Six-dimensional D_N theory and four-dimensional SO-USp quivers
Yuji Tachikawa
TL;DR
The paper extends Gaiotto's construction of 4d $\mathcal{N}=2$ SCFTs from the 6d $\mathrm{A}_{N-1}$ theory to the 6d $\mathrm{D}_{N}$ theory with orientifolds, realizing $\mathrm{SO}$–$\mathrm{USp}$ quivers as compactifications on punctured G-curves. It introduces tails labeled by embeddings of $\mathrm{SU}(2)$ into $\mathrm{SO}(2N)$ or $\mathrm{USp}(2N-2)$, with flavor symmetries given by the corresponding commutants, and constructs new isolated theories such as $T_{\mathrm{SO}(2N)}$ with $SO(2N)^3$ flavor symmetry. The work also uncovers dualities, including an $E_7$-flavored SCFT arising from puncture collisions, and demonstrates a nontrivial equivalence between the $A_3$ and $D_3$ six-dimensional theories in this setup. Overall, it broadens the Gaiotto program to the $D_N$ class and suggests rich connections to six-dimensional defects and potential holographic realizations.
Abstract
We realize four-dimensional N=2 superconformal quiver gauge theories with alternating SO and USp gauge groups as compactifications of the six-dimensional D_N theory with defects. The construction can be used to analyze infinitely strongly-coupled limits and S-dualities of such gauge theories, resulting in a new class of isolated four-dimensional N=2 superconformal field theories with SO(2N)^3 flavor symmetry.
