Preprint
Article

This version is not peer-reviewed.

Entropic Cosmology with New Entropy

Submitted:

17 February 2026

Posted:

03 March 2026

You are already at the latest version

Abstract
We study entropic cosmology with new nonadditive entropy of the apparent horizon $S_K=S_{BH}/(1+\sigma S_{BH})^2$ where $S_{BH}$ is the Bekenstein--Hawking entropy. Making use of the thermodynamics-gravity correspondence a new model of dark energy is analyzed. We obtain the generalised Friedmann equations for Friedmann--Lema\^{i}tre--Robertson--Walker spatially flat universe with the barotropic matter fluid possessing the equation of state (EoS) $w=p/\rho$. The dark energy pressure $p_D$, the energy density $\rho_D$, and the deceleration parameter $q$ of the universe are computed. At some model parameters $w$ and $\sigma$ we obtain the normalized density parameter of the matter $\Omega_{m}\approx 0.315$ and the deceleration parameter $q_0\approx -0.535$ for the current epoch that are in agreement with the Planck data. We show that our model has the phantom divide for the EoS of dark energy. The model under consideration, with the help of the thermodynamics-gravity correspondence, describes the universe inflation and the late time of the universe acceleration. It is proven that the suggested entropic cosmology being equivalent to cosmology within the teleparallel gravity with the function $F(T)$ which we computed.
Keywords: 
;  ;  ;  ;  ;  

1. Introduction

The current universe acceleration can be explained by introducing the cosmological constant Λ in the Einstein equation which plays the role of the dark energy. Such standard cosmology leads to large scale homogeneity and isotropy. The latest observational data show the deviation from such scenario with the constant cosmological constant with better describing the acceleration of universe by dynamical cosmological constant (the dark energy). There are discrepancies with the Λ CDM model called cosmic tensions [1,2,3,4]. At the same time the thermodynamics of the apparent horizon can describe the acceleration of the universe [5,6,7,8,9,10,11,12,13,14,15,16] due to a correspondence between gravity and thermodynamics. It was shown [17,18] that the entropy is expressed through the horizon area and the temperature is connected with the surface gravity [19,20,21,22]. The Friedmann equations can be found by the virtue of the first law of apparent horizon thermodynamics because the apparent horizon (or the Hubble horizon) of the FLRW space-time represents a thermodynamic system [5,7,22,23,24]. Nonadditive entropies [25,26,27,28,29,30,31,32], due to the long-range nature of gravity, were considered and they lead to the generalized Friedmann equations. Some holographic dark energy models were studied in [33,34,35,36,37,38]. Here, we propose new apparent horizon non-extensive entropy S K = S B H / ( 1 + σ S B H ) 2 where S B H being the Bekenstein–Hawking entropy. We use the equation of state (EoS) for barotropic perfect fluid, p = w ρ , where p is the matter pressure and ρ is the enrgy density of the matter. The modified Friedmann equations, dark energy density and pressure were obtained. We show that the early and late time universe acceleration take place. The normalized density parameter of the matter Ω m 0.315 and the deceleration parameter q 0 0.535 for the current epoch are found for some model parameters which are in agreement with the Planck data. It is shown that our model describes the phantom divide for the EoS of dark energy. The entropic cosmology considered is equivalent to cosmology based on the teleparallel gravity with the function F ( T ) evaluated.
We use units with = c = k B = 1 .

