◽  
A Value ◽  
Wide Range ◽  
Time Dependent Solution ◽  
The Universe

The energy density of the universe today may be dominated by the vacuum energy of a slowly rolling scalar field. Making a quantum expansion around such a time-dependent solution breaks fundamental symmetries of quantum field theory. We call this mechanism cosmological symmetry breaking and argue that it is different from the standard phenomenon of spontaneous symmetry breaking. We illustrate this with a toy scalar field theory, whose action displays a U(1) symmetry. We identify a symmetry, called pseudo-scale invariance, which sets the cosmological constant exactly equal to zero, both in classical and quantum theories. This symmetry is also broken cosmologically and leads to a nonzero vacuum or dark energy. The slow-roll condition along with the observed value of dark energy leads to a value of the background scalar field of the order of Planck mass. We also consider a U(1) gauge symmetry model. Cosmological symmetry breaking, in this case, leads to a nonzero mass for the vector field. We also show that a cosmologically broken pseudo-scale invariance can generate a wide range of masses.

scholarly journals EXOTIC LOW DENSITY FERMION STATES IN THE TWO MEASURES FIELD THEORY: NEUTRINO DARK ENERGY

2006 ◽  
Vol 21 (21) ◽  
pp. 4373-4406 ◽  
Author(s):  
E. I. GUENDELMAN ◽  
A. B. KAGANOVICH
Keyword(s):  
Field Theory ◽  
Dark Energy ◽  
Scalar Field ◽  
Energy Density ◽  
Energy Momentum Tensor ◽  
Neutrino Energy ◽  
Momentum Tensor ◽  
Dark Energy Density ◽  
Two Measures ◽  
The Universe

There exist field theory models where the fermionic energy–momentum tensor contains a term proportional to [Formula: see text] which may contribute to the dark energy. We show that this new field theory effect can be achieved in the Two Measures Field Theory (TMT) in the cosmological context. TMT is an alternative gravity and matter field theory where the gravitational interaction of fermionic matter is reduced to that of General Relativity when the energy density of the fermion matter is much larger than the dark energy density. In this case also the fifth force problem is solved automatically. In the opposite limit, where the magnitudes of fermionic energy density and scalar field dark energy density become comparable, nonrelativistic fermions can participate in the cosmological expansion in a very unusual manner. Some of the features of such Cosmo-Low-Energy-Physics (CLEP) states are studied in a toy model of the late time universe filled with homogeneous scalar field and uniformly distributed nonrelativistic neutrinos, and the following results are obtained: neutrino mass increases as m ∝ a3/2 (a is the scale factor); the proportionality factor in the noncanonical contribution to the neutrino energy–momentum tensor (proportional to the metric tensor) approaches a constant as a(t) → ∞ and therefore the noncanonical contribution to the neutrino energy density dominates over the canonical one ~ m/a3 ~ a-3/2 at the late enough universe; hence the neutrino gas equation-of-state approaches w = -1, i.e. neutrinos in the CLEP regime behave as a sort of dark energy as a → ∞; the equation-of-state for the total (scalar field + neutrino) energy density and pressure also approaches w = -1 in the CLEP regime; besides the total energy density of such universe is less than it would be in the universe filled with the scalar field alone. An analytic solution is presented. A domain structure of the dark energy seems to be possible. We speculate that decays of the CLEP state neutrinos may be both an origin of cosmic rays and responsible for a late super-acceleration of the universe. In this sense the CLEP states exhibit simultaneously new physics at very low densities and for very high particle masses.

scholarly journals ONE-LOOP CALCULATION OF COSMOLOGICAL CONSTANT IN A SCALE INVARIANT THEORY

2009 ◽  
Vol 24 (26) ◽  
pp. 2069-2079 ◽  
Author(s):  
PANKAJ JAIN ◽  
SUBHADIP MITRA
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Symmetry Breaking ◽  
Cosmological Constant ◽  
Invariant Theory ◽  
Scale Invariance ◽  
Constant Term ◽  
Scale Invariant ◽  
Gravitational Action ◽  
The One

