Questions tagged [kerr-newman-metric]

The most general asymptotically flat, stationary solution of the Einstein–Maxwell equations in general relativity that describes the spacetime geometry in the region surrounding an electrically charged, rotating mass. It generalises the Kerr metric by taking into account the field energy of an electromagnetic field, in addition to describing rotation.

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Null-geodesic proper velocity from initial conditions

I have simulated the geodesics of massive particles in the Kerr-Newman metric (though I don't think the metric matters) using Hamiltonian mechanics and I am now attempting to simulate null geodesics. ...
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Carter Constant with a Cosmological Constant

The Carter constant for the Kerr Newman metric $$ \rm C = p_{\theta}^{2} + \cos^{2}\theta \ \Bigg[ a^2 \ (m^2 - E^2) + \left(\frac{L_z}{\sin\theta} \right)^{2} \Bigg] $$ with (in $[+---]$ signature) $$...
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Komar energy using Mathematica [closed]

I want to check Komar conserved quantities for Kerr Newman metric using Mathematica. Is there any way to write a programming code for this? Can anyone help me?
Debojyoti Mondal's user avatar
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How does one covert from Cartesian coordinates to Boyer-Lindquist coordinates?

I am new to physics stackexchange, but I have a question which I seem to have not been able to find an answer to. I already know that the transformations from Boyer-Lindquist coordinates to Cartesian ...
Cerealmarrow100's user avatar
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Derivation of the one-form potential in Kerr-Newman spacetime--Sean Carroll GR

In Sean Carroll's GR book, he gives the non-vanishing components of the one-form potential of a Kerr-Newman blackhole, I am not sure how to derive this just from the metric itself. I looked at some ...
Dharil Shah's user avatar
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Are metrics of general relativity tested?

We tested general relativity with effects as gravitational lensing and existence of black holes (Schwarzschild metric). But there are other metrics, e.g. Kerr-Newman metric for a point mass with ...
JavaGamesJAR's user avatar
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How can the ratio of a black hole's (or any object's) angular momentum to its mass be less than one?

In the latest Quanta Magazine article, about Kerr black holes, the researchers say their new solution for these objects only works, so far, for Kerr black holes with a ratio of angular-momentum-to-...
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Metric of spinning magnetically charged black hole

According to Wikipedia (as of 1/20/2021), black holes may be completely classified according to their mass, electric charge and angular momentum. Are there not also 'magnetic monopole' solutions to ...
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Doubt on Newman-Janis algorithm for a traversable Wormhole

Recently in a paper $[1]$ the researchers presented a rotating traversable wormhole solution using the famous Newman-Janis Algorithm $[2]$. But something is anoying me. In $[1]$ they presented the ...
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Does the no-hair theorem apply to non-stationary spacetimes?

Carroll (pg. 238) gives the follow statement of the no-hair theorem: Stationary, asymptotically flat black hole solutions to general relativity coupled to electromagnetism that are nonsingular ...
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Area of Kerr-Newman event horizon

I want to calculate the area of event horizon for a Kerr-Newman black hole by using boyer's coordinates. I searched a lot from web, but I could not find any information about calculating event ...
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Metric diameter of a ring singularity

In the Kerr metric the ring singularity is located at the coordinate radius $r=0$, which corresponds to a ring with the cartesian radius $R=a$. So the center of the ring singularity in cartesian ...
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Would naked singularities have a complex irreducible mass?

The formula for the irreducible mass, also known as the Christodoulou and Ruffini equation, is $$M_{\rm irr} = \frac{\sqrt{2 M^2-Q^2+2 M \sqrt{M^2-Q^2-a^2}}}{2}$$ where M is the mass equivalent of ...
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Coordinate transformation from Boyer-Lindquist to rotating frame

The Kerr-Newman metric in Boyer-Lindquist coordinates $ x^{\mu} = (t,r,\theta,\phi) $ is of the form $$ ds^2 = g_{tt}dt^2 + 2g_{t\phi}dt d\phi + g_{rr}dr^2 + g_{\theta \theta} d\theta^2 + g_{\phi \phi}...
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Equation of motion for a charged particle

To compute the equations of motion of a neutral testparticle in the graviational field, one needs the metric tensor $g_{\mu \nu}$ and $g^{\mu \nu}$ to compute the Christoffel-symbols $${\Gamma^{\rm ...
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Near Horizon Vector Field

I am studying this paper https://arxiv.org/pdf/0811.4393.pdf. I find a probem to find the near horizon form of the vector (2.17) and electromagnetic (2.18) field. I have tried to use the near horizon ...
M. Fitrah Alfian R. S.'s user avatar
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Are electrons points or Kerr naked ring singularities?