2. The Entropy

Let us introduce new entropy
S K = i = 1 W p i ln p i ( 1 σ ln p i ) 2 ,
with W being a number of states and each state has a probability p i with the distribution { p i } and σ is a free dimensionless parameter. The summation in Equation (1) is given by all possible microstates of the system. After putting σ = 0 in Equation (1), it is converted into the Gibbs entropy
S G = i = 1 W p i ln ( p i ) .
We suppose that each microstate is populated with equal probability, and therefore 1 / p i = W ( i = 1 , 2 , . . . , W ) and Equation (2) is converted into the Boltzmann entropy S B = ln ( W ) . Taking into account that 1 / p i = W , one obtains from Equation (1) the equation
S K = ln ( W ) ( 1 + σ ln ( W ) ) 2 .
It is worth noting that the Bekenstein–Hawking entropy reads S B H = ln ( W ) and from Equation (3) we obtain
S K = S B H ( 1 + σ S B H ) 2 .
At σ = 0 the entropy (4) becomes the Bekenstein–Hawking entropy S B H = A / ( 4 G ) , where A = 4 π R h 2 is the horizon area. For two probabilistically independent systems A and B, one has p i j B + C = p i B p j C and we obtain nonadditive entropy S K ( B + C ) S K ( B ) + S K ( C ) . It should be noted that the Bekenstein–Hawking entropy S B H as well as other entropies [25,26,27,28] has a singularity at H = 0 , but the entropy S K does not possess a singularity, S K = 0 at H = 0 . For small σ the entropy becomes
S K = S B H 2 σ S B H 2 + 3 σ 2 S B H 3 + O ( σ 3 ) .
Thus, corrections to the entropy S B H decrease the S K entropy and the same effect takes place in quantum gravity [39]. We suppose that entropy (4) includes the quantum gravity corrections to S B H .

3. The Thermodynamics of the Apparent Horizon

The FLRW spatially flat universe possesses the metric
d s 2 = d t 2 + a ( t ) 2 ( d r 2 + r 2 d Ω 2 2 ) ,
were a ( t ) is a scale factor and d Ω 2 2 represents the 2-dimensional unit sphere line element. The apparent horizon radius ( R h = a ( t ) r ) is given by
R h = 1 H ,
with the Hubble parameter of the universe being H = a ˙ ( t ) / a ( t ) and a ˙ ( t ) = a / t . It is worth noting that the apparent horizon corresponds to the Hubble horizon. The first law of apparent horizon thermodynamics is
d E = T h d S h + W d V h ,
where W is the work density, E = ρ V h = ( 4 π / 3 ) ρ R h 3 and ρ is the energy density of a matter. The work density is given by [22,23,24]
W = 1 2 Tr ( T μ ν ) = 1 2 ( ρ p ) ,
the p is the pressure of the matter and the apparent horizon temperature is
T h = H 2 π 1 + H ˙ 2 H 2 .
From first law of apparent horizon thermodynamics (8), and using Equations (9) and (10) we obtain
H 2 π 1 + H ˙ 2 H 2 d S h = 4 π 3 H 3 d ρ + 2 π ( ρ + p ) H 4 d H .
Making use of the continuity equation
ρ ˙ = 3 H ( ρ + p ) ,
and taking into account Equation (11), one finds
H 2 π 1 + H ˙ 2 H 2 S ˙ h = 4 π ρ ˙ 3 H 3 1 + H ˙ 2 H 2 .

