[HN Gopher] Physicists generate the first snapshots of fermion p...
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       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)
        
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       (page generated 2023-07-06 23:00 UTC)