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Physicists Create a Bizarre ‘Wigner Crystal’ Made Purely of Electrons
- marktangotango 5y agoIt'd be cool if these could be made in a material transparent to protons, then it'd be a good anode for polywell fusion without the energy loss to Bremsstrahlung radiation.
- mensetmanusman 5y agoGlad they finally did it! “ Wigner participated in a meeting with Leo Szilard and Albert Einstein that resulted in the Einstein-Szilard letter, which prompted President Franklin D. Roosevelt to initiate the Manhattan Project to develop atomic bombs. Wigner was afraid that the German nuclear weapon project would develop an atomic bomb first. ”
- dgs_sgd 5y agoAccording to the article scientists have been trying to prove this structure for eight decades. Then two independent groups report having successfully done it in the same month! What are the odds?
- _Microft 5y agoThere are quite a number of similar coincidences in the history of science. It seems to me that at some point the necessary knowledge or techniques are just there to make some discoveries almost inevitable. https://en.wikipedia.org/wiki/Multiple_discovery https://en.wikipedia.org/wiki/Multiple_discovery https://en.wikipedia.org/wiki/List_of_multiple_discoveries https://en.wikipedia.org/wiki/List_of_multiple_discoveries
- dgs_sgd 5y agoYes, they probably relied on the same scientific breakthrough where it basically became a race for who could do it first.
- blueprint 5y agoWell, according to the Hanbury Brown and Twiss effect... more than you might expect.
- jbdistaken 5y agothey aren't exactly independent. several authors are on both papers
- gus_massa 5y agoNote that this is not a 3D crystal of electrons floating in vacuum. It's a 2D crystal of electrons that live in a thin semiconductor that is sandwiched between two layers of other semiconductor. You can't pick it with a tiny gripper. Moreover, I don't understand all the details, but IIUC the surrounding semiconductor provides an effective force that makes the electrons attract each other when they are not too close. So in some sense, the crystal is formed by the electrons, but this does not break the expected behavior of a 100% pure negative particles in vacuum.
- foobarian 5y agoI was confused by not seeing an explanation of where the attraction comes from (there shouldn't be any). Sounds like the top and bottom layers push the electrons together and the electrons settle into a hexagonal grid like a flat arrangement of balls would. To me being able to measure/observe a thing like this is a whole other level of amazing.
- gus_massa 5y agoIt's too far from my area to be sure, but let's guess ... Perhaps it similar to the Cooper pair effect. In this effect, it looks like electrons inside a conductor attract each other. From https://en.wikipedia.org/wiki/Cooper_pair https://en.wikipedia.org/wiki/Cooper_pair > Although Cooper pairing is a quantum effect, the reason for the pairing can be seen from a simplified classical explanation. An electron in a metal normally behaves as a free particle. The electron is repelled from other electrons due to their negative charge, but it also attracts the positive ions that make up the rigid lattice of the metal. This attraction distorts the ion lattice, moving the ions slightly toward the electron, increasing the positive charge density of the lattice in the vicinity. This positive charge can attract other electrons. At long distances, this attraction between electrons due to the displaced ions can overcome the electrons' repulsion due to their negative charge, and cause them to pair up. The rigorous quantum mechanical explanation shows that the effect is due to electron–phonon interactions, with the phonon being the collective motion of the positively-charged lattice. This attraction is too small and is only important when the temperature is very low, and is the explanation of low temperature superconductivity. <guess> So perhaps there is a Cooper-pair-like effect here, that creates the illusion that the electrons attract each other. They are using semiconductors, so perhaps it's caused not by the movement of the nuclei, but the movement of the holes in the other semiconductor.</guess>
- selimthegrim 5y agoWigner crystals have been well known in theory since the 1930s, there's nothing bizarre about them.
- IndianaBones 5y agoSome Indiana Jones bullshit! wow!!!
- memling 5y agoPotential dumb question ahead: how, or does, this relate to the Uncertainty Principle? My five-year-old brain says that freezing the electrons in a lattice so that they don't move means that there's no momentum or velocity, and therefore we should have an infinite? uncertainty concerning position. Obviously something is wrong in my understanding or in the precision of the article's discussion. Can someone ELI5?
- go_elmo 5y agomaybe even dumber answer ahead: the lattice positions might be big enough not to cause any conflict with the uncertainty relation?
- zamadatix 5y agoThe distances between electrons in this lattice are enormous compared to the electron, even bigger than the typcial distances between atoms in a lattice, so being essentially dead still in the overall lattice structure doesn't imply much about the certainty of the position of the electron at the scale the uncertainty principle implies.
- frutiger 5y agoThe uncertainty principle says something different than the common understanding. It says that if you have an ensemble of identically prepared systems, the product of variances of non-commuting observables obtained by measuring different instances in this ensemble will have a lower bound.
- nextaccountic 5y agoWhat does "different instances" mean here? We can't talk about uncertainty principle if we have a single electron?
- gus_massa 5y agoThey are not 100% frozen in a 100% perfect lattice structure. They still move a little around the positions where they "should" be. Something similar happens with atoms in a normal crystal.
- BenoitP 5y ago> Past experiments found hints of Wigner crystallization A member my family actually did his PhD in 1989 on that: http://www.theses.fr/1989PA066388 http://www.theses.fr/1989PA066388 (thesis in French, sorry) The hints were about evidence of shearing transmission displayed by the Wigner crystal when poked with some specific RF frequencies IIRC.
- knuthsat 5y agoI wonder if it's a monopole.
- avsteele 5y agoYou can see a video of a Wigner crystal of laser-cooled Barium ions I made here: https://www.youtube.com/watch?v=Pe3_IosfaTo https://www.youtube.com/watch?v=Pe3_IosfaTo
- Texaner 5y agoIt's just black for me
- zinekeller 5y agoMaybe faulty video decoder on your phone? (Or maybe another device, but that's rather unlikely due to instant fallback to software decode if there's a problem.) The video is in a weird resolution, so your decoder may tripped up there. Here's a photo instead: https://imgur.com/a/l5pj5Ac https://imgur.com/a/l5pj5Ac
- deleted 5y ago[deleted]