4. The Friedmann Equations

From Equations (12) and (13) and using the inequality 1 + H ˙ / ( 2 H 2 ) > 0 , we obtain
H 2 π S ˙ h = 4 π ( ρ + p ) H 2 .
We utilize the entropy
S h = S K = S B H ( 1 + γ S B H ) 2 ,
where S B H = π R h 2 / G = π / ( G H 2 ) . Then from Equations (14) and (15) we obtain the generalized Friedmann equation
H ˙ H 4 ( H 2 b ) ( H 2 + b ) 3 = 4 π G ( ρ + p ) ,
where b = σ π / G . After integrating Equation (16) and with the help of Equation (12) one finds the second generalized Friedmann equation
H 2 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2 4 b ln H 2 + b b = 8 π G 3 ρ ,
with the integration constant C = 4 b ln ( b ) . When σ = 0 ( b = 0 ) Equation (17) is converted into the Friedmann equation of general relativity. Equation (17) can be represented as
H 2 = 8 π G 3 ρ + Λ e f f 3 ,
where
Λ e f f = 3 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2 + 12 b ln H 2 + b b ,
and Λ e f f can be treated as the dynamical cosmological constant. We plotted the Λ e f f versus H at b = 1 , 2 , 3 in Figure 1, were the Planckian units with G = c = = k B = 1 are used.
Figure 1 shows that when b increases, at fixed H, the Λ e f f also increases and we have lim H 0 Λ e f f = 12 b . As a result, at small H (the large apparent horizon radius R h ), the Λ e f f is constant. Making use of Equation (18) we obtain the density of dark energy
ρ D = 3 b 8 π G b ( 4 b + 5 H 2 ) ( H 2 + b ) 2 + 4 ln H 2 + b b .
The normalized density parameters is given by Ω m = ρ / ( 3 M P 2 H 2 ) and Ω D = ρ D / ( 3 M P 2 H 2 ) with M P = 1 / 8 π G being the reduced Planck mass. Then from Equations (17) and (20) we have Ω m + Ω D = 1 . By virtue of Equation (17) one obtains the normalized density for the matter
Ω m = 1 b H 2 b ( 4 b + 5 H 2 ) ( H 2 + b ) 2 + 4 ln H 2 + b b .
With the dimensionless variable x = H 2 / b , Equation (21) is converted into
Ω m = 1 4 + 5 x x ( 1 + x ) 2 4 x ln ( 1 + x ) .
We plotted Ω m versus x in Figure 2.
According to Figure 2 as x ( H , R h 0 ) we have Ω m 1 . For the current epoch, in accordance with the Planck data, Ω m 0 0.315 [40]. At Ω m 0 = 0.315 the solution to Equation (22) is x 17.4 and we find the entropy parameter σ :
σ = b G π = G H 0 2 17.4 π 0.018 G H 0 2 .
Assuming that there is not mutual interaction between various cosmos components, and using Equation (12) for dark energy, we obtain
p D = ρ ˙ D 3 H ρ D .
From Equations (20) and (24) it follows that the pressure corresponding to the dark energy is given by
p D = b ( b 2 + 3 b H 2 + H 4 ) H ˙ 4 π G ( b + H 2 ) 3 3 b 8 π G b ( 4 b + 5 H 2 ) ( H 2 + b ) 2 + 4 ln H 2 + b b .
By virtue of Equations (16), (17) and (25) we find
p D = 3 b ( b 2 + 3 b H 2 + 4 H 4 ) ( 1 + w ) 8 π G H 4 ( H 2 b ) [ H 2 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2
4 b ln H 2 + b b ] 3 b 8 π G b ( 4 b + 5 H 2 ) ( H 2 + b ) 2 + 4 ln H 2 + b b .
Making use of Equations (20) and (26), EoS w D = p D / ρ D for dark energy is
w D = ( b 2 + 3 b H 2 + 4 H 4 ) ( 1 + w ) H 4 ( H 2 b ) H 2 ( H 2 + b ) 2 b ( 4 b + 5 H 2 ) + 4 ( ( H 2 + b ) 2 ln H 2 / b + 1 1
1 .
With the variable x = H 2 / b , Equation (27) becomes
w D = ( 1 + 3 x + 4 x 2 ) ( 1 + w ) x 2 ( x 1 ) x ( x + 1 ) 2 4 + 5 x + 4 ( x + 1 ) 2 ln ( x + 1 ) 1 1 .
The w D versus x is plotted in Figure 3.
