Positivity and the Bootstrap

Contribution List

1. Positivity without Boosts: UV/IR Relations for Cosmology

Scott Melville

31/05/2021, 14:30

Positivity bounds are a powerful tool which can connect IR phenomenology with the underlying fundamental physics in the UV, but to date their implementation has required Lorentz invariance at all scales.
This talk describes recent progress in removing this assumption, deriving a set of bounds which can be applied to systems in which boosts are spontaneously broken, such as cosmology.
For...

2. A Timeless History of Time

Enrico Pajer (University of Cambridge)

31/05/2021, 15:30

Cosmological observations give us the unique opportunity to probe the fundamental laws of physics at very high energies as well as the perturbative regime of quantum gravity. Unfortunately, due to the creativity of theorists and the paucity of data about the primordial universe, there is a huge number of models compatible with all measurements, featuring a wide variety of mechanisms,...

3. On analytic properties of cosmological correlators

Viktor Gorbenko

31/05/2021, 16:30

4. Discussion

Claudia de Rham (Imperial College London)

31/05/2021, 17:30

13. Positivity bounds in SMEFT and the inverse problem.

Cen Zhang (Institute of High Energy Physics, Chinese Academy Sciences)

01/06/2021, 14:30

14. The facets of product moments: from EFThedron to Modularhedron

yu-tin Huang

01/06/2021, 15:30

15. Positive Moments and Loops

Francesco Riva

01/06/2021, 16:30

16. Discussion

Joao Miguel Augusto Penedones Fernandes (EPFL - Ecole Polytechnique Federale Lausanne (CH))

01/06/2021, 17:30

17. Rigorous bounds on the analytic S-matrix

Andrea Guerrieri

02/06/2021, 14:30

In this talk I will introduce a complementary approach to the non-perturbative S-matrix Bootstrap based on duality in optimization theory.
In particular, I will focus on the problem of bounding the quartic coupling for gapped theories in 4-dimensions, both from above and below.
The bounds obtained rely solely on proven analyticity properties and the numerical problem can be efficiently...

18. Celestial amplitudes: from UV constraints to conformal blocks

Raclariu Ana-Maria

02/06/2021, 15:30

Celestial amplitudes describe scattering in a basis of boost eigenstates. In this basis, 4-point scattering is characterized by two variables: the sum over the boost weights $\beta$ which is dual to the center of mass energy, and a cross ratio $z$ related to the bulk scattering angle. In this talk I will describe two aspects of the physics captured by the $\beta$ and $z$ dependence. I will...

19. Positive sum rules in gravitational EFTs

Simon Caron-Huot

02/06/2021, 16:30

We explore constraints on low-energy dynamics which stem from assuming causality of 2->2 scattering at all energy scales. I will review a key ingredient added recently: low-energy crossing symmetry, which bounds the couplings of spinning heavy states and ensures that sum rules are dominated by (unknown) states of low spin. Gravity is special since its tree-level energy growth already...

20. Discussion

Andrew Tolley (Imperial College London)

02/06/2021, 17:30

11. Discussion

Claudia de Rham (Imperial College London)

12. Discussion

Claudia de Rham (Imperial College London)

5. TBA

Scott Melville

6. TBA

Scott Melville

7. TBA

Enrico Pajer (University of Cambridge)

8. TBA

Enrico Pajer (University of Cambridge)

9. TBA

Viktor Gorbenko

10. TBA

Viktor Gorbenko