scholarly journals SSB OF SCALE SYMMETRY, FERMION FAMILIES AND QUINTESSENCE WITHOUT THE LONG-RANGE FORCE PROBLEM

2002 ◽  
Vol 17 (03) ◽  
pp. 417-433 ◽  
Author(s):  
E. I. GUENDELMAN ◽  
A. B. KAGANOVICH
Keyword(s):  
Particle Physics ◽  
Scale Invariance ◽  
Field Potential ◽  
Momentum Tensor ◽  
Kinetic Term ◽  
Exponential Potential ◽  
Scale Invariant ◽  
Fermion Masses ◽  
First Choice ◽  
Scaling Solution

We study a scale-invariant two measures theory where a dilaton field ϕ has no explicit potentials. The scale transformations include the translation of a dilaton ϕ→ϕ+ const . The theory demonstrates a new mechanism for generation of the exponential potential: in the conformal Einstein frame (CEF), after SSB of scale invariance, the theory develops the exponential potential and, in general, the nonlinear kinetic term is generated as well. The scale symmetry does not allow the appearance of terms breaking the exponential shape of the potential that solves the problem of the flatness of the scalar field potential in the context of quintessential scenarios. As examples, two different possibilities for the choice of the dimensionless parameters are presented where the theory permits to get interesting cosmological results. For the first choice, the theory has standard scaling solutions for ϕ usually used in the context of the quintessential scenario. For the second choice, the theory allows three different solutions, one of which is a scaling solution with equation of state pϕ=wρϕ where w is predicted to be restricted by -1<w<-0.82. The regime where the fermionic matter dominates (as compared to the dilatonic contribution) is analyzed. There it is found that starting from a single fermionic field we obtain exactly three different types of spin 1/2 particles in CEF that appears to suggest a new approach to the family problem of particle physics. It is automatically achieved that for two of them, fermion masses are constants, the energy–momentum tensor is canonical and the "fifth force" is absent. For the third type of particles, a fermionic self-interaction appears as a result of SSB of scale invariance.

QUINTESSENTIAL POTENTIAL, FERMION FAMILIES AND SPONTANEOUS BREAKING OF SCALE SYMMETRY

2002 ◽  
Vol 17 (29) ◽  
pp. 4419-4424 ◽  
Author(s):  
E. I. GUENDELMAN ◽  
A. B. KAGANOVICH
Keyword(s):  
Scale Invariance ◽  
Degrees Of Freedom ◽  
Field Potential ◽  
Momentum Tensor ◽  
Kinetic Term ◽  
Spontaneous Breaking ◽  
Exponential Potential ◽  
Covariant Model ◽  
Fermion Masses ◽  
Generally Covariant

We study a generally covariant model with SSB of scale invariance where two measures of integration in the action enter: the standard [Formula: see text] and a new Φd4x, where Φ is a density built out of degrees of freedom independent of the metric. The theory demonstrates a new mechanism for generation of the exponential potential: in the conformal Einstein frame, after SSB of scale invariance, the theory develops the exponential potential and, in general, non-linear kinetic term is generated as well. The scale symmetry does not allow the appearance of terms breaking the exponential shape of the potential that solves the problem of the flatness of the scalar field potential in the context of quintessential scenarios. Under normal laboratory conditions where the fermionic matter dominates, it is found that starting from a single fermionic field we obtain exactly three different types of spin 1/2 particles which can be identified with known fermion families. It is automatically achieved that for two of them, fermion masses are constants, the energy-momentum tensor is canonical and the "fifth force" is absent. For the third family, a self-interaction appears as a result of SSB of scale invariance.

A study of DINKIC inflationary dynamics with non-interacting imperfect fluid

2020 ◽  
Vol 35 (14) ◽  
pp. 2050108
Author(s):  
R. Saleem ◽  
Iqra Shahid ◽  
M. Zubair
Keyword(s):  
Correction Term ◽  
Field Potential ◽  
Large Field ◽  
Kinetic Term ◽  
Frw Universe ◽  
Scale Invariant ◽  
Kinetic Coupling ◽  
Proposed Model ◽  
Imperfect Fluid ◽  
Primordial Gravitational Waves

This paper is keen to study the generalized DBI-inspired non-minimal kinetic coupling inflationary model with non-interacting imperfect fluid in the framework of FRW universe. This is a newly proposed model with an interesting feature of having a correction term [Formula: see text] in the perturbed equation of motion due to the nonlinearity of the kinetic term. The power spectrum remains scale invariant both in large-[Formula: see text] and small-[Formula: see text] limits. In order to discuss the inflationary dynamics, the non-interacting inflaton and imperfect fluid including bulk viscosity are considered to be the cosmic matter contents. We consider large field potential and derive the exact solution of inflaton and perturbed parameters. Further, we investigate the nature of the perturbed parameters in detail, specifically on the potential-driven case, and compare the consequences to the current PLANCK/BICEP observational data. We also analyze the corresponding tensor spectrum, which will be tested by the future observations on primordial gravitational waves.

