Articles de revues : « Scalar field cosmology »

1

Howard, Eric. « Scalar field cosmology ». Contemporary Physics 60, n^o 4 (2 octobre 2019) : 338–39. http://dx.doi.org/10.1080/00107514.2019.1709553.

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VAN HOLTEN, J. W. « SINGLE SCALAR COSMOLOGY ». International Journal of Modern Physics A 28, n^o 26 (20 octobre 2013) : 1350132. http://dx.doi.org/10.1142/s0217751x13501327.

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The cosmology of flat Friedmann–Lemaître–Robertson–Walker (FLRW) universes dominated by a single scalar field is discussed. General features of the evolution of the universe and the scalar field are illustrated by specific examples. It is shown that in some situations the most important contribution to inflation comes from the approach to a region of slow roll, rather than from the period of leaving a slow-roll regime.

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Mansoori, Seyed Ali Hosseini, et Zahra Molaee. « Multi-field Cuscuton cosmology ». Journal of Cosmology and Astroparticle Physics 2023, n^o 01 (1 janvier 2023) : 022. http://dx.doi.org/10.1088/1475-7516/2023/01/022.

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Abstract In this paper, we first introduce a multi-field setup of Cuscuton gravity in a curved field space manifold. Then, we show that this model allows for a regular bouncing cosmology and it does not lead to ghosts or other instabilities at the level of perturbations. More precisely, by decomposing the scalar fields perturbations into the tangential and normal components with respect to the background field space trajectory, the entropy mode perpendicular to the background trajectory is healthy which directly depends on the signature of the field-space metric, whereas the adiabatic perturbation tangential to the background trajectory is frozen. In analogy with the standard Cuscuton theory equipped with an extra dynamical scalar field, the adiabatic field does not have its own dynamics, but it modifies the dynamics of other dynamical fields like entropy mode in our scenario. Finally, we perform a Hamiltonian analysis of our model in order to count the degrees of freedom propagated by dynamical fields.

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Oliveira-Neto, G. « Scalar field cosmology in three-dimensions ». Brazilian Journal of Physics 31, n^o 3 (septembre 2001) : 456–60. http://dx.doi.org/10.1590/s0103-97332001000300017.

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Li, Baojiu. « Voids in coupled scalar field cosmology ». Monthly Notices of the Royal Astronomical Society 411, n^o 4 (6 décembre 2010) : 2615–27. http://dx.doi.org/10.1111/j.1365-2966.2010.17867.x.

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Faraoni, Valerio, et Charles S. Protheroe. « Scalar field cosmology in phase space ». General Relativity and Gravitation 45, n^o 1 (29 septembre 2012) : 103–23. http://dx.doi.org/10.1007/s10714-012-1462-0.

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Zhang, Kai, H. Q. Lu, Wei Fang et Z. G. Huang. « Cosmology with non-linear scalar field ». Astrophysics and Space Science 327, n^o 1 (11 février 2010) : 117–24. http://dx.doi.org/10.1007/s10509-010-0292-3.

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Shchigolev, V. K., et E. A. Semenova. « Scalar field cosmology in Lyra's geometry ». International Journal of Advanced Astronomy 3, n^o 2 (5 novembre 2015) : 117. http://dx.doi.org/10.14419/ijaa.v3i2.5401.

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<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>

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Demiański, M., R. de Ritis, G. Marmo, G. Platania, C. Rubano, P. Scudellaro et C. Stornaiolo. « Scalar field, nonminimal coupling, and cosmology ». Physical Review D 44, n^o 10 (15 novembre 1991) : 3136–46. http://dx.doi.org/10.1103/physrevd.44.3136.

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Szydłowski, Marek, Orest Hrycyna et Aleksander Stachowski. « Scalar field cosmology — geometry of dynamics ». International Journal of Geometric Methods in Modern Physics 11, n^o 02 (février 2014) : 1460012. http://dx.doi.org/10.1142/s0219887814600123.

