Superhelix Density as an Intensive Thermodynamic Variable

1992 ◽  
pp. 23-54 ◽  
Author(s):  
H. Buc ◽  
M. Amouyal
Keyword(s):  
Thermodynamic Variable

scholarly journals Revisit on the thermodynamic stability of Hořava–Lifshitz black hole

2018 ◽  
Vol 27 (04) ◽  
pp. 1850048
Author(s):  
Xudong Meng ◽  
Ruihong Wang
Keyword(s):  
Black Hole ◽  
Thermodynamic Properties ◽  
Thermodynamic Stability ◽  
Detailed Balance ◽  
De Sitter ◽  
Thermodynamic Variable ◽  
Detailed Balance Condition ◽  
First Law Of Thermodynamics ◽  
Balance Condition ◽  
Lifshitz Black Hole

We study the thermodynamic properties of the black hole derived in Hořava–Lifshitz (HL) gravity without the detailed-balance condition. The parameter [Formula: see text] in the HL black hole plays the same role as that of the electric charge in the Reissner–Nordström-anti-de Sitter (RN-AdS) black hole. By analogy, we treat the parameter [Formula: see text] as the thermodynamic variable and obtain the first law of thermodynamics for the HL black hole. Although the HL black hole and the RN-AdS black hole have the similar mass and temperature, due to their very different entropy, the two black holes have very different thermodynamic properties. By calculating the heat capacity and the free energy, we analyze the thermodynamic stability of the HL black hole.

Oberflächenspannung und Thermodynamik des perfekten Gases

1970 ◽  
Vol 25 (8-9) ◽  
pp. 1190-1202 ◽  
Author(s):  
Eberhard Hilf
Keyword(s):  
Particle Density ◽  
Level Density ◽  
Thermodynamic System ◽  
Particle Energy ◽  
External Potential ◽  
Additional Contribution ◽  
Quantum Gas ◽  
Surface Phenomena ◽  
Perfect Gas ◽  
Thermodynamic Variable

Abstract A thermodynamic system of N Fermions or Bosons, bound by an external potential but with almost no additional contribution of the interaction energy between the particles to the binding of the system is called a bound perfect quantum gas. Its single particle energy level density ρ (ε) depends on the properties of the external potential. This is chosen to be zero inside and infinite outside a given arbitrary simple connected closed shape. Within the leptodermous assumption A N1/3 ≫ 1 then ρ (ε) can be written explicitly as a sum of three terms which are proportional to the volume, surface, curvature tension. Its thermodynamics is developed: 1) one thermodynamic variable can be eliminated, reducing the phase space dimensions; 2) the Gibbs - Duhem relation is disfigured only by surface - and curvature terms, stating that the system is still makroscopically homogenious except in the surface area, where e.g. the particle density falls down to zero smoothly; 3) the Landsberg-definition p · V = ⅔ U still holds, confirming that our microscopically defined system is macroscopically a perfect gas in the sense of Landsberg, despite the surface phenomena. In the appendix the advantages of an operatorlike shortwriting of the partial derivative notation are demonstrated.

Thermodynamics and geometrothermodynamics of Born–Infeld black holes with cosmological constant

2015 ◽  
Vol 24 (11) ◽  
pp. 1550092
Author(s):  
Hernando Quevedo ◽  
María N. Quevedo ◽  
Alberto Sánchez
Keyword(s):  
Phase Transition ◽  
Black Holes ◽  
Cosmological Constant ◽  
Thermodynamic System ◽  
Physical Parameters ◽  
Spherically Symmetric ◽  
Transition Structure ◽  
Thermodynamic Variable ◽  
Thermodynamic Variables ◽  
Range Of Values

In this paper, we investigate a class of spherically symmetric Born–Infeld black holes which contains the mass, electric charge, Born–Infeld parameter and the cosmological constant as physical parameters. We show that for the mass to be an extensive thermodynamic variable, it is necessary to consider the cosmological constant and the Born–Infeld parameter as thermodynamic variables as well. We analyze the properties of such a thermodynamic system, explore the range of values where the system is thermodynamically well-defined, and the phase transition structure. In addition, we show that the equilibrium manifold in the context of geometrothermodynamics reproduces correctly the thermodynamic properties of this black hole class.

