Quantum Speed Limit in Quantum Sensing.

Quantum sensors capitalize on advanced control sequences for maximizing sensitivity and precision. However, protocols are not usually optimized for temporal resolution. Here, we establish the limits for time-resolved sensing of dynamical signals using qubit probes.

Charge and Spin Dynamics and Destabilization of Shallow Nitrogen-Vacancy Centers under UV and Blue Excitation.

Shallow nitrogen-vacancy (NV) centers in diamond offer opportunities to study photochemical reactions, including photogeneration of radical pairs, at the single-molecule regime. A prerequisite is a detailed understanding of charge and spin dynamics of NVs exposed to the short-wavelength light required to excite chemical species. Here, we investigate the charge and spin dynamics of shallow NVs under 445 and 375 nm illumination.

Roadmap on nanoscale magnetic resonance imaging.

The field of nanoscale magnetic resonance imaging (NanoMRI) was started 30 years ago. It was motivated by the desire to image single molecules and molecular assemblies, such as proteins and virus particles, with near-atomic spatial resolution and on a length scale of 100 nm. Over the years, the NanoMRI field has also expanded to include the goal of useful high-resolution nuclear magnetic resonance (NMR) spectroscopy of molecules under ambient conditions, including samples up to the micron-scale.

Observation of current whirlpools in graphene at room temperature.

Electron-electron interactions in high-mobility conductors can give rise to transport signatures resembling those described by classical hydrodynamics. Using a nanoscale scanning magnetometer, we imaged a distinctive hydrodynamic transport pattern-stationary current vortices-in a monolayer graphene device at room temperature. By measuring devices with increasing characteristic size, we observed the disappearance of the current vortex and thus verified a prediction of the hydrodynamic model.