Effective Field Theory of Noncritical M-theory from Bosonization

We extend the coadjoint orbit approach to bosonization systematized by Delacretaz-Du-Mehta-Son to double-scaled non-relativistic Fermi liquids with central inverted harmonic oscillator potential. In 1+1d, this reproduces the Das-Jevicki collective field theory describing quasiparticle excitations of the $c=1$ matrix model. In 2+1d, this yields an effective field theory for noncritical M-theory, namely the 2+1d Fermi liquid proposed by Ho\v{r}ava and Keeler as a unified framework for characterizing noncritical string vacua. With a suitable gauge choice this theory reduces to a continuous family of 1+1d chiral bosons resembling Das-Jevicki collective fields coupled by additional interactions. Utilizing the underlying integrability of noncritical M-theory, we compute select fermion density correlation functions order-by-order in perturbation theory, and provide evidence that they agree with their Fermi liquid counterparts in a suitable semiclassical limit. This represents a step toward an effective spacetime gravity description of noncritical M-theory, which we expect to shed light on both the landscape of 2d noncritical strings and 3d quantum gravity in general.