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7 results on '"Khanpour, B."'

1. Surface Tension of Cosmic Voids as a Possible Source for Dark Energy

Author

Yusofi, E., Khanpour, M., Khanpour, B., Ramzanpour, M., and Mohsenzadeh, M.

Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The cosmological constant is estimated by considering the surface tension of supervoids in a void-dominated cosmic fluid by which we can get a possible source of dark energy. Looking at voids as bubbles, we define the concept of surface tension which is shown to have an almost constant value for supervoids that are enclosed by superclusters. The surface tensions of voids are computed by dimensional method for galaxies and superclusters with different values for each group. At large scale which vast voids are dominant the positive cosmological constants obtained of order $ (\simeq+10^{-52} {\rm m^{-2}} )$, which are very close to those given by $Planck$., Comment: 5 pages, 3 figures, 1 table, Title and some figures have been correctedand, published version in MNRASL

Published
2019
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2. The $QCD$ parameters are affected by power-law Maxwell field

Author

Khanpour, B. and Sadeghi, J.

Subjects
High Energy Physics - Theory
Abstract

In this paper, we introduce Einstein power-law Maxwell-Scalar gravity with Liouvill potential in n + 1 dimension. The corresponding metric background or solution of above mentioned action lead us to achieve some thermodynamics quantities of black hole. On the other hand, we take information from $AdS/CFT$ correspondence and investigate some parameters in $QCD$ as jet quenching and entropic force. We note that two obtained parameters give some important information about $Q\bar{Q}$ moving in $QGP$ media and dissociation length of quark-antiquark. Finally, we have several figures for the jet quenching parameter and entropic force. The corresponding figures show how two parameters are affected by power law Maxwell field with different of $p$.

Published
2017

4. Surface tension of cosmic voids as a possible source for dark energy

Author

Yusofi, E., Khanpour, M., Khanpour, B., Ramzanpour, M., and Mohsenzadeh, M.

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

The cosmological constant is estimated by considering the surface tension of supervoids in a void-dominated cosmic fluid by which we can get a possible source of dark energy. Looking at voids as bubbles, we define the concept of surface tension which is shown to have an almost constant value for supervoids that are enclosed by superclusters. The surface tensions of voids are computed by dimensional method for galaxies and superclusters with different values for each group. At large scale which vast voids are dominant the positive cosmological constants obtained of order $ (\simeq+10^{-52} {\rm m^{-2}} )$, which are very close to those given by $Planck$., 5 pages, 3 figures, 1 table, Title and some figures have been correctedand, published version in MNRASL

Published
2022
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5. AdS and QCD with generalized warp factors and stability

Author

Sadeghi, J. and Khanpour, B.

Subjects
Atmospheric thermodynamics -- Research, Quantum chromodynamics -- Research, Warping -- Research, Physics research, Black holes (Astronomy) -- Research, Spacetime -- Research, Physics
Abstract

In this paper, we studied the thermodynamic behavior of generalized warp factor for the corresponding AdS metric background. To discuss the stability of the theory we studied thermodynamical properties of generalized metric background. Here also to obtain the quantity of sound for the measure of stability of the system, we need to calculate the energy density and pressure. Such parameters of sound for the properties of stability constrain some conditions on the corresponding theory as [theta]. We used the corresponding conditions and rewrite the action of theory. The new action give us opportunity to study the AdS black hole and thermally charged AdS black hole. Key words: stability, AdS black hole, thermally charged AdS, generalized warp factors. Nous etudions le comportement thermodynamique d'un facteur de distorsion generalise pour le fond metrique AdS correspondant. Pour pouvoir discuter la stabilite de la theorie, nous etudions les proprietes thermodynamiques du fond metrique generalise. De plus, afin d'obtenir la quantite d'energie sonore pour la mesure de stabilite du systeme, nous devons calculer la densite d'energie et la pression. De tels parametres du son pour les proprietes de stabilite imposent des conditions sur la theorie correspondante comme [theta]. Nous utilisons ces conditions pour recrire l'action de la theorie. La nouvelle action nous donne l'opportunite d'etudier le trou noir AdS et le trou noir AdS avec une charge thermique. [Traduit par la Redaction] Mots-cles: stabilite, trou noir AdS, trou noir AdS avec charge thermique, facteur de distorsion generalise., 1. Introduction As we know, the gauge-gravity duality plays an important role in strongly coupled systems near critical points. Because of this, the corresponding system has a scaling symmetry [1]. [...]

Published
2016
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7. Pressure of Cosmic Voids: A Possible Source for Dark Matter and Dark Energy

Author

Yusofi, E., Khanpour, M., Khanpour, B., Ramzanpour, M., Mohsenzadeh, M., Yusofi, E., Khanpour, M., Khanpour, B., Ramzanpour, M., and Mohsenzadeh, M.

Abstract

The cosmological constant is obtained by considering the surface tension of vast voids in a void-dominated cosmic fluid by which we can get a possible unifying solution to both dark matter and dark energy problems. Looking at voids as bubbles, we define the concept of surface tension which is shown to have almost constant value at large scale. The surface tensions of the cosmic voids are computed by dimensional method for galaxies, clusters and super-clusters with different values for each group. At large scale which vast voids are dominant the positive cosmological constant obtained of order $ (\simeq+10^{-52} m^{-2})$, which are very close to those given by $Planck$ 2018. However, on local scales we are led to a larger cosmological constant $ (\simeq -10^{-49} m^{-2})$ with negative sign. Also, we will show that by adding the local negative cosmological constant to the Kepler formula, the velocity rotation curves of the galaxies will flatten out to several tens of $kpc$, which is consistent with \emph{SPARC} database and justifies dark matter problem. Finally, the model predicts that galaxies without dark matter should be in the inner regions of cosmic voids., Comment: 9 pages, 6 figures, 1 table, Title and some figures have been corrected and section 5. have been added

Published
2019

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