From Equation (28) we have lim x w D = 1 . As a result, the dark energy EoS w D = 1 for the large Hubble parameter H (the small R h ) that corresponds for the inflation epoch. According to Figure 3 the phantom phase with w D < 1 takes place. Making use of Equation (28) the equation for the phantom divide w D = 1 is given by
x ( 1 + x ) 2 4 5 x 4 ( x + 1 ) 2 ln ( x + 1 ) = 0 .
The approximate solution to Equation (29) being x = H 2 / b 10.06 (see also Figure 3) and the model realizes the scenario with the crossing of the phantom divide for the dark energy EoS. Making use of the redshift z = a 0 / a ( t ) 1 with a 0 being a scale factor at the current time, utilizing the continuity Equation (12) and EoS p = w ρ , we obtain the density energy of the matter as follows:
ρ = ρ 0 ( 1 + z ) 3 ( 1 + w ) ,
where ρ 0 is the energy density of the matter at the present time. By virtue of Equations (17) and (30) one finds the equation
H 2 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2 4 b ln H 2 + b b = 8 π G ρ 0 3 ( 1 + z ) 3 ( 1 + w ) .
With the aid of Equation (31) we obtain the redshift
z = 3 8 π ρ 0 G H 2 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2 4 b ln H 2 + b b 1 / ( 3 ( 1 + w ) ) 1 .
By using dimensionless parameters H ¯ = H / G ρ 0 , b ¯ = b / ( G ρ 0 ) , Equation (32) is converted into
z = 3 8 π H ¯ 2 b ¯ 2 ( 4 b ¯ + 5 H ¯ 2 ) ( H ¯ 2 + b ¯ ) 2 4 b ¯ ln H ¯ 2 + b ¯ b ¯ 1 / ( 3 ( 1 + w ) ) 1 .
In Figure 4 we depicted the reduced Hubble parameter H ¯ versus redshift z.
Figure 4 shows that when redshift z increases the reduced Hubble parameter H ¯ also increases. In accordance with the left panel of Figure 4, when parameter w increases (at fixed H ¯ ) the redshift z decreases. Right panel of Figure 4 shows that if parameter b ¯ increases (at fixed z) the reduced Hubble parameter H ¯ also increases.
Let us consider the deceleration parameter
q = a ¨ a a ˙ 2 = 1 H ˙ H 2 .
When q < 0 the acceleration phase of the universe takes place and when q > 0 the deceleration phase occurs. From Equations (16), (17) and (34) we obtain
q = 4 π G ρ 0 ( 1 + w ) ( H 2 + b ) 3 H 6 ( H 2 b ) 1 + z 3 ( 1 + w ) 1 .
With the help of Equations (31) and (35) one finds
q = 3 ( 1 + w ) ( H 2 + b ) 3 2 H 6 ( H 2 b ) H 2 b 2 ( 4 b + 5 H 2 ) ( H 2 + b ) 2 4 b ln H 2 + b b 1 .
By using dimensionless variable x = H 2 / b Equation (36) takes the form
q = 3 ( 1 + w ) ( 1 + x ) 3 2 x 2 ( x 1 ) 1 4 + 5 x x ( 1 + x ) 2 4 x ln ( 1 + x ) 1 .
Taking into consideration the value x = H 0 2 / b 17.4 ( σ H 0 2 G / ( 17.4 π ) ) that reproduces the normalized density of the matter field at the current time Ω m 0 0.315 and the deceleration parameter q 0 0.535 [40], one finds the solution to Equation (37) for the EoS parameter of the matter w 0.2157 .
The deceleration parameter q versus the x is depicted in Figure 5.
According to Figure 5 two phases takes place, the universe acceleration and deceleration.
By virtue of Equation (36), the asymptotic is
lim H q = 3 w + 1 2 .
According to Equation (38) when w > 1 / 3 ( q > 0 ) (at small R h ) the universe decelerates. The universe acceleration at small R h occurs at w < 1 / 3 . From Equation (37) at q = 0 , the equation for the transition phase is given by
w = 2 x 3 ( x 1 ) 3 ( 1 + x ) x 3 + 2 x 2 4 x 4 4 ( 1 + x ) 2 ln ( 1 + x ) 1 .
The EoS parameter for the matter w versus x is depicted in Figure 6.
According to Figure 6 when 1 > x > 0 we have w > 1 . Figure 6 shows that when x = H 2 / b increases from x = 1 the EoS parameter w decreases from w = 1 (de Sitter space) and becomes the phantom space.

