Strings on AdS2 and the high-energy limit of noncritical M-theory

Noncritical M-theory in 2 + 1 dimensions has been defined as a double-scaling limit of a nonrelativistic Fermi liquid on a flat two-dimensional plane. Here we study the noncritical M-theory in the limit of high energies, analogous to the alpha '-> infinity limit of string theory. In the related case of two-dimensional Type 0A strings, it has been argued that the conformal alpha ' -> infinity limit leads to AdS(2) with a propagating fermion whose mass is set by the value of the RR flux. Here we provide evidence that in the high-energy limit, the natural ground state of noncritical M-theory similarly describes the AdS(2) X S-1 spacetime, with a massless propagating fermion. We argue that the spacetime effective theory in this background is captured by a topological higher-spin extension of conformal Chern-Simons gravity in 2 + 1 dimensions, consistently coupled to a massless Dirac field. Intriguingly, the two-dimensional plane populated by the original nonrelativistic fermions is essentially the twistor space associated with the symmetry group of AdS(2) X S-1 spacetime; thus, at least in the high-energy limit, noncritical M-theory can be nonperturbatively described as a "Fermi liquid on twistor space".