Physically realizable planar graphs in amplituhedron approach

[nrqed]

I have a few questions on these graphs. For example if there is a way to tell directly from a complicated graph if it is "physical" in the sense that it describes an actual process. I have also questions on the building of graphs using BCFW bridges, on determining the value of the parameter "k" directly from the permutation associated to a graph, etc.

I won't type all my questions yet, I will wait to see if someone is familiar with these questions first.

But one question is this: I think that the value of "k" (=number of negative helicities) can be obtained directly from the permutation by counting how many of the values are mapped by the permutation to a value above n. Is that correct? I have not seen this stated explicitly like this or proved anywhere.

Thanks!

 

[PeterDonis]

I have a few questions on these graphs.

What graphs? What are you talking about?

A reference would help.

 

[nrqed]

What graphs? What are you talking about?

A reference would help.

I meant the graphs mentioned in the title of my post: the plabic graphs in the amplituhedron program.

 

[PeterDonis]

I meant the graphs mentioned in the title of my post: the plabic graphs in the amplituhedron program.

Which doesn't help, since I have no idea what "the amplituhedron program" is, much less what "the plabic graph" in it are. Even if I did, I would have no idea what version of those things you are talking about. That's why you need to give a reference.

 

[nrqed]

Which doesn't help, since I have no idea what "the amplituhedron program" is, much less what "the plabic graph" in it are. Even if I did, I would have no idea what version of those things you are talking about. That's why you need to give a reference.

If someone asks a question about Feynman diagrams and someone replies "what diagrams? What are you talking about?", it is probably a sign that the person cannot help with the question.

I wonder how you know that if you knew about plabic graphs as used for the amplituhedron, you would still not know what I am talking about. That's quite amazing to me :-)

If you need a specific reference, you can of course look for example at the "bible" on the topic, "Grassmannian Geometry of Scattering Amplitudes" by Akani-Hamed et al.

 

[PeterDonis]

Thread closed for moderation.