scholarly journals The hidden scalar Lagrangians within Horndeski theory

2020 ◽  
Vol 29 (14) ◽  
pp. 2043004
Author(s):  
Gregory W. Horndeski
Keyword(s):  
Scalar Field ◽  
Generating Function ◽  
Cotangent Bundle ◽  
Tensor Field ◽  
Scalar Fields ◽  
Field Theories ◽  
Metric Tensor ◽  
Cosmological Solutions ◽  
Different Types ◽  
Vacuum Solutions

In this paper, I show that there exists a new way to obtain scalar–tensor field theories by combining a special scalar field on the cotangent bundle with a scalar field on spacetime. These two scalar fields act as a generating function for the metric tensor. When using these two scalar fields in the Horndeski Lagrangians, we discover, while seeking Friedmann–Lemaître–Robertson–Walker-type cosmological solutions, that hidden in the Horndeski Lagrangians are nondegenerate second-order scalar Lagrangians. In accordance with Ostrogradsky’s work, these hidden scalar Lagrangians lead to multiple vacuum solutions, and thereby predict the existence of the multiverse. The multiverse is comprised of numerous different types of individual universes. For example, some begin explosively, and then coast along exponentially forever at an accelerated rate, while others begin in that manner, and then stop expanding and contract.

scholarly journals Scalar field cosmology in Lyra's geometry

2015 ◽  
Vol 3 (2) ◽  
pp. 117 ◽  
Author(s):  
V. K. Shchigolev ◽  
E. A. Semenova
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Generating Function ◽  
Function Method ◽  
Scalar Fields ◽  
First Order ◽  
Homogeneous Cosmological Models ◽  
Different Types ◽  
Lyra’S Geometry ◽  
Scalar Field Cosmology

<p>The new classes of homogeneous cosmological models for the scalar fields are build in the context of Lyra’s geometry. The different types of exact solution for the model are obtained by applying two procedures, viz the generating function method and the first order formalism.</p>

scholarly journals DUALITY INVARIANCE OF COSMOLOGICAL SOLUTIONS WITH TORSION

1999 ◽  
Vol 14 (31) ◽  
pp. 4953-4966 ◽  
Author(s):  
DEBASHIS GANGOPADHYAY ◽  
SOUMITRA SENGUPTA
Keyword(s):  
Physical Meaning ◽  
Tensor Field ◽  
Antisymmetric Tensor ◽  
Dilaton Field ◽  
Maximal Symmetry ◽  
Killing Vectors ◽  
Cosmological Solutions ◽  
Antisymmetric Tensor Field ◽  
Vacuum Solutions

We show that for a string moving in a background consisting of maximally symmetric gravity, dilaton field and second rank antisymmetric tensor field, the O(d) ⊗ O(d) transformation on the vacuum solutions gives inequivalent solutions that are not maximally symmetric. We then show that the usual physical meaning of maximal symmetry can be made to remain unaltered even if torsion is present and illustrate this through two toy models by determining the torsion fields, the metric and Killing vectors. Finally we show that under the O(d) ⊗ O(d) transformation this generalized maximal symmetry can be preserved under certain conditions. This is interesting in the context of string related cosmological backgrounds.

Vacuum solutions for a twisted scalar field

1978 ◽  
Vol 363 (1715) ◽  
pp. 581-596 ◽  
Keyword(s):  
Scalar Field ◽  
Ground State ◽  
Characteristic Length ◽  
Scalar Fields ◽  
Finite Energy ◽  
Critical Value ◽  
Dimensional Model ◽  
Translational Invariance ◽  
Spontaneous Breakdown ◽  
Vacuum Solutions

The properties of the ground state of a classical self-interacting twisted scalar field on a two-dimensional Einstein cylinder are discussed. In parti­cular there is a spontaneous breakdown of the spatial translational invariance of the twisted ground state as a characteristic length increases across a critical value. Similar properties are shown to hold in a four­-dimensional model. Finally, it is shown that there exist four-dimensional models which do not have any finite-energy twisted scalar fields.

scholarly journals Aspects of the polynomial affine model of gravity in three dimensions

2022 ◽  
Vol 82 (1) ◽  
Author(s):  
Oscar Castillo-Felisola ◽  
Oscar Orellana ◽  
José Perdiguero ◽  
Francisca Ramírez ◽  
Aureliano Skirzewski ◽  
...  
Keyword(s):  
Tensor Field ◽  
Affine Connection ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Metric Tensor ◽  
Affine Model ◽  
Cosmological Solutions ◽  
Affine Gravity

AbstractThe polynomial affine gravity is a model that is built up without the explicit use of a metric tensor field. In this article we reformulate the three-dimensional model and, given the decomposition of the affine connection, we analyse the consistently truncated sectors. Using the cosmological ansatz for the connection, we scan the cosmological solutions on the truncated sectors. We discuss the emergence of different kinds of metrics.

