[ExI] Quantum Radar

[Stuart LaForge]

Quoting John Clark:

> https://www.technologyreview.com/s/614160/quantum-radar-has-been-demonstrated-for-the-first-time/
> https://arxiv.org/abs/1908.03058
>
> Apparently this is an idea whose time has come because they're not  
> just using it with microwave photons for use in radar they've done  
> it with X rays too, although before this becomes practical for  
> medical applications a way must be found to shrink the size of the  
> particle accelerator that produces the X ray photons:   
> Quantum Enhanced X-ray Detection
<https://journals.aps.org/prx/pdf/10.1103/PhysRevX.9.031033>

Does PDC to x-ray wavelengths require a particle accelerator to  
generate the input beam? Something like a free-electron laser? Are  
x-rays the best wavelength to map the brain? Isn't brain-tissue  
largely transparent to x-rays? I mean if you get refraction off an  
atomic nucleus here and there, that's great and all but if the  
radiative flux is near background, then is that going to be enough  
photons to make a complete image?

> They say they have been able to "improve the visibility and the  
> signal-to-noise ratio of an image with a small number of photons in  
> an environment with a noise level that is higher than the signal by  
> many orders of magnitude". If they could determine whether the  
> photons are entangled or not they could vastly improve the  
> resolution of the picture even more, but to do that they'd have to  
> measure the time the photons hit the detector with Attosecond  
> (10^-18 sec) accuracy and that is beyond current technology. That's  
> one of many reasons i think the development of a Thorium-229 nuclear  
> clock is so important, it could bring accuracy to the 10^-19 sec  
> level.
>
> En route to the optical nuclear clock

I imagine something like this would revolutionize x-ray  
crystallography of proteins and what not.

>
> I can't help but wonder if a brain scan made with this technology  
> would provide enough information for a mind upload.

I wonder if something similar could be done with ultrasound using  
phonons. Ultrasound might be a better approach to imaging the brain  
then x-rays provided you figure out a way to get the sound waves  
through the skull. Maybe use the ear canal?

Stuart LaForge