Mohammad Kashfi Haghighi

Topic

Optimal Embedding of the Phase Unwrapping Problem onto the Quantum Annealers

Department of Electrical and Computer Engineering

Date & location

• Wednesday, March 27, 2024

• 10:30 A.M.

• Engineering Office Wing 

• Room 502

Reviewers

Supervisory Committee

• Dr. Nikitas Dimopoulos, Department of Electrical and Computer Engineering, University of Victoria (Supervisor)

• Dr. Mihai Sima, Department of Electrical and Computer Engineering, UVic (Member) 

External Examiner

• Dr. Hausi Muller, Department of Computer Science, University of Victoria 

Chair of Oral Examination

• Dr. Sang H. Nam, School of Business, UVic

   

Abstract

Quantum computers and algorithms are undergoing rapid development, offering promising solutions to complex computational problems. This study focuses on harnessing the potential of quantum annealing to address the challenging phase unwrapping problem. Specifically, we employed D-Wave’s quantum annealers, currently among the most powerful in existence. To effectively utilize these systems, it is crucial to embed the problem onto their underlying structure, the Pegasus graph in the case of the D-Wave Advantage system. A shorter chain length in the embedding process generally correlates with improved results. In the course of this thesis, we devised an algorithm for efficiently embedding the phase unwrapping problem onto the D-Wave Advantage system. Our approach yielded promising results when compared to D-Wave’s automatic embeddings. Notably, our introduced embedding boasts the minimum chain length and utilizes the native structure of the target graph. Additionally, we leveraged D-Wave’s hybrid workflow, combining classical and quantum computing capabilities, to tackle larger image problems. Refinements to the hybrid method were implemented, resulting in enhanced performance. Experimental evaluations were conducted on actual quantum annealers, demonstrating that our refined algorithms outperform those provided by D-Wave.