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We study the Scalar Field Cosmology (SFC) using the geometric language of the phase space. We define and study an ensemble of dynamical systems as a Banach space with a Sobolev metric. The metric in the ensemble is used to measure a distance between different models. We point out the advantages of visualization of dynamics in the phase space. It is investigated the genericity of some class of models in the context of fine tuning of the form of the potential function in the ensemble of SFC. We also study the symmetries of dynamical systems of SFC by searching for their exact solutions. In this context, we stressed the importance of scaling solutions. It is demonstrated that scaling solutions in the phase space are represented by unstable separatrices of the saddle points. Only critical point itself located on two-dimensional stable submanifold can be identified as scaling solution. We have also found a class of potentials of the scalar fields forced by the symmetry of differential equation describing the evolution of the Universe. A class of potentials forced by scaling (homology) symmetries was given. We point out the role of the notion of a structural stability in the context of the problem of indetermination of the potential form of the SFC. We characterize also the class of potentials which reproduces the ΛCDM model, which is known to be structurally stable. We show that the structural stability issue can be effectively used is selection of the scalar field potential function. This enables us to characterize a structurally stable and therefore a generic class of SFC models. We have found a nonempty and dense subset of structurally stable models. We show that these models possess symmetry of homology.

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Kleidis, K., et V. K. Oikonomou. « Loop quantum cosmology scalar field models ». International Journal of Geometric Methods in Modern Physics 15, n^o 05 (2 avril 2018) : 1850071. http://dx.doi.org/10.1142/s0219887818500718.

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In this work, we use the Loop Quantum Cosmology (LQC) modified scalar–tensor reconstruction techniques in order to investigate how bouncing and inflationary cosmologies can be realized. With regard to the inflationary cosmologies, we shall be interested in realizing the intermediate inflation and the Type IV singular inflation, while with regard to bouncing cosmologies, we shall realize the superbounce and the symmetric bounce. In all the cases, we shall find the kinetic term of the LQC holonomy corrected scalar–tensor theory and the corresponding scalar potential. In addition, we shall include a study of the effective Equation of State (EoS), emphasizing at the early- and late-time eras. As we demonstrate, in some cases it is possible to have a nearly de Sitter EoS at the late-time era, a result that could be interpreted as the description of a late-time acceleration era. Also, in all cases we shall examine the dynamical stability of the LQC holonomy corrected scalar-tensor theory, and we shall confront the results with those coming from the corresponding classical dynamical stability theory. The most appealing cosmological scenario is that of a Type IV singular inflationary scenario, in which the singularity may occur at the late-time era. As we demonstrate, for this model, during the dark energy era, a transition from non-phantom to a phantom dark energy era occurs.

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12

Singh, T. P., et T. Padmanabhan. « Semiclassical cosmology with a scalar field ». Physical Review D 35, n^o 10 (15 mai 1987) : 2993–3001. http://dx.doi.org/10.1103/physrevd.35.2993.

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13

RUDRA, PRABIR. « EMERGENT UNIVERSE WITH EXOTIC MATTER IN LOOP QUANTUM COSMOLOGY, DGP BRANE-WORLD AND KALUZA–KLEIN COSMOLOGY ». Modern Physics Letters A 27, n^o 33 (24 octobre 2012) : 1250189. http://dx.doi.org/10.1142/s0217732312501891.

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In this work we have investigated the emergent scenario of the Universe described by loop quantum cosmology model, DGP brane model and Kaluza–Klein cosmology. Scalar field along with barotropic fluid as normal matter is considered as the matter content of the Universe. In loop quantum cosmology it is found that the emergent scenario is realized with the imposition of some conditions on the value of the density of normal matter in case of normal and phantom scalar field. This is a surprising result indeed considering the fact that scalar field is the dominating matter component! In case of tachyonic field, emergent scenario is realized with some constraints on the value of ρ1 for both normal and phantom tachyon. In case of DGP brane-world realization of an emergent scenario is possible almost unconditionally for normal and phantom fields. Plots and table have been generated to testify this fact. In case of tachyonic field emergent scenario is realized with some constraints on [Formula: see text]. In Kaluza–Klein cosmology emergent scenario is possible only for a closed Universe in case of normal and phantom scalar field. For a tachyonic field, realization of emergent Universe is possible for all models (closed, open and flat).

