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We provide an efficient recursive formula to compute the canonical forms of arbitrary $d$-dimensional simple polytopes, which are convex polytopes such that every vertex lies precisely on $d$ facets. For illustration purposes, we explicitly derive recursive formulae for the canonical forms of Stokes polytopes, which play a similar role for a theory with quartic interaction as the Associahedron does in planar bi-adjoint $phi^3$ theory. As a by-product, our formula also suggests a new way to obtain the full planar amplitude in $phi^4$ theory by taking suitable limits of the canonical forms of constituent Stokes polytopes.
In this thesis, we investigate the low-energy expansion of scattering amplitudes of closed strings at one-loop level (i.e. at genus one) in a ten-dimensional Minkowski background using a special class of functions called modular graph forms. These al
Recent years have seen a surprising connection between the physics of scattering amplitudes and a class of mathematical objects--the positive Grassmannian, positive loop Grassmannians, tree and loop Amplituhedra--which have been loosely referred to a
Let $G$ be a finite graph allowing loops, having no multiple edge and no isolated vertex. We associate $G$ with the edge polytope ${cal P}_G$ and the toric ideal $I_G$. By classifying graphs whose edge polytope is simple, it is proved that the toric
In this paper we provide a formula for the canonical differential form of the hypersimplex $Delta_{k,n}$ for all $n$ and $k$. We also study the generalization of the momentum amplituhedron $mathcal{M}_{n,k}$ to $m=2$, and we conclude that the existin
Any totally positive $(k+m)times n$ matrix induces a map $pi_+$ from the positive Grassmannian ${rm Gr}_+(k,n)$ to the Grassmannian ${rm Gr}(k,k+m)$, whose image is the amplituhedron $mathcal{A}_{n,k,m}$ and is endowed with a top-degree form called t