21–30 of 94 posts
A video lecture by Nima Arkani-Hamed here on the topic: http://susy2013.ictp.it/video/05_Friday/2013_08_30_Arkani-Ha...
(btw: entire careers have been based on susy, without a spec of experimental evidence: on might say, it is not even wrong)
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…
1. The notion of unitarity is a "common sense" rule that implies that you can consistently assign probabilities to possible outcomes in a quantum mechanical experiment (http://en.wikipedia.org/wiki/Unitarity_%28physics%29)
2. The notion of locality states that what happens on Jupiter better not affect how fast your code compiles this morning (or how experiments run on earth). This is an important postulate, because if this weren't true, we might as well give up on doing science as there would be arbitrarily many external influences we couldn't take into account.
All our experiments so far are perfectly consistent with these two principles. Quantum field theory is the brainchild of the marriage of unitarity (from quantum mechanics) and the idea of locality (in field theory). Our world view today ("Standard model of particle physics") is based on this.
In practice, calculating answers using this theory is painfully difficult. YOu will add up thousand pages worth of algebraic terms and then your answer will 'miraculously' reduce to a few terms. This and other observations have inspired researchers to search for underlying structure... leading to what is now being called the 'amplitude revolution' by some people.
Rejecting unitarity is a bold thing to do. What can it mean for the probabilities of alternatives to sum to more than 1?
The paper from the arxiv mentioned in the article: http://arxiv.org/pdf/1212.5605v1.pdf
I was talking to a friend in the physics department at Stanford a few months ago about how one of the people whose work is cited in this paper (Greg Moore of Rutgers) had found analytic expressions purely rooted in geometry for Bethe Ansatz[1] results in (1+1) dimensional systems. Based on that, I told my friend I believed these "physical mathematics types" (as they call themselves) were on to something. He concurred…
On another note, if I see the word "illusion" or "illusory" one more time in these science blogs, I'm going to have a fit. This must be the meaningless new buzzword of the day. 1) Spacetime is not an "illusion" 2) Gravity is not an "illusion" 3) is not an "illusion". That doesn't even make sense.
The paper from the arxiv mentioned in the article: http://arxiv.org/pdf/1212.5605v1.pdf
This is really cool. I didn't understand most of it, even though I'm taking QFT right now. Shows you how deep the subject goes. On another note, if I see the word "illusion" or "illusory" one more time in these science blogs, I'm going to have a fit. This must be the meaningless new buzzword of the day. 1) Spacetime is not an "illusion" 2) Gravity is not an "illusion" 3) is not an "illusion". That doesn't even make s…
This is really cool. I didn't understand most of it, even though I'm taking QFT right now. Shows you how deep the subject goes. On another note, if I see the word "illusion" or "illusory" one more time in these science blogs, I'm going to have a fit. This must be the meaningless new buzzword of the day. 1) Spacetime is not an "illusion" 2) Gravity is not an "illusion" 3) is not an "illusion". That doesn't even make s…
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…
You say that like it's so obvious. But why do they move in the first place?
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?
Earlier quoted context omitted.
I was talking to a friend in the physics department at Stanford a few months ago about how one of the people whose work is cited in this paper (Greg Moore of Rutgers) had found analytic expressions purely rooted in geometry for Bethe Ansatz[1] results in (1+1) dimensional systems. Based on that, I told my friend I believed these "physical mathematics types" (as they call themselves) were on to something. He concurred…
I think there's a lot of exciting research going on in the context of integrable systems (~Bethe Ansatz) and N=2 quantum field theories. However, some people are also working on integrability in N=4 theories, which might be relevant to the ideas in this article. It's a thought some people (including Arkani-Hamed) have expressed, but it's too early to tell.