Year: 2021
Type: dissertation
Abstract: Over the past two decades there has been considerable and growing interest in the development of quantum sensors. These are devices whose function is based on quantum systems and offer the potential for unprecedented sensitivity in a range of measurements. This PhD has developed three different theoretical projects examining the sensitivity improvement of these devices with a focus on atom gravimeters, which are particularly useful for measuring inertial quantities such as rotations and accelerations. We have investigated the theoretical sensitivity limits of atom gravimeters and we examined different entanglement-enhanced schemes, in order to increase their performance. To start with, we used tools from estimation theory, in order to quantify the performance of current atom gravimeters. We showed that there is additional metrological potential in these devices, and that we can extract all this information by making innovative measurements, other than the conventional population difference measurement. Our analysis introduces a new way of evaluating the performance of atom gravimeters that could influence future sensor designs. In addition, we examined entanglement-enhanced schemes, in order to improve the performance of quantum sensors, which are limited by the atom shot-noise limit. We considered entanglement generation schemes based on atom-light interactions, in order for them to be compatible with atom interferometer based sensors. More particularly, we examined a quantum non-demolition measurement scheme and an one-axis-twisting scheme with cavity feedback. In both schemes we incorporated relevant decoherence mechanisms and we analysed how the optimum parameter regime can be found, by balancing between coherence loss and spin-squeezing strength. We also examined several modifications in both models that could offer additional improvements. The results presented here could have a big impact on the future design and understanding of atom-based quantum-enhanced sensors.
Author: Michail Kritsotakis
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3168957348