Signature flips in time-varying Λ(t) cosmological models with observational data
Myrzakulov Y. Koussour M. Karimov M. Rayimbaev J.
July 2024Springer Nature
European Physical Journal C
2024#84Issue 7
In this study, we investigate signature flips within the framework of cosmological models featuring a time-varying vacuum energy term Λ(t). Specifically, we consider the power-law form of Λ=αHn, where α and n are constants. To constrain the model parameters, we use the MCMC technique, allowing for effective exploration of the model’s parameters. We apply this approach to analyze 31 points of observational Hubble Data (OHD), 1048 points from the Pantheon data, and additional CMB data. We consider three scenarios: when n is a free parameter (Case I), when n=0 (Case II), and when n=1 (Case III). In our analysis across all three cases, we observe that our model portrays the universe’s evolution from a matter-dominated decelerated epoch to an accelerated epoch, as indicated by the corresponding deceleration parameter. In addition, we investigate the physical behavior of total energy density, total EoS parameter, and jerk parameter. Our findings consistently indicate that all cosmological parameters predict an accelerated expansion phase of the universe for all three cases (q0<0, ω0<-13, j0>0). Furthermore, our analysis reveals that the Om(z) diagnostics for Cases I and III align with the quintessence region, while Case II corresponds to the ΛCDM model.
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Department of General and Theoretical Physics, L.N. Gumilyov Eurasian National University, Astana, 010008, Kazakhstan
Ratbay Myrzakulov Eurasian International Center for Theoretical Physics, Astana, 010009, Kazakhstan
Department of Physics, University of Hassan II Casablanca, Casablanca, Morocco
Faculty of Mathematics, Namangan State University, Boburshoh Str. 161, Namangan, 160107, Uzbekistan
New Uzbekistan University, Mustaqillik Ave. 54, Tashkent, 100007, Uzbekistan
University of Tashkent for Applied Sciences, Gavhar Str. 1, Tashkent, 100149, Uzbekistan
Fundamental and Applied Research, National Research University TIIAME, Kori Niyoziy 39, Tashkent, 100000, Uzbekistan
Department of General and Theoretical Physics
Ratbay Myrzakulov Eurasian International Center for Theoretical Physics
Department of Physics
Faculty of Mathematics
New Uzbekistan University
University of Tashkent for Applied Sciences
Fundamental and Applied Research
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