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One of the most interesting science articles I have read for a while! We now may very well be on the road to quantum gravity reality, but it ain't in OUR dimensions!? Holy Schmoly what fascinating junk science keeps spitting out at us! Read this!

https://www.quantamagazine.org/physicis ... -20130917/

NEW Discovery?

You saw that the article is 5 years old - right?

Why do you think this is junk?

Yeah, if we haven't heard a lot more about this in the past five years then it looks as though this is another one of those things that, as my advisor used to say, "went away."

The Wikipedia article says they're still working on it, but apparently the amplituhedron is still something that only works for N=4 supersymmetric Yang-Mills theory in the limit of an infinite number of colors. That's a fictitious theory that definitely doesn't apply to the real world; it's a very highly simplified theory that people study as a sort of test case—kind of a "spherical cow" of quantum field theories. Studying such highly simplified models is a good strategy, if only because there's so little else we can do, but it carries the obvious inherent risk that what one finds in the simple model is not the first hint of a general pattern but only a special feature of the simple model. It's one thing to study hypothetical spherical cows in order to get hints about how cows give milk but it's another thing to get all excited about the discovery that cows can roll in any direction.

So it looks pretty unlikely now that this whole amplituhedron theory is going to turn into a big revolution that changes how we think about space and time. Even if that somehow did happen, though, it would not mean that space and time were unreal. It would just mean that they were not fundamental. But water as a liquid isn't fundamental, either. All the properties we associate with water are effective behaviors on macroscopic scales of jostlings among molecules that are mostly empty space with some tiny electric charges zipping around. Water is still real. It's what lots of H2O molecules are like when they're together.

The realization that real things can start to look very different when you look very closely at them is a more basic scientific concept than any particular theory. "Reality" versus "illusion" is not a good way to think about that basic aspect of how reality works.

DrW wrote:

Philo Sofee wrote:One of the most interesting science articles I have read for a while! We now may very well be on the road to quantum gravity reality, but it ain't in OUR dimensions!? Holy Schmoly what fascinating junk science keeps spitting out at us! Read this!

https://www.quantamagazine.org/physicis ... -20130917/

NEW Discovery?

You saw that the article is 5 years old - right?

Why do you think this is junk?

(sputtering).... well, it was new to me....

I said "junk" as hyperbole, not literally. I thought it was just fascinating that there are easier ways now than Feynman's interesting line diagrams to gather and process information much faster and more efficiently, and easier, and that gives us a larger overall possible geometric dimension of a dimension that's not one of ours.....

Physics Guy wrote:Yeah, if we haven't heard a lot more about this in the past five years then it looks as though this is another one of those things that, as my advisor used to say, "went away."

The Wikipedia article says they're still working on it, but apparently the amplituhedron is still something that only works for N=4 supersymmetric Yang-Mills theory in the limit of an infinite number of colors. That's a fictitious theory that definitely doesn't apply to the real world; it's a very highly simplified theory that people study as a sort of test case—kind of a "spherical cow" of quantum field theories. Studying such highly simplified models is a good strategy, if only because there's so little else we can do, but it carries the obvious inherent risk that what one finds in the simple model is not the first hint of a general pattern but only a special feature of the simple model. It's one thing to study hypothetical spherical cows in order to get hints about how cows give milk but it's another thing to get all excited about the discovery that cows can roll in any direction.

So it looks pretty unlikely now that this whole amplituhedron theory is going to turn into a big revolution that changes how we think about space and time. Even if that somehow did happen, though, it would not mean that space and time were unreal. It would just mean that they were not fundamental. But water as a liquid isn't fundamental, either. All the properties we associate with water are effective behaviors on macroscopic scales of jostlings among molecules that are mostly empty space with some tiny electric charges zipping around. Water is still real. It's what lots of H2O molecules are like when they're together.

The realization that real things can start to look very different when you look very closely at them is a more basic scientific concept than any particular theory. "Reality" versus "illusion" is not a good way to think about that basic aspect of how reality works.

Heh.... it's why I post things I am reading on this group for you and Dr.W to see, and keep guiding me along in my quest for learning "truth" and discerning between viable and worthless. Thanks to you BOTH!

Philo, you didn’t need Physics Guy or Dr W to assess this article. All you needed was to use the skeptical tools you already possess.

In Philo's defense, you had to read the fine print at the bottom to see that this article was from 2013, and the kind of thing it was saying was actually not so implausible.

A breakthrough in quantum field theory that generalized away from locality and unitarity would indeed mean a fundamental revision in our understanding of space and time. That kind of breakthrough is unlikely in the sense that you don't expect it to happen on any given day, but it's the kind of thing that could happen at any time, and if it did happen, this is the sort of thing it could be and these are the kinds of things that would be said about it by those kinds of people. The researchers quoted in that article are significant scientists. Ed Witten in particular is a god in his field.

In fact it's clear that this was somewhat of a breakthrough in quantum field theory, just not (at least, after five years still not yet) at a level that should really put it onto the radar of non-specialists.

I haven't worked in this field for many years but I flirted with it in grad school and to me this article was night-and-day different from, say, Deepak Chopra. I'm starting to get curious about just how well critical thinking and a general education can serve as a BS detector in technical science. Maybe N=4 supersymmetry doesn't actually sound much different from Chopra's woo.

Rush Limbaugh had an interesting question about the big bang theory. If the entire universe were in a hot dense space the size of a tennis ball, where was it, and how did it get there?

ajax18 wrote:Rush Limbaugh had an interesting question about the big bang theory. If the entire universe were in a hot dense space the size of a tennis ball, where was it, and how did it get there?

How is that an interesting question? Where is the universe right now?

- Doc

If at a level smaller than the Planck length (and time at Planck time - both very, astonishingly, incredibly, and outrageously smaller than we even can imagine small to be, by many orders of billions of magnitude, literally), the universe existed, not as a singularity (Hawking back tracked from that), but as utterly minisculely teeny, there was no where, or time, especially if the Big Bang produced both space and time. It is a meaningless question on that ground.

It's like asking from the photons point of view where it is. It is literally everywhere all at once since from its frame of reference it is traveling at infinite speed, which means on its level there is no space or time at all, (the Lorentz transformations mathematically show this) which means it is simply standing still! Ain't Relativity fun?!