10,030 research outputs found
Entropic force law in the presence of a noncommutative inspired spacetime for a solar system scale
We first study some aspects of a physically inspired kind of a noncommutative
spherically symmetric spacetime based on the Gaussian-smeared mass distribution
for a solar system scale. This leads to the elimination of a singularity
appeared in the origin of the spacetime. Afterwards, we investigate some
features of Verlinde's scenario in the presence of the mentioned spacetime and
derive several quantities such as Unruh-Verlinde temperature, the energy and
the entropic force on three different types of holographic screens, namely the
static, the stretched horizon and the accelerating surface.Comment: 11 pages, 3 figure
Gravitational energy of a noncommutative Vaidya black hole
In this paper we evaluate the components of the energy-momentum pseudotensors
of Landau and Lifshitz for the noncommutative Vaidya spacetime. The effective
gravitational mass experienced by a neutral test particle present at any finite
distance in the gravitational field of the noncommutative Vaidya black hole is
derived. Using the effective mass parameter one finds that the naked
singularity is massless and this supports Seifert's conjecture.Comment: 10 pages, no figure, to appear in Can. J. Phy
Planck-scale nonthermal correlations in a noncommutative geometry inspired Vaidya black hole
Using the noncommutative geometry inspired Vaidya metric obtained in terms of
coordinate coherent states and also utilizing the generalized uncertainty
principle (GUP), we show that the nonthermal nature of the Hawking spectrum
leads to Planck-scale nonthermal correlations between emitted modes of
evaporation. Our analysis thus exhibits that owing to self-gravitational
effects plus noncommutativity and GUP influences, information can emerge in the
form of Planck-scale correlated emissions from the black hole.Comment: 16 pages, no figure, minor revisio
Emergent GUP from Modified Hawking Radiation in Einstein-NED Theory
We present a general procedure for constructing exact black hole (BH)
solutions with the magnetic charge in the context of nonlinear electrodynamics
(NED) theory as well as in the coherent state approach to noncommutative
geometry (NCG). In this framework, the Lagrangian density for the
noncommutative Hayward BH is obtained and the weak energy condition (WEC) is
satisfied. The noncommutative Hayward solution depends on two kind of charges
which for the vanishing of them yields the Schwarzschild solution. Moreover, in
order to find a link between the BH evaporation and uncertainty relations, we
may calculate the Hawking temperature and find the effect of the Lagrangian
density of BHs on the Hawking radiation. Therefore, a generalized uncertainty
principle (GUP) emerges from the modified Hawking temperature in Einstein-NED
theory. The origin of this GUP is the combined influence of a nonlinear
magnetic source and an intrinsic property of the manifold associated with a
fictitious charge. Finally, we find that there is an upper bound on the
Lagrangian uncertainty of the BHs which are sourced by the NED field and/or the
fictitious charge.Comment: 24 pages, 3 figures, 1 table, new issues in Introduction and new
References are added, Title is changed, minor revisions in Abstract and
Conclusion
Thermodynamical features of Verlinde's approach for a non-commutative Schwarzschild-anti-deSitter black hole in a broad range of scales
We try to study the thermodynamical features of a non-commutative inspired
Schwarzschild-anti-deSitter black hole in the context of entropic gravity
model, particularly for the model that is employed in a broad range of scales,
from the short distances to the large distances. At small length scales, the
Newtonian force is failed because one finds a linear relation between the
entropic force and the distance. In addition, there are some deviations from
the standard Newtonian gravity at large length scales.Comment: 17 pages, 4 figures, accepted for publication in EPJ Plu
Bounds on the degrees of birational maps with arithmetically Cohen-Macaulay graphs
A rational map whose source and image are projectively embedded varieties has
an {\em Arithmetically Cohen-Macaulay graph} if the Rees algebra of one (hence
any) of its base ideals is a Cohen-Macaulay ring. If the map is birational onto
the image one considers how this property forces an upper bound on the degree
of a representative of the map. In the plane case a complete description is
given of the Cremona maps with Cohen-Macaulay graph, while in arbitrary
dimension it is shown that a Cremona map with Cohen-Macaulay graph has
degree at most .Comment: Last version to appear in Journal of Algebr
Some examples of different descriptions of energy-momentum density in the context of Bianchi IX cosmological model
Based on the Bianchi type IX metric, we calculate the energy and momentum
density components of the gravitational field for the five different
definitions of energy-momentum, namely, Tolman, Papapetrou, Landau-Lifshitz,
M{\o}ller and Weinberg. The energy densities of M{\o}ller and Weinberg become
zero for the spacetime under consideration. In the other prescriptions, i.e.,
Tolman, Papapetrou and Landau-Lifshitz complexes, we find different
non-vanishing energy-momentum densities for the given spacetime, supporting the
well-known argument in General Relativity that the different definitions may
lead to different distributions even in the same spacetime background.Comment: 11 pages, no figure, typos corrected, accepted for publication in
Indian J. Phy
On A Generalization of Weak Armendariz Rings
We introduce the notion of J-Armendariz rings, which are a generalization of
weak Armendariz rings and investigate their properties. We show that any local
ring is J-Armendariz, and then fined a local ring that is not weak Armendariz.Comment:
Vehicle as a Resource (VaaR)
Intelligent vehicles are considered key enablers for intelligent
transportation systems. They are equipped with resources/components to enable
services for vehicle occupants, other vehicles on the road, and third party
recipients. In-vehicle sensors, communication modules, and on-board units with
computing and storage capabilities allow the intelligent vehicle to work as a
mobile service provider of sensing, data storage, computing, cloud, data
relaying, infotainment, and localization services. In this paper, we introduce
the concept of Vehicle as a Resource (VaaR) and shed light on the services a
vehicle can potentially provide on the road or parked. We anticipate that an
intelligent vehicle can be a significant service provider in a variety of
situations, including emergency scenarios
On Central Skew Armendariz rings
For a ring endomirphism, we introduce the central skew Armendariz rings,
which are a generalization of skew Armendariz rings and central Armendariz
rings, and investigate their properties.Comment: 9 page
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