Sergio Boixo

Generalized Limits for Single-Parameter Quantum Estimation

TitleGeneralized Limits for Single-Parameter Quantum Estimation
Publication TypeJournal Article
Year of Publication2007
AuthorsS. Boixo, S. T. Flammia, C. M. Caves, and J. M. Geremia
JournalPhysical Review Letters
Date Publishedmar

We develop generalized bounds for quantum single-parameter estimation problems for which the coupling to the parameter is described by intrinsic multisystem interactions. For a Hamiltonian with k-system parameter-sensitive terms, the quantum limit scales as 1/N ot the k, where N is the number of systems. These quantum limits remain valid when the Hamiltonian is augmented by any parameter-independent interaction among the systems and when adaptive measurements via parameter-independent coupling to ancillas are allowed