Is there a gravitational variant of the Schwinger limit ?

[Giovanni]

Is there a gravitational variant of the Schwinger limit? I mean: a strong gravitational field can separate virtual dipoles with tidal forces. The force applied to the positron is different from that applied to the electron (though both are attractive) and, if this difference is high enough, the two particles can be separated permanently. Do you agree with this? Has this occurrence been studied in physics in the literature of the past? I have not found anything on the internet and it seems strange.

Edited March 5, 2018 by Giovanni
Forgotten question mark

[swansont]

Should be straightforward to test to see if that would put you inside or outside of the Schwarzschild radius of a body of mass M, if you knew what tidal force was necessary.

 

 

[Giovanni]

Thanks for your answer.

I believe that I will avoid the General Relativity (that I do not know) and I will use the  Gravitoelectromagnetism (https://en.wikipedia.org/wiki/Gravitoelectromagnetism) (an approximation of the General Relativity similar to the Maxwell equations) that recently also has a 'quantum' version (https://arxiv.org/abs/1605.07207)

Since the equations are similar to those of Maxwell, the derivation of the threshold value should not be very different from that of the electromagnetic counterpart. (The Schwinger limit of Quantum Electrodynamics) Or at least I hope so.

I really do not know the applicability conditions of the GEM approximation: they hold for so high fields? I will check this.

 

[Giovanni]

I was motivated by this: http://www.dailymail.co.uk/sciencetech/article-2853083/Scientists-lightning-sparking-supermassive-black-hole-appears-travel-faster-speed-light.html

Maybe there is a simpler explanation but anyway is interesting.

 

Edited March 8, 2018 by Giovanni

[Strange]

Your link doesn’t work for me - just takes me to a page full of gossip, lies and hate.

But I really wouldn’t rely on the Mail as a source of information on anything. Perhaps you could find a science website (or even a real newspaper) with the info?

[swansont]

30 minutes ago, Giovanni said:

I was motivated by this: http://www.dailymail.co.uk/sciencet...k-hole-appears-travel-faster-speed-light.html

Maybe there is a simpler explanation but anyway is interesting.

 

When you copy a shortened link it does not give you the actual link. Anything with a "..." in the actual url won't work.

[Giovanni]

Edited: a cut and paste mistake. Sorry. Now works.

Quote

But I really wouldn’t rely on the Mail as a source of information on anything.

Good point. With little time i will find the original source.

[MigL]

I couldn't get to the link either, but I now know what color underwear Kim Kardashian is wearing today...

IIRC the Schwinger limit is where the EM field is strong enough so that interactions are not 'linear' anymore, such that photon-photon interactions are possible because of intermediary electron-positron virtual particle creation.
Virtual particles are a requirement of quantum field theory, and as such are present right up to the event horizon of a BH ( most likely inside also but very hard to get evidence ).
The fact that an extremely steep gravitational potential could separate virtual particles, allowing one to escape and become real, while the other 'evaporates' the BH seems a no-brainer, and is, in fact, a simplistic explanation of Hawking radiation.

But I don't see a relation to the Schwinger limit.

[Giovanni]

https://www.mpg.de/8741005/radiationoutburst_galaxy_ic310

From the linked article:

Quote

“No object can suddenly light up its entire surface faster than light takes to travel across it,” says Julian Sitarek from the Institut de Fisica d'Altes Energies (IFAE) in Barcelona.

 

Quote

 couldn't get to the link either

try now with the link at the post number 4.

[Strange]

I found the Mail article pretty confusing. Looking at the abstract of the paper, it doesn’t obviously match the Mail article. 

This article, despite being apparently being google-translated, seems to make a bit more sense: https://www.sciencedaily.com/releases/2014/11/141110090721.htm

 

The original paper is available here: https://arxiv.org/abs/1412.4936

[MigL]

Just read Giovanni's new link.
Isn't that basically the accepted explanation for polar jets from a BH ?

