37 citations · 338 across the 18 of their papers we have counts for
18 papers
Information, entropy and the paradox of choice: A model for understanding human choice behavior
Mojtaba Madadi Asl, Kamal Hajian, Saeideh Ramezani Akbarabadi +2
Choice overload occurs when individuals feel overwhelmed by excessive alternatives during decision making. Although larger choice sets are often assumed to be more satisfying, beha…
Coupling Constants as Conserved Charges in Black Hole Thermodynamics
Kamal Hajian, Bayram Tekin
In a generic theory of gravity coupled to matter fields, the Smarr formula for black holes does not work properly if the contributions of the coupling constants defining the theory…
Single-rotating Five-dimensional Near-horizon Extremal Geometry in General Relativity
Kamal Hajian
The geometries with SL and some axial U isometries are called ``near-horizon extremal geometries" and are found usually, but not necessarily, in the near-horiz…
On the Origin of Black Hole Paradoxes
Kamal Hajian
Black hole firewall paradox is an inconsistency between four postulates in black hole physics: (1) the unitary evolution in quantum systems, (2) application of the semi-classical f…
First law of black hole thermodynamics and Smarr formula with a cosmological constant
Kamal Hajian, Hikmet Özşahin, Bayram Tekin
The first law of black hole thermodynamics in the presence of a cosmological constant can be generalized by introducing a term containing the variation . Similar to other t…
On Black Hole Temperature in Horndeski Gravity
K. Hajian, S. Liberati, M. M. Sheikh-Jabbari +1
It has been observed that for black holes in certain family of Horndeski gravity theories Wald's entropy formula does not lead to the correct first law for black hole thermodynamic…
Light speed memory as a local observable for soft hairs
Kamal Hajian
Einstein observers in flat space-time are inertial observers which use light to synchronize their clocks. For such observers, speed of light is a constant by construction. However,…
Cosmological constant is a conserved charge
Dmitry Chernyavsky, Kamal Hajian
Cosmological constant can always be considered as the on-shell value of a top form in gravitational theories. The top form is field strength of a gauge field, and the theory enjoys…
Redundant and Physical Black Hole Parameters: Is there an independent physical dilaton charge?
K. Hajian, M. M. Sheikh-Jabbari
Black holes as solutions to gravity theories, are generically identified by a set of parameters. Some of these parameters are associated with black hole physical conserved charges,…
Revisiting Conserved Charges in Higher Curvature Gravitational Theories
M. Ghodrati, K. Hajian, M. R. Setare
Restricting the covariant gravitational phase spaces to the manifold of parametrized families of solutions, the mass, angular momenta, entropies, and electric charges can be calcul…
Black Hole Entropy from Entropy of Hawking Radiation
Sajad Aghapour, Kamal Hajian
We provide a simple way for calculating the entropy of a Schwarzschild black hole from the entropy of its Hawking radiation. To this end, we show that if a thermodynamic system los…
Conserved Charges and First Law of Thermodynamics for Kerr-de Sitter Black Holes
Kamal Hajian
Recently, a general method for calculating conserved charges for (black hole) solutions to generally covariant gravitational theories, in any dimensions and with arbitrary asymptot…
Quantum Jump from Singularity to Outside of Black Hole
Furkan Semih Dündar, Kamal Hajian
Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as…
On Thermodynamics and Phase Space of Near Horizon Extremal Geometries
Kamal Hajian
Near Horizon Extremal Geometries (NHEG), are geometries which may appear in the near horizon region of the extremal black holes. These geometries have $SL(2,\mathbb{R})\!\times\!U(…
Wiggling Throat of Extremal Black Holes
G. Compère, K. Hajian, A. Seraj +1
We construct the classical phase space of geometries in the near-horizon region of vacuum extremal black holes as announced in [arXiv:1503.07861]. Motivated by the uniqueness theor…
Extremal Rotating Black Holes in the Near-Horizon Limit: Phase Space and Symmetry Algebra
G. Compère, K. Hajian, A. Seraj +1
We construct the NHEG phase space, the classical phase space of Near-Horizon Extremal Geometries with fixed angular momenta and entropy, and with the largest symmetry algebra. We f…
Near Horizon Extremal Geometry Perturbations: Dynamical Field Perturbations vs. Parametric Variations
K. Hajian, A. Seraj, M. M. Sheikh-Jabbari
In arXiv:1310.3727 we formulated and derived the three universal laws governing Near Horizon Extremal Geometries (NHEG). In this work we focus on the Entropy Perturbation Law (EPL)…
NHEG Mechanics: Laws of Near Horizon Extremal Geometry (Thermo)Dynamics
K. Hajian, A. Seraj, M. M. Sheikh-Jabbari
Near Horizon Extremal Geometries (NHEG) are solutions to gravity theories with (for some N) symmetry, are smooth geometries and have no event horizon, unl…