Group Seminar via Zoom: Hamiltonian engineering for quantum sensing and quantum simulation

September 22, 2020

Yi-Xiang Liu, MIT
Group meeting via video conference (Zoom)
Tuesday, September 2nd, 15:00! (MEZ)

Dealing with the unique situation of partial lock downs worldwide and home office solutions at our Institute due to the current spreading of the Covid 19 virus, we are now holding our group seminars and journal clubs via video conference. This procedure enables us to continue our research, enhance discussions and exchange important information.


Advanced control techniques are required to make full use of the quantum sensor and extract all the sensing target information. Unfortunately, due to hardware clock rate limitations, the optimal control sequence, which allows maximum information extraction, is not always directly implementable. To overcome this challenge, we developed a novel control technique inspired by quantum simulation ("quantum interpolation") and achieved an effective six picoseconds sampling rate, from the hardware-constrained two nanoseconds. This improved sampling rate enabled not only a higher precision in measuring classical fields but also the quantum signal arising from a single nuclear. The quantum formulation of the problem directly motivates us to find Trotter expansions with high fidelity, improving digital quantum simulation precision. As a direct application of the Hamiltonian engineering technique we developed, we build a vector dc magnetometry using the NV electronic spin and the Nitrogen nuclear spin as an ancillary tool. In this scheme, the transverse component of a magnetic field is first up-converted in frequency by the Nitrogen nuclear spin acting as a "local oscillator," followed by a quantum lock-in detection via dynamical decoupling. Measuring the up-converted frequency benefitted from the "quantum interpolation" sequence. We achieved comparable sensitivities for both longitudinal and transverse magnetic field components, thus engineering a vector magnetometer with a nanoscale footprint and spatial resolution.

If you would like to join our group seminars via Zoom, please contact us for more information.

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