Me inside Jesus Rafael Soto's 'Penetrable BBL Blue 2/8' at the Perez Art Museum in Miami

Theo Johnson-Freyd

Assistant Professor of Mathematics
Dalhousie University
Perimeter Institute

Brief bio

My research focuses on "homotopical physics": the interplay between mathematical physics (particularly quantum field theory) and higher (aka categorical) algebra. Other buzzwords that describe my work: higher symmetries, topological field theory, phases of condensed matter, "moonshine" phenomena, perturbative quantization, categories, representation theory, and algebraic topology. For more details, see my Research Statement (PDF), read my publications, or watch my seminar presentations.

A lightning summary of my Curriculum Vitae (PDF): I received my PhD from UC Berkeley in 2013, under the supervision of Nicolai Reshetikhin; I served as an NSF postdoc and Boas Assistant Professor at Northwestern University from 2013–16 and then as a Senior Postdoctoral Fellow at the Perimeter Institute 2016–20; I joined the Dalhousie faculty in January, 2021, and I hold a joint appointment as an associate faculty member at the Perimeter Institute. I am currently a principal investigator for the Simons Collaboration on Global Categorical Symmetries.

Graduate students: Jessica Weitbrecht (MSc 2018). Alissa Furet (MSc 2022). Matthew Yu (PhD 2023). Ruizhi Liu (MSc 2023, PhD 2027). Adrien DeLazzer Meunier (PhD 2026). Daniel Teixeira (PhD 2026).

I used to be a dancer. I choreographed the 2007 Stanford Viennese Ball opening ceremonies. My husband and I are avid cooks. Unless you are immediate family, we will not cater your wedding cake.

I am a signatory to the Commitment to gender equity at scholarly conferences: I will only accept invitations to conferences if the panel of speakers includes a diversity of genders. Students interested in asking me about feminism or queer life in mathematics are encouraged to contact me.

The Perimeter Institute is in the Haldimand Tract, land promised to the Haudenosaunee Six Nations. Dalhousie University is in Mi`kma`ki, the ancestral and unceded territory of the Mi`kmaq.

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