Here are a couple excerpts from the article to which you linked that appear to me to present a conflict.
'"Even though light does not have mass, it does carry energy," Polo-Gómez said, adding that, in Einstein's theory of general relativity, energy is responsible for creating curvatures in space-time that result in gravitational attractions. "Because of that, it is in principle possible for light to form black holes — if we concentrate enough of it in a small enough volume," he said.'
This does NOT say that general relativity tells us that a black hole of light may be formed. Only that light curves space time.
"In their
study, which has been accepted for publication in the journal
Physical Review Letters but has not been published yet, the team calculated the rate at which electron-positron pairs produced in an electromagnetic field would deplete energy. If this rate surpasses the replenishment rate of the electromagnetic field's energy in a given region, a kugelblitz cannot form.
The team found that, even under the most extreme circumstances, pure light could never reach the required energy threshold to form a black hole."
This states that as EM energy is concentrated in an attempt to form a kugelblitz, the rate at which electron-positron pairs are formed increases and bleeds off energy. But it adds the qualifier "if this rate surpasses the replenishment rate". The unasked or answered question is what limits the replenishment rate?
"What we prove is that kugelblitze are impossible to form by concentrating light, either artificially in the laboratory or in naturally occurring astrophysical scenarios," study co-author
Luis J. Garay, also of IPARCOS, told Live Science.
This
seems to say that the rate of energy lost to the Schwinger Effect's particle pair generation will always exceed what is needed to reach, in effect, the Chadresekhar limit for black hole formation. But IS THAT what they are saying. The following statement:
'"For instance, even if we used the most intense
lasers on Earth, we would still be more than 50 orders of magnitude away from the intensity required to create a kugelblitz."'
This statement does two things that throw some uncertainty on what has been accomplished here. By using the example of the capabilities of humans to create sufficiently intense EM, they have thrown in an artificial limit. And then the phrase "50 orders of magnitude away from the intensity required to create a kugelblitz" indicates there IS an intensity that will create a kugelblitz, but humans, at present, are not technologically capable of reaching it. To my knowledge, there is no technological control of the Schwinger effect and the effect is not mentioned in this last paragraph. They seem to simply be saying that humans cannot currently create a kugelblitz in the lab, not that it is physically impossible to do.
The other option: "in naturally occurring astrophysical scenarios" simply says that we know of no naturally occurring event that could create a kugelblitz. That has two weaknesses. Our knowledge of the universe is finite and it is entirely possible for humans to create conditions that exist - naturally - nowhere else in the universe.
And you have to admit that this article hasn't created any flood of physicists attempting to rewrite general relativity. As you may have noted in the beginning of the article, there is no problem creating a kugelblitz using classic general relativity. The supposed conflict arose when the study authors combined general relativity and quantum mechanics, a combination that decades of physicists and mathematicians have been finding impossible to do.
science.nasa.gov
