Quantum metrology for non-Markovian processes

Understand

Quantum metrology is a rapidly developing branch of quantum technologies.

• While various theories have been established on quantum metrology for Markovian processes, i.e., quantum channel estimation, quantum metrology for non-Markovian processes is much less explored.
• In this Letter, we establish a general framework of non-Markovian quantum metrology.
• For any parametrized non-Markovian process on a finite-dimensional system, we derive a formula for the maximal amount of quantum Fisher information that can be extracted from it by an optimally controlled probe state.