scholarly journals Holographic heat engines and static black holes: A general efficiency formula

2019 ◽  
Vol 28 (02) ◽  
pp. 1950030 ◽  
Author(s):  
Felipe Rosso
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Upper Bound ◽  
Heat Engine ◽  
Thermodynamic System ◽  
Ideal Gas ◽  
Heat Flows ◽  
Heat Engines ◽  
Static Black Hole

Starting from simple observations regarding heat flows for static black holes (or any thermodynamic system with [Formula: see text]), we get inequalities which restrict their change in energy and adiabatic curves in the [Formula: see text] plane. From these observations, we then derive an exact efficiency formula for virtually any holographic heat engine defined by a cycle in the [Formula: see text] plane, whose working substance is a static black hole. Moreover, we get an upper bound for its efficiency and show that for a certain class of black holes, this bound is universal and achieved by an “ideal gas” hole. Finally, we compute exact efficiencies for some particular and new engines.

scholarly journals Benchmarking black hole heat engines, II

2018 ◽  
Vol 27 (16) ◽  
pp. 1950006 ◽  
Author(s):  
Avik Chakraborty ◽  
Clifford V. Johnson
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Velocity ◽  
Upper Bound ◽  
Exact Formula ◽  
Ideal Gas ◽  
Static Case ◽  
Rotating Black Hole ◽  
Heat Engines ◽  
Ads Black Holes

We extend to nonstatic black holes our benchmarking scheme that allows for cross–comparison of the efficiencies of asymptotically AdS black holes used as working substances in heat engines. We use a circular cycle in the [Formula: see text] plane as the benchmark cycle. We study Kerr black holes in four spacetime dimensions as an example. As in the static case, we find an exact formula for the benchmark efficiency in an ideal gas-like limit, which may serve as an upper bound for rotating black hole heat engines in a thermodynamic ensemble with fixed angular velocity. We use the benchmarking scheme to compare Kerr to static black holes charged under Maxwell and Born–Infeld sectors.

scholarly journals Massive gravity with Lorentz symmetry breaking: Black holes as heat engines

2018 ◽  
Vol 33 (31) ◽  
pp. 1850177 ◽  
Author(s):  
Sharmanthie Fernando
Keyword(s):  
Black Hole ◽  
Symmetry Breaking ◽  
Heat Engine ◽  
Massive Gravity ◽  
Lorentz Symmetry ◽  
Extended Phase ◽  
Heat Engines ◽  
Static Black Hole ◽  
Lorentz Symmetry Breaking ◽  
Two Parameters

In extended phase space, a static black hole in massive gravity is studied as a holographic heat engine. In the massive gravity theory considered, the graviton gains a mass due to Lorentz symmetry breaking. Exact efficiency formula is obtained for a rectangle engine cycle for the black hole considered. The efficiency is computed by varying two parameters in the theory, the scalar charge Q and [Formula: see text]. The efficiency is compared with the Carnot efficiency for the heat engine. It is observed that when Q and [Formula: see text] are increased that the efficiency for the rectangle cycle increases. When compared to the Schwarzschild–AdS black hole, the efficiency for the rectangle cycle is larger for the massive gravity black hole.

Benchmarking black hole heat engines, I

2018 ◽  
Vol 27 (16) ◽  
pp. 1950012 ◽  
Author(s):  
Avik Chakraborty ◽  
Clifford V. Johnson
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Exact Result ◽  
Ideal Gas ◽  
Heat Engines ◽  
Gas System

We present the results of initiating a benchmarking scheme that allows for cross-comparison of the efficiencies of black holes used as working substances in heat engines. We use a circular cycle in the [Formula: see text] plane as the benchmark engine. We test it on Einstein–Maxwell, Gauss–Bonnet and Born–Infeld black holes. Also, we derive a new and surprising exact result for the efficiency of a special “ideal gas” system to which all the black holes asymptote.

scholarly journals Thermodynamics and heat engines of black holes with Born–Infeld-type electrodynamics

2021 ◽  
pp. 2150102
Author(s):  
Leonardo Balart ◽  
Sharmanthie Fernando
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Phase Transitions ◽  
Heat Engine ◽  
Nonlinear Electrodynamics ◽  
Extended Phase ◽  
Charged Black Holes ◽  
Heat Engines ◽  
Two Parameters ◽  
Electrically Charged

In this paper, we have studied electrically charged black holes in a new model of nonlinear electrodynamics introduced by Kruglov in Mod. Phys. Lett. A 32, 1750201 (2017). There are two parameters for the theory and the black hole could have up to two horizons. Thermodynamics is studied in the extended phase space where the pressure is proportional to the cosmological constant. First law and the Smarr formula are derived. There are phase transitions similar to the Van der Waals liquid-gas phase transitions. Black hole is also studied as a heat engine and we have discussed how the parameters in the nonlinear electrodynamics theory affect the efficiency of the heat engine.

scholarly journals ENERGY EXTRACTION FROM GRAVITATIONAL COLLAPSE TO STATIC BLACK HOLES

2003 ◽  
Vol 12 (01) ◽  
pp. 121-127 ◽  
Author(s):  
REMO RUFFINI ◽  
LUCA VITAGLIANO
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Extraction Process ◽  
Maximum Efficiency ◽  
Energy Extraction ◽  
Mass Energy ◽  
Classical Level ◽  
Static Black Hole ◽  
Exact Analytic Expression ◽  
Analytic Expression

