Nathan Geer Ph.D.
Mathematics and Statistics
Professor

Contact Information
Office Location: Animal Science (ANSC) 306Phone: (435) 797-0755
Email: nathan.geer@usu.edu
Additional Information:
Awards
CIMI Scientific Research Fellow, 2024
Institut de Mathematiques de Toulouse, France
Invited Member, 2023
Max-Planck Institute for Mathematics, Bonn, Germany
CNRS Directeur de Recherches, 2015
University of Paris Sorbonne
Japan Society for the Promotion of Science (JSPS) Research Fellowship, 2015
Waseda University, Tokyo Japan
Invited Member, 2015
Max-Planck Institute for Mathematics, Bonn, Germany
College of Science Researcher of the Year, 2013
Utah State University
Department of Mathematics and Statistics, Researcher of the Year, 2013
Utah State University
Thank a Teacher Certificate, 2008
Georgia Institute of Technology
Take Your Professor to Lunch, 2005
Georgia Institute of Technology
Harrison Research Award, 2004
University of Oregon
Johnson Research Fellowship, 2003
University of Oregon
Publications | Journal Articles
Academic Journal
- Geer, N.C, Ha, ., Patureau-Mirand, B., (2024). Modified symmetrized integral in G-coalgebras. Journal of Knot Theory and Its Ramifications
- Geer, N.C, Lauda, A., Patureau-Mirand, B., Sussan, J., (2022). A Hermitian TQFT from a non-semisimple category of quantum sl(2)-modules. Lett. Math. Phys., 112
- Geer, N.C, Kujawa, J., Patureau-Mirand, B., (2022). M-traces in (non-unimodular) pivotal categories. Algebras and Representation Theory, 25
- Geer, N.C, Ha, ., Patureau-Mirand, B., (2022). Modified graded Hennings invariants from unrolled quantum groups and modified integral. J. Pure Appl. Algebra, 226
- Geer, N.C, Lauda, A., Patureau-Mirand, B., Sussan, J., (2022). Pseudo-Hermitian Levin-Wen models from non-semisimple TQFTs. Ann. Physics, 442
- Anghel, C., Geer, N.C, Patureau-Mirand, B., (2021). Relative (pre)-modular categories from special linear Lie superalgebras. Journal of Algebra, 586, 479-525.
- Hu, Y., Geer, N.C, Wu, Y., (2018). Full Dyon Excitation Spectrum in Generalized Levin-Wen Models. Phys. Rev. B, 97:195154
- Geer, N.C, Patureau-Mirand, B., (2018). The trace on projective representations of quantum groups. Letters in Mathematical Physics, 108
- Blanchet, C., Costantino, F., Geer, N.C, Patureau-Mirand, B., (2016). Non semi-simple TQFTs from unrolled quantum sl(2). Proceedings of the Gokova Geometry-Topology Conference 2015, 218--231.
- Blanchet, C., Costantino, F., Geer, N.C, Patureau-Mirand, B., (2016). Non semi-simple TQFTs, Reidemeister torsion and Kashaev’s invariants. Advances in Mathematics, 301, 1-78.
- Costantino, F., Geer, N.C, Patureau-Mirand, B., (2015). Relations between Witten–Reshetikhin–Turaev and nonsemisimple sl (2) 3–manifold invariants. Algebraic & Geometric Topology, 15:3, 1363–1386.
- Costantino, F., Geer, N.C, Patureau-Mirand, B., (2015). Some remarks on the unrolled quantum group of sl (2). Journal of Pure and Applied Algebra, 219:8, 3238–3262.
- Costantino, F., Geer, N.C, Patureau-Mirand, B., (2014). Quantum invariants of 3-manifolds via link surgery presentations and non-semi-simple categories. Journal of Topology, jtu006.
- Geer, N.C, (2014). The Kontsevich integral and re-normalized link invariants arising from Lie superalgebras. Knots in Poland. III. Part 1, 79–84, Banach Center Publ., 100, Polish Acad. Sci. Inst. Math., Warsaw
- Geer, N.C, Kujawa, J., Patureau-Mirand, B., (2013). Ambidextrous objects and trace functions for nonsemisimple categories. Proceedings of the American Mathematical Society, 141:9, 2963–2978.
