David Penneys
Professor of Mathematics at The Ohio State University
Office: Room 752 Math Tower
Email: penneys (dot) 2 (at) osu (dot) edu

dsp in berkeley

Unitary Quantum Symmetries Lite

I am in the process of compiling my notes from 3 topics courses at OSU from 2018 (Quantum Algebra), 2021 (Topological Phases of Matter), and 2023 (Higher Linear Algebra) into a book with Giovanni Ferrer and Kyle Kawagoe.

The book has 3 parts. Each part discusses objects, their endomorphisms, a weaker version of equivalence, some important examples, and applications.
  • Part I: Hilb: Finite dimensional Hilbert spaces.
  • Part II: 2Hilb: Finite semisimple unitary categories.
    • Chapter 7: Semisimple categories, 41 pages
    • Chapter 8: Unitary categories, [in progress]
    • Chapter 9: Fusion categories, [in progress]
    • Chapter 10: Unitary fusion categories, [in progress]
    • Chapter 11: (Unitary) Braided fusion categories, [in progress]
    • Chapter 12: Module categories and algebra objects, [in progress]
    • Chapter 13: Topological quantum field theory and topological order, [in progress]
  • Part III: 3Hilb: Finite semisimple unitary 2-categories.
  • References

Files

Here are notes from my 2023 course on Higher Linear Algebra. Here are notes from my 2021 course on Topological Phases of Matter. Here are notes from my 2018 course on Quantum algebra.
\begin{warning} There are known errors in these notes. \end{warning}

Here are other helpful links.

Announcements for UQSL

2026/7/8, 16:39
Chapters 5 and 7
Drafts of Chapters 5 and 7 are posted. Chapter 5 is still very much a work in progress, but we are happier with Chapter 7. We expect unitary categories to be live soon.

2025/5/15, 16:50
Chapters 3-4
Drafts of Chapters 3-4 posted. Chapter 3 is still very much a work in progress. We may be able to simplify the exposition -- we are in the process of balancing operator algebraic techniques with the (semi)simplicity of the various unitary versions of representation theory.

2025/4/30, 13:02
Up and running
Drafts of Chapters 1-2 posted. More updates coming soon (in geological time).


last modified: 2025/5/15