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Kamenshchik, A. Yu, I. M. Khalatnikov et A. V. Toporensky. « Complex Inflaton Field in Quantum Cosmology ». International Journal of Modern Physics D 06, n^o 06 (décembre 1997) : 649–71. http://dx.doi.org/10.1142/s0218271897000406.

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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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FABRIS, JÚLIO C., OLIVER F. PIATTELLA, DAVI C. RODRIGUES, CARLOS E. M. BATISTA et MAHAMADOU H. DAOUDA. « RASTALL COSMOLOGY ». International Journal of Modern Physics : Conference Series 18 (janvier 2012) : 67–76. http://dx.doi.org/10.1142/s2010194512008227.

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We review the difficulties of the generalized Chaplygin gas model to fit observational data, due to the tension between background and perturbative tests. We argue that such issues may be circumvented by means of a self-interacting scalar field representation of the model. However, this proposal seems to be successful only if the self-interacting scalar field has a non-canonical form. The latter can be implemented in Rastall's theory of gravity, which is based on a modification of the usual matter conservation law. We show that, besides its application to the generalized Chaplygin gas model, other cosmological models based on Rastall's theory have many interesting and unexpected new features.

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Leon, Genly, Alfredo D. Millano et Andronikos Paliathanasis. « Scalar Field Cosmology from a Modified Poisson Algebra ». Mathematics 11, n^o 1 (27 décembre 2022) : 120. http://dx.doi.org/10.3390/math11010120.

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We investigate the phase space of a scalar field theory obtained by minisuperspace deformation. We consider quintessence or phantom scalar fields in the action that arises from minisuperspace deformation on the Einstein–Hilbert action. We use a modified Poisson algebra where Poisson brackets are the α-deformed ones and are related to the Moyal–Weyl star product. We discuss early- and late-time attractors and reconstruct the cosmological evolution. We show that the model can have the ΛCDM model as a future attractor if we initially consider a massless scalar field without a cosmological constant term.

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ESPOSITO, GIAMPIERO, RAJU ROYCHOWDHURY, CLAUDIO RUBANO et PAOLO SCUDELLARO. « ON THE TRANSITION FROM COMPLEX TO REAL SCALAR FIELDS IN MODERN COSMOLOGY ». International Journal of Geometric Methods in Modern Physics 08, n^o 08 (décembre 2011) : 1815–32. http://dx.doi.org/10.1142/s0219887811005956.

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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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CHINGANGBAM, PRAVABATI, et TABISH QURESHI. « DYNAMICS OF ROLLING MASSIVE SCALAR FIELD COSMOLOGY ». International Journal of Modern Physics A 20, n^o 26 (20 octobre 2005) : 6083–92. http://dx.doi.org/10.1142/s0217751x05024298.

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We study the inflationary consequences of the rolling massive scalar field in the braneworld scenario with a warped metric. We find that in order to fit observational constraints the warp factor must be tuned to be < 10-3. We also demonstrate the inflationary attractor behavior of the massive scalar field dynamics both in the standard FRW case as well as in braneworld scenario.

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19

Benaoum, H. B. « Modified Chaplygin Gas Cosmology ». Advances in High Energy Physics 2012 (2012) : 1–12. http://dx.doi.org/10.1155/2012/357802.

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Modified Chaplygin gas as an exotic fluid has been introduced by H. B. Benaoum (2002). Essential features of the modified Chaplygin gas as a cosmological model are discussed. Observational constraints on the parameters of the model have been included. The relationship between the modified Chaplygin gas and a homogeneous minimally coupled scalar field is reevaluated by constructing its self-interacting potential. In addition, we study the role of the tachyonic field in the modified Chaplygin gas cosmological model and the mapping between scalar field and tachyonic field is also considered.

