How Richard Feynman's Diagrams Almost Saved Space (quantamagazine.org) 42
An anonymous Slashdot reader shares a fond remembrance of Richard Feynman written by Nobel prize-winner Frank Wilczek, describing not only the history of dark energy and field theory, but how Feynman's influential diagrams "embody a deep shift in thinking about how the universe is put together... a beautiful new way to think about fundamental processes".
Richard Feynman looked tired when he wandered into my office. It was the end of a long, exhausting day in Santa Barbara, sometime around 1982... I described to Feynman what I thought were exciting if speculative new ideas such as fractional spin and anyons. Feynman was unimpressed, saying: "Wilczek, you should work on something real..."
Looking to break the awkward silence that followed, I asked Feynman the most disturbing question in physics, then as now: "There's something else I've been thinking a lot about: Why doesn't empty space weigh anything?"
Feynman replied "I once thought I had that one figured out. It was beautiful..." then launched into a "surreal" monologue about how "there's nothing there!" But Wilczek remembers that "The calculations that eventually got me a Nobel Prize in 2004 would have been literally unthinkable without Feynman diagrams, as would my calculations that established a route to production and observation of the Higgs particle." His article culminates with a truly beautiful supercomputer-generated picture showing gluon field fluctuations as we now understand them today, and demonstrating the kind of computer-assisted calculations which in coming years "will revolutionize our quantitative understanding of nuclear physics over a broad front."
Looking to break the awkward silence that followed, I asked Feynman the most disturbing question in physics, then as now: "There's something else I've been thinking a lot about: Why doesn't empty space weigh anything?"
Feynman replied "I once thought I had that one figured out. It was beautiful..." then launched into a "surreal" monologue about how "there's nothing there!" But Wilczek remembers that "The calculations that eventually got me a Nobel Prize in 2004 would have been literally unthinkable without Feynman diagrams, as would my calculations that established a route to production and observation of the Higgs particle." His article culminates with a truly beautiful supercomputer-generated picture showing gluon field fluctuations as we now understand them today, and demonstrating the kind of computer-assisted calculations which in coming years "will revolutionize our quantitative understanding of nuclear physics over a broad front."
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You do?
Exothermic or Endothermic (Score:1)
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When it says 'almost saved space' I don't think they are refering to the 'saving' thtat Jesus does
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Better to be a free man (or woman) in hell than a slave in heaven.. :) baaa... baaa....
Don't make him into a Saint (Score:1, Interesting)
Look the big issue with particle physics is time going backwards. Feyman put a nice diagram on it, but its just wrong. The niceness of the diagram causes you to fail to question the underlying assumption.
We have lots of systems where time *appears* to go backwards, and they are *observational* effects, not real effects.
So for example, lightning appears to travel from ground to sky often. Yet the sky is discharging to the ground, not the ground to the sky. Is this lightning going backwards in time? No. We un
Re:Don't make him into a Saint (Score:5, Insightful)
This clearly falls into the 'not even wrong' category
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The Internet. Where science goes to die.
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Not exactly. Physicists and laymen alike have been confused about the weirder aspects of quantum mechanics since long before the internet.
I remember silently refusing to believe that my middle school science teacher was telling the truth about the double slit experiment. It seemed obviously wrong. Some searching on Altavista changed (and blew) my mind.
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The other thing is that you're taking about particles going back in time as an optional thing. In Feynman's formulation, they're not. "Everything not forbidden is compulsory." Since particles *can* go back in time, then they do, always and in every way they can. Why don't we see this happening normally? Self consistency. Particles traveling back in time can do so in a large number of different ways. When you run the numbers, you see that most of those different ways have quantum mechanical interference with each other. This means most, if not all, of the backward-in-time paths cancel each other out, leaving only the forward-in-time path we actually observe.
"Everything not forbidden is compulsory"
"Why don't we see this happening normally?"
"most, if not all, of the backward-in-time paths cancel each other out"
If we don't see it happening then it's not compulsory and is forbidden.
Please stop clinging to celebrity scientists because you like the idea of what they say. Testable theories, experimentation, and results (positive or negative) or STFU.
I have an Ikea wall-size cabinet with many drawers (Score:2)
It saves a lot of space too. Just so you know it isn't just Feynman doing all the cool stuff.
Deeper than it appears (Score:3)
From the summary, you could be excused for thinking that the article it's talking about is rubbish. You'd be wrong. The subject of the mass density of space is a lot deeper than you might think if you're not a theoretical physicist. The article is actually remarkably good at laying out and discussing the problem. In fact, the subject is a bit like Feynman diagrams themselves: initially they look like simple cartoons (which they are) that can't have any deep meaning ... but they can. Definitely worth a read if you have an interest in, and basic understanding of, the modern ideas regarding particles and fields.
Why doesn't empty space weigh anything? (Score:3)
At the end of the paper, we realize that decades after Feynman, we still not know why empty space does not weight anything, while at the same time it is full of particles created by quantum fluctuation.
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If a region of space contains mass it is not empty.
There I fixed it.
Huffman saved space, not Feynman (Score:2)
I don't know how much space Feynman diagrams saved but that's certainly nothing compared to Huffman coding.