We prove tight query complexity bounds for unstructured search in multimode bosonic systems under energy constraints. Non-Gaussianity—not entanglement—enables optimal quantum speedup. Coherent-state protocols suffice under strong loss.

We prove tight query complexity bounds for unstructured search in multimode bosonic systems under energy constraints. Non-Gaussianity—not entanglement—enables optimal quantum speedup. Coherent-state protocols suffice under strong loss.