4.1. Inflation

At the phase of inflation the matter density of energy and pressure are zero, ρ = p = 0 . The dark energy density results the universe to accelerate. From Equation (16) we obtain H ˙ = 0 , and during inflation the Hubble parameter is constant. The scale factor becomes a ( t ) = a 0 exp ( H t ) corresponding to the de Sitter space-time. At the de Sitter stage the eternal inflation occurs. The Hubble parameter at the inflation phase being H 10 3 M P l ( M P l = 1 / 8 π G ) and G H 2 4 · 10 8 . Making use of Equation (17), at ρ = 0 with the variable x = H 2 / b we find the equation
x 4 + 5 x ( x + 1 ) 2 4 ln ( x + 1 ) = 0 ,
corresponding to Equation (29) for the phantom divide. The solution to Equation (40) is x = 10.0559 with the relation
H 2 = 10.0559 b .
From the Hubble parameter at the inflation phase H 10 3 M P l , we obtain parameter b from Equation (41) and the entropy parameter σ = b G / π 1.27 × 10 9 .

5. F(T)-Gravity from Generalized Entropy

The scalar torsion T in teleparallel gravity is a field analogous to the curvature R in the Einstein theory [43,44]. The teleparallel theory of gravity explores the Weitzenböck connection and in the F ( T ) theory the field equations are the second-order. The torsion field T is defined as [45,46],
T = S ρ μ ν T μ ν ρ .
The tensors S ρ μ ν and T μ ν ρ are given by
S ρ μ ν = 1 2 K ρ μ ν + δ ρ μ T α α ν δ ρ ν T α α μ ,
K ρ μ ν = 1 2 T ρ μ ν T ρ ν μ T ρ μ ν ,
T μ ν ρ = e i ρ μ e ν i ν e μ i ,
with e ν i ( i = 0 , 1 , 2 , 3 ) being a vierbein field. The metric tensor is g μ ν = η i j e μ i e ν j , where η i j is the flat metric of the tangent spacetime. For FLRW metric (5) e μ i = d i a g ( 1 , a , a , a ) and the torsion scalar is T = 6 H 2 . The variation of the action with respect to e μ i (the Lagrangian is F ( T ) ) gives the equation [47]
1 6 F ( T ) 2 T F ( T ) | T = 6 H 2 = 8 π G 3 ρ .
From equations (17) and (44) we obtain
F ( T ) F ( T ) 2 T = 1 2 + 18 b 2 ( 24 b 5 T ) T ( 6 b T ) 2 + 12 b T ln 1 T 6 b .
Integrating Equation (45) one finds
F ( T ) = T 3 b ( 48 b 7 T ) T 6 b 24 b ln 1 T 6 b
+ ( 8 6 7 1.5 ) b T arctan T 6 b ,
with the integration constant C = 0 . Because T = 6 H 2 < 0 , we have used the relation i tanh 1 ( i x ) = arctan ( x ) . It should be noted that F ( T ) in Equation (46) is the real function. The teleparallel gravity models with some functions F ( T ) were investigated in [48,49] The entropic cosmology with entropy (15) can be considered as a cosmology within the teleparallel gravity with the function (46).

6. Conclusions

We have proposed a new entropy S K = S B H / ( 1 + γ S B H ) 2 with S B H being the Bekenstein–Hawking entropy and S K becomes zero when the apparent horizon radius R h vanishes. The entropic cosmology with our entropy leads to inflation and current acceleration of the universe. The matter barotropic perfect fluid and the spatial flat FLRW universe are assumed. Making use of the first law of apparent horizon thermodynamics we obtained the modified Friedmann equations which have a term corresponding to the density of dark energy. Also, such term can be considered as a dynamical cosmological constant. We assume that there is no interaction between various components of dark energy (the dark energy density and pressure ρ D and p D obey ordinary conservation law). The p D and the dark energy EoS w D = p D / ρ D have been computed with lim H w D = 1 . This shows that at the small apparent horizon radius R h the inflation of the universe occurs. In our model the universe may have two phases, acceleration and deceleration, because of the dark energy. The deceleration parameter was computed which shows that the acceleration at the current epoch takes place. At the entropy parameter σ 1.27 × 10 9 and w = 0.2157 the deceleration parameter possesses the value q 0 0.535 and the normalized density parameter is Ω m 0 0.315 that are in accordance with the Planck data at the current epoch [40]. In addition, our model has the phantom divide for the EoS of dark energy. We have showed that entropic cosmology with our entropy can be considered as the cosmology within the teleparallel gravity with the function F ( T ) obtained.

