Complex Inflaton Field in Quantum Cosmology

We investigate the cosmological model with the complex scalar self-interacting inflaton field non-minimally coupled to gravity. The different geometries of the Euclidean classically forbidden regions are represented. The instanton solutions of the corresponding Euclidean equations of motion are found by numerical calculations supplemented by the qualitative analysis of Lorentzian and Euclidean trajectories. The applications of these solutions to the no-boundary and tunneling proposals for the wave function of the Universe are studied. Possible interpretation of obtained results and their connection with inflationary cosmology is discussed. The restrictions on the possible values of the new quasifundamental constant of the theory — non-zero classical charge — are obtained. The equations of motion for the generalized cosmological model with complex scalar field are written down and investigated. The conditions of the existence of instanton solutions corresponding to permanent values of an absolute value of scalar field are obtained.

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A General Method for Transforming Nonphysical Configurations in BPS States

Advances in High Energy Physics ◽

10.1155/2019/5431067 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

J. R. L. Santos ◽

A. de Souza Dutra ◽

O. C. Winter ◽

R. A. C. Correa

Keyword(s):

Scalar Field ◽

Condensed Matter ◽

Equations Of Motion ◽

Cosmological Parameters ◽

Topological Defects ◽

Scalar Fields ◽

Complex Scalar ◽

Complex Scalar Field ◽

Bps States ◽

General Method

In this work, we apply the so-called BPS method in order to obtain topological defects for a complex scalar field Lagrangian introduced by Trullinger and Subbaswamy. The BPS approach led us to compute new analytical solutions for this model. In our investigation, we found analytical configurations which satisfy the BPS first-order differential equations but do not obey the equations of motion of the model. Such defects were named nonphysical ones. In order to recover the physical meaning of these defects, we proposed a procedure which can transform them into BPS states of new scalar field models. The new models here founded were applied in the context of hybrid cosmological scenarios, where we derived cosmological parameters compatible with the observed Universe. Such a methodology opens a new window to connect different two scalar fields systems and can be implemented in several distinct applications such as Bloch Branes, Lorentz and Symmetry Breaking Scenarios, Q-Balls, Oscillons, Cosmological Contexts, and Condensed Matter Systems.

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ON THE TRANSITION FROM COMPLEX TO REAL SCALAR FIELDS IN MODERN COSMOLOGY

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887811005956 ◽

2011 ◽

Vol 08 (08) ◽

pp. 1815-1832 ◽

Cited By ~ 3

Author(s):

GIAMPIERO ESPOSITO ◽

RAJU ROYCHOWDHURY ◽

CLAUDIO RUBANO ◽

PAOLO SCUDELLARO

Keyword(s):

Dark Energy ◽

Scalar Field ◽

Scalar Fields ◽

Complex Nature ◽

Complex Scalar ◽

Real Scalar ◽

Symmetry Approach ◽

Modern Cosmology ◽

Complex Scalar Field ◽

The Universe

We study some problems arising from the introduction of a complex scalar field in cosmology, modeling its possible behaviors in both the inflationary and dark energy stages of the universe. Such examples contribute to show that, while the complex nature of the scalar field can be indeed important during inflation, it loses its meaning in the later dark-energy dominated era of cosmology, when the phase of the complex field is practically constant, and there is indeed a transition from complex to real scalar field. In our considerations, the Noether symmetry approach turns out to be a useful tool once again. We arrive eventually at a potential containing the sixth and fourth powers of the scalar field, and the resulting semiclassical quantum cosmology is studied to gain a better understanding of the inflationary stage.

