Singularity resolution at finite ’t Hooft coupling in N=4 super Yang–Mills theory

Determine whether the singularity-resolution mechanism produced by nonperturbative finite-string-length effects in the SL(2,R)_k/U(1) coset also occurs in N=4 super Yang–Mills theory as the ’t Hooft coupling is lowered from infinity.

Background

The paper demonstrates that the classical bouncing singularity of the cigar geometry is resolved at finite coset level k by worldsheet effects, although this resolution is nonperturbative in the large-k expansion. The authors ask whether this phenomenon is specific to the SL(2,R)_k/U(1) worldsheet theory or reflects a more general finite-string-length effect. In particular, they leave unresolved whether analogous physics appears in N=4 super Yang–Mills when the ’t Hooft coupling is reduced from the classical supergravity regime of infinite coupling.

References

There are several open questions to be addressed in the future. Firstly, it would be good to understand how generally this singularity resolution occurs. While our example shows that nonperturbative effects at finite string length can resolve the singularity, it remains to be seen whether similar physics occurs in, for example, $\mathcal{N}=4$ super Yang--Mills theory as the 't Hooft coupling $\lambda$ is lowered from infinity.

— Stringy resolution of bouncing singularities  (2610.12311 - Burić et al., 8 Oct 2026) in Section Discussion