References

  1. Lusso, E.; Piedipalumbo, E.; Risaliti, G.; Paolillo, M.; Bisogni, S.; Nardini, Emanuel E.; Amati, Lorenzo. Tension with the flat ΛCDM model from a high-redshift hubble diagram of supernovae, quasars, and gamma-ray bursts. Astron. Astrophys. 2019, 628, L4. [Google Scholar] [CrossRef]
  2. Di Valentino, E. Cosmology Intertwined II: The Hubble Constant Tension, Astropart. Phys. 2021, 131, 102605. [Google Scholar]
  3. Riess, A. G. Type Ia supernova discoveries at. Astrophys. J. 2004, 607, 665. [Google Scholar] [CrossRef]
  4. Riess, A. G.; Casertano, S.; Yuan, W.; Macri, L. M.; Scolnic, D. Large magellanic cloud cepheid standards provide a One percent foundation for the determination of the hubble constant and stronger evidence for physics beyond ΛCDM. Astrophys. J. 2019, 876, 85. [Google Scholar]
  5. Akbar, M.; Cai, R. G. Thermodynamic Behavior of Friedmann Equation at Apparent Horizon of FRW Universe. Phys. Rev. D 2007, 75, 084003. [Google Scholar] [CrossRef]
  6. Cai, R. G.; Cao, L. M. Unified First Law and Thermodynamics of Apparent Horizon in FRW Universe. Phys. Rev. D 2007, 75, 064008. [Google Scholar] [CrossRef]
  7. Cai, R. G.; Kim, S. P. First Law of Thermodynamics and Friedmann Equations of Friedmann-Robertson-Walker Universe. JHEP 2005, 0502, 050. [Google Scholar]
  8. Paranjape, A.; Sarkar, S.; Padmanabhan, T. Thermodynamic route to Field equations in Lanczos-Lovelock Gravity. Phys. Rev. D 2006, 74, 104015. [Google Scholar] [CrossRef]
  9. Sheykhi, A.; Wang, B.; Cai, R. G. Thermodynamical Properties of Apparent Horizon in Warped DGP Braneworld. Nucl. Phys. B 2007, 779, 1. [Google Scholar] [CrossRef]
  10. Cai, R. G.; Ohta, N. Horizon Thermodynamics and Gravitational Field Equations in Horava-Lifshitz Gravity. Phys. Rev. D 2010, 81, 084061. [Google Scholar]
  11. Wang, S.; Wang, Y.; Li, M. Holographic Dark Energy. Phys. Rept 2017, 696, 1. [Google Scholar] [CrossRef]
  12. Jamil, M.; Saridakis, E. N.; Setare, M. R. The generalized second law of thermodynamics in Horava-Lifshitz cosmology. JCAP 2010, 1011, 032. [Google Scholar] [CrossRef]
  13. Gim, Y.; Kim, W.; Yi, S. H. The first law of thermodynamics in Lifshitz black holes revisited. JHEP 2014, 1407, 002. [Google Scholar] [CrossRef]
  14. Fan, Z. Y.; Lu, H. Thermodynamical First Laws of Black Holes in Quadratically-Extended Gravities. Phys. Rev. D 2015, 91, 064009. [Google Scholar] [CrossRef]
  15. D’Agostino, R. Holographic dark energy from nonadditive entropy: Cosmological perturbations and observational constraints. Phys. Rev. D 2019, 99, 103524. [Google Scholar] [CrossRef]
  16. Sanchez, L. M.; Quevedo, H. Thermodynamics of the FLRW apparent horizon. Phys. Lett B 2023, 839, 137778. [Google Scholar] [CrossRef]
  17. Bekenstein, J. D. Black Holes and Entropy. Phys. Rev. D 1973, 7, 2333–2346. [Google Scholar] [CrossRef]
  18. S.W. Hawking, Particle creation by black holes, Commun. Math. Phys. 43 (1975), 199-220; Erratum: Ibid. 46 (1976), 206. [CrossRef]
  19. Jacobson, T. Thermodynamics of Spacetime: The Einstein Equation of State. Phys. Rev. Lett. 1995, 75, 1260. [Google Scholar] [CrossRef] [PubMed]
  20. T. Padmanabhan, Gravity and the Thermodynamics of Horizons, Phys. Rept. 406 (2005), 49. [CrossRef]
  21. Padmanabhan, T. Thermodynamical Aspects of Gravity: New insights. Rept. Prog. Phys. 2010, 73, 046901. [Google Scholar] [CrossRef]
  22. Hayward, S. A. Unified first law of black-hole dynamics and relativistic thermodynamics. Class. Quant. Grav. 1998, 15, 3147–3162. [Google Scholar] [CrossRef]
  23. Hayward, S. A.; Mukohyana, S.; Ashworth, M.C. Dynamic black-hole entropy. Phys. Lett. A 1999, 256, 347. [Google Scholar] [CrossRef]