We compute the cosmological constant in a scale invariant scalar field theory. The gravitational action is also suitably modified to respect scale invariance. Due to scale invariance, the theory does not admit a cosmological constant term. The scale invariance is broken by a recently introduced mechanism called cosmological symmetry breaking. This leads to a nonzero cosmological constant. We compute the one-loop corrections to the cosmological constant and show that it is finite.

scholarly journals The Dirac Sea, T and C Symmetry Breaking, and the Spinor Vacuum of the Universe

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 124
Author(s):  
Vadim Monakhov
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Symmetry Breaking ◽  
Momentum Space ◽  
Quantum Field ◽  
Conjugation Operator ◽  
Dirac Sea ◽  
Canonical Anticommutation Relations ◽  
The Universe ◽  
Dirac Conjugation

We have developed a quantum field theory of spinors based on the algebra of canonical anticommutation relations (CAR algebra) of Grassmann densities in the momentum space. We have proven the existence of two spinor vacua. Operators C and T transform the normal vacuum into an alternative one, which leads to the breaking of the C and T symmetries. The CPT is the real structure operator; it preserves the normal vacuum. We have proven that, in the theory of the Dirac Sea, the formula for the charge conjugation operator must contain an additional generalized Dirac conjugation operator.

scholarly journals Coherent states and spontaneous symmetry breaking in light-front scalar field theory

2006 ◽  
Vol 161 ◽  
pp. 223-229 ◽  
Author(s):  
J.P. Vary ◽  
D. Chakrabarti ◽  
A. Harindranath ◽  
R. Lloyd ◽  
L. Martinovic ◽  
...  
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Coherent States ◽  
Light Front ◽  
Scalar Field Theory

scholarly journals Constraints on barotropic dark energy models by a new phenomenological q(z) parameterization

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Jaime Román-Garza ◽  
Tomás Verdugo ◽  
Juan Magaña ◽  
Verónica Motta
Keyword(s):  
Dark Energy ◽  
Joint Analysis ◽  
Effective Equation ◽  
Phantom Divide ◽  
Plane Analysis ◽  
Energy Models ◽  
A Value ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Universe

Abstract In this paper, we propose a new phenomenological two parameter parameterization of q(z) to constrain barotropic dark energy models by considering a spatially flat Universe, neglecting the radiation component, and reconstructing the effective equation of state (EoS). This two free-parameter EoS reconstruction shows a non-monotonic behavior, pointing to a more general fitting for the scalar field models, like thawing and freezing models. We constrain the q(z) free parameters using the observational data of the Hubble parameter obtained from cosmic chronometers, the joint-light-analysis Type Ia Supernovae (SNIa) sample, the Pantheon (SNIa) sample, and a joint analysis from these data. We obtain, for the joint analysis with the Pantheon (SNIa) sample a value of q(z) today, $$q_0=-0.51\begin{array}{c} +0.09 \\ -0.10 \end{array}$$q0=-0.51+0.09-0.10, and a transition redshift, $$z_t=0.65\begin{array}{c} +0.19 \\ -0.17 \end{array}$$zt=0.65+0.19-0.17 (when the Universe change from an decelerated phase to an accelerated one). The effective EoS reconstruction and the $$\omega '$$ω′–$$\omega $$ω plane analysis point towards a transition over the phantom divide, i.e. $$\omega =-1$$ω=-1, which is consistent with a non parametric EoS reconstruction reported by other authors.

Evolution of the Universe with two rotating fluids

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040042
Author(s):  
V. F. Panov ◽  
O. V. Sandakova ◽  
E. V. Kuvshinova ◽  
D. M. Yanishevsky
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Scalar Field ◽  
Bianchi Type ◽  
Relativity Theory ◽  
Anisotropic Fluid ◽  
Rotating Fluids ◽  
General Relativity Theory ◽  
Exponential Expansion ◽  
The Universe

An anisotropic cosmological model with expansion and rotation and the Bianchi type IX metric has been constructed within the framework of general relativity theory. The first inflation stage of the Universe filled with a scalar field and an anisotropic fluid is considered. The model describes the Friedman stage of cosmological evolution with subsequent transition to accelerated exponential expansion observed in the present epoch. The model has two rotating fluids: the anisotropic fluid and dust-like fluid. In the approach realized in the model, the anisotropic fluid describes the rotating dark energy.

scholarly journals CAN BRANS–DICKE SCALAR FIELD ACCOUNT FOR DARK ENERGY AND DARK MATTER?

