Non-adiabatic-like accelerated expansion of the late universe in
  entropic cosmology
  In `entropic cosmology', instead of a cosmological constant $\Lambda$, an
extra driving term is added to the Friedmann equation and the acceleration
equation, taking into account the entropy and the temperature on the horizon of
the universe. By means of the modified Friedmann and acceleration equations, we
examine a non-adiabatic-like accelerated expansion of the universe in entropic
cosmology. In this study, we consider a homogeneous, isotropic, and spatially
flat universe, focusing on the single-fluid (single-component) dominated
universe at late-times. To examine the properties of the late universe, we
solve the modified Friedmann and acceleration equations, neglecting high-order
corrections for the early universe. We derive the continuity (conservation)
equation from the first law of thermodynamics, assuming non-adiabatic expansion
caused by the entropy and temperature on the horizon. Using the continuity
equation, we formulate the generalized Friedmann and acceleration equations,
and propose a simple model. Through the luminosity distance, it is demonstrated
that the simple model agrees well with both the observed accelerated expansion
of the universe and a fine-tuned standard $\Lambda$CDM (lambda cold dark
matter) model. However, we find that the increase of the entropy for the simple
model is likely uniform, while the increase of the entropy for the standard
$\Lambda$CDM model tends to be gradually slow especially after the present
time. In other words, the simple model predicts that the present time is not a
special time, unlike for the prediction of the standard $\Lambda$CDM model.
