Publications associées à Where Is String Theory in the Space of Scattering Amplitudes?

Bootstrapping amplitudes of scalar particles

Quantum Field Theories are a central object of interest of modern physics, describing fundamental interactions of matter. However, current methods give limited insight into strongly coupling theories. S-matrix bootstrap program, described in this thesis, a ...

EPFL2024

Where is M-theory in the space of scattering amplitudes?

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri

We use the S-matrix bootstrap to carve out the space of unitary, analytic, crossing symmetric and supersymmetric graviton scattering amplitudes in nine, ten and eleven dimensions. We extend and improve the numerical methods of our previous work in ten dime ...

Springer Nature2023

Nonperturbative aspects of scattering amplitudes

Miguel Alexandre Ribeiro Correia

In this thesis we study how physical principles imposed on the S-matrix, such as Lorentz invariance, unitarity, crossing symmetry and analyticity constrain quantum field theories at the nonperturbative level. We start with a pedagogical introduction to the ...

EPFL2023

An analytical toolkit for the S-matrix bootstrap

Miguel Alexandre Ribeiro Correia, Amit Sever, Alexander Zhiboedov

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

Solving the 2D SUSY Gross-Neveu-Yukawa model with conformal truncation

Matthew Thomas Walters

We use Lightcone Conformal Truncation to analyze the RG flow of the two-dimensional supersymmetric Gross-Neveu-Yukawa theory, i.e. the theory of a real scalar superfield with a DOUBLE-STRUCK CAPITAL Z(2)-symmetric cubic superpotential, aka the 2d Wess-Zumi ...

Springer Nature2021

Non-Wilson-Fisher kinks of O(N) numerical bootstrap: From the deconfined phase transition to a putative new family of CFTs

Ning Su

It is well established that the O(N) Wilson-Fisher (WF) CFT sits at a kink of the numerical bounds from bootstrapping four point function of O(N) vector. Moving away from the WF kinks, there indeed exists another family of kinks (dubbed non-WF kinks) on th ...

2021

Numerical investigations of 3D CFTs using conformal bootstrap methods

Marten Jan Reehorst

Conformal field theories (CFTs) play a very significant role in modern physics, appearing in such diverse fields as particle physics, condensed matter and statistical physics and in quantum gravity both as the string worldsheet theory and through the AdS/C ...

EPFL2020

Bootstrapping QCD Using Pion Scattering Amplitudes

João Miguel Augusto Penedones Fernandes, Andrea Guerrieri

We consider the S-matrix bootstrap of four-dimensional scattering amplitudes with O(3) symmetry and no bound states. We explore the allowed space of scattering lengths which parametrize the interaction strength at threshold of the various scattering channe ...

2019

Supergravity with broken Lorentz invariance: theory and phenomenological consequences

Sergey Sibiryakov

We construct and study supersymmetric extension of the Einstein-aether gravitational theory. Using superfield formalism we carry out unique linearized Lorentz violating supergravity action invariant under super-gauge transformations and obtain its bosonic ...

IOP PUBLISHING LTD2019

Large field excursions and approximate discrete symmetries from a clockwork axion

Riccardo Rattazzi

We present a renormalizable theory of scalars in which the low-energy effective theory contains a pseudo-Goldstone boson with a compact field space of 2 pi F and an approximate discrete shift symmetry Z(Q) with Q >> 1, yet the number of fields in the theor ...

American Physical Society2016

Planck 2013 results. XXV. Searches for cosmic strings and other topological defects

Julien Lesgourgues, Fabio Finelli, Jason Douglas McEwen

Planck data have been used to provide stringent new constraints on cosmic strings and other defects. We describe forecasts of the CMB power spectrum induced by cosmic strings, calculating these from network models and simulations using line-of-sight Boltzm ...

Edp Sciences S A2014

Metastable spontaneous breaking of N=2 supersymmetry

Claudio Scrucca, Benoît Légeret, Paul Smyth

We show that contrary to the common lore it is possible to spontaneously break N = 2 supersymmetry even in simple theories without constant Fayet-Iliopoulos terms. We consider the most general N = 2 supersymmetric theory with one hypermultiplet and one vec ...

Elsevier Science Bv2013

Supersymmetric vacua in N=2 supergravity

Paul Smyth

We use the embedding tensor formalism to analyse maximally symmetric backgrounds of N = 2 gauged supergravities which have the full N = 2 supersymmetry. We state the condition for N = 2 vacua and discuss some of their general properties. We show that if th ...

Springer Nature2012

Metastable de Sitter vacua in N=2 to N=1 truncated supergravity

Claudio Scrucca, Paul Smyth, Francesca Catino

We study the possibility of achieving metastable de Sitter vacua in general N=2 to N=1 truncated supergravities without vector multiplets, and compare with the situations arising in N=2 theories with only hypermultiplets and N=1 theories with only chiral m ...

Springer Nature2012

Plasmon evolution and charge-density wave suppression in potassium intercalated 2H-TaSe2

Helmuth Berger

We have investigated the influence of potassium intercalation on the formation of the charge-density wave (CDW) instability in 2H-TaSe2 by means of electron energy-loss spectroscopy and density functional theory. Our observations are consistent with a fill ...

IOP Publishing - EPL Association2012

A reduced basis model with parametric coupling for fluid-structure interaction problems

Alfio Quarteroni, Gianluigi Rozza, Toni Mikael Lassila

We present a new model reduction technique for steady fluid-structure interaction problems. When the fluid domain deformation is suitably parametrized, the coupling conditions between the fluid and structure can be formulated in the low-dimensional space o ...

Society for Industrial and Applied Mathematics2012

Tackling the Supersymmetric Flavour Problem in String Models

Christopher John Andrey

In this work we address one of the phenomenological issues of beyond the Standard Model scenarios which embed Supersymmetry, namely the Supersymmetric Flavour Problem, in the context of String Theory. Indeed, the addition of new interactions to the Standar ...

EPFL2011

Sequestering by global symmetries in Calabi–Yau string models

Christopher John Andrey, Claudio Scrucca

We study the possibility of realizing an effective sequestering between visible and hidden sectors in generic heterotic string models, generalizing previous work on orbifold constructions to smooth Calabi-Yau compactifications. In these theories, genuine s ...

Elsevier2011

Vacuum Stability in Supersymmetric Effective Theories

Leonardo Brizi

The main topics discussed in this thesis are supersymmetric low-energy effective theories and metastability conditions in generic non-renormalizable models with global and local supersymmetry. In the first part we discuss the conditions under which the low ...

EPFL2011

Mildly sequestered supergravity models and their realization in string theory

Christopher John Andrey, Claudio Scrucca

We elaborate on the idea that five-dimensional models where sequestering is spoiled due to contact interactions induced by vector multiplets may still be mildly sequestered if a global version of the gauge symmetry associated to the latter survives in the ...

2010