🤖 AI Summary
This study addresses the fundamental challenge of identifying fractional quantum Chern insulator (FQCI) ground states and their topological order in strongly correlated topological matter—without prior symmetry assumptions or topological knowledge. We propose an attention-based deep variational wavefunction embedded within a variational Monte Carlo framework, enabling end-to-end discovery of FQCI ground states solely via energy minimization. Crucially, we introduce a real-space, single-wavefunction decomposition into many-body momentum configurations—bypassing symmetry constraints or post-hoc projection—to directly extract topological degeneracy in translationally invariant systems. This provides an efficient, unsupervised diagnostic for topological order. Numerical experiments across multiple filling factors accurately reproduce both ground-state energies and topological degeneracies of FQCIs, demonstrating the method’s efficacy and broad applicability to discovering strongly correlated topological phases.
📝 Abstract
Topologically ordered states are among the most interesting quantum phases of matter that host emergent quasi-particles having fractional charge and obeying fractional quantum statistics. Theoretical study of such states is however challenging owing to their strong-coupling nature that prevents conventional mean-field treatment. Here, we demonstrate that an attention-based deep neural network provides an expressive variational wavefunction that discovers fractional Chern insulator ground states purely through energy minimization without prior knowledge and achieves remarkable accuracy. We introduce an efficient method to extract ground state topological degeneracy -- a hallmark of topological order -- from a single optimized real-space wavefunction in translation-invariant systems by decomposing it into different many-body momentum sectors. Our results establish neural network variational Monte Carlo as a versatile tool for discovering strongly correlated topological phases.