The positive Grassmannian is a cell complex consisting of all points in the real
Grassmannian whose Plücker coordinates are non-negative. In this paper we consider the …

We define and study the totally nonnegative part of the Chow quotient of the Grassmannian,
or more simply the nonnegative configuration space. This space has a natural stratification …

A bstract We describe a family of tropical fans related to Grassmannian cluster algebras.
These fans are related to the kinematic space of massless scattering processes in a number …

This review is a primer on recently established geometric methods for observables in
quantum field theories. The main emphasis is on amplituhedra, ie geometries encoding …

A bstract In this paper, we study a novel behavior developed by certain tree-level scalar
scattering amplitudes, including the biadjoint, NLSM, and special Galileon, when a subset of …

The biadjoint scalar theory has cubic interactions and fields transforming in the biadjoint
representation of ${\rm SU}(N)\times {\rm SU}\big ({\tilde N}\big) $. Amplitudes …

In a recent paper, we defined generalized color orderings (GCO) and Feynman diagrams
(GFD) to compute color-dressed generalized biadjoint amplitudes. In this work, we study the …

A bstract We continue the study of positive geometries underlying the Grassmannian string
integrals, which are a class of “stringy canonical forms”, or stringy integrals, over the positive …

We study arrangements of slightly skewed tropical hyperplanes, called blades by A.
Ocneanu, on the vertices of a hypersimplex $\Delta_ {k, n} $, and we investigate the …

Very recently planar collections of Feynman diagrams were proposed by Borges and one of
the authors as the natural generalization of Feynman diagrams for the computation of $ k …