I have heard contradictory descriptions of electrons as both points and kerr naked ring singularities, with that said which is it? Are they rings or are they points? Are they somehow both?
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Gravitation Acceleration in General of Kerr-Newman Black Hole

The surface gravity (acceleration at event horizon, as measured by an observer at infinity, since the proper acceleration is infinite) of a Kerr-Newman black hole is given (e.g. here) as:$$ \kappa ...
geometrian's user avatar
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Correlation between gravitational and electromagnetic radiation from collision of Kerr-Newman black holes

When black holes collide, they produce a gravitational wave, as has been recently established by LIGO. When a charge is accelerated, it creates an electromagnetic wave. Does an accelerated massive ...
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Explain Kerr-Newmann Black Hole Spins in SI Units

I'm trying to run some calculations on Kerr-Newman black holes, but I'm having two major difficulties. First, most equations I've been able to find are only for Kerr black holes. Second, essentially ...
geometrian's user avatar
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Escape velocity from a rotating black hole

Under Newton, the escape velocity is $$v_{esc} = \rm c \ \sqrt{r_s/r}$$ where $\rm r_s=2 \ GM/c^2$. In the nonrotating relativistic case (the Schwarzschild case) the radial escape velocity is the ...
Yukterez's user avatar
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Why doesn't the Kerr-Newman metric reduce to the Schwarzschild metric?

I hope this is not just an algebra mistake (and I'm very sorry if it is). Also, note I use the convention that the time argument is negative. Setting $G=M=c=1$ for the Schwarzschild metric, it ...
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Does the event horizon of a black hole need to be an oblate sphere?

Suppose two black holes where rotating around each other, perhaps spinning into each other, at a distance such that their event horizons merge into one event horizon. It seems to me that the event ...
sebastianspiegel's user avatar
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How to find the Hawking temperature for this metric?

I am reading this paper about "Hawking radiation of Kerr-Newman-de Sitter black hole", where the authors find Hawking temperature of this metric The authors state that hawking temperature is given by ...
WhyME's user avatar
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GR Verification for a Charged Black Hole

For a charged ($Q$) rotating ($L$) mass ($M$), the Kerr-Newman equations give the angular deflection of light. Has there been observational verification (I would prefer to use only the angular ...
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Electromagnetic four-potential for Kerr-Newman solution

Any textbook or paper on the Kerr-Newman metric I found contains the solution for the electromagnetic tensor $ F^{\mu}_{\phantom{\mu} \nu}$. Can you provide a (reliable) reference for the solution ...
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Charged versus rotating black holes as different kinds of wormholes

I've heard that a maximally extended charged black hole can be a traversable wormhole to the same universe whereas a maximally extended uncharged rotating black hole can only be a wormhole to ...
Timaeus's user avatar
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Generalized Bekenstein-Hawking temperature for Kerr-Newmann-dS black holes

What is the formula for the Bekenstein-Hawking temperature in a Kerr-Newmann-de Sitter spacetime, i.e., the temperature for a black hole with Mass (M), angular momentum (J), electric charge (Q) and ...
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Surface gravity for a rotating charged black hole

I have that the surface gravity (at the outer event horizon) for a Kerr-Newman black hole is $$ K_+ = \frac{r_+-r_-}{2(r_+^2+(J/M)^2)} = \frac{\sqrt{M^2-Q^2-J^2/M^2}}{2M^2-Q^2+2M\sqrt{M^2-Q^2-J^2/M^2}}...
Charles's user avatar
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is this generalized Hawking radiation formula right?

Look at equation 11.2.17 in this page. The expression is: $$ T = 10^{-5} \text{K m} \frac{\xi}{\frac{GM}{c^2} \lbrace \frac{GM}{c^2} + \xi \rbrace - e^2 }$$ where $$ \xi = (r_s^2 - a^2 - e^2)^{1/2}$...
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Kerr-Newman black holes and infinite charge

Recall the first law of BH thermodynamics $ dM=\frac{\kappa}{8\pi} dA + \Omega dJ + \Phi dQ $ Now, let's consider the Reissner-Nordstrom solution $J=0$ such that $m>Q$ but only slightly greater. ...
eherrtelle59's user avatar
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If a Kerr-Newman black hole is like a charged, spinning, heavy magnet, what kind of magnet is it like?

I was reading up on De Sitter spaces, which states that the gravitational effects from a black hole is indistinguishable from any other spherically symmetric mass distribution. This makes a lot of ...
Alan Rominger's user avatar