In our previous paper [N. Fukui, K.-I. Kondo, A. Shibata, and T. Shinohara, Phys. Rev. D 82, 045015 (2010)], we have shown that the Jackiw-Nohl-Rebbi (JNR) two-instanton generates a circular loop of magnetic monopole in the four-dimensional Euclidean SU(2) Yang-Mills theory. On the other hand, it is claimed in Brower et al. [Phys. Rev. D 55, 6313 (1997); Nucl. Phys. B, Proc. Suppl. 53, 488 (1997)] that the ’t Hooft two-instanton does not generate magnetic monopole loop. It seems that the two results are inconsistent with each other, since the JNR two-instanton converges to the ’t Hooft two-instanton in a certain limit. In this paper, we clarify that the two results are compatible with each other by demonstrating how the magnetic monopole loop generated from the JNR two-instanton deforms in the process of taking the ’t Hooft two-instanton limit.

• Received 22 May 2012

DOI:https://doi.org/10.1103/PhysRevD.86.065020