# QED in d=3 from the epsilon-expansion.

- Institution: CERN
- Department: TH String Theory Seminar
- Speaker: Lorenzo Di Pietro
- Year: 2015
- Language: English
- Source: [CERN](https://videos.cern.ch/record/3002771)
- Licence: [CERN](http://copyright.web.cern.ch)
- Who can watch: Teens profiles and older (sources give no ratings; placed by Invisible Network from the source's own words)

In my talk, based on the recent work 1508.06278, I will consider the Renormalization Group flow of Quantum Electrodynamics in d=3 coupled to N_f flavors of fermions. For N_f smaller than a critical value N_f^c, chiral symmetry breaking is believed to take place. For N_f > N_f^c, the theory flows to an interacting fixed point that can be studied in the epsilon-expansion, using the fixed point in d=4-2\epsilon. I will discuss the computation of the anomalous dimensions of fermion bilinears and quadrilinear operators, as well as some more conceptual aspects concerning the enhancement of global symmetries in d=3. For small N_f, a quadrilinear operator can become relevant in the IR and destabilize the fixed point. Therefore, the epsilon-expansion can be used to estimate N_f^c..

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## Lectures

1. [QED in d=3 from the epsilon-expansion.](https://invisiblenetwork.ai/learn/cern/3002771/d2fadc1c7add), 49 min (CERN's player)