A molecular probe for quantum metrology

Haidong Yuan, Chi‐Hang Fred Fung

Vittorio Giovannetti, Seth Lloyd, Lorenzo Maccone

Frank Schlawin

Pump-probe spectroscopies form an irreplaceable tool for the investigation of ultrafast dynamics and energy relaxation. The extent to which they can benefit from new quantum technologies is an open question and a very active field of research. To provide a solid theoretical foundation for this research, here we formulate the measurement of a molecular relaxation rate with a two-pulse experiment as a parameter estimation problem. We derive a quantum map for the light fields and use it to investigate possible enhancement by the use of squeezed quantum states of light and pump-probe entanglement in the impulsive limit.

Yingkai Ouyang, Nathan Shettell, Damian Markham

Quantum metrology is a promising practical use case for quantum technologies, where physical quantities can be measured with unprecedented precision. In lieu of quantum error correction procedures, near term quantum devices are expected to be noisy, and we have to make do with noisy probe states. We prove that, for a set of carefully chosen symmetric probe states that lie within certain quantum error correction codes, quantum metrology exhibits an advantage over classical metrology even after the probe states are corrupted by a constant number of erasure and dephasing errors. These probe states prove useful for robust metrology not only in the NISQ regime, but also in the asymptotic setting where they achieve Heisenberg scaling. This brings us closer towards making robust quantum metrology a technological reality.

David P. DeMille, Nicholas R. Hutzler, Ana María Rey +1 more

Sisi Zhou