Do recent observations favor a cosmological event horizon: A thermodynamical prescription?

Abstract

Recent observational evidences claim an accelerating expansion of the universe at present epoch. It is commonly incorporated in standard cosmology by the introduction of an exotic matter (that violates the strong energy condition) known as dark energy (DE). As event horizon exists for accelerating universe so there has been a lot of work on universal thermodynamics (i.e., thermodynamics of the universe bounded by apparent or event horizon). Recently, thermodynamical equilibrium has been examined for both the horizons. In the present work we show that universal thermodynamics with event horizon is favored by DE from the point of view of equilibrium thermodynamical prescription.

A study of universal thermodynamics in massive gravity: modified entropy on the horizons

“…4 shows that validity of TE for the event horizon is restricted only for normal fluid. Therefore, based on the above analysis, we can conclude that in the present unstable cosmological scenario (in massive gravity theory), the apparent horizon is more favourable as compared to the event horizon from thermodynamical perspective in massive gravity, which is in contrast to our earlier observations [17].…”

“…Thus, for a universe filled with a fluid and bounded by a horizon, the (generalized) second law of thermodynamics and the thermodynamical equilibrium respectively take the forms [16,17] …”

Particle production and universal thermodynamics

“…From the above table and Fig. 4, it is evident that for these bounds on b 2 , the particle production rate Γ diminishes in the phantom domain and the thermodynamical equilibrium of the Universe bounded by the event horizon supports these bounds on b 2 [57].…”

“…Also, the parameter b 2 is known as the interacting (or coupling) parameter and is related to the interaction term as Q = 3b 2 Hρ. Using three Planck data sets [56,57], we have evaluated the bounds on the interacting (or coupling) parameter b 2 for which γ becomes negative. The results have been presented in Table I.…”

Atomic stability and the quantum mass equivalence

“…Even with this limitation our approach can be relevant to study the interplay between gravitation and quantum theory. Note, at this respect, that it has been proposed to use the non-relativistic COW experiment as a lowenergy window to look into the structure of space-time [18]. The non-relativistic approach notoriously simplifies the mathematical treatment of the problem.…”