Yazar "Dil, Emre" seçeneğine göre listele

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    Astronomy organizations should lead in our battle against the climate crisis
    (Nature Portfolio, 2022) Burtscher, Leo; Balaguer-Nunez, Lola; D'Orazi, Valentina; Barret, Didier; Beuchert, Tobias; Dil, Emre; Janiuk, Agnieszka
    [Abstract Not Available]
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    Cosmic future of universe inferred from the horizon behaviours in ? ? a-2, ? ? H2, ? ? ? cosmological constant models
    (Indian Acad Sciences, 2021) Oztas, Ahmet Mecit; Dil, Emre; Tufekci, Onur
    To investigate the cosmic future of the universe, first, we obtain the particle and event horizons, and their evolution in time for three well-known varying cosmological constant models. We investigate the implications of these varying cosmological constant models on the particle and event horizons, and their time evolution during the universe history and future. We study the behaviours around the origin and at the far future of the universe for all cases. Finally, we obtained the general behaviours of the horizons and time evolution functions with respect to the general scale factor a for each of the three cases of varying cosmological constant. The results show that for two of our three cases, a big bounce scenario is inevitable for the universe starting from the big bang and ending up with a bouncing re-collapse to its initial state.
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    Entropic source of cosmological constant and implications: Generalization to higher dimensions
    (Elsevier, 2021) Oztas, Ahmet Mecit; Dil, Emre
    Considering the entropic force on the holographic Hubble horizon of the universe which carries a Bekenstein-Hawking entropy and temperature leads to the entropic force cosmology, and it assumes that the entropic force is responsible from the increase of entropy and accelerated expansion of the universe as a source of cosmological constant. This assumption naturally solves the cosmological constant problem with the variable nature of the entropic pressure on the Hubble parameter. We investigate the implications of entropic force cosmology by obtaining the density parameters and the distance measures. Then, we generalize the model into higher dimensional universes in order to investigate the early period accelerations and density values of universe contents. After obtaining the density parameters, we find the luminosity distance and modulus equations. By comparing the luminosity distance values of standard.CDM and our model, we infer that the considered model presents a faster acceleration in the early periods of the universe implied from larger luminosity distances of the model for higher redshift values, which is completely supported by the inflationary paradigm. In addition, it is found that the luminosity distance becomes larger in higher dimensions for higher redshifts implying the early acceleration is larger. Moreover, from the distance modulus comparison of the model and the observational Gold Data, we find the considered model and its higher dimensional generalization are in accordance with the data, also the universe starts from higher dimensions with higher dark energy densities to lower compactified dimensions with lower dark energy densities, while the matter density increases. (C) 2021 Elsevier B.V. All rights reserved.
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    Generalization of Differential Operators by Using Differential Forms
    (2018) Dil, Emre
    In this study, we derive the mostly used differential operators in physics, such as gradient, divergence, curl and Laplacian in differentcoordinate systems; Cartesian, cylindrical and spherical coordinate systems by using the differential forms. Also, we finally derive thesedifferential operators for the generalized coordinates.
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    Generalization of Differential Operators by Using Differential Forms = Diferansiyel Formlar ile Diferansiyel Operatörlerin Genelleştirilmesi
    (Bülent Ecevit University, 2018) Dil, Emre
    In this study, we derive the mostly used differential operators in physics, such as gradient, divergence, curl and Laplacian in different coordinate systems; Cartesian, cylindrical and spherical coordinate systems by using the differential forms. Also, we finally derive these differential operators for the generalized coordinates.
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    Holographic eternal multiverse
    (Elsevier, 2020) Dil, Emre
    We propose a novel eternal multiverse model whose inflationary dynamics is described by a dual theory stating that the inflationary bulk universe is holographically identical to the lower dimensional boundary theory. By introducing the order measure for the expansion width of the inflating bubble universe, we obtain a relationship between the order measure and the boundary area, recovering the area-entropy law of Bekenstein. As a second aspect of the study, we explore the effect of order measure on the scale factor measure of the nucleating bubble multiverses in IR and UV limits, giving consistent results with the previous holographic multiverse models. (C) 2020 Elsevier B.V. All rights reserved.
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    Interaction of Fermionic Matter and ECSK Black Hole Leading to Bouncing Universe
    (Springer, 2022) Dil, Emre
    The interactions between spin of fermionic matter and torsion in Einstein–Cartan–Sciama–Kibble (ECSK) theory of gravity provide a repulsive gravitational potential at very dense states of fermionic matter, which prevents the formation of black hole singularities inside the deeper horizon. While the fermionic matter in the black hole is attracted by the black hole at the beginning, after a critical point it is repelled to bounce at a critical high density and then expand into other side of the horizon as a newly created space, which may be considered as a non-singular, closed universe. We constructed the action of these fermions in a black hole with torsion in the framework of ECSK theory of gravity from which the free Dirac action is inferred and the interaction potential is obtained. Also, this scenario naturally solves the flatness and horizon problems of cosmology without introducing finely tuned scalar fields, or more complicated functions of the Ricci scalar R in gravitational action.
