scholarly journals Conservation of second-order cosmological perturbations in a scalar field dominated universe

2005 ◽  
Vol 71 (6) ◽  
Author(s):  
Filippo Vernizzi
Keyword(s):  
Scalar Field ◽  
Second Order ◽  
Cosmological Perturbations

scholarly journals Generalized Gaussian Effective Potential: Second-Order Thermal Corrections

1997 ◽  
Vol 12 (15) ◽  
pp. 1077-1085
Author(s):  
Paolo Cea ◽  
Luigi Tedesco
Keyword(s):  
Scalar Field ◽  
Effective Potential ◽  
Finite Temperature ◽  
Spatial Dimension ◽  
Simple Relation ◽  
Second Order ◽  
The Self ◽  
Gaussian Effective Potential

We discuss the finite temperature generalized Gaussian effective potential. We put out a very simple relation between the thermal corrections to the generalized Gaussian effective potential and those of the effective potential. We evaluate explicitly the second-order thermal corrections in the case of the self-interacting scalar field in one spatial dimension.

SECOND-ORDER LAGRANGIAN DYNAMICS IN THE PHASE-SPACE: SOME EXAMPLES

2012 ◽  
Vol 27 (10) ◽  
pp. 1250062
Author(s):  
CONSTANTIN BIZDADEA ◽  
MARIA-MAGDALENA BÂRCAN ◽  
MIHAELA TINCA MIAUTĂ ◽  
SOLANGE-ODILE SALIU
Keyword(s):  
Phase Space ◽  
Scalar Field ◽  
Finite Number ◽  
Configuration Space ◽  
Degrees Of Freedom ◽  
Hamiltonian Formulation ◽  
Second Order ◽  
Lagrangian Formulation ◽  
Field Theories ◽  
Lagrangian Dynamics

By means of a class of nondegenerate models with a finite number of degrees of freedom, it is proved that given a Hamiltonian formulation of dynamics, there exists an equivalent second-order Lagrangian formulation whose configuration space coincides with the Hamiltonian phase-space. The above result is extended to scalar field theories in a Lorentz-covariant manner.

G-INFLATION: INFLATION WITH THE MOST GENERAL SECOND-ORDER FIELD EQUATIONS

2012 ◽  
Vol 10 ◽  
pp. 77-84
Author(s):  
TSUTOMU KOBAYASHI ◽  
MASAHIDE YAMAGUCHI ◽  
JUN'ICHI YOKOYAMA
Keyword(s):  
Power Spectra ◽  
Second Order ◽  
Stability Criteria ◽  
Cosmological Perturbations ◽  
Field Equations ◽  
Special Cases ◽  
Single Field ◽  
The Stability

In this talk, we have discussed generalized Galileons as a framework to develop the most general single-field inflation models ever, (Generalized) G-inflation, containing previous examples such as k-inflation, extended inflation, and new Higgs inflation as special cases. We have also investigated the background and perturbation evolution in this model, calculating the most general quadratic actions for tensor and scalar cosmological perturbations to give the stability criteria and the power spectra of primordial fluctuations.

scholarly journals Condensation of a scalar field non-minimally coupled to gravity in a cosmological context

2020 ◽  
Vol 35 (32) ◽  
pp. 2050270
Author(s):  
Amir Ghalee
Keyword(s):  
Scalar Field ◽  
Energy Density ◽  
Condensed Phase ◽  
Condensed State ◽  
De Sitter ◽  
Cosmological Perturbations ◽  
Cosmological Context ◽  
Background Density ◽  
The Universe ◽  
Bonnet Term

We present a new mechanism to condense a scalar field coupled to the Gauss–Bonnet term. We propose a scenario in which the condensed state will emerge from the background energy density in the late-Universe. During the radiation and dust-dominated eras, the energy density of the scalar field, [Formula: see text], decreases at a slower rate than the background density. Eventually, [Formula: see text] dominates over the energy density of dust and the scalar field could be condensed. In the condensed phase, we have the de Sitter phase for the universe with [Formula: see text]. Moreover, we study the cosmological perturbations of the model and explore predictions of the model.

scholarly journals COMPLEX q-ANALYSIS AND SCALAR FIELD THEORY ON A q-LATTICE

1994 ◽  
Vol 09 (12) ◽  
pp. 1121-1130 ◽  
Author(s):  
MARCELO R. UBRIACO
Keyword(s):  
Field Theory ◽  
Scalar Field ◽  
Minkowski Space ◽  
Function Space ◽  
Laplace Equation ◽  
Difference Equations ◽  
Second Order ◽  
Inner Product ◽  
Two Dimensional ◽  
Scalar Field Theory

We develop the basic formalism of complex q-analysis to study the solutions of second order q-difference equations which reduce, in the q → 1 limit, to the ordinary Laplace equation in Euclidean and Minkowski space. After defining an inner product on the function space we construct and study the properties of the solutions, and then apply this formalism to the Schrödinger equation and two-dimensional scalar field theory.

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