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20

Nesteruk, Alexei V. « Inflationary Cosmology with Scalar Field and Radiation ». General Relativity and Gravitation 31, n^o 7 (juillet 1999) : 983–98. http://dx.doi.org/10.1023/a:1026627430400.

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21

Alho, Artur, Claes Uggla et John Wainwright. « Dynamical systems in perturbative scalar field cosmology ». Classical and Quantum Gravity 37, n^o 22 (22 octobre 2020) : 225011. http://dx.doi.org/10.1088/1361-6382/abb73a.

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Ansari, Rizwan ul Haq, et P. K. Suresh. « Bulk scalar field in DGP braneworld cosmology ». Journal of Cosmology and Astroparticle Physics 2007, n^o 09 (28 septembre 2007) : 021. http://dx.doi.org/10.1088/1475-7516/2007/09/021.

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Dimitrijevic, Dragoljub D., Neven Bilić, Goran S. Djordjevic, Milan Milosevic et Marko Stojanovic. « Tachyon scalar field in a braneworld cosmology ». International Journal of Modern Physics A 33, n^o 34 (10 décembre 2018) : 1845017. http://dx.doi.org/10.1142/s0217751x18450173.

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We analyze a tachyon cosmological model based on the dynamics of a 3-brane in the bulk of the second Randall–Sundrum model. This model contains extended general warp functions, i.e. generalized bulk geometry. We study a power law warp factor in cosmological context. This type of warp factor generates an inverse power law tachyonic potential.

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NG, KIN-WANG. « A COSMOLOGY WITH CONFORMALLY COUPLED SCALAR FIELD ». International Journal of Modern Physics A 06, n^o 03 (30 janvier 1991) : 479–86. http://dx.doi.org/10.1142/s0217751x91000290.

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A theory of gravitation with a conformally coupled scalar field is considered in which the gravitational “constant” is associated with the vacuum expectation value of the scalar field. It is found that the universe will remain dominated by classical radiation unless the conformal symmetry is broken. The equations of motion thus derived bear a de Sitter phase solution, which could have an exponential growth of the cosmic scale factor with no vacuum energy. We discuss the cosmological implications of this kind of “inflation”. We also find that in the present theory the smallness of the vacuum energy for most time of the universe is due to the constancy of the gravitational “constant”.

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Amendola, L. « Perturbations in a coupled scalar field cosmology ». Monthly Notices of the Royal Astronomical Society 312, n^o 3 (1 mars 2000) : 521–30. http://dx.doi.org/10.1046/j.1365-8711.2000.03165.x.

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Mulki, F. A. M., et H. Wulandari. « Matter perturbation in coupled scalar field cosmology ». Journal of Physics : Conference Series 1354 (octobre 2019) : 012007. http://dx.doi.org/10.1088/1742-6596/1354/1/012007.

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Vakili, Babak. « Scalar field quantum cosmology : A Schrödinger picture ». Physics Letters B 718, n^o 1 (novembre 2012) : 34–42. http://dx.doi.org/10.1016/j.physletb.2012.10.036.

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Lemos, Nivaldo A. « Singularities in a scalar field quantum cosmology ». Physical Review D 53, n^o 8 (15 avril 1996) : 4275–79. http://dx.doi.org/10.1103/physrevd.53.4275.

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Malekolkalami, Behrooz, et Mehrdad Farhoudi. « Noncommutativity effects in FRW scalar field cosmology ». Physics Letters B 678, n^o 2 (juillet 2009) : 174–80. http://dx.doi.org/10.1016/j.physletb.2009.06.023.

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Gao, Chang-Jun, et You-Gen Shen. « Quintessence cosmology with coupled complex scalar field ». Physics Letters B 541, n^o 1-2 (août 2002) : 1–5. http://dx.doi.org/10.1016/s0370-2693(02)02232-3.

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Mahato, Prasanta. « Torsion, Scalar Field, Mass and FRW Cosmology ». International Journal of Theoretical Physics 44, n^o 1 (janvier 2005) : 79–93. http://dx.doi.org/10.1007/s10773-005-1487-1.

