Browsing by Author "Ferro, Livia"

Now showing items 1-15 of 15

    • Amplituhedra, and Beyond 

      Ferro, Livia; Lukowski, Tomasz (2020-12-29)
      This review is a primer on recently established geometric methods for observables in quantum field theories. The main emphasis is on amplituhedra, i.e. geometries encoding scattering amplitudes for a variety of theories. ...

    • Amplituhedron meets Jeffrey-Kirwan Residue 

      Ferro, Livia; Lukowski, Tomasz; Parisi, Matteo (2018-12-28)
      The tree amplituhedra A^(m)_n,k are mathematical objects generalising the notion of polytopes into the Grassmannian. Proposed for m=4 as a geometric construction encoding tree-level scattering amplitudes in planar N=4 super ...

    • From Momentum Amplituhedron Boundaries to Amplitude Singularities and Back 

      Ferro, Livia; Lukowski, Tomasz; Moerman, Robert (2020-07-28)
      The momentum amplituhedron is a positive geometry encoding tree-level scattering amplitudes in $\mathcal{N}=4$ super Yang-Mills directly in spinor-helicity space. In this paper we classify all boundaries of the momentum ...

    • The Grassmannian for celestial superamplitudes 

      Ferro, Livia; Moerman, Robert (2021-11-25)
      Recently, scattering amplitudes in four-dimensional Minkowski spacetime have been interpreted as conformal correlation functions on the two-dimensional celestial sphere, the so-called celestial amplitudes. In this note we ...

    • Kleiss-Kuijf relations from momentum amplituhedron geometry 

      Damgaard, David; Ferro, Livia; Lukowski, Tomasz; Moerman, Robert (2021-07-16)
      Abstract: In recent years, it has been understood that color-ordered scattering amplitudes can be encoded as logarithmic differential forms on positive geometries. In particular, amplitudes in maximally supersymmetric ...

    • The Loop Momentum Amplituhedron 

      Ferro, Livia; Łukowski, Tomasz (2023-05-22)
      In this paper we focus on scattering amplitudes in maximally supersymmetric Yang-Mills theory and define a long sought-after geometry, the loop momentum amplituhedron, which we conjecture to encode tree and (the integrands ...

    • The Momentum Amplituhedron 

      Damgaard, David; Ferro, Livia; Lukowski, Tomasz; Parisi, Matteo (2019-08-08)
      In this paper we define a new object, the momentum amplituhedron, which is the long sought-after positive geometry for tree-level scattering amplitudes in N = 4 super Yang-Mills theory in spinor helicity space. Inspired ...

    • Momentum Amplituhedron meets Kinematic Associahedron 

      Damgaard, David; Ferro, Livia; Lukowski, Tomasz; Moerman, Robert (2021-02-03)
      In this paper we study a relation between two positive geometries: the momen- tum amplituhedron, relevant for tree-level scattering amplitudes in N = 4 super Yang-Mills theory, and the kinematic associahedron, encoding ...

    • N=4 Scattering Amplitudes and the Deformed Grassmannian 

      Ferro, Livia; Lukowski, Tomasz; Staudacher, Matthias (2014-12-01)
      Some time ago the general tree-level scattering amplitudes of N=4 Super Yang-Mills theory were expressed as certain Grassmannian contour integrals. These remarkable formulas allow to clearly expose the super-conformal, ...

    • Prescriptive Unitarity from Positive Geometries 

      Ferro, Livia; Glew, Ross; Lukowski, Tomasz; Stalknecht, Jonah (2024-03-01)
      In this paper, we define the momentum amplituhedron in the four-dimensional split-signature space of dual momenta. It encodes scattering amplitudes at tree level and loop integrands for N=4 super Yang-Mills in the planar ...

    • Spectral Parameters for Scattering Amplitudes in N=4 Super Yang-Mills Theory 

      Ferro, Livia; Lukowski, Tomasz; Meneghelli, Carlo; Plefka, Jan; Staudacher, Matthias (2014-01-17)
      Planar N=4 Super Yang-Mills theory appears to be a quantum integrable four-dimensional conformal theory. This has been used to find equations believed to describe its exact spectrum of anomalous dimensions. Integrability ...

    • Towards the Amplituhedron Volume 

      Ferro, Livia; Lukowski, Tomasz; Orta, Andrea; Parisi, Matteo (2016-03-03)
      It has been recently conjectured that scattering amplitudes in planar N=4 super Yang-Mills are given by the volume of the (dual) amplituhedron. In this paper we show some interesting connections between the tree-level ...

    • Transmuting CHY formulae 

      Ferro, Livia; Bollmann, Max (2019-01)
      The various formulations of scattering amplitudes presented in recent years have underlined a hidden unity among very different theories. The KLT and BCJ relations, together with the CHY formulation, connect the S-matrices ...

    • Tree-level scattering amplitudes from the amplituhedron 

      Ferro, Livia; Lukowski, Tomasz; Orta, Andrea; Parisi, Matteo (2017-06-07)
      A central problem in quantum field theory is the computation of scattering amplitudes. However, traditional methods are impractical to calculate high order phenomenologically relevant observables. Building on a few decades ...

    • Yangian Symmetry for the Tree Amplituhedron 

      Ferro, Livia; Lukowski, Tomasz; Orta, Andrea; Parisi, Matteo (2017-06-29)
      Tree-level scattering amplitudes in planar N=4 super Yang-Mills are known to be Yangian-invariant. It has been shown that integrability allows to obtain a general, explicit method to find such invariants. The uplifting of ...