Bosonic M Theory

TL;DR

The paper proposes a 27 dimensional bosonic M theory as the strong coupling limit of the 26D bosonic string, realized by compactification on a line interval $S^1/Z_2$ and containing gravity plus a 3-form field. It argues that this framework can remove the closed string tachyon and yields stable ground states for uncompactified $M_{27}$, with brane spectra including 2-branes and 21-branes whose tensions reproduce stringy scales. The authors analyze the low-energy action, show how the weak-coupling limit recovers bosonic string physics, and develop holographic duals via AdS/CFT in the near-horizon limit, predicting 2+1D CFTs with large symmetry groups. They discuss cosmological constant issues, Dp-brane analogs, and the broader implications for tachyon condensation and the ground state structure of the theory, offering a cohesive 27D picture that connects to familiar 26D string phenomena. The work provides concrete predictions, notably a $2+1$ CFT with $SO(24)$ symmetry, and outlines several critical open questions for nonperturbative bosonic gravity.

Abstract

We conjecture that there exists a strong coupling limit of bosonic string theory which is related to the 26 dimensional theory in the same way that 11 dimensional M theory is related to superstring theory. More precisely, we believe that bosonic string theory is the compactification on a line interval of a 27 dimensional theory whose low energy limit contains gravity and a three-form potential. The line interval becomes infinite in the strong coupling limit, and this may provide a stable ground state of the theory. We discuss some of the consequences of this conjecture.