scholarly journals On the entropy variation in the scenario of entropic gravity

2018 ◽  
Vol 780 ◽  
pp. 34-36
Author(s):  
Yong Xiao ◽  
Shi-Yang Bai
Keyword(s):  
Entropic Gravity ◽  
Entropy Variation

Can quantum black holes be (q, p)-fermions?

2017 ◽  
Vol 32 (15) ◽  
pp. 1750080 ◽  
Author(s):  
Emre Dil
Keyword(s):  
Black Holes ◽  
Gravitational Field ◽  
Fermi Gas ◽  
Einstein Equations ◽  
Quantum Corrections ◽  
Field Equations ◽  
Gravitational Field Equations ◽  
Entropic Gravity ◽  
Two Parameter

In this study, to investigate the very nature of quantum black holes, we try to relate three independent studies: (q, p)-deformed Fermi gas model, Verlinde’s entropic gravity proposal and Strominger’s quantum black holes obeying the deformed statistics. After summarizing Strominger’s extremal quantum black holes, we represent the thermostatistics of (q, p)-fermions to reach the deformed entropy of the (q, p)-deformed Fermi gas model. Since Strominger’s proposal claims that the quantum black holes obey deformed statistics, this motivates us to describe the statistics of quantum black holes with the (q, p)-deformed fermions. We then apply the Verlinde’s entropic gravity proposal to the entropy of the (q, p)-deformed Fermi gas model which gives the two-parameter deformed Einstein equations describing the gravitational field equations of the extremal quantum black holes obeying the deformed statistics. We finally relate the obtained results with the recent study on other modification of Einstein equations obtained from entropic quantum corrections in the literature.

The cooperation between loop quantum gravity and Entropic gravity

2021 ◽  
Author(s):  
Wen-Xiang Chen
Keyword(s):  
Boundary Condition ◽  
Quantum Gravity ◽  
Gravitational Potential ◽  
Complex Number ◽  
Loop Quantum Gravity ◽  
Gravitational Entropy ◽  
Entropic Gravity ◽  
New Form

In this paper, we show that bosons can produce bochromatic condensation without an energy layer when the boundary condition $\frac{T}{T_{c}}=z$(when z is complex) is preset. $r_{R}=zr_{A}\left(1-\frac{v^{2}}{c^{2}}\right)^{\frac{1}{2}}$(when z is A complex number). A new form of gravitational potential is obtained by combining the theory of gravitational entropy with loop quantum gravity.

scholarly journals Phase Competitions behind the Giant Magnetic Entropy Variation: Gd5Si2Ge2 and Tb5Si2Ge2 Case Studies

Entropy ◽  
2014 ◽  
Vol 16 (7) ◽  
pp. 3813-3831 ◽  
Author(s):  
Ana Pires ◽  
João Belo ◽  
Armandina Lopes ◽  
Isabel Gomes ◽  
Luis Morellón ◽  
...  
Keyword(s):  
Case Studies ◽  
Magnetic Entropy ◽  
Entropy Variation

Green Function Calculations of Properties for the Magnetocaloric Layered Structures Based Upon FeMnAsP

SPIN ◽  
2016 ◽  
Vol 06 (03) ◽  
pp. 1650010
Author(s):  
Osvaldo F. Schilling
Keyword(s):  
Magnetic Field ◽  
Phase Transitions ◽  
Green Function ◽  
Landau Theory ◽  
Random Phase ◽  
Layered Structures ◽  
Continuous Phase ◽  
Theoretical Treatment ◽  
Entropy Variation ◽  
Commercial Applications

The alternating Fe–Mn layered structures of the compounds FeMnAsxP[Formula: see text] display properties which have been demonstrated experimentally as very promising as far as commercial applications of the magnetocaloric effect are concerned. However, the theoretical literature on this and other families of magnetocaloric compounds still adopts simple molecular-field models in the description of important statistical mechanical properties like the entropy variation that accompanies applied isothermal magnetic field cycling, as well as the temperature variation following adiabatic magnetic field cycles. In the present paper, a random phase approximation Green function theoretical treatment is applied to such structures. The advantages of such approach are well known since the details of the crystal structure are easily incorporated in the model, as well as a precise description of correlations between neighbor spins can be obtained. We focus on a simple one-exchange parameter Heisenberg model, and the observed first-order phase transitions are reproduced by the introduction of a biquadratic term in the Hamiltonian whose origin is related both to the magnetoelastic coupling with the phonon spectrum in these compounds as well as with the values of spins in the Fe and Mn ions. The calculations are compared with experimental magnetocaloric data for the FeMnAsxP[Formula: see text] compounds. In particular, the magnetic field dependence for the entropy variation at the transition temperature predicted from the Landau theory of continuous phase transitions is reproduced even in the case of discontinuous transitions.

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