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Lemos, Nivaldo A. « Quantum cosmology with conformally invariant scalar field ». Physics Letters A 221, n^o 6 (octobre 1996) : 359–64. http://dx.doi.org/10.1016/0375-9601(96)00607-x.

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RODRÍGUEZ-MARTÍNEZ, M. « BRANE COSMOLOGY WITH A BULK SCALAR FIELD ». International Journal of Modern Physics A 17, n^o 20 (10 août 2002) : 2774. http://dx.doi.org/10.1142/s0217751x02012016.

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In the last few years, brane cosmological models with extra dimensions have been actively studied. In these scenarios, ordinary matter is confined in a (3+1)-dimensional surface (the world-sheet of a 3-brane) while gravity lives in the bulk space-time2,3. In this regard, it has been shown that the cosmology of such models is characterized by a non standard Friedmann equation4,5. Some analytic solutions have been found when the scalar field couples to the brane6, but they correspond to static solutions where the cosmological evolution is due to the motion of the brane into the bulk. In this talk I have presented two kinds of exact solutions obtained by solving Einstein's equations in the light-cone coordinate system and making two different assumptions : a. proportionality between the scalar field and the logarithm of the bulk scale factor7 and b. separable solutions. It has been shown that the first kind of solutions correspond to moving branes into static backgrounds : somehow the hypothesis of proportionality froze the evolution of the metric. On the contrary, in the second kind of solution the bulk is really dynamic. The induced cosmology in the brane has been explored for both types of solutions, confirming, in particular, the non standard cosmological evolution of the scale factor.

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Wang, Anzhong, David Wands et Roy Maartens. « Scalar field perturbations in Hořava-Lifshitz cosmology ». Journal of Cosmology and Astroparticle Physics 2010, n^o 03 (9 mars 2010) : 013. http://dx.doi.org/10.1088/1475-7516/2010/03/013.

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35

Weiss, Nathan. « Cosmology with an extremely light scalar field ». Physical Review D 39, n^o 6 (15 mars 1989) : 1517–23. http://dx.doi.org/10.1103/physrevd.39.1517.

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Bleyer, U., et A. Zhuk. « Scalar field instability in multi-dimensional cosmology ». Astronomische Nachrichten 316, n^o 4 (1995) : 197–204. http://dx.doi.org/10.1002/asna.2103160402.

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Martínez-Pérez, Nephtalí E., Cupatitzio Ramírez-Romero et Víctor M. Vázquez-Báez. « Phenomenological Inflationary Model in Supersymmetric Quantum Cosmology ». Universe 8, n^o 8 (6 août 2022) : 414. http://dx.doi.org/10.3390/universe8080414.

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We consider the effective evolution of a phenomenological model from FLRW supersymmetric quantum cosmology with a scalar field. The scalar field acts as a clock and inflaton. We examine a family of simple superpotentials that produce an inflation whose virtual effect on inhomogeneous fluctuations shows very good agreement with PLANCK observational evidence for the tensor-to-scalar ratio and the scalar spectral index.

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Sheykin, A. A., et S. A. Paston. « Friedmann cosmology in Regge-Teitelboim gravity ». International Journal of Modern Physics : Conference Series 41 (janvier 2016) : 1660128. http://dx.doi.org/10.1142/s2010194516601289.

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This paper is devoted to the approach to gravity as a theory of a surface embedded in a flat ambient space. After the brief review of the properties of original theory by Regge and Teitelboim we concentrate on its field-theoretic reformulation, which we call splitting theory. In this theory embedded surfaces are defined through the constant value surfaces of some set of scalar fields in high-dimensional Minkowski space. We obtain an exact expressions for this scalar fields in the case of Friedmann universe. We also discuss the features of quantization procedure for this field theory.

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GUMJUDPAI, BURIN. « QUINTESSENTIAL POWER-LAW COSMOLOGY : DARK ENERGY EQUATION OF STATE ». Modern Physics Letters A 28, n^o 29 (6 septembre 2013) : 1350122. http://dx.doi.org/10.1142/s0217732313501228.

