Aspects of Amplitudes

13 Jun 2016, 09:00 → 2 Jul 2016, 18:00 Europe/Stockholm

122:026 (Nordita, Stockholm)

Henrik Johansson (Nordita and Uppsala University), Nima Arkani-Hamed (IAS Princeton), Paolo Di Vecchia (Nordita), Ruth Britto (Trinity College Dublin), Zvi Bern (UCLA)

Scope

Scattering amplitudes in relativistic quantum theories possess a multitude of remarkable hidden structures and correspondences. They are of vital importance for high-precision comparisons of theory and experiment at the LHC, yet they also have the promise of revealing fundamentally new approaches to quantum field theory and of exposing interrelations that unify gauge theories, gravity, and string theory. This program will provide a meeting ground to communicate the current themes and recent progress in various areas of theoretical physics touched by scattering amplitudes. This includes N = 4 SYM, higher-loop QCD, perturbative gravity, string amplitudes, polylogarithms, Grassmannians and the amplituhedron, soft theorems, twistor strings, color-kinematics duality and double-copy properties of gravity, supergravity UV behavior, and more.

Participants include:

Samuel Abreu Alexandros Anastasiou Simon Badger Niklas Beisert Marcus Berg Johan Bijnens Emil Bjerrum-Bohr Rutger Boels Jacob Bourjaily Lars Brink Andreas Brandhuber Johannes Broedel

Simon Caron-Huot John Joseph Carrasco Eduardo Casali Marco Chiodaroli Lance Dixon Claude Duhr Oluf Engelund Bo Feng Marialuisa Frau Einan Gardi Yvonne Geyer Monica Guica

Murat Gunaydin Song He Johannes Henn Enrico Herrmann Yu-tin Huang Harald Ita Gregory Korchemsky David Kosower Kirill Krasnov Kasper Larsen Alberto Lerda Carlos Mafra

Lorenzo Magnea Lionel Mason Raffaele Marotta David McGady Joseph Minahan Ricardo Monteiro Matin Mojaza Dhritiman Nandan Josh Nohle Alexander Ochirov Donnal O’Connell Olof Ohlsson Sax

Erik Panzer Ettore Remiddi Radu Roiban Rodolfo Russo Robert Schabinger Oliver Schlotterer Chia-Hsien Shen Vladimir Smirnov Stephan Stieberger David Skinner Marcus Spradlin Martin Sprenger

Bo Sundborg Lárus Thorlacius Piotr Tourkine Gabriele Travaglini Jaroslav Trnka Pierre Vanhove Leonardo Vernazza Anastasia Volovich Christopher White Matthias Wilhelm Ellis Yuan Yang Zhang

Application deadline: 15 March 2016. Application form.

The program will be immediately followed by the Amplitudes 2016 International Conference 4-8 July, 2016.

The program is supported through funding from Nordita, Uppsala University and the Knut and Alice Wallenberg Foundation.

Monday, 13 June

10:00 → 11:00 Ambitwistor Strings, Loop Amplitudes, and Strings

Speaker: Piotr Tourkine (Cambridge)

16:00 → 17:00 Nordita Seminar: Modern Approaches to Quantum Scattering Amplitudes

Quantum scattering amplitudes, classically given by the famous pictorial representation of Richard Feynman which describe the many ways the collisions between particles could take place in space-time, are a cornerstone of today's quantum field theory. In the past decade, we have learned a great deal about scattering amplitudes for completely general theories. Central to these developments has been the N = 4 Super- Yang-Mills theory. The quest to more loops, more legs and less symmetry led to completely different ways of visualizing and computing scattering amplitudes, some of which reach beyond the standard framework of flat space relativistic quantum field theory and place quantum scattering amplitudes at the intersection several fields of physics (and mathematics). We shall highlight some of the surprising advances and illustrate them with examples from N=8 supergravity and N = 4 super-Yang-Mills theory, discuss applications to particle physics experiments, two-dimensional integrable models and other observables in quantum field theories.

Speaker: Radu Roiban (Penn State)

18:00 → 19:00 Welcome reception: food and drinks

Tuesday, 14 June

10:00 → 11:00 String Amplitudes in the High and Low Energy Limits

Perturbative string amplitudes encode information that is relevant in many different contexts, from determining the effective action to studying the high energy behaviour of the theory. I will discuss how to isolate from the full string amplitudes the leading and subleading contributions to these different limits by focusing in particular on some concrete, interesting examples.

