Multi-qubit doilies: Enumeration for all ranks and classification for ranks four and five

Axel Muller
Metod Saniga
Alain Giorgetti
Henri De Boutray
Frédéric Holweck
September 7, 2022

Abstract

For N≥2, an qubit doily is a doily living in the -qubit symplectic polar space. These doilies are related to operator-based proofs of quantum contextuality. Following and extending the strategy of Saniga et al. (Mathematics 9 (2021) 2272) that focused exclusively on three-qubit doilies, we first bring forth several formulas giving the number of both linear and quadratic doilies for any . Then we present an effective algorithm for the generation of all -qubit doilies. Using this algorithm for  and , we provide a classification of -qubit doilies in terms of types of observables they feature and number of negative lines they are endowed with. We also list several distinguished findings about -qubit doilies that are absent in the three-qubit case, point out a couple of specific features exhibited by linear doilies and outline some prospective extensions of our approach.