We propose a new model-independent method for determining hadronic resonances from lattice QCD. The formalism is derived from the general principles of unitarity and analyticity, as encoded in the N/D representation of a partial-wave two-body amplitude. The associated quantization condition relates the finite-volume spectrum to the infinite-volume numerator, N, used to reconstruct the scattering amplitude from dispersive relations. Unlike the original L\"uscher condition, this new formalism is valid for energies coinciding with the left-hand cuts from arbitrary one- and multi-particle exchanges.
@article{arxiv.2411.15730,
title = {Finite-volume quantization condition from the $N/D$ representation},
author = {Sebastian M. Dawid and Andrew W. Jackura and Adam P. Szczepaniak},
journal= {arXiv preprint arXiv:2411.15730},
year = {2024}
}