Microscopic realization of fractional Hall conductance

Construct a microscopic model for which the ground state has rigorously provable fractional Hall conductance.

Background

The authors describe the absence of a known microscopic example proving fractional Hall conductance as a central puzzle in the theory of the fractional quantum Hall effect.

They contrast this gap with the existence of exactly solvable models realizing modular tensor categories associated with quantum doubles. The unresolved task is to produce a concrete microscopic Hamiltonian whose ground state is known mathematically to exhibit fractional Hall conductance.

References

Yet, the theory of fractional quantum Hall effect contains a puzzle -- we do not know a single microscopic model where we can prove that the ground state has fractional Hall conductance.

— Free Fermion frustration-free models have zero Hall conductance  (2610.21172 - Bachmann et al., 15 Oct 2026) in Section 1, Introduction