[Giovanni]

Quote

But I don't see a relation to the Schwinger limit.

https://arxiv.org/pdf/1711.05194.pdf (Klaus Scharnhorst: peer reviewed and well known)

From the previous article: paragraph 2.2.2

Quote

Propagation of light in macroscopic, constant magnetic and electrical fields....From out the modern point of view of quantum electrodynamics a null result does not come unexpected.....  recognizes that the strong electric field used by Stark is too weak to give rise to any nonlinear quantum electrodynamic effects.

In short: with fields greater than Schwinger limit you can affect the speed of light. (or, at least, >= Schwinger limit it's a necessary condition)

Edited March 8, 2018 by Giovanni

[Strange]

22 minutes ago, MigL said:

Just read Giovanni's new link.
Isn't that basically the accepted explanation for polar jets from a BH ?

I think the key thing they are reporting is that they are effectively able to resolve something smaller than the even horizon (the area where the "lightning" originates).

[MigL]

On the contrary , while your posted Shamhosrt link does mention what I previously mentioned about non-linearity and photon-photon scattering, the only mention on, on page 9, about variability of the speed of light is one experimental case, in air ( which I could imagine happening ), but subsequent experiments have failed to comfirm, and the last paragraph in that section clearly states...

" Not long after the publication of his work [1] they have checked his assertion in other experiments with higher precision and found no indication for any intensity dependence of the speed of light hereby ruling out any noticeable self-interaction of a light beam with itself (F. Lippich, University of Prague, Austria: [2]; H. Ebert (University of Erlangen, Germany "

Edit: @ Giovanni

Edited March 8, 2018 by MigL

[Giovanni]

Yes but this is about 'Influence of the intensity on the propagation of light'

....and or me that's ok that there is no influence.

I'm talking about the following paragraph.

I thought that your statement

Quote

I don't see a relation to the Schwinger limit.

was about relation between the Schwinger limit and the interaction between external fields and speed of light in vacuum

 

Anyway searching for the dailymail article i discovered this:

http://cerncourier.com/cws/article/cern/28606

<<Quantum effects such as vacuum polarization in gravitational fields appear to permit "superluminal" photon propagation and give a fascinating new perspective on our understanding of time and causality in the microworld.>>

I have not read it yet so i cannot say but it seems relevant.

[MigL]

I still don't see a relation, because at no time or place ( except at the possible singularity ) does the gravitational field become non-linear.
There is no abrupt change in the way the gravitational field acts at the event horizon, or with increased gravitational 'intensity'.
Or do we have differing definitions of the Schwinger limit ?

Edited for clarification.

Edited March 8, 2018 by MigL

[Giovanni]

I define the Schwinger limit as the minimal value for the E field to produce the Schwinger effect 

From the previous:

Quote

However, the electric field required to see this effect is astronomically huge, E_critical~ 10^(16) V/cm, and so it has not yet been directly observed, even using the strongest lasers.

Is not true.

http://www.nytimes.com/1997/09/16/science/scientists-use-light-to-create-particles.html

 

 

Ok finally i have found a clear explanations:

Read the paragraph Schwinger effect

the key words are "and continue to move apart".

Personal hypothesis:

So, since the distance between the now reals electron and positron increases they are not more a dipole: they are no more capable of absorbing photons (single electrons and positrons cannot absorb photons)....so for the Scharnhorst effect the speed of light increase.

(sorry for me all those things are obvious....but for the readers are not)

Edited March 8, 2018 by Giovanni

[MigL]

Schwinger limit

https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjd9dWct93ZAhVn5IMKHZwbD4AQFggnMAA&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FSchwinger_limit&usg=AOvVaw1loYPQGfJvq7eBz7J7xg94

[Giovanni]

I have posted also on physicsforum.com: https://www.physicsforums.com/threads/is-there-a-gravitational-variant-of-the-schwinger-limit.941397/

[Giovanni]

finally, by simply looking for "pair production tidal forces", I found the following article:

https://www.sciencedirect.com/science/article/pii/S0370269317307888

I do not have the right background to understand the content but some sentences are clear to me and it seems extremely relevant to the discussion. It's exactly what i was searching for: a gravitational analog of the Schwinger effect based on tidal forces.

The only thing that must now be done is showing that in this black hole 'atmosphere' photons can be superluminal.