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    On the entropic nature of unified interactions
    (Iop Publishing Ltd, 2019) Dil, Emre; Yumak, Tugrul
    In this paper, we generalize Verlinde's entropic gravity proposal on the other fundamental interactions of nature. We begin by introducing the entropic origin of the Coulomb's electrostatic force, and then the magnetic force, by assuming the holographic principle holds when a charged particle approaches a screen enclosing the emerged part of the spacetime due to a source. We assume that the entropy of the screen changes when the charge approaches as in the Verlinde's approach. Thereafter, we obtain the entropic Maxwell equations in both classical and covariant form by means of the holographic principle hold for the source. Considering the gauge covariant structure of the fundamental forces, we implicitly generalize the entropic origin of the electromagnetic force into the strong and weak nuclear forces. The possibility of the entropic origin of the all fundamental forces of nature is assumed to make a meaningful contribution to the unification scheme of the fundamental forces.
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    Sociophysics of income distributions modeled by deformed fermi-dirac distributions
    (Taylor & Francis Inc, 2023) Dil, Emre; Dil, Elif
    In order to model the income data, the physical distributions of Fermi-Dirac and Bose-Einstein families have already been proposed in the literature. In this study, we generalize Fermi-Dirac distribution by using a q,p-deformed version of Fermi-Dirac distribution which provides the advantage of working with flexible free q, p deformation parameters as the regression parameters for modeling the income data. We analyze the accuracy of the generalized version, q,p-deformed Fermi-Dirac distribution, on describing the data of income share held by quintiles for countries, and household income for the states of U.S.A. in 2018. We also use chi(2) minimization routine for modeling the data which leads to the best fit parameters for the deformation parameters q and p. Subsequently, we plot the fitted q, p-deformed Fermi-Dirac distribution as income distribution with the obtained deformation parameters, then find the statistical confidence values r(2) from the fitted curve. We figure out that our model properly describes the income data for the systems experiencing a high level of income inequality, and also r(2) values are correlated with the Gini index for those of considered systems.
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    Testing adiabatic expansion of polytropic universe model with SNe Ia data
    (Iop Publishing Ltd, 2020) Dil, Emre; Oztas, Ahmet Mecit; Dil, Elif
    In order to obtain a better fit for the observational data, various cosmological models have been developed in the literature. For this purpose, we propose an adiabatic expansion of the Universe with a polytropic fluid matter-radiation content and a varying cosmological constant. Basic motivation of this study basically differs from the previous models because our model does not neglect the pressure of the matter content of the Universe. We present the details of our new derivations by obtaining the polytropic matter density and luminosity distances. After constructing the model, two large collections of observational data of supernovae type Ia (SNe Ia) are conducted to diagnose the model. Examining the fitness of our new models of a polytropic universe with the observational data, we find a significant influence of polytropic matter on the cosmological parameters of the expanding universe. We find that our flat constant ? model and varying ? model describes the SNe Ia data significantly better than the other models including the standard model for Gold Data and Union2.1 Data, respectively.
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    The varying cosmological constant models tested with Supernovae Type Ia and HII Galaxy Data
    (Elsevier, 2019) Dil, Emre; Oztas, Ahmet Mecit; Dil, Elif
    We have recently proposed a varying cosmological constant model for which we now test our proposal with the use of two large collections of observational Gold data of supernovae Type Ia (SNe Ia) and HII Galaxies (HIIGx) data as standard candles for constructing the Hubble diagram at redshifts beyond the current reach of Type Ia supernovae. For this aim, we obtain the luminosity distances from the proposed varying. models which have been briefly summarized. Using these luminosity distance values, we present the modulus values from which we test the accuracy of the models by probing the Gold data and HII Data confirming that the relation between the emission-line luminosity and ionized-gas velocity dispersion is a reliable modulus indicator. From the chi(2) minimization and the maximization of the likelihood function, we optimize the cosmological parameters in each cosmological model. While the best model is obtained as the Lambda CDM for Gold data, our model with a Lambda depending on the matter density rho is obtained as the best model for HII data. Moreover, the statistical tools, such as the Akaike (AIC), and Bayes (BIC) Information Criteria favor the standard Lambda CDM model over our Lambda proportional to rho model with a relative BIC of 372/383 for Gold data, but same criteria favor our Lambda proportional to rho model over Lambda CDM with 1055/1120 for HII Galaxy data. We also test the accuracy of our models by comparison of the theoretical and observational modulus values for both data, and illustrate the Hubble diagrams for all varying Lambda models showing a worse fit with respect to Lambda CDM model for Gold Data, and a best fit with Lambda proportional to rho model for HII Data, through given statistical confidence tables. (C) 2019 Elsevier B.V. All rights reserved.