1/2-BPS membrane instantons in AdS$_4 \times$S$^7 / \mathbf{Z}_k$

TL;DR

This paper identifies and evaluates 1/2-BPS instantonic M2-brane configurations in AdS4 x S7/Zk, connecting eleven-dimensional M-theory with ten-dimensional D-brane instantons in AdS4 x CP3.

Contribution

It provides a new M-theoretic description of 1/2-BPS instantonic branes in AdS4 x S7/Zk, linking them to known ten-dimensional instantons and analyzing their actions.

Findings

Identified 1/2-BPS instantonic M2-branes in AdS4 x S7/Zk.

Compared M2-brane instantons with known D-brane instantons in ten dimensions.

Evaluated the action values of these instantonic configurations.

Abstract

According to the covariant open superstring description of D-branes in the AdS$_4 \times \mathbf{CP}^3$ background, 1/2-BPS D2-branes are purely instantonic. Based on this and by taking the eleven dimensional viewpoint, we identify the 1/2-BPS instantonic M2-brane configurations in the AdS$_4 \times$ S$^7 / \mathbf{Z}_k$ background, which reduces to the AdS$_4 \times \mathbf{CP}^3$ under the large $k$ limit, and evaluate their action values. We also consider the previously known 1/2-BPS instantonic objects in ten dimensions from the M2-brane viewpoint to compare with our results.