[HN Gopher] Physicists generate the first snapshots of fermion p... ___________________________________________________________________ Physicists generate the first snapshots of fermion pairs Author : hhs Score : 56 points Date : 2023-07-06 18:15 UTC (4 hours ago) (HTM) web link (news.mit.edu) (TXT) w3m dump (news.mit.edu) | DaniFong wrote: | can anyone find the link to the paper? I want to see the actual | images | something168581 wrote: | The paper is linked in a sidebar on the article itself, and a | 1-second google of the title plus "PDF" resulted in an arxiv | link. | | arxiv.org/pdf/2208.05948.pdf | FredPret wrote: | > "To get a decent view of their behavior, Zwierlein and his | colleagues study the particles as a very dilute gas of about | 1,000 atoms, that they place under ultracold, nanokelvin | conditions that slow the atoms to a crawl. The researchers also | contain the gas within an optical lattice, or a grid of laser | light that the atoms can hop within, and that the researchers can | use as a map to pinpoint the atoms' precise locations." | | This is so cool. It's unbelievable what's possible nowadays | jug wrote: | "I can ride my bike with no handlebars..." | | Nah, I'm not trying to be a killjoy or anything. This quote | just reminded me of that song after so long of not thinking | about it. | warent wrote: | I don't understand how is it possible that they can slow the | atoms to a crawl and pinpoint their precise location. Isn't | that a violation of the uncertainty principle? Sounds like a | lot of certainty to me | bowsamic wrote: | The Heisenberg uncertainty principle indeed says that we can | only achieve a position uncertainty of delta x >= hbar / (2 * | delta p). However, this is of course a lower limit on the | uncertainty of the position, and hbar is _extremely_ tiny. In | practise, we have many other classical noise sources that | limit us far before we can ever reach a point where we are | Heisenberg-limited. | | The noise due to the Heisenberg uncertainty principle would | only become "visible" when all of the classical noise sources | are reduced such that the classical contribution to delta x * | delta y is less than hbar / 2. I don't think this experiment | reached such levels of precision | warent wrote: | Ahh this makes sense. I wasn't entirely sure if that was | actually how hbar/2 related to it, so this clarification is | helpful, thanks | [deleted] | erikaww wrote: | I am not educated about particle physics or whatnot, but isnt | the uncertainty principle momentum and position cannot be | both estimated to arbitrary accuracy? so one could estimate | only one of them to arbitrary accuracy and then 1000 | particles increases the confidence of that position estimate? | MengerSponge wrote: | Position and momentum are not separate things that you can | measure separately and recombine. They're deeply | interrelated. | | You would improve your counting statistics somewhat with | 1000 particles*, but basically you'd just resolve the | Gaussian distribution more clearly. The uncertainty of the | measurement comes from the width of the Gaussian, and it's | not like measuring more points is going to somehow make | that distribution skinnier. | | *(a hilariously, impossibly small number in quantum world, | where photons come in doses of 10^20/second, or electrons | come as 10^18/second) ___________________________________________________________________ (page generated 2023-07-06 23:00 UTC)