Universität zu Köln

Singh, Juhi (2026). Quantum control methods for neutral atoms. PhD thesis, Universität zu Köln.

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Abstract

Neutral atoms, trapped in optical tweezers and lattices, have gained significant attention owing to advances in laser technologies, control hardware, and innovative experimental techniques. These systems offer unique advantages such as long coherence times, natural homogeneity, and scalability, while also presenting challenges related to gate speed limitations, atom loss, slow measurements, and other imperfections. Quantum control theory has emerged as a crucial tool for advancing these technologies by enabling precise manipulation of atoms. In this thesis, we review the foundational concepts in quantum control theory, outlining both analytical approaches and numerical optimization techniques, including methods to account for experimental imperfections. A concise overview of neutral atom platforms follows, covering two distinct operational regimes: Rydberg atoms in optical tweezers and fermionic atoms in optical superlattices. The core of the thesis is dedicated to our work addressing practical control problems in neutral atom systems. First, we develop a platform-independent method for estimating and compensating nonlinear pulse distortions in experimental setups and demonstrate its use numerically for Rydberg atom excitations. Next, we tackle the challenge of implementing fast and robust gates in fermionic atom systems trapped in superlattices by optimizing lattice depths. Finally, we explore the application of Rydberg-based analog quantum simulators for variational quantum eigensolvers, using Lie-algebraic tools to analyze symmetry restrictions. This work highlights the essential role of quantum control methods in enhancing the fidelity, robustness, and applicability of neutral atom quantum technologies. It also demonstrates how combining theoretical tools, numerical optimization, and experimental considerations leads to practical solutions for scalable and high-performance quantum systems. The methods and insights developed here also offer transferable strategies for other quantum hardware architectures.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Singh, Juhi juhisingh9697@gmail.com UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-802272
Date:	2026
Publisher:	University of Cologne
Place of Publication:	Cologne
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute for Theoretical Physics
Subjects:	Physics
Uncontrolled Keywords:	Keywords Language Quantum control English Quantum computing English Neutral atoms English
Date of oral exam:	10 October 2025
Referee:	Name Academic Title Calarco, Tommaso Dr. Gross, Christian Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/80227