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Power-law cosmology with scale factor as power of cosmic time, a ∝tα, is investigated. We review and discuss value of α obtained from various types of observation. Considering dark energy dominant era in late universe from z < 0.5, we use observational derived results from Cosmic Microwave Background (CMB) (WMAP7), Baryon Acoustic Oscillations (BAOs) and observational Hubble data to find power exponent α and other cosmological variables. α is found to be 0.99 ±0.02 ( WMAP7 + BAO +H0) and 0.99 ±0.04 (WMAP7). These values do not exclude possibility of acceleration at 1σ hence giving viability to power-law cosmology in general. When considering scenario of canonical scalar field dark energy with power-law cosmology, we derive scalar field potential, exact scalar field solution and equation of state parameter. We found that the scenario of power-law cosmology containing dynamical canonical scalar field predicts present equation of state parameter wϕ, 0 = -0.449±0.030 while the w CDM with WMAP7 data (model independent, w constant) allows a maximum (+1σ) value of wϕ, 0 at -0.70 which is off the prediction range. However, in case of varying wϕ, the wϕ, 0 value predicted from quintessential power-law cosmology is allowed within 1σ uncertainty.

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KIM, HYEONG-CHAN. « INFLATION AS AN ATTRACTOR IN SCALAR COSMOLOGY ». Modern Physics Letters A 28, n^o 20 (28 juin 2013) : 1350089. http://dx.doi.org/10.1142/s0217732313500892.

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We study an inflation mechanism based on attractor properties in cosmological evolutions of a spatially flat Friedmann–Robertson–Walker spacetime based on the Einstein-scalar field theory. We find a new way to get the Hamilton–Jacobi equation solving the field equations. The equation relates a solution "generating function" with the scalar potential. We analyze its stability and find a later time attractor which describes a Universe approaching to an eternal-de Sitter inflation driven by the potential energy, V0>0. The attractor exists when the potential is regular and does not have a linear and quadratic terms of the field. When the potential has a mass term, the attractor exists if the scalar field is in a symmetric phase and is weakly coupled, λ<9V0/16. We also find that the attractor property is intact under small modifications of the potential. If the scalar field has a positive mass-squared or is strongly coupled, there exists a quasi-attractor. However, the quasi-attractor property disappears if the potential is modified. On the whole, the appearance of the eternal inflation is not rare in scalar cosmology in the presence of an attractor.

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Korunur, Murat. « Holographic reconstruction of scalar fields in extended Kaluza–Klein cosmology ». Modern Physics Letters A 33, n^o 01 (9 janvier 2018) : 1850002. http://dx.doi.org/10.1142/s0217732318500025.

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In recent years, many studies have been conducted to reconstruct the physical properties of scalar fields by establishing a connection between some energy densities and a scalar field of dark energies. In this paper, using the extended five-dimensional (5D) Kaluza–Klein model, we establish a correspondence among modified holographic dark energy and the tachyon, K-essence and dilaton scalar-field models. We also graphically illustrate the evolution of the equation-of-state parameter versus time.

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Ghalee, Amir. « On the late-time cosmology of a condensed scalar field ». Modern Physics Letters A 31, n^o 12 (19 avril 2016) : 1650078. http://dx.doi.org/10.1142/s0217732316500784.

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We study the late-time cosmology of a scalar field with a kinetic term non-minimally coupled to gravity. It is demonstrated that the scalar field dominate the radiation matter and the cold dark matter (CDM). Moreover, we show that eventually the scalar field will be condensed and results in an accelerated expansion. The metric perturbations around the condensed phase of the scalar field are investigated and it has been shown that the ghost instability and gradient instability do not exist.

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NOJIRI, SHIN'ICHI, et SERGEI D. ODINTSOV. « QUANTUM EFFECTS AND STABILITY OF CHAMELEON COSMOLOGY ». Modern Physics Letters A 19, n^o 17 (7 juin 2004) : 1273–80. http://dx.doi.org/10.1142/s0217732304013933.

