# Simultaneous accurate determination of both gravity and its vertical gradient

## TL;DR

This paper introduces a dual atom interferometer method to simultaneously measure gravity and its vertical gradient with high accuracy, using a dual lock technique to eliminate positional uncertainties.

## Contribution

The novel dual lock technique enables precise, simultaneous measurements of gravity and gravity gradient without relying on the exact positions of atomic samples.

## Key findings

- Achieved accurate simultaneous measurements of gravity and gravity gradient.
- Method reduces uncertainties related to atomic sample positioning.
- Demonstrated potential for improved inertial sensing applications.

## Abstract

We present a method for the accurate measurements of both the gravity acceleration and its vertical gradient using a dual atom interferometer, in principle free from any uncertainty related to the absolute or relative positions of the two atomic samples. The method relies on the use of a dual lock technique, which stirs simultaneously the chirp rate applied to the frequency difference between the interferometer lasers to compensate the gravity acceleration, and the frequency jump applied to the lasers at the mid pulse of the interferometer to compensate for the gravity gradient. This allows in the end to determine the two inertial quantities of interest in terms of frequencies.