scholarly journals STANDARD MODEL WITH COSMOLOGICALLY BROKEN QUANTUM SCALE INVARIANCE

2010 ◽  
Vol 25 (03) ◽  
pp. 167-177 ◽  
Author(s):  
PANKAJ JAIN ◽  
SUBHADIP MITRA
Keyword(s):  
Perturbation Theory ◽  
Standard Model ◽  
Particle Physics ◽  
Scale Invariance ◽  
Hierarchy Problem ◽  
Scale Invariant ◽  
Scalar Particles ◽  
Cosmological Observations ◽  
The Standard Model ◽  
Physical Spectrum

We consider a locally scale invariant extension of the Standard Model of particle physics and argue that it fits both the particle and cosmological observations. The model is scale invariant both classically and quantum mechanically. The scale invariance is broken (or hidden) by a mechanism which we refer to as cosmological symmetry breaking. This produces all the dimensionful parameters in the theory. The cosmological constant or dark energy is a prediction of the theory and can be calculated systematically order by order in perturbation theory. It is expected to be finite at all orders. The model does not suffer from the hierarchy problem due to the absence of scalar particles, including the Higgs, from the physical spectrum.

scholarly journals Maintained avalanche dynamics during task-induced changes of neuronal activity in nonhuman primates

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Shan Yu ◽  
Tiago L Ribeiro ◽  
Christian Meisel ◽  
Samantha Chou ◽  
Andrew Mitz ◽  
...  
Keyword(s):  
Cognitive Processing ◽  
Neuronal Activity ◽  
Unit Activity ◽  
Scale Invariance ◽  
Nonhuman Primates ◽  
Field Potential ◽  
Scale Invariant ◽  
Ongoing Activity ◽  
Statistical Regularities ◽  
Induced Changes

Sensory events, cognitive processing and motor actions correlate with transient changes in neuronal activity. In cortex, these transients form widespread spatiotemporal patterns with largely unknown statistical regularities. Here, we show that activity associated with behavioral events carry the signature of scale-invariant spatiotemporal clusters, neuronal avalanches. Using high-density microelectrode arrays in nonhuman primates, we recorded extracellular unit activity and the local field potential (LFP) in premotor and prefrontal cortex during motor and cognitive tasks. Unit activity and negative LFP deflections (nLFP) consistently changed in rate at single electrodes during tasks. Accordingly, nLFP clusters on the array deviated from scale-invariance compared to ongoing activity. Scale-invariance was recovered using ‘adaptive binning’, that is identifying clusters at temporal resolution given by task-induced changes in nLFP rate. Measures of LFP synchronization confirmed and computer simulations detailed our findings. We suggest optimization principles identified for avalanches during ongoing activity to apply to cortical information processing during behavior.

Scale invariance and the energy–momentum tensor

1970 ◽  
Vol 48 (20) ◽  
pp. 2371-2375
Author(s):  
Peter Bendix
Keyword(s):  
Gravitational Field ◽  
Scale Invariance ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Scale Invariant ◽  
New Energy ◽  
Klein Gordon

A method is described by which an energy–momentum tensor can be constructed such that in addition to the usual properties of this tensor it acquires the property of scale invariance in the absence of masses and charges. (The new energy–momentum tensor constructed here is not the source of the gravitational field, however.) It is shown that the usual construction for the massless Klein–Gordon field yields an energy–momentum tensor which is not scale invariant, whereas using the construction described here, one finds a scale invariant energy–momentum tensor for this case.

scholarly journals SCALE INVARIANCE, NEW INFLATION AND DECAYING Λ-TERMS

1999 ◽  
Vol 14 (16) ◽  
pp. 1043-1052 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
Scale Invariance ◽  
Degrees Of Freedom ◽  
Vacuum Energy ◽  
Scalar Potential ◽  
Field Potential ◽  
Vacuum State ◽  
Gravitational Theory ◽  
Global Scale ◽  
Kinetic Term ◽  
Decaying Λ

Realizations of scale invariance are studied in the context of a gravitational theory where the action (in the first-order formalism) is of the form [Formula: see text] where Φ is a density built out of degrees of freedom, the "measure fields" independent of gμν and matter fields appearing in L1, L2. If L1 contains the curvature, scalar potential V(ϕ) and kinetic term for ϕ, L2 another potential for ϕ, U(ϕ), then the true vacuum state has zero energy density, when theory is analyzed in the conformal Einstein frame (CEF), where the equations assume the Einstein form. Global scale invariance is realized when V(ϕ)=f1eαϕ and U(ϕ)=f2e2αϕ. In the CEF the scalar field potential energy V eff (ϕ) has, in addition to a minimum at zero, a flat region for αϕ→∞, with nonzero vacuum energy, which is suitable for either a new inflationary scenario for the early universe or for a slowly rolling decaying Λ-scenario for the late universe, where the smallness of the vacuum energy can be understood as a kind of seesaw mechanism.

