Recent progress in lattice QCD calculations of hadron interactions

Quantum Chromodynamics (QCD) has long been established as the correct theory for describing the strong nuclear force. However, a significant challenge remains in connecting this deceptively simple theory to the vast experimental results it is believed to produce. In particular, there are difficulties in understanding how the large number of observed hadrons, most of which are resonances, arise from the underlying degrees of freedom that define QCD. Lattice QCD offers a first-principles approach to confirm or discover hadron resonances and bound states, as well calculate their properties, through the determination of the appropriate multi-hadron interactions. These calculations give important complementary information to experiment and results from models. In this talk, I will review the state-of-the-art methods for performing these calculations with lattice QCD and show several recent highlights.