# Multi-particle observables from a finite Euclidean spacetime*

- Institution: CERN
- Department: TH institutes
- Speaker: Maxwell Hansen
- Year: 2022
- Language: English
- Subjects: Physics
- Source: [CERN](https://videos.cern.ch/record/3015321)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Tweens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

Numerical calculations using lattice-regularized QFTs are a powerful tool to understand nonperturbative systems when analytic methods are unavailable. However, the utility of numerical results can be affected by two issues: (i) calculations are necessarily performed in a finite-volume spacetime and (ii) Euclidean- (rather than Minkowski-) signature correlation functions are evaluated. Both aspects play an especially important role for multi-particle observables including scattering and decay amplitudes and inclusive rates. In this talk, I will discuss progress in extracting such observables from numerical lattice field theory, based on two strategies. One is to use the finite-volume as a tool, rather than an unwanted artefact, and to apply generic field theoretic relations between finite-volume quantities and infinite-volume amplitudes. The second is to carefully regulate the inverse Laplace transform, in order to estimate Minkowski observables directly from numerical Euclidean correlators.

## Lectures

1. [Multi-particle observables from a finite Euclidean spacetime*](https://invisiblenetwork.ai/learn/cern/3015321/a5b09e9e3701), 1 h 6 min (CERN's player)