25 citations · 83 across the 8 of their papers we have counts for
7 papers · 1 filter
The orthogonal momentum amplituhedron and ABJM amplitudes
Yu-tin Huang, Ryota Kojima, Congkao Wen +1
In this paper, we introduce the momentum space amplituhedron for tree-level scattering amplitudes of ABJM theory. We demonstrate that the scattering amplitude can be identified as…
Weights, Recursion relations and Projective triangulations for Positive Geometry of scalar theories
Renjan Rajan John, Ryota Kojima, Sujoy Mahato
The story of positive geometry of massless scalar theories was pioneered in [1] in the context of bi-adjoint theories. Further study proposed that the positive geometry for a…
Triangulation-free Trivialization of 2-loop MHV Amplituhedron
Ryota Kojima, Junjie Rao
This article introduces a new approach to implement positivity for the 2-loop n-particle MHV amplituhedron, circumventing the conventional triangulation with respect to positive va…
Weights and recursion relations for tree amplitudes from the positive geometry
Ryota Kojima
Recently, the accordiohedron in kinematic space was proposed as the positive geometry for planar tree-level scattering amplitudes in the theory \cite{Raman:2019utu}. The scat…
Sign Flip Triangulations of the Amplituhedron
Ryota Kojima, Cameron Langer
We present new triangulations of the amplituhedron relevant for scattering amplitudes in planar super-Yang-Mills, obtained directly from the combinatorial def…
Triangulation of 2-loop MHV Amplituhedron from Sign Flips
Ryota Kojima
In this paper, we consider the triangulation of 2-loop MHV amplituhedron from "sign flip" definition. Using the isomorphism between tree amplituhedron and 1-loop MHV phy…
Non-Gaussian and loop effects of inflationary correlation functions in BRST formalism
Hiroyuki Kitamoto, Yoshihisa Kitazawa, Ryota Kojima
We investigate inflationary correlation functions in single field inflation models. We adopt a BRST formalism where locality and covariance at the sub-horizon scale are manifest. T…