Speaker: Rodolfo Russo (Queen Mary)

Slides Russo.pdf

16:00 → 17:00 Multiloop Amplitudes with the Non-Minimal Pure Spinor Formalism

Speaker: Carlos Mafra (IAS Princeton & Southampton)

Wednesday, 15 June

10:00 → 11:00 Introduction to Color-kinematics Duality and the Double Copy

Speaker: John Joseph Carrasco (IPhT/CEA Saclay & IAS Princeton)

16:00 → 17:00 Classical Squaring Relations Between Gauge Theory and Gravity

Speaker: Donal O'Connell (Edinburgh)

Slides OConnell.pdf

Thursday, 16 June

10:00 → 10:45 Introduction to Ambitwistor Strings I

Speaker: David Skinner (Cambridge)

10:45 → 11:30 Introduction to Ambitwistor Strings II

Speaker: Lionel Mason (Oxford)

Slides Mason.pdf

16:00 → 17:00 Berends-Giele Currents in String Amplitudes

Speaker: Oliver Schlotterer (AEI Potsdam)

Friday, 17 June

10:00 → 11:00 Scattering Equations and Analytic Gluon Amplitudes

Speaker: Emil Bjerrum-Bohr (NBIA Copenhagen)

Slides Bjerrrum_Bohr.pptx

11:00 → 12:00 From Maximal to Minimal Supersymmetry in String Loop Amplitudes

Speaker: Marcus Berg (Karlstad)

Slides Berg.pdf

Monday, 20 June

10:00 → 11:00 Yangian Symmetry of Planar N = 4 SYM

Speaker: Niklas Beisert (ETH Zurich)

Slides Beisert.pdf

16:00 → 17:00 Scattering via Riemann Spheres

Speaker: Song He (Institute of Theoretical Physics, CAS, Beijing)

Slides He.pdf

18:00 → 19:00 BBQ/reception: food and drinks

Tuesday, 21 June

10:00 → 11:00 N=2 theories: duality, instantons and all that

Speaker: Alberto Lerda (Università del Piemonte Orientale, and INFN)

Slides Lerda.pdf

16:00 → 17:00 The Three-Loop Cusp Anomalous Dimension in QCD and in N=4 SYM

Speaker: Gregory Korchemsky (IPhT/CEA Saclay)

Slides Korchemsky.pdf

Wednesday, 22 June

10:00 → 11:00 Symmetries and Soft Theorems in String and Field Theories

Speaker: Raffaele Marotta (INFN Napoli)

Slides Marotta.pdf

16:00 → 17:00 Lessons from Perturbative Unitarity of String Theory Amplitudes

Speaker: Yu-tin Huang (National Taiwan University)

18:30 → 21:00 Program dinner

Thursday, 23 June

10:00 → 11:00 BCFW Recursion and Boundary Contributions

Speaker: Bo Feng (Zhejiang U.)

Slides Feng.pdf

16:00 → 18:00 Short Talks by O Engelund, E Herrmann, C-H Shen, A Anastasiou

16:00 SUSY Decomposition of Multiloop Amplitudes and Form Factors

Speaker: Oluf Engelund (Uppsala U.)

16:25 On-Shell Diagrams for Gravity

Speaker: Enrico Herrmann (Caltech)

Slides Herrmann.pdf

17:00 Carving out EFT Space via Soft Limits

Speaker: Chia-Hsien Shen (Caltech)

Slides shen.pdf

17:25 Yang-Mills Origin of Gravitational Symmetries

Speaker: Alexandros Anastasiou (Imperial College)

Slides Anastasiou.pdf

Friday, 24 June

10:00 → 11:00 Remainder Functions and Operators in N=4 SYM

Speaker: Gabriele Travaglini (Queen Mary)

Slides Travaglini.pdf

11:00 → 12:00 Six-Point Remainder Function in Multi-Regge-Kinematics

Speaker: Johannes Broedel (Humboldt)

13:00 → 18:00 Midsummer Eve: free activities

For instructions to this holiday, see here:
https://www.youtube.com/watch?v=u8ZLpGOOA1Q

Monday, 27 June

10:00 → 11:00 Numerical Unitarity Method for Two-Loop Amplitudes in QCD

Speaker: Harald Ita (Freiburg)

Slides Ita.pdf

16:00 → 17:00 Integration-by-Parts Reductions from Unitarity Cuts and Algebraic Geometry

Speaker: Kasper Larsen (ETH Zurich)

Slides Larsen.pdf

18:00 → 19:00 Welcome reception: food and drinks

Tuesday, 28 June

10:00 → 11:00 Local Integrands for Two-Loop All-Plus Yang-Mills Amplitudes

Speaker: Simon Badger (Edinburgh)

Slides Badger.pdf

16:00 → 17:00 Precision Theory for the LHC

Speaker: David Kosower (IPhT/CEA Saclay)

Slides Kosower.webarchive

Wednesday, 29 June

10:00 → 11:00 Landau Singularities and Symbology

Speaker: Anastasia Volovich (Brown)

Slides Volovich.pdf

16:00 → 17:00 The Many Uses of Form Factors

Speaker: Andreas Brandhuber (Queen Mary)

Slides Brandhuber.pdf

Thursday, 30 June

10:00 → 11:00 Amplitudes and logs in Chiral Perturbation Theory

Speaker: Johan Bijnens (Lund U.)

Slides Bijnens.pdf

16:00 → 17:00 The Four-Loop Cusp Anomalous Dimension in QCD

Speaker: Johannes Henn (JGU Mainz)

Slides Henn.pdf

Friday, 1 July

10:00 → 11:00 Diagrammatic Hopf Algebra of Cut Feynman Integrals: the One-Loop Case

Speaker: Samuel Abreu (Freiburg)

Slides abreu.pdf

16:00 → 17:00 Collinear Corrections to Next-to-Soft Theorems

Speaker: Lorenzo Magnea (Torino)

Slides Magnea.pdf