Graph-Theoretic Formulation of Hamiltonian and Ground-State Sign Structures in Heisenberg Antiferromagnets
The paper investigates how to find the ground state phase structure of Heisenberg antiferromagnets, which is computationally hard. It maps this problem onto a weighted Max-Cut instance on a specific graph derived from the Hamiltonian. This shows that reconstructing wavefunction signs is equivalent to solving a known NP-hard combinatorial optimization problem, linking quantum physics directly to complexity theory.