I remember doing laser cooling of rubidium atoms in physics class. It's really cool how it works:<p>* Rubidium will absorb photons of a certain wavelength and re-emit it in a random direction. Since photons have momentum, it will get some net momentum change from absorbing photons all coming from a particular direction, but the re-emissions are in random directions so they have net zero momentum.<p>* Shine laser light at it from all directions but at a wavelength slightly longer than the wavelength at which it will absorb. Now, if the rubidium atom is moving, the light hitting it head on will be Doppler shifted into the wavelength that it absorbs, slowing it down, whereas the other light wouldn't affect it. So, no matter how it is moving, it will slow down.<p>Rubidium is a good material since it has an S shell on the outside as though it were a big hydrogen atom, but it is so massive that it is a lot nicer to work with for this application.
Journalists get it wrong, again. Sigh. It will never replace GNSS. It's quantum inertial navigation (QIN) that double-integrates acceleration like another method, requiring external position, heading, and velocity (re)calibration and drifts without them. It has absolutely no idea where it is from only itself.
Even as somebody relatively familiar with inertial navigation, it took me almost the entire article to figure out that that's what this is doing.<p>I really wish the words "inertial navigation" or "dead reckoning" would have occurred at least once in the article, but obviously "quantum navigation" sounds much cooler and as an added bonus makes it sound more like magic than technology.
This work proposes a more accurate means of dead reckoning using a quantum-level source for inertial measurement in an Inertial Navitagation System (INS). Useful for robotic navigation underground, inside RF-shielded structures, on other planetary bodies, or underwater. The issue of localization error drift reduction from INS's seems very much like a Moore's law challenge, though I haven't mapped out the advances in intertial measurement accuracy/precision by year to see if the projected rate is similar or not. In any event, pretty cool; we'll see if this one pans out.
The science is cool, but I wonder if a specialized popular science magazine of yester-year would do a better job at presenting it? "We made a high-precision accelerometer that uses lasers and quantum effects; let me tell you everything about it." Right now, it reads more like "Dr. C has this very peculiar quirk when he goes to the London underground. Admittedly, it is not as bizarre as his habit of drinking coffee instead of tea, but going to the underground carrying an aluminum tube instead of a newspaper is just a tad flummoxing..."
So far as I can tell, it's this accelerometer: <a href="https://www.imperial.ac.uk/news/188973/quantum-compass-could-allow-navigation-without/" rel="nofollow">https://www.imperial.ac.uk/news/188973/quantum-compass-could...</a><p>(2018, I'm unclear what's changed since then?)
This will become more and more common, see <a href="https://rmi.org/insight/the-cleantech-revolution/" rel="nofollow">https://rmi.org/insight/the-cleantech-revolution/</a><p>Direct link to PDF: <a href="https://rmi.org/wp-content/uploads/dlm_uploads/2024/06/RMI-Cleantech-Revolution-pdf.pdf" rel="nofollow">https://rmi.org/wp-content/uploads/dlm_uploads/2024/06/RMI-C...</a>
It's a shame all the cool stuff is all hidden in a white box, but I suppose it does look a bit like a Hollywood depiction of a homemade nuclear bomb so the British Transport Police would be getting a few panicked calls if it were in a perspex box.<p>There's also no step-free access at South Kensington or Gloucester Road, so that must be a fun struggle for a grad student!
Is the idea here to accurately track the acceleration that the sensor is undergoing? So, if you started at a known location with velocity=0 and integrate the acceleration data wrt time twice, you get the relative change in position and can thus know your new location?
Russian shenanigans was my first thought too, but the real game changer is probably:<p>>under ground and under water<p>Tunnels, fiber cables, pipelines, submarines, autonomous subs etc would all benefit from less location guessing. (Tunnels tbf you can do with lasers already)
I realize no one would be allowed to tell me if I am correct, but this tech sounds like it is perfect for military use. I am guessing there is already a pretty polished version of this roaming the oceans now.