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Constraining the f(R,T)=R+2λT cosmological model using recent observational data

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Chinese Physics C 2023年第11期47卷 167-176页

作者： n.myrzakulov M.Koussour Alnadhief H.A.Alfedeel E.I.Hassan L.n.Gumilyov Eurasian national University Astana 010008Kazakhstan Ratbay myrzakulov Eurasian International Centre for Theoretical Physics Astana 010009Kazakhstan Quantum Physics and Magnetism Team LPMCFaculty of Science Ben M'sikCasablanca Hassan II UniversityMorocco Department of Mathematics and Statistics Imam Mohammad Ibn Saud Islamic University(IMSIU)Riyadh 13318Saudi Arabia Department of Physics Faculty of ScienceUniversity of KhartoumP.O.Box 321Khartoum 11115Sudan Centre for Space Research North-West UniversityPotchefstroom 2520South Africa

In this study,we conduct a comprehensive investigation of the cosmological model described by f(R,T)=R+2λT(whereλrepresents a free parameter)in light of the most recent observational *** constraining the model using the Hubble and Pantheon datasets,we determine its compatibility with the observed behavior of the *** this purpose,we adopt a parametric form for the effective equation of state(EoS)*** parametric form allows us to describe the evolution of the EoS parameter with respect to redshift and investigate its behavior during different cosmic *** analysis of the deceleration parameter reveals an accelerating Universe with a present value of q0=−0.64_(−0.03)^(+0.03),indicating the current phase of accelerated *** transition redshift is found to be ztr=0.53_(−0.03)^(+0.04),marking the epoch of transition from deceleration to *** also analyze the evolution of important cosmological parameters,including the density parameter,pressure,effective EoS,and *** findings collectively demonstrate the viability of the f(R,T)cosmological model as a robust candidate capable of engendering the requisite negative pressure,thereby efficiently propelling cosmic ***,the undertaken stability analysis underscores the model's stability within the broader cosmic *** providing the best-fit values for the coupling parameterλ,this approach motivates and encourages further exploration into the extensive landscape of this model and its potential applications across diverse realms of cosmology and astronomy.

关键词： f(R,T)gravity EoS parameter observational constraints dark energy

f(T,B)gravity with statistically fitting of H(z)

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Communications in Theoretical Physics 2023年第9期75卷 79-90页

作者： S H Shekh n myrzakulov A Bouali A Pradhan Department of Mathematics S.P.M.Science and Gilani ArtsCommerce CollegeGhatanjiYavatmalMaharashtra 445301India L.n.Gumilyov Eurasian national University Astana 010008Kazakhstan Ratbay myrzakulov Eurasian International Center for Theoretical Physics Astana010009Kazakhstan Laboratory of Physics of Matter and Radiation Mohammed I UniversityBP 717OujdaMorocco Centre for Cosmology Astrophysics and Space Science(CCASS)GLA UniversityMathura-281406Uttar PradeshIndia

Some recent developments(accelerated expansion)in the Universe cannot be explained by the conventional formulation of general *** apply the recently proposed f(T,B)gravity to investigate the accelerated expansion of the *** parametrizing the Hubble parameter and estimating the best fit values of the model parameters b_(0),b_(1),and b_(2)imposed from Supernovae type la,Cosmic Microwave Background,B aryon Acoustic Oscillation,and Hubble data using the Markov Chain Monte Carlo method,we propose a method to determine the precise solutions to the field *** then observe that the model appears to be in good agreement with the observations.A change from the deceleration to the acceleration phase of the Universe is shown by the evolution of the deceleration *** addition,we investigate the behavior of the statefinder analysis,equation of state(EoS)parameters,along with the energy ***,to discuss other cosmological parameters,we consider some wellknown f(T,B)gravity models,specifically,f(T,B)=aT^(b)+cB^(d).Lastly,we find that the considered f(T,B)gravity models predict that the present Universe is accelerating and the EoS parameter behaves like the ACDM model.

关键词： isotropic homogeneous space-time f(T,B)gravity statistical fitting of H(z)data cosmology

Phase structures and critical behavior of rational non-linear electrodynamics Anti de Sitter black holes in Rastall gravity

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Communications in Theoretical Physics 2024年第4期76卷 134-152页

作者： Yassine Sekhmani Dhruba Jyoti Gogoi Ratbay myrzakulov Javlon Rayimbaev Ratbay myrzakulov Eurasian International Centre for Theoretical Physics Astana 010009Kazakhstan L.n.Gumilyov Eurasian national University Astana 010008Kazakhstan Department of Physics Moran CollegeMoranhatCharaideo 785670AssamIndia Theoretical Physics Division Centre for Atmospheric StudiesDibrugarh UniversityDibrugarh 786004AssamIndia new Uzbekistan University Movarounnahr Str.1Tashkent 100000Uzbekistan University of Tashkent for Applied Sciences Gavhar Str.1Tashkent 100149Uzbekistan national University of Uzbekistan Tashkent 100174Uzbekistan

This research paper presents a black hole solution with a rational nonlinear electrodynamics source within the Rastall gravity *** paper analyzes the thermodynamic properties of the solution in normal phase space and explores its critical *** phase structure is examined using the extended first law of thermodynamics,with the cosmological constantΛserving as pressure *** isotherms exhibit van der Waals behavior at small values of horizon r_(+).The paper also investigates the Gibbs free energy behavior and finds two critical points with two pressures where the re-entrant phase transition occurs and *** also explore the prevalent microstructure of black holes in Ruppeiner geometry,uncovering significant deviations in the nature of particle interactions from conventional ***,the thermodynamic geometry is analyzed using the Ruppeiner formalism,with the normalized Ricci scalar indicating possible point-phase transitions of the heat capacity,and the normalized extrinsic curvature having the same sign as the normalized Ricci *** three-phase transitions of the heat capacity are those that we find for the normalized Ruppeiner ***,there is an absolute correspondence.

关键词： Rastall gravity biack hole Phase structures