Publications de Alexander Zhiboedov

Probing multi-particle unitarity with the Landau equations

Miguel Alexandre Ribeiro Correia, Alexander Zhiboedov, Amit Sever

We consider the 2 -> 2 scattering amplitude of identical massive particles. We identify the Landau curves in the multi-particle region 16m(2)

2022

An analytical toolkit for the S-matrix bootstrap

Miguel Alexandre Ribeiro Correia, Alexander Zhiboedov, Amit Sever

We revisit analytical methods for constraining the nonperturbative S-matrix of unitary, relativistic, gapped theories in d >= 3 spacetime dimensions. We assume extended analyticity of the two-to-two scattering amplitude and use it together with elastic uni ...

Springer Nature2021

Applications of dispersive sum rules: epsilon-expansion and holography

João Miguel Augusto Penedones Fernandes, Alexander Zhiboedov, João Pedro Alves Da Silva, Din Carmi

We use Mellin space dispersion relations together with Polyakov conditions to derive a family of sum rules for Conformal Field Theories (CFTs). The defining property of these sum rules is suppression of the contribution of the double twist operators. First ...

SCIPOST FOUNDATION2021

Nonperturbative Mellin amplitudes: existence, properties, applications

João Miguel Augusto Penedones Fernandes, Alexander Zhiboedov, João Pedro Alves Da Silva

We argue that nonperturbative CFT correlation functions admit a Mellin amplitude representation. Perturbative Mellin representation readily follows. We discuss the main properties of nonperturbative CFT Mellin amplitudes: subtractions, analyticity, unitari ...

Springer Nature2020