Should we use parameterized quantum circuits for machine learning?
Abstract: Recent years have seen an incredible interest in the use of parameterized quantum circuits (PQCs) for machine learning tasks. As of yet however, it remains unclear to what extent one can use PQC based algorithms to obtain a meaningful advantage over state-of-the-art classical methods. In this talk I will discuss evidence for and against the use of some specific PQC based algorithms. Specifically, I will first show that the output distributions of local quantum circuits are hard to learn on average, and discuss the implications this has for quantum circuit born machines. Next, I will shift the focus to supervised learning, and discuss the extent to which a widely-used class of PQC based algorithms can be dequantized via classical kernel regression with random Fourier features. Finally, I will ask whether it is possible to delegate quantum machine learning tasks to untrusted classical servers — something that will indeed be crucial in the future world where most quantum computations are out-sourced to external service providers.
Bio: Ryan Sweke is the Alexander von Humboldt
German Research Chair of Mathematics and its Applications at AIMS, as well as a senior lecturer at Stellenbosch University. He leads the Quantum at AIMS group, whose research is focused on a wide variety of topics under the broad umbrella of quantum computing and quantum information. Ryan completed his PhD at the University of KwaZulu-Natal in 2017, with a focus on quantum algorithms for the simulation of open quantum systems. After this, he spent almost five years (2018-2022) as a post-doctoral researcher at the Freie Universität Berlin, first as an Alexander von Humboldt post-doctoral fellow (2018-2019) and then as a senior post-doc of the PlanQK project, the flagship quantum machine learning initiative of the German government. After his time in Berlin, Ryan spent just over two years as a research scientist at IBM Quantum, in San Jose, California (2022-2024) before joining AIMS as German Research Chair in January 2025.
On Thursday, 16 January 2025, we will start our weekly Group Meetings series again.
Title: NITheCS Colloquium: The role of intermolecular interactions in chemical processes and materials science
Speaker: Prof Catharine Esterhuysen (Stellenbosch University)
Abstract:
The most challenging aspect in understanding the properties of materials in the solid state is to identify the role that intermolecular interactions play in their behaviour. For instance, molecules (“guests”) are taken up into porous materials (“hosts”) as a result of the interactions between these species, while the manner in which they interact has an influence on the sorption ability of the porous material. So too for catalysts, where the first step in their mechanism of action is the formation of weak interactions between the metal centres and the catalytic substrates. Therefore, the reactivity and selectivity or a catalytic reaction can be tuned by positioning of the substrate relative to the catalyst with the aid of weak intermolecular interactions. In this presentation, several examples from our work will be used to show that computational methods allow us to explain the role that intermolecular interactions play in a range of chemical processes. In particular, I will focus on how interactions between water, CO2 and other solvents influence the properties of porous materials, such as allowing the release of water down to temperatures as low as – 70°C, anomolous sorption behaviour and solvatochromic effects. The influence of hydrogen and halogen bonding and other weak interactions in catalysis and crystal engineering will also be demonstrated.
Biography:
After completing a PhD in crystallography under the supervision of Gert Kruger at the University of Johannesburg, Catharine Esterhuysen joined Stellenbosch University in 2000. During her studies she developed an interest in computational chemistry, which she was able to develop through Alexander von Humboldt fellowships with Gernot Frenking in Marburg and Tim Clark at Erlangen. Her main research focus is the study of intermolecular interactions, combining her knowledge of computational chemistry and crystallography to explain unusual interactions and their role in the properties of materials. In this context, she has published more than 70 articles in top peer-reviewed journals including Nature, Angewandte Chemie and Journal of the American Chemical Society and has delivered numerous plenary, keynote and invited talks on her work at an international level. She has served on numerous committees and editorial boards, including as president of the South African Crystallographic Society and Associate Editor at New Journal of Chemistry
A link to the announcement may be found here.
Title and abstract to be announced.
Title: Applications of topological algebras to quantum computing and information
Speaker: Dr Martin Weigt (Nelson Mandela University)
Abstract:
A well-known mathematical tool that is applied to quantum computing and information is operator space theory. To be brief, completely positive linear mappings between operator spaces serve as quantum channels. Observables in a quantum system can be represented as self adjoint elements of a *-algebra consisting of self-adjoint elements in a locally convex *-algebra. Reversible time dynamics of a quantum system can be represented as a one parameter group of * automorphisms of the locally convex algebra, whereas if the time dynamics is irreversible, one parameter semi-groups of completely positive linear mappings of the locally convex algebra are used. The role of locally convex algebras specifically in quantum computing and information appears not be well known in the literature. On of the aims of this talk to show how locally convex algebras can add to the existing mathematical techniques from operator space theory in quantum computing. Some results of the speaker will also be presented, especially results having to do with quantum entanglement. A brief recap on the role of quantum entanglement in quantum information will also be discussed.
Biography:
Dr Martin Weigt is a C2-rated researcher with the National Research Foundation (NRF), and works in topological algebras, and operator and unbounded operator algebras, which include applications to mathematical physics. He was born in Cape Town and obtained his BSc, BSc Honours degree in Mathematics, and Master of Science degree in Mathematics at the University of Stellenbosch. He obtained his doctoral degree in Mathematics at the University of Cape Town, and undertook postdoctoral research at the University of Athens in Greece.
A link to the announcement may be found here.
Title: NITheCS Micro-School: The Power of Pandas – Introduction to the Pandas Library
Speaker: Pashlene Naidoo (Stellenbosch University)
Abstract:
Pandas is a powerful and flexible open-source data manipulation library for Python, designed to make data analysis fast and expressive. This micro-school will provide an introduction to the basics of Pandas, highlighting its key features. Attendees will learn how to handle structured data through DataFrames and perform basic data cleaning. The goal of this session is to leave participants with a foundational understanding of the potential of Pandas to unlock valuable insights from their data.
