Abstract:
In this study, we investigate signature flips within
the framework of cosmological models featuring a timevarying vacuum energy term (t). Specifically, we consider
the power-law form of = 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 < −1
3 , 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 CDM model.