2006 ◽  
Vol 21 (15) ◽  
pp. 1241-1248 ◽  
Author(s):  
M. ARIK ◽  
M. C. ÇALIK
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Energy Density ◽  
Late Time ◽  
Energy Contribution ◽  
Time Solution ◽  
The Universe

By using a linearized non-vacuum late time solution in Brans–Dicke cosmology, we account for the 75% dark energy contribution but not for approximately 23% dark matter contribution to the present day energy density of the universe.

scholarly journals Effective Abelian-Higgs Theory from SU(2) gauge field theory

2005 ◽  
Vol 20 (15) ◽  
pp. 3481-3487 ◽  
Author(s):  
VLADIMIR DZHUNUSHALIEV ◽  
DOUGLAS SINGLETON ◽  
DANNY DHOKARH
Keyword(s):  
Field Theory ◽  
Gauge Theory ◽  
Scalar Field ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Mass Term ◽  
Gauge Field Theory ◽  
Ginzburg Landau ◽  
Flux Tubes ◽  
Color Confinement

In the present work we show that it is possible to arrive at a Ginzburg-Landau (GL) like equation from pure SU (2) gauge theory. This has a connection to the dual superconducting model for color confinement where color flux tubes permanently bind quarks into color neutral states. The GL Lagrangian with a spontaneous symmetry breaking potential, has such (Nielsen-Olesen) flux tube solutions. The spontaneous symmetry breaking requires a tachyonic mass for the effective scalar field. Such a tachyonic mass term is obtained from the condensation of ghost fields.

scholarly journals CONSTRAINING TEVES GRAVITY AS EFFECTIVE DARK MATTER AND DARK ENERGY

2007 ◽  
Vol 16 (12a) ◽  
pp. 2055-2063 ◽  
Author(s):  
HONGSHENG ZHAO
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Gravitational Lensing ◽  
Cold Dark Matter ◽  
High Redshift ◽  
Elliptical Galaxies ◽  
Dual Roles ◽  
Acceleration Of The Universe ◽  
The Universe

The phenomena customarily described with the standard ΛCDM model are broadly reproduced by an extremely simple model in TeVeS, Bekenstein's1 modification of general relativity motivated by galaxy phenomenology. Our model can account for the acceleration of the Universe seen at SNeIa distances without a cosmological constant, and the accelerations seen in rotation curves of nearby spiral galaxies and gravitational lensing of high-redshift elliptical galaxies without cold dark matter. The model is consistent with BBN and the neutrino mass between 0.05 eV to 2 eV. The TeVeS scalar field is shown to play the effective dual roles of dark matter and dark energy, with the amplitudes of the effects controlled by a μ function of the scalar field, called the μ essence here. We also discuss outliers to the theory's predictions on multiimaged galaxy lenses and outliers on the subgalaxy scale.

THE ROLE OF A CHAMELEON FIELD IN AN ANISOTROPIC UNIVERSE WITH LOGAMEDIATE AND INTERMEDIATE SCENARIOS

2010 ◽  
Vol 25 (24) ◽  
pp. 4691-4701 ◽  
Author(s):  
SHUVENDU CHAKRABORTY ◽  
UJJAL DEBNATH
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Anisotropic Universe ◽  
Anisotropic Model ◽  
Scale Factors ◽  
Slow Roll ◽  
Energy Scalar ◽  
The Universe

In this work, we consider the Universe is being filled with matter composed of a chameleon-type dark energy scalar field. Employing a particular form of potential, we discuss the field's role in the accelerating phase of the Universe for an anisotropic model using the logamediate and intermediate forms of scale factors. The natures of statefinder and slow-roll parameters are discussed diagrammatically.

Sign in / Sign up

Export Citation Format

Share Document