Quantum super-spherical pairs
D. Algethami, A. Mudrov, V. Stukopin
TL;DR
The paper develops a $ abla Z_2$-graded framework for quantum symmetric pairs by constructing quantum super-spherical pairs as coideal subalgebras inside general linear and orthosymplectic quantum supergroups $U_q(rak{g})$. It builds a systematic classification using graded Satake diagrams and formulates a $ abla Z_2$-graded Reflection Equation to produce $K$-matrices that realize quantum isotropy subgroups, linking them to left coideal subalgebras. Explicit K-matrices are derived for type $A$, $B$, and $C$ in the graded setting, with mixture parameters encoding the deformation data and root-vector constructions $F_{ ilde{oldsymbol{eta}}}$ guiding the coideal generation. The work provides a solid foundation for quantum super-symmetric spaces by connecting graded Satake data to coideal subalgebra quantization and graded RE solutions, and it outlines conjectural extensions for more intricate type II diagrams and twisted RE variants, signaling directions for future integrable-system applications.
Abstract
We introduce quantum super-spherical pairs as coideal subalgebras in general linear and orthosymplectic quantum supergroups. These subalgebras play a role of isotropy subgroups for matrices solving $\mathbb{Z}_2$-graded reflection equation. They generalize quantum (pseudo)-symmetric pairs of Letzter-Kolb-Regelskis-Vlaar.