Biography:
Pashlene is a first-year Masters student in the Quantum Research Group at Stellenbosch University, under the supervision of Dr Yaseera Ismail. Her current research focuses on the investigation of high-dimensional encoding for Quantum Communication. Pashlene completed her BSc and BSc(Honours) at the University of KwaZulu Natal, majoring in Applied Physics
A link to the announcement may be found here.
Title: NITheCS MINI-SCHOOL: An Introduction to the Quantum Simulation of Closed and Open Quantum Systems
Speaker: Ian Joel David
University of KwaZulu-Natal
Abstract:
Quantum Simulation, the emulation of quantum system dynamics with quantum computers, is an application of quantum computing which showcases a clear advantage over classical computing. This advantage arises from the inherent difficulty in simulating quantum dynamics on classical systems, a challenge that originally inspired Feynman and others to propose quantum computing. The efficient simulation of quantum dynamics on quantum computers promises profound insights into various physical systems including many-body physics, quantum chemistry and quantum field theory. Quantum Simulation has also been pivotal in developing new quantum algorithms for state preparation and for solving both ordinary and partial differential equations on quantum computers. The goal of Quantum Simulation is to construct a quantum channel that approximates the evolution operator of a quantum system within some specified precision. This channel should be constructed such that it can be efficiently implemented on a quantum computer. We focus on two primary types of quantum systems: closed quantum systems, which evolve via unitary evolution, and open quantum systems, which interact with their environment and experience dissipation and decoherence. This mini-school will convey the essential concepts and principles underlying the Quantum Simulation of both closed and open quantum systems. Attendees will gain sufficient working knowledge to engage with and understand contemporary research literature on this cutting-edge topic.
Biography:
Ian studied Physics at the University of KwaZulu-Natal (UKZN) and has obtained a Masters degree in Physics. He is currently completing a PhD in Physics at UKZN under the supervision of Prof I. Sinayskiy and Prof F. Petruccione , focusing on the digital simulation of Quantum Systems. He has spent several years as a research assistant in Prof Petruccioneʼs Quantum Research Group. He has given several introductory and advanced quantum computing talks and mini-courses at various institutions and conferences.
A link to the announcement may be found here.
Title: NITheCS Micro-School: Introduction to NumPy – Powering Your Data with Efficient Array Operations
Speaker: Abbas (Omid) Hassasfar (Stellenbosch University)
Abstract:
In the realm of scientific computing and data analysis, having a powerful and efficient tool for numerical operations is crucial. NumPy, a fundamental library for array processing in Python, provides this power and efficiency. This presentation will introduce NumPy arrays, highlight their core functionalities, and compare them with Python lists. In this micro-school, we will cover essential topics such as array creation, indexing, and slicing. Attendees will learn how to leverage NumPy for performing fast, complex mathematical operations, enabling them to handle and analyse data more effectively. The goal is to equip participants with the knowledge to use NumPy as a cornerstone for their data-driven projects.
Biography:
Omid is a second-year international PhD student in the Quantum Research Group at Stellenbosch University, under the supervision of Prof Francesco Petruccione. His research focuses on Quantum Biology, an emerging interdisciplinary field that investigates the potential role of non-trivial quantum mechanical effects, such as quantum coherence, entanglement, superposition, and quantum tunnelling in describing some biological phenomena inside living organisms. Omid earned his BSc from the University of Guilan and his MSc from Isfahan University of Technology in Iran, both in theoretical physics. He is actively involved in promoting quantum computing as a co-founder of QSouthAfrica and QIran and is also a Qiskit Advocate.
A link to the announcement may be found here.
Title: NITheCS Colloquium: Charting the Future of NITheCS: Progress and Prospects in Research, Training, Engagement, and Africa
Speaker: Prof Francesco Petruccione (NITheCS and Stellenbosch University)
Abstract:
As the newly appointed Director of the National Institute for Theoretical and Computational Sciences (NITheCS), I am excited to present our strategic vision and achievements in the realms of research, training, and engagement, with a particular focus on our contributions to the future of South Africa and Africa. This presentation will provide a comprehensive overview of our recent progress, highlight key research initiatives, and outline our ambitious plans to foster inclusive growth and excellence in the scientific community. Emphasizing the societal impact of our research, we aim to address critical challenges and drive innovation that benefits all sectors of society. Join us as we embark on this journey of transformation and innovation, committed to making a lasting impact on education, research, and societal development across the continent.
Biography:
Francesco Petruccione is a physicist and academic leader, serving as both a professor of Physics at Stellenbosch University (SU) and since May 2024 the Substantive Director of NITheCS. He pursued his undergraduate studies in physics at the University of Freiburg, Germany. Continuing the same institution, he earned his doctorate in 1988 and Habilitation degree (Dr. rer. nat. habil.) in 1994. In 2004, he was appointed a professor of Theoretical Physics at the University of KwaZulu-Natal (UKZN). A year later, he was awarded an Innovation Fund grant to establish a Centre for Quantum Technology. Prof Petruccione went on to hold the position of South African Research Chair for Quantum Information Processing and Communication Technology in 2007. In addition to his role as interim director of NITheCS, he held an adjunct professor position at the Korean Advanced Institute for Science and Technology. In 2018, he was appointed Pro Vice-Chancellor of Big Data and Informatics at UKZN. Four years later, he moved to SU as a professor of Physics and Quantum Computing in the Physics Department and the School of Data Science and Computational Thinking. Prof Petruccione is a member of the Academy of Science of South Africa and a Fellow of the Royal Society of South Africa. In 2023 he was honoured with the title of Order of the Star of Italy for his work in physics and quantum computing
A link to the announcement may be found here.