The mass-energy formula of black holes implies that up to 50% of the energy can be extracted from a static black hole. Such a result is reexamined using the recently established analytic formulas for the collapse of a shell and the expression for the irreducible mass of a static black hole. It is shown that the efficiency of energy extraction process during the formation of the black hole is linked in an essential way to the gravitational binding energy, the formation of the horizon and the reduction of the kinetic energy of implosion. Here a maximum efficiency of 50% in the extraction of the mass energy is shown to be generally attainable in the collapse of a spherically symmetric shell: surprisingly this result holds as well in the two limiting cases of the Schwarzschild and extreme Reissner–Nordström space–times. Moreover, the analytic expression recently found for the implosion of a spherical shell to an already formed black hole leads to a new exact analytic expression for the energy extraction which results in an efficiency strictly less than 100% for any physical implementable process. There appears to be no incompatibility between General Relativity and Thermodynamics at this classical level.

scholarly journals Causality of black holes in 4-dimensional Einstein–Gauss–Bonnet–Maxwell theory

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Xian-Hui Ge ◽  
Sang-Jin Sin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Shear Viscosity ◽  
Upper Bound ◽  
Causal Structure ◽  
Density Ratio ◽  
Entropy Density ◽  
Coupling Constant ◽  
Maxwell Theory ◽  
Black Hole Solutions

Abstract We study charged black hole solutions in 4-dimensional (4D) Einstein–Gauss–Bonnet–Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes an upper bound on the Gauss–Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss–Bonnet coupling constant $$\alpha _{GB}$$αGB to be bounded by $$\alpha _{GB}\le 0$$αGB≤0 as $$D\rightarrow 4$$D→4.

scholarly journals Black hole solutions in gravity with nonminimal derivative coupling and nonlinear material fields

2020 ◽  
Vol 29 (03) ◽  
pp. 2050025 ◽  
Author(s):  
Mykola M. Stetsko
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Field ◽  
Nonlinear Material ◽  
Derivative Coupling ◽  
First Law Of Thermodynamics ◽  
Tensor Theory ◽  
Static Black Hole ◽  
Nonlinear Lagrangians ◽  
Black Hole Solutions

Scalar–tensor theory of gravity with nonlinear electromagnetic field, minimally coupled to gravity is considered and static black hole solutions are obtained. Namely, power-law and Born–Infeld nonlinear Lagrangians for the electromagnetic field are examined. Since the cosmological constant is taken into account, it allowed us to investigate the so-called topological black holes. Black hole thermodynamics is studied, in particular temperature of the black holes is calculated and examined and the first law of thermodynamics is obtained with help of Wald’s approach.

Three-dimensional static black hole with Λ and nonlinear electromagnetic fields and its thermodynamics

2019 ◽  
Vol 28 (12) ◽  
pp. 1950160
Author(s):  
M. B. Tataryn ◽  
M. M. Stetsko
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Electromagnetic Fields ◽  
Three Dimensional ◽  
Nonlinear Electrodynamics ◽  
Extended Phase Space ◽  
Field Equations ◽  
Extended Phase ◽  
Dimensional Spacetime ◽  
Static Black Hole

Static black hole with the Power Maxwell invariant (PMI), Born–Infeld (BI), logarithmic (LN), exponential (EN) electromagnetic fields in three-dimensional spacetime with cosmological constant was studied. It was shown that the LN and EN fields represent the Born–Infeld type of nonlinear electrodynamics. It the framework of General Relativity the exact solutions of the field equations were obtained, corresponding thermodynamic functions were calculated and the [Formula: see text] criticality of the black holes in the extended phase-space thermodynamics was investigated.

scholarly journals GENERAL BPS BLACK HOLES IN FIVE DIMENSIONS

1998 ◽  
Vol 13 (03) ◽  
pp. 239-252 ◽  
Author(s):  
W. A. SABRA
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Phase Transitions ◽  
Moduli Space ◽  
Arbitrary Number ◽  
Five Dimensions ◽  
Geometry Structure ◽  
Static Black Hole ◽  
Hole Configuration ◽  
M Theory

An algorithm for constructing general static black hole configuration for the theory of N=2, d= 5 supergravity coupled to an arbitrary number of Abelain vector multiplets is given. The underlying very special geometry structure plays a major role in this construction. From the viewpoint of M-theory compactified on a Calabi–Yau threefold, these black holes are identified with BPS winding states of the membrane around two-cycles of the Calabi–Yau threefold, and thus are of importance in the probing of the phase transitions in the moduli space of M-theory compactified on a Calabi–Yau threefold.

scholarly journals Black holes with topological charges in Chern-Simons AdS5 supergravity

2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Laura Andrianopoli ◽  
Gaston Giribet ◽  
Darío López Díaz ◽  
Olivera Miskovic
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Hamiltonian Formalism ◽  
Naked Singularity ◽  
Extremal Black Hole ◽  
Pure Gauge ◽  
Static Black Hole ◽  
Abelian Field ◽  
Chern Simons ◽  
Spatial Section

Abstract We study static black hole solutions with locally spherical horizons coupled to non-Abelian field in $$ \mathcal{N} $$ N = 4 Chern-Simons AdS5 supergravity. They are governed by three parameters associated to the mass, axial torsion and amplitude of the internal soliton, and two ones to the gravitational hair. They describe geometries that can be a global AdS space, naked singularity or a (non-)extremal black hole. We analyze physical properties of two inequivalent asymptotically AdS solutions when the spatial section at radial infinity is either a 3-sphere or a projective 3-space. An important feature of these 3-parametric solutions is that they possess a topological structure including two SU(2) solitons that wind nontrivially around the black hole horizon, as characterized by the Pontryagin index. In the extremal black hole limit, the solitons’ strengths match and a soliton-antisoliton system unwinds. That limit admits both non-BPS and BPS configurations. For the latter, the pure gauge and non-pure gauge solutions preserve 1/2 and 1/16 of the original supersymmetries, respectively. In a general case, we compute conserved charges in Hamiltonian formalism, finding many similarities with standard supergravity black holes.

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