https://doi.org/10.1140/epjc/s10052-024-13019-7
Regular Article - Theoretical Physics
Signature flips in time-varying 
cosmological models with observational data
1
Department of General and Theoretical Physics, L.N. Gumilyov Eurasian National University, 010008, Astana, Kazakhstan
2
Ratbay Myrzakulov Eurasian International Center for Theoretical Physics, 010009, Astana, Kazakhstan
3
Department of Physics, University of Hassan II Casablanca, Casablanca, Morocco
4
Faculty of Mathematics, Namangan State University, Boburshoh Str. 161, 160107, Namangan, Uzbekistan
5
New Uzbekistan University, Mustaqillik Ave. 54, 100007, Tashkent, Uzbekistan
6
University of Tashkent for Applied Sciences, Gavhar Str. 1, 100149, Tashkent, Uzbekistan
7
Fundamental and Applied Research, National Research University TIIAME, Kori Niyoziy 39, 100000, Tashkent, Uzbekistan
Received:
18
March
2024
Accepted:
11
June
2024
Published online:
5
July
2024
In this study, we investigate signature flips within the framework of cosmological models featuring a time-varying vacuum energy term . Specifically, we consider the power-law form of 
, where 
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 
(Case II), and when 
(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 (
, 
, 
). 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 
CDM model.
© The Author(s) 2024
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