this post was submitted on 27 Dec 2023
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176
Physicists Designed an Experiment to Turn Light Into Matter (gizmodo.com)
submitted 10 months ago by L4s to c/technology
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Physicists Designed an Experiment to Turn Light Into Matter::It would be a tangible demonstration of Einstein's famous E = mc^2 equation.

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[–] ook_the_librarian 19 points 10 months ago (1 children)

It seems that the paper is making theoretical strides in the limitations of producing a positron beam via the Breit-Wheeler process. From Wikipedia

This mechanism is theoretically characterized by a very weak probability, so producing a significant number of pairs requires two extremely bright, collimated sources of photons having photon energy close to or above the electron and positron rest mass energy. Manufacturing such a source, for instance, a gamma-ray laser, is still a technological challenge.

I'm not claiming I know this stuff. I was just trying to figure out what was new here since I didn't find the headline very surprising.

[–] supercriticalcheese 8 points 10 months ago

Abstract:

We discovered a simple regime where a near-critical plasma irradiated by a laser of experimentally available intensity can self-organize to produce positrons and accelerate them to ultrarelativistic energies. The laser pulse piles up electrons at its leading edge, producing a strong longitudinal plasma electric field. The field creates a moving gamma-ray collider that generates positrons via the linear Breit-Wheeler process—annihilation of two gamma rays into an electron-positron pair. At the same time, the plasma field, rather than the laser, serves as an accelerator for the positrons. The discovery of positron acceleration was enabled by a first-of-its-kind kinetic simulation that generates pairs via photon-photon collisions. Using available laser intensities of 1022  W/cm2, the discovered regime can generate a GeV positron beam with a divergence angle of around 10° and a total charge of 0.1 pC. The result paves the way to experimental observation of the linear Breit-Wheeler process and to applications requiring positron beams.

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