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Omar Loisel
53,027 followers -
Amateur astronomy, cosmology, astrophysics and physics in general, music, film, photography, painting, sports and many other things - Amateur d'astronomie, de cosmologie, d'astrophysique et de physique en général, de musique, de cinéma, de photo, de peinture, de sport ainsi que de beaucoup d'autres choses
Amateur astronomy, cosmology, astrophysics and physics in general, music, film, photography, painting, sports and many other things - Amateur d'astronomie, de cosmologie, d'astrophysique et de physique en général, de musique, de cinéma, de photo, de peinture, de sport ainsi que de beaucoup d'autres choses

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Une nouvelle méthode pour tester directement la gravité quantique

L’unification de la relativité générale et de la mécanique quantique est un des enjeux primordiaux de la physique moderne. Ces dernières années, de nombreuses théories à gravité quantique ont progressivement émergé, parmi lesquelles la théorie des superformes, la gravitation quantique à boucles ou encore la géométrie non commutative.

Plus d'info : http://trustmyscience.com/nouvelle-methode-de-test-pour-la-gravite-quantique/

Illustration montrant un espace-temps non commutatif. L’on y aperçoit l’interaction électrofaible entre les deux feuillets bleus et la propagation du boson de Higgs (H). Quant à l’interaction forte, elle se situe sur le feuillet multicolore. Crédits : non commutativegeometry.nl
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It's been a while since I would like to know more about #markdown and #pandoc. Markdown is a good alternative to LaTeX if you want to create quickly short documents containing mathematical formulas and source code . I've found a lot of Markdown editors with integrated preview and html/latex/ods/pdf export but some incompatibilities appears between editor rendering and export for mathematical formulas. For example with Retext I get :

$...$ no rendering no latex export
$$...$$ no rendering good latex export
\(...\) good rendering no latex export
\[...\] good rendering no latex export

I've finally found a workaround :
* I use \(...\) and \[...\] in the markdown editor
* then I use sed to replace \(...\) and \[...\] by $...$ and $$...$$
* then I call pandoc -f markdown t latex -o file.pdf http://file.md to export

It was hard to find a solution on the web so I would wrote a blog entry about this ...

more informations
https://en.wikipedia.org/wiki/Markdown
https://pandoc.org/
editors
https://github.com/retext-project/retext available in default ubuntu repositories
https://github.com/atareao/utext I like its rendering !!
https://yhatt.github.io/marp/ perfect for slides
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Gamma rays reach beyond the limits of light

Researchers have discovered a highly efficient way to produce high energy photon beams. The obtained energy is a billion times higher than the energy of photons in visible light. These high-intensity gamma rays significantly exceed all known limits, and pave the way towards new fundamental studies.

Read more : https://phys.org/news/2017-10-gamma-rays-limits.html

Gamma rays are electromagnetic waves, just like visible light or X-rays, but with much higher energy. The most energetic gamma rays in the world could be created by the help of advanced laser physics. When the laser light is intense enough and all parameters are right, trapped particles (green) could efficiently convert the laser energy (surfaces in red, orange and yellow) into cascades of super-high energy photons (pink). Credit: Arkady Gonoskov
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