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# Physics Colloquium: Lucas Platter

## November 29, 2021 | 4:00 pm - 5:00 pm

**Title: **From nucleons to atoms: The effective field theory tower

**Abstract: **The effective field theory approach is to simplify a complicated physical problem by reducing the number of degrees of freedom and using available separations of scales. A classical example of an effective theory is the multipole decomposition of a charged object to describe its electric field / potential at larger distances. In this colloquium, I will introduce the effective field theory method and show how it can relate physics at very different scales to each other. Specifically, I will discuss how starting from nucleons we can use different EFTs to build up tower up to the 4He trimer state, a bound state of three 4He atoms. Doing so, I will introduce several examples of non-relativistic EFTs that together connect distance scales from Fermi to Angstrom.

**Host: **Sebastian Koenig