Motional Dynamics in Trapped Ions and Rydberg Atoms, and Hybrid Quantum Algorithm for Classical Optimization
| dc.contributor.advisor | Hazzard, Kaden RA | en_US |
| dc.creator | Zhang, Zewen | en_US |
| dc.date.accessioned | 2025-01-17T17:43:18Z | en_US |
| dc.date.created | 2024-12 | en_US |
| dc.date.issued | 2024-12-06 | en_US |
| dc.date.submitted | December 2024 | en_US |
| dc.date.updated | 2025-01-17T17:43:18Z | en_US |
| dc.description.abstract | Quantum information science has emerged as one of the most promising fields in contemporary research, relying on both software and hardware innovations. This thesis looks for both algorithms with quantum features that provide advantages over classical algorithms, and better hardware platforms for experiments and quantum computing. The work spans theoretical studies in both algorithm and hardware design, including hybrid quantum-classical algorithms and the development of quantum information processing platforms. The algorithmic part has focused on the performance of a hybrid quantum algorithm - the Grover Quantum Approximate Optimization Algorithm (Grover QAOA) - designed for problems with multiple solutions. In practice, we find its potential for speedup in solution search and its ability to find all solutions. Furthermore, we propose a simplified protocol that reduces the classical complexity of optimizing the algorithm’s parameters, enhancing its practicality for future applications. Our implementation of Grover QAOA for multiple combinatorial optimization problems on trapped-ion quantum computers demonstrates that the algorithm can fulfill its fair-sampling advantage even on noisy devices. In the hardware part, we mainly explore how the motion of cold atoms can either be used to engineer interactions or lead to previously overlooked decoherence. The first hardware platform we discuss is trapped ions, where we focus on implementing individual addressing to natively simulate new types of many-body systems. Our proposal leverages the exceptional controllability of trapped ions to explore dynamical models such as topological pumping. The second hardware platform we study is Rydberg atom lattices, where we investigate the decoherence processes introduced by atomic motion during dynamics. Using the numerical tool of discrete truncated Wigner approximation, we simulate the coupled dynamics of electronic and motional degrees of freedom, demonstrating that atom motion induced by strong van der Waals interactions in Rydberg atoms can lead to significant decoherence in analog simulation experiments. We have also explored specialized topics involving other quantum hardware platforms. One area of study is the reduction of frequency crowding in superconducting circuit quantum chips. By properly designing the frequencies for each transmon qubit, we can improve the manufacturing yield of collision-free processors. Another area focuses on the SU(N) Fermi-Hubbard models on alkaline-earth-metal optical lattice platforms. We have obtained the phase diagram of unit-filling models with imbalanced spin flavors. This work aids future experiments in searching for potential ground states of the unit-filling SU(N) model. | en_US |
| dc.embargo.lift | 2025-06-01 | en_US |
| dc.embargo.terms | 2025-06-01 | en_US |
| dc.format.mimetype | application/pdf | en_US |
| dc.identifier.uri | https://hdl.handle.net/1911/118244 | en_US |
| dc.language.iso | en | en_US |
| dc.subject | Rydberg atom | en_US |
| dc.subject | trapped-ion | en_US |
| dc.subject | quantum computing | en_US |
| dc.subject | quantum simulation | en_US |
| dc.subject | quantum algorithms | en_US |
| dc.title | Motional Dynamics in Trapped Ions and Rydberg Atoms, and Hybrid Quantum Algorithm for Classical Optimization | en_US |
| dc.type | Thesis | en_US |
| dc.type.material | Text | en_US |
| thesis.degree.department | Physics and Astronomy | en_US |
| thesis.degree.discipline | Physics | en_US |
| thesis.degree.grantor | Rice University | en_US |
| thesis.degree.level | Doctoral | en_US |
| thesis.degree.name | Doctor of Philosophy | en_US |