# Robust and accurate electric field sensing with solid state spin ensembles

## TL;DR

This paper demonstrates a highly sensitive method for measuring macroscopic AC electric fields using ensembles of NV center spins in diamond, achieving nanotesla-level precision at room temperature.

## Contribution

It introduces a novel approach combining classical lock-in detection with quantum phase estimation to enhance electric field measurement sensitivity with solid state spin ensembles.

## Key findings

- Achieved electric field sensitivity down to 10^{-7} V/μm.
- Demonstrated effective suppression of technical noise.
- Enabled $t^{-1/2}$ uncertainty scaling over extended periods.

## Abstract

Electron spins in solids constitute remarkable quantum sensors. Individual defect centers in diamond were used to detect individual nuclear spins with nanometer scale resolution, and ensemble magnetometers rival SQUID and vapor cell magnetometers when taking into account room temperature operation and size. NV center spins can also detect electric field vectors, despite their weak coupling to electric fields. %even that of an isolated fundamental charge, despite their weak coupling to electric fields. Here, we employ ensembles of NV center spins to measure macroscopic AC electric vector fields with high precision. We utilize low strain, $^{12}$C enriched diamond to achieve maximum sensitivity and tailor the spin Hamiltonian via proper magnetic field adjustment to map out the AC electric field strength and polarization and arrive at refined electric field coupling constants. For high precision measurements we combine classical lock-in detection with aspects from quantum phase estimation for effective suppression of technical noise. Eventually, this enables $t^{-1/2}$ uncertainty scaling of the electric field strength over extended averaging periods, enabling us to reach a sensitivity down to $10^{-7}$ V/$\mu$m.