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A Jewel at the Heart of Quantum Physics

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Re: A Jewel at the Heart of Quantum Physics

#31

Post by miloszf »

ars wrote: post #28
crntaylor wrote: post #27

Earlier quoted context omitted.

I think what they mean is that the force we call gravity is an illusion that we experience because we perceive spacetime as flat. In a curved spacetime, you don't need to posit a force to explain motion due to a nearby mass - the mass curves spacetime, and objects move along geodesics in the curved spacetime. So while it would be incorrect to say "gravity is an illusion" I think it makes sense to say "the force of gr…

> and objects move along geodesics You say that like it's so obvious. But why do they move in the first place?

In short because things move from a state of higher energy to lower energy. Not subduing yourself to gravity would take energy in opposite direction to counteract it (or the geometric slope in this analogy). Newtonian conservation of energy is a pretty good model analogy (although isn't the same thing) and the geometric one is even better. But that's all they are, however accurate - analogies, constructed on the basis of available information and mathematical models.

Outside of that there really isn't a 'reason'. This isn't how physics works, although it's certainly in our nature to create and expect meaning and cause everywhere. Brain is bound to think in hierarchies, because that's how it's built to operate, but the universe doesn't have that limitation.

Re: A Jewel at the Heart of Quantum Physics

#32

Post by selimthegrim »

gaze wrote: post #15
redhat-reallyp wrote: post #13

Earlier quoted context omitted.

"it contains signs of a genuine conceptual breakthrough." It contains claims of such signs, which seems to be the point of this fluff piece. Alarm bells should go off when you read statements like this: "...giving up space and time as fundamental constituents of nature and figuring out how the Big Bang and cosmological evolution of the universe arose out of pure geometry." Ah yes, well that solves the mystery, doesn'…

Things that work on simple models motivate work on more complex models. He STARTS OUT by saying N=4 SYM is a toy model. The klein-gordon equation is unphysical but motivated a lot of good physics.

In condensed-matter physics, toy models play with you!

http://arxiv.org/abs/cond-mat/0007254

Re: A Jewel at the Heart of Quantum Physics

#33

Post by has2k1 »

noonespecial wrote: post #5

Every once in a while I get the feeling that the greatest discoveries are still ahead and these next few decades might be the real "golden age of science". The "individual genius" phase is just behind us and the "collaborative brilliance" phase is just beginning.

It is possible that Gravity as we know it is an illusion. For example, the Newtonian take on Gravity was that it was a force. That according to Einstein was illusory, Gravity was really a geometric manifestation due to the curvature of space-time. With that take Gravity as we know it is different from the Gravity as was once known. However the Newtonian view that Gravity is a force can and still does facilitate useful everyday computations.

The go to illusion when we think of illusions is the mirage, you can see as water complete with the wavy nature of water and if you had no way of getting closer to inspect it, it might as well be the real thing. Depending on your philosophical take either it is always an illusion, or it becomes an illusion when you find out that it is not water.

A note of agreement with what seems like your main query, we might as well drop the word illusion when it comes to the physical description of the universe. Any framework of description is full of illusions that may never be proven otherwise.

I took QFT some years back and it also went over my head. There is still that mental gap of where the only way you can think about time is via time-(in)dependent wave function.

Re: A Jewel at the Heart of Quantum Physics

#34

Post by raverbashing »

derleth wrote: post #19
xenophanes wrote: post #11

Earlier quoted context omitted.

Why do you think there will be or should be a golden age, rather then continuous progress forever? http://beginningofinfinity.com

To expand on what Osmium said, a "golden age" is more like a "goldrush age": A big breakthrough opens up a new conceptual frontier, and the golden age is scientists rushing in to homestead and start mining the new landscape. This isn't to say that all progress is done in goldrushes, but the most basic and, therefore, best-known work of a given field will be done in that period.

Yes

There's no continuum because some things are harder, others are easy.

Computers have evolved pretty much "continually" since the personal computer era, but they took some time to be invented.

Quantum mechanics evolved "quickly" once we found out there was such a thing as quantum mechanics, up until them it was a lot of "banging heads" and freewheeling.

Not to mention delays because of other constraints: wars, political instabilities, etc

Re: A Jewel at the Heart of Quantum Physics

#35

Post by bsullivan01 »

redhat-reallyp wrote: post #13
gruseom wrote: post #2

Is anyone here familiar with this work? I would like to hear more about it. At a minimum, this article is very much better than the usual science blog filler—it contains signs of a genuine conceptual breakthrough. For example: “You can easily do, on paper, computations that were infeasible even with a computer before.” That doesn't happen very often! Or this: [T]he new geometric approach to particle interactions remo…

"it contains signs of a genuine conceptual breakthrough." It contains claims of such signs, which seems to be the point of this fluff piece. Alarm bells should go off when you read statements like this: "...giving up space and time as fundamental constituents of nature and figuring out how the Big Bang and cosmological evolution of the universe arose out of pure geometry." Ah yes, well that solves the mystery, doesn'…

what are your qualifications? No offense meant, but I am trying to see if this is real or not.

Quite a few smart people seem excited by it, yet you dismiss it

Re: A Jewel at the Heart of Quantum Physics

#36

Post by Sniffnoy »

freyrs3 wrote: post #4

The paper from the arxiv mentioned in the article: http://arxiv.org/pdf/1212.5605v1.pdf

A note -- when linking to arXiv, please link to the abstract[1], not directly to the PDF. The abstract has other information about the paper, and one can see different versions of the paper, and of course one can click through to the actual paper. Going the other way requires manually editing the URL.

[1]http://arxiv.org/abs/1212.5605v1

Re: A Jewel at the Heart of Quantum Physics

#39

Post by scotty79 »

From what I get they managed to vastly simplify calculations of super-symmetric Yang-Mills theory by representing results as volumes of geometric object.

Super-symmetric Yang-Mills theory is not shown to represent reality (yet?) but they hope they can use similar method to simplify calculations of the quantum field theories that are currently believed to represent reality.

Re: A Jewel at the Heart of Quantum Physics

#40

Post by shadowmint »

bsullivan01 wrote: post #35
redhat-reallyp wrote: post #13

Earlier quoted context omitted.

"it contains signs of a genuine conceptual breakthrough." It contains claims of such signs, which seems to be the point of this fluff piece. Alarm bells should go off when you read statements like this: "...giving up space and time as fundamental constituents of nature and figuring out how the Big Bang and cosmological evolution of the universe arose out of pure geometry." Ah yes, well that solves the mystery, doesn'…

what are your qualifications? No offense meant, but I am trying to see if this is real or not. Quite a few smart people seem excited by it, yet you dismiss it

I think the point here is don't hold your breath.

Science like this has to be slow and careful. Sudden magical breakthroughs are vanishingly rare, and this probably isn't one; but it is interesting, and worth getting excited about.

.. just don't go throwing your Standard Model quite yet. :)

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