- Geer, N.C, Patureau-Mirand, B., (2013). G-LINKS INVARIANTS, MARKOV TRACES AND THE SEMI-CYCLIC Uq (2)-MODULES. Journal of Knot Theory and Its Ramifications, 22:11, 1350063.
- Geer, N.C, Patureau-Mirand, B., (2013). Topological invariants from nonrestricted quantum groups. Algebraic & Geometric Topology, 13:6, 3305–3363.
- Geer, N.C, Patureau-Mirand, , Virelizier, , (2013). Traces on ideals in pivotal categories. Quantum Topology, 4:no. 1, 91-124.
- Geer, N.C, Kashaev, R., Turaev, V., (2012). Tetrahedral forms in monoidal categories and 3-manifold invariants. Journal für die reine und angewandte Mathematik (Crelles Journal), 2012:673, 69–123.
- Geer, N.C, Patureau-Mirand, B., Kujawa, J., (2011). Generalized trace and modified dimension functions on ribbon categories. Selecta Mathematica, 17:no. 2, 453-504.
- Geer, N.C, Patureau-Mirand, B., (2011). Polynomial 6j-Symbols and States Sums. Algebraic and Geometric Topology, 11, 1821-1860.
- Geer, N.C, Patureau-Mirand, B., Turaev, V., (2011). Modified 6j-Symbols and 3-Manifold Invariants. Advances in Mathematics, 228:no. 2, 1163--1202.
- Geer, N.C, Patureau-Mirand, B., (2010). Multivariable link invariants arising from Lie superalgebras of type I. Journal Knot Theory Ramifications, 19:1, 93-115.
- Geer, N.C, Enriquez, B., (2009). Compatibility of quantization functors of Lie bialgebras with duality and doubling operations. Selecta Mathematica, 15:1, 1-59.
- Geer, N.C, Patureau-Mirand, B., Turaev, V., (2009). Modified quantum dimensions and re-normailized link invariants. Composiito Mathematica, 145:1, 196-212.
- Geer, N.C, Reshetikhin, N., (2009). On Invariants of Graphs Related to Quantum sl(2) at Roots of Unity. Letters in Mathematical Physics, 88:1-3, 321-331.
- Geer, N.C, Patureau-Mirand, B., (2008). An invariant supertrace for the category of representations of Lie superalgebras of type I. Pacific Journal of Mathematicis, 238:2, 331-348.
- Geer, N.C, Patureau-Mirand, B., (2008). On the colored HOMFLY-PT, multivariable and Kashaev link invariants. Communications in Contemporary Mathematics, 10:1, 993-1011.
- Geer, N.C, Etingof, P., (2007). Monodromy of the trigonometric KZ equations. International Mathematics Research Notices, 24
- Geer, N.C, Patureau-Mirand, B., (2007). Multivariable link invariants arising from sl (2| 1) and the Alexander polynomial. Journal of Pure and Applied Algebra, 210:1, 283–298.
- Geer, N.C, (2007). Some remarks on quantized Lie superalgebras of classical type. Journal of Algebra, 314:2, 565-580.
- Geer, N.C, (2006). Etingof–Kazhdan quantization of Lie superbialgebras. Advances in Mathematics, 207:1, 1–38.
- Geer, N.C, (2005). The Kontsevich integral and quantized Lie superalgebras. Algebr. Geom. Topol., 5:45, 1111-1139.
An asterisk (*) at the end of a publication indicates that it has not been peer-reviewed.
Publications | Other
An asterisk (*) at the end of a publication indicates that it has not been peer-reviewed.
Teaching
Graduate Students Mentored
Research

Dr. Geer's research is centered around low-dimensional topology (left) and representation theory (right). Much of the productive interplay between quantum topology (green) and quantum algebra (blue) relies on categories having certain properties, like being semi-simple. His current research focuses on broadening this interplay to a larger framework which includes non-semi-simple categories (orange). In particular, he is developing a new theory of re-normalized invariants of links and 3-manifold within quantum topology and drawing connections with this theory and a variety of topics including the Volume Conjecture, TQFTs, and mapping class groups. The topological techniques in this theory lead to a new notion of modified traces (orange) which are closely related to some basic concepts in representation theory. These traces are useful tools in providing addition examples in topology. Much of this work is interconnected with mathematical physics which Dr. Geer is investigating within the context of Levin-Wen models.