Slashdot Mirror


E=mc^2 Verified In Quantum Chromodynamic Calculation

chirishnique and other readers sent in a story in AFP about a heroic supercomputer computation that has verified Einstein's most famous equation at the level of subatomic particles for the first time. "A brainpower consortium led by Laurent Lellouch of France's Centre for Theoretical Physics, using some of the world's mightiest supercomputers, have set down the calculations for estimating the mass of protons and neutrons, the particles at the nucleus of atoms. ... [T]he mass of gluons is zero and the mass of quarks is only five per cent. Where, therefore, is the missing 95 per cent? The answer, according to the study published in the US journal Science on Thursday, comes from the energy from the movements and interactions of quarks and gluons. ... [E]nergy and mass are equivalent, as Einstein proposed in his Special Theory of Relativity in 1905." Update: 11/21 15:50 GMT by KD : New Scientist has a slightly more technical look at the accomplishment.

6 of 268 comments (clear)

  1. Re:Pretty cool by evanbd · · Score: 5, Informative

    Not really the same thing. Einstein derived it for non-quantum objects (ie large ones, or ones for which we can otherwise ignore quantum effects). This team verified it for quantum objects. This is interesting because the two theories don't mesh well -- one works at small scales and the other at large scales. It's not a theory of everything, because it doesn't touch gravity, but it's important to know where precisely the region the two are in conflict is. This calculation helps map that border.

  2. Re:I've only got one thing to say... by underpants_gnome · · Score: 5, Informative

    I wouldn't say that. Not in this case. Just because the equation is "works" in one scale (non-quantum), doesn't mean it works at ALL scales.

    Newtonian Mechanics at Relativistic speeds comes is a good example of that.

  3. My proof by Chapter80 · · Score: 5, Funny
    My proof:

    We know that e^(pi*i)=-1
    and i=Sqrt(-1)
    So, to prove that e=mc^2,
    we substitute for e, and you get
    (mc^2)^(pi*sqrt(-1))=-1 or
    (mc^2)^(sqrt(-pi^2)=-1
    mc Hammer only had 15 minutes of fame, so squaring that is 225 minutes
    If you had a pie, and you squared it off, and I took it from you, and made it round again, you'd have the square root of a negative pie squared.
    But this is pi, not pie, so we need to divide by e, which we know is 2.71828...
    So 225^(1/2.71828)=-1

    I know this worked yesterday... one moment....

  4. Re:I've only got one thing to say... by tonywestonuk · · Score: 5, Informative

    Newtonian Mechanics is wrong at any speed. Just the error becomes more noticeable near light speed.

    F=MA, yet a 1kg mass accelerated by 10 neutons for 1 second from stationary, will NOT be traveling at 10 m/s
    It will be traveling just, very slightly slower....

    Anyhow, I thought the actual thought experiment that leads to the derivation of e=mc2, (the one with a photon and a box), assumes the existance of the 'photon' a quantum scale particle.

  5. Re:I've only got one thing to say... by Daniel+Dvorkin · · Score: 5, Funny

    Yeah, all those stupid PhD physicists, wasting money on experimental rigorous verification of stuff that any random geek on /. already knows is true. Tell you what, why don't you send them an e-mail explaining how they're wasting time and money, and let us know how that turns out?

    --
    The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
  6. Re:I've only got one thing to say... by digitig · · Score: 5, Insightful

    Newtonian Mechanics as it's taught in schools is wrong at any scale. Newtonian Mechanics as Newton stated it is still valid when relativity is taken into account. Newton didn't state "F = MA", he said that "force is proportional to the rate of change of momentum". A 1kg mass accelerated by 10 neutons for 1 second from stationary will not be traveling at 10 m/s, but it will no longer be a 1kg mass either. The momentum will still be 10 newton seconds, though, just as Newton said it would be.

    --
    Quidnam Latine loqui modo coepi?