2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/223100Quantum control requires full knowledge of the system many-body Hamiltonian. In many cases this information is not directly available due to restricted access to the system. Here we show how to indirectly estimate all the coupling strengths in a spin chain by measuring one spin at the end of the chain. We also discuss the efficiency of this "quantum inverse problem" and give a numerical example.improved version with additional referenceQuantum Physicstext