  24. Bak, D.; Rey, S. J. Cosmic holography. Class. Quant. Grav. 2000, 17, 83. [Google Scholar] [CrossRef]
  25. C. Tsallis, Possible generalization of Boltzmann-Gibbs statistics, J. Stat. Phys., 52 (1-2) (1988), 479-487; C. Tsallis, The Nonadditive Entropy Sq and Its Applications in Physics and Elsewhere: Some Remarks, Entropy 13 (2011), 1765. [CrossRef]
  26. J. D. Barrow, The Area of a Rough Black Hole, Phys. Lett. B 808 (2020), 135643. [CrossRef] [PubMed]
  27. Rényi, A. Proceedings of the Fourth Berkeley Symposium on Mathematics, Statistics and Probability; University of California Press, 1960; pp. 547–56. [Google Scholar]
  28. Kaniadakis, G. Statistical mechanics in the context of special relativity II. Phys. Rev. E 2005, 72, 036108. [Google Scholar] [CrossRef]
  29. Masi, Marco. A step beyond Tsallis and Rényi entropies. Phys. Lett. A 2005, 338, 217–224. [Google Scholar] [CrossRef]
  30. Czinner, V. G.; Iguchi, H. Rényi entropy and the thermodynamic stability of black holes. Phys. Lett. B 2016, 752, 306–310. [Google Scholar] [CrossRef]
  31. Kruglov, S. I. Cosmology Due to Thermodynamics of Apparent Horizon. Annalen der Phys. 2025, 534, e00204. [Google Scholar] [CrossRef]
  32. Kruglov, S. I. Cosmology, new entropy and thermodynamics of apparent horizon. Chin. J. Phys. 2025, 98, 277–286. [Google Scholar] [CrossRef]
  33. Sayahian Jahromi, A.; Moosavi, S. A.; Moradpour, H.; Morais Graca, J. P.; Lobo, I. P.; Salako, I. G.; Jawad, A. Generalized entropy formalism and a new holographic dark energy model. Phys. Lett. B 2018, 780, 21–24. [Google Scholar] [CrossRef]
  34. Ren, J. Analytic critical points of charged Rényi entropies from hyperbolic black holes. JHEP 2021, 05, 080. [Google Scholar] [CrossRef]
  35. Mejrhit, K.; Ennadifi, S. E. Thermodynamics, stability and Hawking–Page transition of black holes from non-extensive statistical mechanics in quantum geometry. Phys. Lett. B 2019, 794, 45–49. [Google Scholar] [CrossRef]
  36. A. Majhi, Non-extensive Statistical Mechanics and Black Hole Entropy From Quantum Geometry, Phys. Lett. B 775 (2017), 32-36. [CrossRef]
  37. Pavon, D.; Zimdahl, W. Holographic dark energy and cosmic coincidence. Phys. Lett. B 2005, 628, 206. [Google Scholar] [CrossRef]
  38. Landim, R. C. G. Holographic dark energy from minimal supergravity. Int. J. Mod. Phys. D 2016, 25, 1650050. [Google Scholar] [CrossRef]
  39. Ashtekar, Abhay; Wilson-Ewing, Edward. The covariant entropy bound and loop quantum cosmology. Phys. Rev. D 2008, 78, 064047. [Google Scholar] [CrossRef]
  40. Aghanim, N.; et al. [Planck], Cosmological parameters. Astron. Astrophys. 2020, 641, A6, Erratum: Ibid 652(2021), C4. [Google Scholar]
  41. Di Gennaro, Sofia; Xu, Hao; Chin Ong, Yen. How barrow entropy modifies gravity: With comments on Tsallis entropy. Eur. Phys. J. C 2022, 82, 1066. [Google Scholar] [CrossRef]
  42. M. Roos, Introduction to Cosmology (John Wiley and Sons, UK, 2003).
  43. Hehl, F. W.; Von Der Heyde, P.; Kerlick, G. D.; Nester, J. M. General Relativity with Spin and Torsion: Foundations and Prospects. Rev. Mod. Phys. 1976, 48, 393–416. [Google Scholar] [CrossRef]
  44. Bajardi, Francesco; Blixt, Daniel; Capozziello, Salvatore. Hamilton equations in teleparallel gravity and in new general relativity. Phys. Rev. D 2025, 111, 084012. [Google Scholar] [CrossRef]
  45. Weitzenböck R., Invarianten Theorie, (Nordhoff, Groningen, 1923).
  46. Maluf, J. W. Hamiltonian formulation of the teleparallel description of general relativity. J. Math. Phys. 1994, 35, 335. [Google Scholar] [CrossRef]
  47. Bengochea, G. R.; Ferraro, R. Dark torsion as the cosmic speed-up. Phys. Rev. D 2009, 79, 124019. [Google Scholar] [CrossRef]
