English

The distinguished invertible object as ribbon dualizing object in the Drinfeld center

Quantum Algebra 2025-01-03 v3 Algebraic Topology Representation Theory

Abstract

We prove that the Drinfeld center Z(C)Z(\mathcal{C}) of a pivotal finite tensor category C\mathcal{C} comes with the structure of a ribbon Grothendieck-Verdier category in the sense of Boyarchenko-Drinfeld. Phrased operadically, this makes Z(C)Z(\mathcal{C}) into a cyclic algebra over the framed E2E_2-operad. The underlying object of the dualizing object is the distinguished invertible object of C\mathcal{C} appearing in the well-known Radford isomorphism of Etingof-Nikshych-Ostrik. Up to equivalence, this is the unique ribbon Grothendieck-Verdier structure on Z(C)Z(\mathcal{C}) extending the canonical balanced braided structure that Z(C)Z(\mathcal{C}) already comes equipped with. The duality functor of this ribbon Grothendieck-Verdier structure coincides with the rigid duality if and only if C\mathcal{C} is spherical in the sense of Douglas-Schommer-Pries-Snyder. The main topological consequence of our algebraic result is that Z(C)Z(\mathcal{C}) gives rise to an ansular functor, in fact even a modular functor regardless of whether C\mathcal{C} is spherical or not. In order to prove the aforementioned uniqueness statement for the ribbon Grothendieck-Verdier structure, we derive a seven-term exact sequence characterizing the space of ribbon Grothendieck-Verdier structures on a balanced braided category. This sequence features the Picard group of the balanced version of the M\"uger center of the balanced braided category.

Keywords

Cite

@article{arxiv.2212.07910,
  title  = {The distinguished invertible object as ribbon dualizing object in the Drinfeld center},
  author = {Lukas Müller and Lukas Woike},
  journal= {arXiv preprint arXiv:2212.07910},
  year   = {2025}
}

Comments

21 pages, diagrams partly in color; v2: minor changes, Cor. 3.1 strengthened; v3: 23 pages, minor changes in response to reports