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DARPA's military-grade 'quantum laser' will use entangled photons to outshine (livescience.com)
12 points by smarm52 7 days ago | hide | past | favorite | 3 comments





It's hard to see how preserving phase information translates to immunity to distortion from air turbulence. Entanglement has physical binding properties akin to gravity or electrostatic attraction? The source article says this is still a work in progress:

https://source.wustl.edu/2024/05/quantum-physics-may-help-la...

Photons can "protect each other"? If this is true then is entanglement the source of dark energy/matter?


What a terrible article. There was one part that may have actually communicated some information though

>But by using entangled photons, the quantum photonic-dimer laser can maintain precision and strength over greater distances and in adverse conditions, the scientists said in a statement.

This makes me think the "photonic-dimer laser" has very narrow linewidth/extremely long coherence length, but also at very high power. There's usually a big tradeoff between laser power and spectral purity. A laser with a longer coherence length has favourable beam characteristics which allow it to be less divergent and less susceptible to diffraction from the atmosphere. The ideal propagation characteristics combined with the high output power is the story I guess.

Quantum entanglement contributes to the longer coherence length, which I guess could described poetically as photons protecting each other...


> What a terrible article.

I agree.

Have you read the additionalinformation liked in the article? They make no sense.

> “The unique thing about this project is its dual focus on generating these novel strongly correlated quantum photonic states and developing the theoretical framework and advanced algorithms for their efficient detection, potentially revolutionizing quantum imaging and communication,” Shen said.

> “Our goal is to support the advancement of imaging technologies and provide access to and training on these state-of-the-art tools so that researchers can drive towards discoveries,” said CZI Imaging Program Officer Stephani Otte. “By collaborating closely with the imaging community and providing both funding and expertise in technology development, we hope to help make the next breakthroughs in imaging possible.”

It looks like they have some kind of new type of laser, but they are overpromising aplications results. I can't find any of the fantastic new features tested experimentaly.

(And I stil can't imagine how they may work in theory. In particular fog is made of a lot of small drops of water that scater light in all directions, and entanglement can't magicaly solve that.)




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