scholarly journals Varying Newton Constant and Black Hole to White Hole Quantum Tunneling

2020 ◽  
Author(s):  
Grigory Volovik
Keyword(s):  
Black Hole ◽  
Quantum Tunneling ◽  
Black Hole Thermodynamics ◽  
Black Hole Mass ◽  
Schwarzschild Black Hole ◽  
Dimensionless Quantity ◽  
White Hole ◽  
Thermodynamic Variable ◽  
Euclidean Action ◽  
Thermodynamics Of Black Holes

The thermodynamics of black holes is discussed for the case, when the Newton constant G is not a constant, but is the thermodynamic variable. This gives for the first law of the Schwarzschild black hole thermodynamics: d S BH = − A d K + d M T BH , where the gravitational coupling K = 1 / 4 G , M is the black hole mass, A is the area of horizon, and T BH is Hawking temperature. From this first law it follows that the dimensionless quantity M 2 / K is the adiabatic invariant, which in principle can be quantized if to follow the Bekenstein conjecture. From the Euclidean action for the black hole it follows that K and A serve as dynamically conjugate variables. This allows us to calculate the quantum tunneling from the black hole to the white hole, and determine the temperature and entropy of the white hole.

An Exact and Simple Approach to log-log Plots for Defect and Ionic Equilibria

1997 ◽  
Vol 52 (8-9) ◽  
pp. 629-636
Author(s):  
Giorgio Spinolo ◽  
Umberto Anselmi-Tamburini ◽  
Paolo Ghigna
Keyword(s):  
Traditional Approach ◽  
Functional Dependence ◽  
Total Concentration ◽  
Free Ligand ◽  
Spreadsheet Program ◽  
Thermodynamic Variable ◽  
Defect Equilibria ◽  
Simple Oxide ◽  
Ionic Equilibria ◽  
Alternative Approach

Abstract An alternative approach to log-log plots for defect equilibria in the solid state and ionic equilibria in solution is presented. The method is based on the strictly monotone character of the functional dependence of an externally controlled thermodynamic variable (e.g. the oxygen partial pressure P(O2) for the defect equilibria in a simple oxide, or a total concentration for the ionic equilibria in solution) on a chemically relevant compositional variable (such as the electron concentration n for defect equilibria, or [H3O+] or a free ligand concentration for solution equilibria). This functional dependency can be safely inverted. The concentration of all species and the externally controlled thermodynamic variable can be calculated as a function of the chemically relevant compositional variable. The appropriate plots are then obtained using naively a spreadsheet program. This method gives exact results in many more cases than the traditional approach.

scholarly journals Evidence for the role of the diabatic heating in synoptic scale processes: a case study example

1997 ◽  
Vol 15 (4) ◽  
pp. 487-493 ◽  
Author(s):  
M. L. Martin ◽  
M. Y. Luna ◽  
F. Valero
Keyword(s):  
Diabatic Heating ◽  
Potential Temperature ◽  
Principal Component ◽  
Phase Changes ◽  
Synoptic Scale ◽  
Thermodynamic Variable ◽  
Dynamic Forcing ◽  
Diabatic Forcing

Abstract. The quasigeostrophic theory is used to address the role of diabatic forcing in synoptic scale processes over Iberia. A parametrization of diabatic heating is obtained in terms of a thermodynamic variable called the ice-liquid water potential temperature which is conservative under all phase changes of water. A case study objectively selected by means of a rotated principal component analysis over the diabatic field is analyzed to test the proposed parametrization. This study highlights the fact that the magnitudes of diabatic forcing and dynamic forcing are very nearly the same throughout the troposphere. The results also show that the composite diabatic heating is a better representation for both cloudiness and precipitation fields than the dynamic forcing.

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