High precision measurements with continuously observed quantum mechanical systems

PhD defense, Thursday 15 November 2018. Alexander Holm Kiilerich.

2018.11.15 | Olivia Elsebeth Belling-Nami

Alexander Holm Kiilerich.

During his PhD study, Alexander Kiilerich researched applications of quantum mechanical systems for high precision measurements. The recruitment of quantum effects holds the potential to revolutionize the precision and applicability range offered by state-of-the-art sensors and measurement devices, and thereby to facilitate profound advancements in all branches of science and in our technology-based society. When a quantum system is measured, its state collapses to be consistent with the outcome. It is crucial to take this measurement backaction into account if a quantum probe system is repeatedly measured or if it is continuously monitored.

Alexander focused mainly on the effects of backaction when a probe system is continuously monitored. The results reveal that it can be either beneficial or detrimental to the precision in different circumstances. They show, furthermore, that a feedback can cancel the backaction and thereby facilitate the observation of a topological transition in a quantum system, and that an adaptive scheme can induce a Lévy flight which efficiently identifies a dark resonance. Two other directions of the PhD project present a highly sensitive quantum thermometer and explores, based on an experiment, the possibility of increasing the sensitivity in spin detection by squeezing the uncertainty in a probe field.

The PhD degree was completed at the Department of Physics and Astronomy, Science and Technology, Aarhus University.

This résumé was prepared by the PhD student.

Time: Thursday 15 November 2018 at 14.00
Place: Building 1531, room 113, Lecture Theater D1, Department of Mathematics, Aarhus University
Title of PhD thesis: Quantum Metrology with Continuous Measurements
Contact information: Alexander Holm Kiilerich, e-mail: kiilerich@phys.au.dk, tel.: +45 41150970
Members of the assessment committee:
Professor Juan P. Garrahan, School of Physics & Astronomy, University of Nottingham, United Kingdom
Professor Susana Huelga, Institute of Theoretical Physics,  Ulm University, Germany
Professor Karsten Riisager (chair), Department of Physics and Astronomy, Aarhus University
Main supervisor:
Professor Klaus Mølmer, Department of Physics and Astronomy, Aarhus University
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Science and Technology/GSST, Ny Munkegade 120, building 1520, rooms 128-134, 8000 Aarhus C.

PhD defence
Comments on content: 
Olivia Elsebeth Belling-Nami

Revised 12.11.2018