scholarly journals COSMOLOGICAL MODEL OF INTERACTING TACHYON FIELD

2012 ◽  
Vol 27 (17) ◽  
pp. 1250086 ◽  
Author(s):  
V. K. SHCHIGOLEV ◽  
M. P. ROTOVA
Keyword(s):  
Exact Solution ◽  
Scalar Field ◽  
Cosmological Model ◽  
Energy Flow ◽  
Field Model ◽  
Scalar Fields ◽  
Tachyon Field ◽  
First Order ◽  
Different Types ◽  
Phantom Fields

In this paper we investigate a tachyon field model in cosmology, provided its interaction with the quintessence or phantom fields. The model takes into account this interaction beyond the usual approach, in which the interaction is phenomenologically described by the energy flow between the matter components. In our model, the interaction of tachyon field with a canonical scalar field is taken into account through the interaction potential in the total Lagrangian of the system, like in the case of two or more canonical scalar fields. We obtain the different types of exact solution for the model by employing the so-called "first order formalism" procedures.

scholarly journals Constructing Carrollian CFTs

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Nishant Gupta ◽  
Nemani V. Suryanarayana
Keyword(s):  
Scalar Fields ◽  
Higher Dimensions ◽  
Field Theories ◽  
Conformal Field Theories ◽  
Relativistic Limit ◽  
Conformal Field ◽  
Local Symmetries ◽  
Derivatives Of ◽  
Special Case

Abstract We construct classical theories for scalar fields in arbitrary Carroll spacetimes that are invariant under Carrollian diffeomorphisms and Weyl transformations. When the local symmetries are gauge fixed these theories become Carrollian conformal field theories. We show that generically there are at least two types of such theories: one in which only time derivatives of the fields appear and the other in which both space and time derivatives appear. A classification of such scalar field theories in three (and higher) dimensions up to two derivative order is provided. We show that only a special case of our theories arises in the ultra-relativistic limit of a covariant parent theory.

scholarly journals Weak cosmic censorship with self-interacting scalar and bound on charge to mass ratio

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Yan Song ◽  
Tong-Tong Hu ◽  
Yong-Qiang Wang
Keyword(s):  
Scalar Field ◽  
Scalar Fields ◽  
Cosmic Censorship ◽  
Mass Ratio ◽  
Quartic Coupling ◽  
Scalar Theory ◽  
Free Scalar ◽  
The One ◽  
Nonzero Scalar ◽  
Large Charge

Abstract We study the model of four-dimensional Einstein-Maxwell-Λ theory minimally coupled to a massive charged self-interacting scalar field, parameterized by the quartic and hexic couplings, labelled by λ and β, respectively. In the absence of scalar field, there is a class of counterexamples to cosmic censorship. Moreover, we investigate the full nonlinear solution with nonzero scalar field included, and argue that these counterexamples can be removed by assuming charged self-interacting scalar field with sufficiently large charge not lower than a certain bound. In particular, this bound on charge required to preserve cosmic censorship is no longer precisely the weak gravity bound for the free scalar theory. For the quartic coupling, for λ < 0 the bound is below the one for the free scalar fields, whereas for λ > 0 it is above. Meanwhile, for the hexic coupling the bound is always above the one for the free scalar fields, irrespective of the sign of β.

scholarly journals FERMIONIC AND SCALAR FIELDS AS SOURCES OF INTERACTING DARK MATTER–DARK ENERGY

2011 ◽  
Vol 20 (13) ◽  
pp. 2543-2558 ◽  
Author(s):  
SAMUEL LEPE ◽  
JAVIER LORCA ◽  
FRANCISCO PEÑA ◽  
YERKO VÁSQUEZ
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Scalar Field ◽  
Analytical Solution ◽  
Scalar Fields ◽  
Nonminimal Coupling ◽  
Field Equations ◽  
Fermionic Field ◽  
Minimal Coupling ◽  
Constant Type

From a variational action with nonminimal coupling with a scalar field and classical scalar and fermionic interaction, cosmological field equations can be obtained. Imposing a Friedmann–Lemaître–Robertson–Walker (FLRW) metric, the equations lead directly to a cosmological model consisting of two interacting fluids, where the scalar field fluid is interpreted as dark energy and the fermionic field fluid is interpreted as dark matter. Several cases were studied analytically and numerically. An important feature of the non-minimal coupling is that it allows crossing the barrier from a quintessence to phantom behavior. The insensitivity of the solutions to one of the parameters of the model permits it to find an almost analytical solution for the cosmological constant type of universe.

scholarly journals Monte Carlo and renormalization-group effective potentials in scalar field theories

1995 ◽  
Vol 51 (12) ◽  
pp. 7017-7025 ◽  
Author(s):  
J. R. Shepard ◽  
V. Dmitrašinović ◽  
J. A. McNeil
Keyword(s):  
Monte Carlo ◽  
Renormalization Group ◽  
Scalar Field ◽  
Field Theories ◽  
Effective Potentials
Sign in / Sign up

Export Citation Format

Share Document