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QUANTIZATION OF THE BIANCHI TYPE IX MODEL IN N=1 SUPERGRAVITY IN THE PRESENCE OF SUPERMATTER

International Journal of Modern Physics A ◽

10.1142/s0217751x96000948 ◽

1996 ◽

Vol 11 (10) ◽

pp. 1763-1795 ◽

Cited By ~ 12

Author(s):

P.V. MONIZ

Keyword(s):

Wave Function ◽

Scalar Field ◽

General Theory ◽

Bianchi Type ◽

Two Dimensional ◽

Kahler Geometry ◽

Complex Scalar ◽

Analytical Potential ◽

Complex Scalar Field ◽

The Universe

The general theory of N=1 supergravity with supermatter is applied to a Bianchi type IX diagonal model. The supermatter is constituted by a complex scalar field and its [Formula: see text] fermionic partners. The Kähler geometry is chosen to be a two-dimensional flat one. The Lorentz-invariant ansatz for the wave function of the universe is taken to be as simple as possible in order to obtain new solutions. The set of differential equations derived from the quantum constraints are analyzed in two different cases: if the supermatter terms include an analytical potential or not. In the latter the wave function is found to have a simple form.

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QUANTUM REMNANT AS DARK ENERGY AND DARK MATTER

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194511000407 ◽

2011 ◽

Vol 01 ◽

pp. 277-284

Author(s):

SANG PYO KIM ◽

SEOKTAE KOH

Keyword(s):

Dark Matter ◽

Dark Energy ◽

Scalar Field ◽

Uncertainty Principle ◽

Dark Energy Model ◽

Quantum Fluctuations ◽

Complex Scalar ◽

Linear Perturbations ◽

Complex Scalar Field ◽

The Universe

We study the quantum remnant of a scalar field protected by the uncertainty principle. The quantum remnant that survived the later stage of evolution of the universe may provide dark energy and dark matter depending on the potential. Though the quantum remnant shares some useful property of complex scalar field (spintessence) dark energy model, quantum fluctuations are still unstable to the linear perturbations for V ~ ϕq with q < 1 as in the spintessence model.

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INFLATIONARY SOLUTIONS WITH A FIVE-DIMENSIONAL COMPLEX SCALAR FIELD

Modern Physics Letters A ◽

10.1142/s0217732306019700 ◽

2006 ◽

Vol 21 (05) ◽

pp. 409-419

Author(s):

J. J. VAN DER BIJ ◽

EUGEN RADU

Keyword(s):

Scalar Field ◽

Field Potential ◽

Accelerated Expansion ◽

Complex Scalar ◽

Dimensional Spacetime ◽

Klein Gordon ◽

Expansion Of The Universe ◽

Complex Scalar Field ◽

New Feature ◽

The Universe

We discuss inflationary solutions of the coupled Einstein–Klein–Gordon equations for a complex field in a five-dimensional spacetime with a compact x5 dimension. As a new feature, the scalar field contains a dependence on the extra dimension of the form exp (imx5), corresponding to Kaluza–Klein excited modes. In a four-dimensional picture, a nonzero m implies the presence of a new term in the scalar field potential. An interesting feature of these solutions is the possible existence of several periods of oscillation of the scalar field around the equilibrium value at the minimum of the potential. These oscillations lead to cosmological periods of accelerated expansion of the universe.

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COSMIC RELIC TORSION FROM INFLATIONARY COSMOLOGY

International Journal of Modern Physics D ◽

10.1142/s0218271899000535 ◽

1999 ◽

Vol 08 (06) ◽

pp. 725-729 ◽

Cited By ~ 4

Author(s):

L. C. GARCIA DE ANDRADE

Keyword(s):

General Relativity ◽

Scalar Field ◽

Inflationary Cosmology ◽

De Sitter ◽

Planck Mass ◽

Present Epoch ◽

Inflaton Field ◽

Upper Limit ◽

Cartan Torsion ◽

The Universe

An inflationary de Sitter solution of Teleparallel Equivalent of General Relativity (TERG) is obtained. In this model Cartan torsion is shown to be a cosmological relic in the sense that it decays from earlier epochs of the Universe until extremely small values at the present epoch. This would be the reason why it is very difficult to measure cosmological torsion at the present epoch and only extremely small relic torsion would be left. Torsion plays a role similar to the inflaton field in its interaction with the scalar field. The torsion mass is determined from the teleparallel action in terms of the Planck mass. The value of the torsion mass is of the order of Planck mass. An upper limit for torsion of 10-18s-1 is obtained for the de Sitter phase. By considering the Friedmann phase it is possible to show that torsion induces an oscillation on the Universe.

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