Protecting quantum spin coherence of nanodiamonds in living cells

TL;DR

This paper demonstrates a method to significantly extend the spin coherence time of nitrogen-vacancy centers in nanodiamonds within living cells, enhancing their potential for in vivo quantum sensing applications.

Contribution

The study introduces a concatenated continuous dynamical decoupling technique that improves spin coherence times of nanodiamonds in biological environments, with less microwave power.

Findings

Extended spin coherence time to 30 microseconds in living cells.

Improved quantum sensing performance in biological environments.

Achieved coherence times approaching the T1 limit.

Abstract

Due to its superior coherent and optical properties at room temperature, the nitrogen-vacancy (N-V ) center in diamond has become a promising quantum probe for nanoscale quantum sensing. However, the application of N-V containing nanodiamonds to quantum sensing suffers from their relatively poor spin coherence times. Here we demonstrate energy efficient protection of N-V spin coherence in nanodiamonds using concatenated continuous dynamical decoupling, which exhibits excellent performance with less stringent microwave power requirement. When applied to nanodiamonds in living cells we are able to extend the spin coherence time by an order of magnitude to the $T_1$-limit of up to $30\mu$s. Further analysis demonstrates concomitant improvements of sensing performance which shows that our results provide an important step towards in vivo quantum sensing using N-V centers in nanodiamond.