3 ms·
This article got me interested to learn more. There's a related phenomenon called the Rydberg Blockade[1], wherein a group of Rydberg atoms can be tuned to mul
by pmayrgundter 6y ago
This article got me interested to learn more. There's a related phenomenon called the Rydberg Blockade[1], wherein a group of Rydberg atoms can be tuned to multiple quantum states and because of their large radii, form a coverage area over space in which those quantum states are excluded for other particles (by Pauli exclusion?). There's work to create large arrays, 1D and 2D of tens to hundreds of elements, of Rydberg atoms with packed configurations that can be continuously replenished atom-by-atom. This bit is being used for optical coupling in quantum computing[2].
But this got me wondering... does this mean that such a 2D array of Rydberg atoms, continually replenished, could effectively operate as an energy capturing force field? I'm imagining a surface that for a given maintenance energy is minimally dense while maximally extensive in space, and medium duration (the Rydberg excitations last longer the more they're pumped, e.g. micro and milliseconds). Also because of the dipole coupling and high-frequency tunability (~100s of atoms in packed arrays < 1s again see 2), it could be quickly restored from perturbation.
If so, this seems to present a candidate for energy capture from photonic emissions in e.g. fusion reactions, but crucially, one that could be maintained without large amounts of mass or that mass ablating away. That might make a handy energy shield for a spaceship fusion engine (I believe that's a key problem for small fusion engine designs), esp if you could recycle the captured energy :)
[1] https://blogs.unimelb.edu.au/atomopt/rydberg-atoms/ https://blogs.unimelb.edu.au/atomopt/rydberg-atoms/
[2] Quantum Simulators and Processors Based on Rydberg Atom Arrays https://www.youtube.com/watch?v=7MXIVZLaCII https://www.youtube.com/watch?v=7MXIVZLaCII
- ShinyRice 6y agoA bigger problem in getting power from fusion is dealing with the resulting neutrons. You can't redirect them out the exhaust, so it's energy you've lost (unless you harness the thermal power of the reactor rather than straight up using it for thrust); they bombard the reactor and can cause regular matter to become radioactive...
- pmayrgundter 6y agoI think that's true for the easier to ignite reactions like D-T, but there are others that are aneutronic, eg Proton+Boron. It's much harder to initiate, but the fuel is cheap and the energy output higher. "Aneutronic fusion loses much of its energy as light... Since X-rays can go through far greater material thickness than electrons, many hundreds or thousands of layers are needed to absorb the X-rays." https://en.m.wikipedia.org/wiki/Aneutronic_fusion https://en.m.wikipedia.org/wiki/Aneutronic_fusion Now the Army research in the OP doesn't go up to XRay frequencies, but I haven't found a hard upper limit to the coupling effect yet.
- infogulch 6y agoWhat if the fusion container was an x-ray laser? Could it induce fusion, where emitted xrays are in phase with the laser? I can imagine that an extreme high energy, directable, phase aligned, giant laser power source could be pretty useful.
- pmayrgundter 6y agoYeah, the NIF experiment is laser driven fusion, but I don't think that even being in phase would help capture the light. Not sure. It's the Ryberg coupling with light (without the usual requirement of just lots of mass/shielding) that's kind of unique here