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One possibility to explain the current accelerated expansion of the universe may be related with the presence of cosmologically evolving scalar whose mass depends on the local matter density (chameleon cosmology). We point out that matter quantum effects in such scalar–tensor theory produce the chameleon scalar field dependent conformal anomaly. Such conformal anomaly adds higher derivative terms to chameleon field equation of motion. As a result, the principal possibility for instabilities appears. These instabilities seem to be irrelevant at small curvature but may become dangerous in the regions where gravitational field is strong.

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Espinoza-García, Abraham, Efraín Torres-Lomas, Sinuhé Pérez-Payán et Luis Rey Díaz-Barrón. « Noncommutativity in Effective Loop Quantum Cosmology ». Advances in High Energy Physics 2019 (7 février 2019) : 1–10. http://dx.doi.org/10.1155/2019/9080218.

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We construct a noncommutative extension of the Loop Quantum Cosmology effective scheme for the flat FLRW model with a free scalar field via a theta deformation. Firstly, a deformation is implemented in the configuration sector, among the holonomy variable and the matter degree of freedom. We show that this type of noncommutativity retains, to some degree, key features of the Loop Quantum Cosmology paradigm for a free field. Secondly, a deformation is implemented in the momentum sector, among the momentum associated with the holonomy variable and the momentum associated with the matter field. We show that in this latter case the scalar field energy density is the same as the one in standard Loop Quantum Cosmology.

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LU, H. Q. « PHANTOM COSMOLOGY WITH A NONLINEAR BORN–INFELD TYPE SCALAR FIELD ». International Journal of Modern Physics D 14, n^o 02 (février 2005) : 355–62. http://dx.doi.org/10.1142/s021827180500513x.

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Recent many physicists suggest that the dark energy in the universe might result from the Born–Infeld (B–I) type scalar field of string theory. The universe of B–I type scalar field with potential can undergo a phase of accelerating expansion. The corresponding equation of state parameter lies in the range of -1<ω<-⅓. The equation of state parameter of B–I type scalar field without potential lies in the range of 0≤ω≤1. We find that weak energy condition and strong energy condition are violated for phantom B–I type scalar field. The equation of state parameter lies in the range of ω<-1.

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Toporensky, A. « Stable periodic regime in a scalar field cosmology ». Annalen der Physik 522, n^o 3-5 (8 mars 2010) : 268–70. http://dx.doi.org/10.1002/andp.201052203-518.

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Zhuravlev, V. M., et S. V. Chervon. « Method of multiple scales in scalar field cosmology ». Journal of Physics : Conference Series 2081, n^o 1 (1 novembre 2021) : 012037. http://dx.doi.org/10.1088/1742-6596/2081/1/012037.

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Abstract In this work, the method of multiple scales is applied to analysis of cosmological dynamics. The method is used to construct solutions to the dynamic equations of the Universe filled with a scalar field in the Friedman-Robertson-Walker metric. A general scheme is described for choosing small dimensionless parameters of the expansion of model functions and applying the method itself to the equations of cosmological dynamics. Solutions are given that are constructed for two different types of a small parameter - a small field value and a small slow roll parameter.

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Cid, Antonella, Fernando Izaurieta, Genly Leon, Perla Medina et Daniela Narbona. « Non-minimally coupled scalar field cosmology with torsion ». Journal of Cosmology and Astroparticle Physics 2018, n^o 04 (13 avril 2018) : 041. http://dx.doi.org/10.1088/1475-7516/2018/04/041.

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Christodoulakis, T., et N. Dimakis. « (2+1) Cosmology with a general scalar field ». Journal of Physics : Conference Series 68 (1 mai 2007) : 012040. http://dx.doi.org/10.1088/1742-6596/68/1/012040.

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Gunzig, E., V. Faraoni, A. Figueiredo, T. M. Rocha Filho et L. Brenig. « The dynamical system approach to scalar field cosmology ». Classical and Quantum Gravity 17, n^o 8 (24 mars 2000) : 1783–814. http://dx.doi.org/10.1088/0264-9381/17/8/304.

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