Entangled momentum modes for atom interferometry

authored by: Fabian Anders
supervised by: Carsten Klempt
Abstract: Entangled ensembles have been created in versatile atomic systems and find a promising application in entanglement-enhanced metrology. Here, entangled spin-states have been successfully applied within interferometers that allow to measure magnetic fields and frequencies with enhanced sensitivities. In contrast, atom interferometers for the measurement of inertial forces and gravitational fields are operated in external degrees of freedom and span an area in space-time. To make use of entangled states here, the entanglement has to be generated among momentum modes with suitable spatial extent and velocity width. In this thesis, a source of momentum-entangled atoms that is compatible with present-day light-pulse atom interferometers is presented. Utilising a quasi-adiabatic ramp through a quantum phase transition, highly-entangled twin-Fock states are created in the internal spindegree of freedom of a 87Rb Bose-Einstein condensate. Hereon, the entanglement is successfully transferred to distinct momentum-modes by a stimulated Raman coupling and verified by the direct measurement of an entanglement criterion. The observed mode quality and the residual expansion demonstrate that this entangled source is wellsuited to the successive application in light-pulse atom interferometers and opens up a path to gravimetry beyond the standard quantum limit. Furthermore could the demonstrated techniques be employed to realise a scalable atomic Bell test. In the long run, similar entangled sources could specifically enhance the performance of gravity gradiometers, tests of the Einstein Equivalence Principle and future atomic gravitational wave detectors.
Organisation(s): Institute of Quantum Optics
QUEST-Leibniz Research School
Type: Doctoral thesis
No. of pages: 113
Publication date: 2022
Publication status: Published
Electronic version(s): https://doi.org/10.15488/12802 (Access: Open)
: Details in the research portal "Research@Leibniz University"

BibTeX

@phdthesis{7cf163308c124b7f986234432f8b6d5e,
title = "Entangled momentum modes for atom interferometry",
abstract = "Entangled ensembles have been created in versatile atomic systems and find a promising application in entanglement-enhanced metrology. Here, entangled spin-states have been successfully applied within interferometers that allow to measure magnetic fields and frequencies with enhanced sensitivities. In contrast, atom interferometers for the measurement of inertial forces and gravitational fields are operated in external degrees of freedom and span an area in space-time. To make use of entangled states here, the entanglement has to be generated among momentum modes with suitable spatial extent and velocity width. In this thesis, a source of momentum-entangled atoms that is compatible with present-day light-pulse atom interferometers is presented. Utilising a quasi-adiabatic ramp through a quantum phase transition, highly-entangled twin-Fock states are created in the internal spindegree of freedom of a 87Rb Bose-Einstein condensate. Hereon, the entanglement is successfully transferred to distinct momentum-modes by a stimulated Raman coupling and verified by the direct measurement of an entanglement criterion. The observed mode quality and the residual expansion demonstrate that this entangled source is wellsuited to the successive application in light-pulse atom interferometers and opens up a path to gravimetry beyond the standard quantum limit. Furthermore could the demonstrated techniques be employed to realise a scalable atomic Bell test. In the long run, similar entangled sources could specifically enhance the performance of gravity gradiometers, tests of the Einstein Equivalence Principle and future atomic gravitational wave detectors.",
author = "Fabian Anders",
note = "Doctoral thesis",
year = "2022",
doi = "10.15488/12802",
language = "English",
publisher = "Leibniz Universit{\"a}t Hannover",
school = "Leibniz University Hannover",
}