FERMION FAMILIES AND LONG-RANGE FORCE PROBLEMS: INTERRELATION AND RESOLUTION

2002 ◽  
Vol 11 (10) ◽  
pp. 1591-1595
Author(s):  
E. I. GUENDELMAN ◽  
A. B. KAGANOVICH
Keyword(s):  
Scale Invariance ◽  
Degrees Of Freedom ◽  
Momentum Tensor ◽  
Covariant Model ◽  
Fermion Masses ◽  
Different Types ◽  
Two Measures ◽  
Generally Covariant ◽  
Range Force ◽  
Normal Laboratory

We study a generally covariant model with SSB of scale invariance where two measures of integration in the action enter: the standard [Formula: see text] and a new Φd4x, where Φ is a density built out of degrees of freedom independent of the metric. Under normal laboratory conditions where the fermionic matter dominates, it is found that starting from a single fermionic field we obtain exactly three different types of spin 1/2 particles which can be identified with known fermion families. It is automatically achieved that for two of them, fermion masses are constants, the energy-momentum tensor is canonical and the "fifth force" is absent. For the third family, a self-interaction appears as a result of SSB of scale invariance.

scholarly journals A non-relativistic limit of NS-NS gravity

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
E. A. Bergshoeff ◽  
J. Lahnsteiner ◽  
L. Romano ◽  
J. Rosseel ◽  
C. Şimşek
Keyword(s):  
Scale Invariance ◽  
Sigma Model ◽  
Equations Of Motion ◽  
Geometric Constraints ◽  
Target Space ◽  
Kinetic Term ◽  
Scale Invariant ◽  
Relativistic Limit ◽  
Cartan Geometry ◽  
Form Field

Abstract We discuss a particular non-relativistic limit of NS-NS gravity that can be taken at the level of the action and equations of motion, without imposing any geometric constraints by hand. This relies on the fact that terms that diverge in the limit and that come from the Vielbein in the Einstein-Hilbert term and from the kinetic term of the Kalb-Ramond two-form field cancel against each other. This cancelling of divergences is the target space analogue of a similar cancellation that takes place at the level of the string sigma model between the Vielbein in the kinetic term and the Kalb-Ramond field in the Wess-Zumino term. The limit of the equations of motion leads to one equation more than the limit of the action, due to the emergence of a local target space scale invariance in the limit. Some of the equations of motion can be solved by scale invariant geometric constraints. These constraints define a so-called Dilatation invariant String Newton-Cartan geometry.

scholarly journals Scale Invariance, Horizons, and Inflation

2021 ◽  
Author(s):  
Andre Maeder ◽  
Vesselin G Gueorguiev
Keyword(s):  
Scalar Field ◽  
Scale Invariance ◽  
Maxwell Equations ◽  
High Redshift ◽  
Empty Space ◽  
Causal Connection ◽  
Cosmological Constant Problem ◽  
Scale Invariant ◽  
Starting Point ◽  
Final Answer

Abstract Maxwell equations and the equations of General Relativity are scale invariant in empty space. The presence of charge or currents in electromagnetism or the presence of matter in cosmology are preventing scale invariance. The question arises on how much matter within the horizon is necessary to kill scale invariance. The scale invariant field equation, first written by Dirac in 1973 and then revisited by Canuto et al. in 1977, provides the starting point to address this question. The resulting cosmological models show that, as soon as matter is present, the effects of scale invariance rapidly decline from ϱ = 0 to ϱc, and are forbidden for densities above ϱc. The absence of scale invariance in this case is consistent with considerations about causal connection. Below ϱc, scale invariance appears as an open possibility, which also depends on the occurrence of in the scale invariant context. In the present approach, we identify the scalar field of the empty space in the Scale Invariant Vacuum (SIV) context to the scalar field ϕ in the energy density $\varrho = \frac{1}{2} \dot{\varphi }^2 + V(\varphi )$ of the vacuum at inflation. This leads to some constraints on the potential. This identification also solves the so-called “cosmological constant problem”. In the framework of scale invariance, an inflation with a large number of e-foldings is also predicted. We conclude that scale invariance for models with densities below ϱc is an open possibility; the final answer may come from high redshift observations, where differences from the ΛCDM models appear.

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