Efficient tensor networks for control-enhanced quantum metrology

Understand

Optimized quantum control can enhance the performance and noise resilience of quantum metrology.

• However, the optimization quickly becomes intractable when multiple control operations are applied sequentially.
• In this work, we propose efficient tensor network algorithms for optimizing strategies of quantum metrology enhanced by a long sequence of control operations.
• Our approach covers a general and practical scenario where the experimenter applies $N-1$ interleaved control operations between $N$ queries of the channel to estimate and uses no or bounded ancilla.