  48. Wu, P.; Yu, H. W. f(T) models with phantom divide line crossing. Eur. Phys. J. C 2011, 71, 1552. [Google Scholar] [CrossRef]
  49. Nesseris, S.; Basilakos, S.; Saridakis, E. N.; Perivolaropoulos, L. Viable f(T) models are practically indistinguishable from LCDM. Phys. Rev. D 2013, 88, 103010. [Google Scholar] [CrossRef]
Figure 1. The function Λ e f f versus H at b = π σ / G = 1 , 2 , 3 . According to Figure 1  Λ e f f increases as b increases. As H 0 ( R h ) one has Λ e f f 12 b .
Figure 1. The function Λ e f f versus H at b = π σ / G = 1 , 2 , 3 . According to Figure 1  Λ e f f increases as b increases. As H 0 ( R h ) one has Λ e f f 12 b .
Preprints 199390 g001
Figure 2. The Ω m versus x is shown in figure. The Ω m increases if x increases and when x ( R h 0 ) one has Ω m 1 .
Figure 2. The Ω m versus x is shown in figure. The Ω m increases if x increases and when x ( R h 0 ) one has Ω m 1 .
Preprints 199390 g002
Figure 3. The w D versus x = H 2 / b is depicted at w = 0 , 1 / 3 , 2 / 3 . When x is large, the EoS parameter w D possesses the limit lim x w D = 1 .
Figure 3. The w D versus x = H 2 / b is depicted at w = 0 , 1 / 3 , 2 / 3 . When x is large, the EoS parameter w D possesses the limit lim x w D = 1 .
Preprints 199390 g003
Figure 4. Left panel: The H ¯ versus z with b ¯ = 0.1 , w = 1 / 3 , 0 , 0.1 . Figure shows that H ¯ increases when z increases. When EoS parameter for the matter w increases, at fixed H ¯ , the redshift z decreases. Right panel: According to figure, when parameter b ¯ increases (at fixed z), the reduced Hubble parameter H ¯ also increases.
Figure 4. Left panel: The H ¯ versus z with b ¯ = 0.1 , w = 1 / 3 , 0 , 0.1 . Figure shows that H ¯ increases when z increases. When EoS parameter for the matter w increases, at fixed H ¯ , the redshift z decreases. Right panel: According to figure, when parameter b ¯ increases (at fixed z), the reduced Hubble parameter H ¯ also increases.
Preprints 199390 g004
Figure 5. The deceleration parameter q versus x with w = 0 , 1 / 3 , 2 / 3 . Figure shows that the deceleration parameter q increases when the parameter x increases. If the EoS parameter of the matter w increases (at fixed x) the deceleration parameter q also increases. We observe two phases, universe acceleration at q < 0 and deceleration at q > 0 .
Figure 5. The deceleration parameter q versus x with w = 0 , 1 / 3 , 2 / 3 . Figure shows that the deceleration parameter q increases when the parameter x increases. If the EoS parameter of the matter w increases (at fixed x) the deceleration parameter q also increases. We observe two phases, universe acceleration at q < 0 and deceleration at q > 0 .
Preprints 199390 g005
Figure 6. According to figure at 1 > x > 0 we have w > 1 . When x increases from x = 1 , the EoS parameter w decreases from w = 1 (the de Sitter space) and w corresponds to the fantom space.
Figure 6. According to figure at 1 > x > 0 we have w > 1 . When x increases from x = 1 , the EoS parameter w decreases from w = 1 (the de Sitter space) and w corresponds to the fantom space.
Preprints 199390 g006
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.
Copyright: This open access article is published under a Creative Commons CC BY 4.0 license, which permit the free download, distribution, and reuse, provided that the author and preprint are cited in any reuse.
Prerpints.org logo

Preprints.org is a free preprint server supported by MDPI in Basel, Switzerland.

Subscribe

Disclaimer

Terms of Use

Privacy Policy

Privacy Settings

© 2026 MDPI (Basel, Switzerland) unless otherwise stated