189 citations · 1.1k across the 28 of their papers we have counts for
29 papers
Neural S-matrix bootstrap II: solvable 4d amplitudes with particle production
Mehmet Asim Gumus, Damien Leflot, Piotr Tourkine +1
We study a model for nonperturbative unitarization of the four-point contact scalar amplitude in four dimensions. It is defined through an infinite sum of planar diagrams, construc…
Tracking S-matrix bounds across dimensions
Mehmet Asim Gumus, Simon Metayer, Piotr Tourkine
We study massive scattering of identical scalar particles in spacetime dimensions 3 to 11 using non-perturbative S-matrix bootstrap techniques. Treating as a continuo…
Regge trajectories for UV completions of graviton scattering from polynomial boundedness
Christopher Eckner, Felipe Figueroa, Simon Metayer +1
We study graviton scattering amplitudes. Assuming they are UV completed by a theory of weakly coupled massive higher spins, we demonstrate that the UV completion must possess infin…
The S-matrix bootstrap with neural optimizers I: zero double discontinuity
Mehmet Asim Gumus, Damien Leflot, Piotr Tourkine +1
In this work, we develop machine learning techniques to study nonperturbative scattering amplitudes. We focus on the two-to-two scattering amplitude of identical scalar particles,…
Eikonal amplitudes on the celestial sphere
Tim Adamo, Wei Bu, Piotr Tourkine +1
Celestial scattering amplitudes for massless particles are Mellin transforms of momentum-space scattering amplitudes with respect to the energies of the external particles, and beh…
On the number of Regge trajectories for dual amplitudes
Christopher Eckner, Felipe Figueroa, Piotr Tourkine
Regge poles connect the analytic structure of scattering amplitudes, analytically continued in spin, to the high-energy limit in momentum space. Dual models are expected to have on…
The Regge bootstrap, from linear to non-linear trajectories
Christopher Eckner, Felipe Figueroa, Piotr Tourkine
We present a numerical linear programming bootstrap to construct dual model scattering amplitudes. Dual models describe tree-level exchanges of higher spin resonances in theories l…
Scattering amplitudes from dispersive iterations of unitarity
Piotr Tourkine, Alexander Zhiboedov
We present and numerically implement a computational method to construct relativistic scattering amplitudes that obey analyticity, crossing, elastic and inelastic unitarity in thre…
The ultrarelativistic limit of Kerr
Tim Adamo, Andrea Cristofoli, Piotr Tourkine
The massless (or ultrarelativistic) limit of a Schwarzschild black hole with fixed energy was determined long ago in the form of the Aichelburg-Sexl shockwave, but the status of th…
On the unitarity and low energy expansion of the Coon amplitude
Felipe Figueroa, Piotr Tourkine
The Coon amplitude is a deformation of the Veneziano amplitude with logarithmic Regge trajectories and an accumulation point in the spectrum, which interpolates between string theo…
Eikonal amplitudes from curved backgrounds
Tim Adamo, Andrea Cristofoli, Piotr Tourkine
Eikonal exponentiation in QFT describes the emergence of classical physics at long distances in terms of a non-trivial resummation of infinitely many diagrams. Long ago, 't Hooft p…
Scattering from production in 2d
Piotr Tourkine, Alexander Zhiboedov
In 1968, Atkinson proved the existence of functions that satisfy all S-matrix axioms in four spacetime dimensions. His proof is constructive and to our knowledge it is the only res…
Loop amplitudes monodromy relations and color-kinematics duality
Eduardo Casali, Sebastian Mizera, Piotr Tourkine
Color-kinematics duality is a remarkable conjectured property of gauge theory which, together with double copy, is at the heart of a wealth of new developments in scattering amplit…
Monodromy relations from twisted homology
Eduardo Casali, Sebastian Mizera, Piotr Tourkine
We reformulate the monodromy relations of open-string scattering amplitudes as boundary terms of twisted homologies on the configuration spaces of Riemann surfaces of arbitrary gen…
On integrands and loop momentum in string and field theory
Piotr Tourkine
The notion of a unique integrand does not a priori makes sense in field theory: different Feynman diagrams have different loop momenta and there should be no reason to compare them…
Windings of twisted strings
Eduardo Casali, Piotr Tourkine
Twistor string models have been known for more than a decade now but have come back under the spotlight recently with the advent of the scattering equation formalism which has grea…
The complex null string, Galilean conformal algebra and scattering equations
Eduardo Casali, Yannick Herfray, Piotr Tourkine
The scattering equation formalism for scattering amplitudes, and its stringy incarnation, the ambitwistor string, remains a mysterious construction. In this paper, we pursue the st…
One-loop monodromy relations on single cuts
Alexander Ochirov, Piotr Tourkine, Pierre Vanhove
The discovery of colour-kinematic duality has led to significant progress in the computation of scattering amplitudes in quantum field theories. At tree level, the origin of the du…
Higher-loop amplitude monodromy relations in string and gauge theory
Piotr Tourkine, Pierre Vanhove
The monodromy relations in string theory provide a powerful and elegant formalism to understand some of the deepest properties of tree-level field theory amplitudes, like the color…
Two-Loop Scattering Amplitudes from the Riemann Sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations give striking formulae for massless scattering amplitudes at tree level and, as shown recently, at one loop. The progress at loop level was based on ambitw…
On the null origin of the ambitwistor string
Eduardo Casali, Piotr Tourkine
In this paper we present the null string origin of the ambitwistor string. Classically, the null string is the tensionless limit of string theory, and so too is the Ambitwistor str…
One-loop amplitudes on the Riemann sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations provide a powerful framework for the study of scattering amplitudes in a variety of theories. Their derivation from ambitwistor string theory led to propos…
Loop Integrands for Scattering Amplitudes from the Riemann Sphere
Yvonne Geyer, Lionel Mason, Ricardo Monteiro +1
The scattering equations on the Riemann sphere give rise to remarkable formulae for tree-level gauge theory and gravity amplitudes. Adamo, Casali and Skinner conjectured a one-loop…
Infrared behaviour of the one-loop scattering equations and supergravity integrands
Eduardo Casali, Piotr Tourkine
The recently introduced ambitwistor string led to a striking proposal for one-loop maximal supergravity amplitudes, localised on the solutions of the ambitwistor one-loop scatterin…