Fortuity in ABJM
Alexandre Belin, Palash Singh, Rita Vadala, Alberto Zaffaroni
TL;DR
This work analyzes fortuitous (non-monotone) BPS cohomologies in ABJM theory, focusing on the $1/12$-BPS sector and, at special levels, the $1/16$-BPS sector. It develops a framework based on Q-cohomology, monopole operators, and the superconformal index to identify and classify fortuitous states across $N=1,2$ and varying Chern–Simons level $k$, including nontrivial monopole sectors. A key finding is that fortuitous states can appear at much smaller quantum numbers than in $ ext{N}=4$ SYM, with explicit operators (such as $ ext{O}_f$ at large $k$) and, at $k=2$, a richer monopole sector giving additional fortuitous cohomologies tied to an SU(4) flavor symmetry. The authors formulate a one-loop exactness conjecture for ABJM cohomologies below a threshold, and demonstrate strong consistency with the superconformal index, shedding light on the black-hole-like microstates in AdS$_4$/CFT$_3$ and the role of trace relations in finite-$N$ spectra.
Abstract
We study $1/12$-BPS and $1/16$-BPS cohomologies and the fortuitous mechanism in ABJM theory. We first establish the existence of fortuitous states in the $N=1$ theory, where the theory is abelian and trace relations are extreme. We then provide explicit constructions of fortuitous states at $N=2$. We find fortuitous states both at weak coupling, in direct parallel to what has been done in $\mathcal{N}=4$ SYM, but we also find additional fortuitous states at $k=2$, which is in the strongly coupled regime. The extra fortuitous states that appear at $k=2$ are in non-trivial monopole sectors. A striking distinction from $\mathcal{N}=4$ SYM is that the fortuitous states appear at much smaller quantum numbers, making them easier to find. Along the way, we formulate a non-renormalization conjecture for cohomologies in ABJM.
