CHEM 740/7400 - Spin-based Quantum Information Processing
Semester: Fall 2026
Professor: J.D. Baugh | Discipline: Theoretical | Campus: WaterlooDescription
This graduate-level course introduces the physics of gate-defined semiconductor quantum dots, with an emphasis on spin qubits for solid-state quantum information processing. Topics include semiconductor heterostructures, electrostatic confinement, Coulomb blockade, quantum transport, double-dot charge stability diagrams, spin states, exchange interactions, Pauli spin blockade, spin-to-charge conversion, coherent control, readout, and decoherence. The course alternates between lectures, research-paper discussions and a problem-based exercises, where students present solutions to foundational problems. The goal is to help students develop the conceptual foundation and explanatory fluency needed to read the semiconductor spin-qubit literature and communicate their understanding in academic and research settings.
Unit 1: Quantum-dot foundations and single-dot transport
Semiconductor heterostructures, electrostatic confinement, quantum dots as artificial atoms, charging and orbital energy scales, constant-interaction model, electrochemical potentials, Coulomb blockade, Coulomb diamonds, tunnel and thermal broadening, excited-state spectroscopy, cotunneling, and charge sensing.
Unit 2: Double quantum dots and Pauli spin blockade
Double-dot electrostatics, interdot charging energy, charge stability diagrams, triple points, finite-bias triangles, sequential tunneling cycles, interdot tunnel coupling, charge hybridization, two-electron spin states, spin-conserving tunneling, Pauli spin blockade, and leakage mechanisms.
Unit 3: Spin-qubit Hamiltonians, control, and readout
Fermionic operators, two-site Hubbard model, exchange coupling, singlet-triplet qubits, magnetic-field gradients, coherent control, ESR/EDSR, relaxation and dephasing, spin-to-charge conversion, energy-selective readout, Pauli-blockade readout, and readout fidelity.
Unit 4: Current research topics and scaling
Contemporary semiconductor spin-qubit platforms; valley, spin-orbit, interface, disorder, and noise physics; two-qubit gates; spin shuttling and arrays; cryogenic control and reflectometry; tuning and automation; benchmarking; and student-led discussion of recent research papers.
Materials
There is no required textbook. An undergraduate-level knowledge of quantum mechanics is assumed, and previous exposure to semiconductor physics, condensed-matter physics, or quantum information will be helpful but is not required. Most technical development will be done at the board, supported by instructor-provided problem sets for the quantum dots boot camp. The course will be organized around foundational review articles, selected research papers, and student-led problem presentations.
Review articles for the course will include:
- L. P. Kouwenhoven, C. M. Marcus, P. L. McEuen, S. Tarucha, R. M. Westervelt, and N. S. Wingreen, “Electron transport in quantum dots,” in Mesoscopic Electron Transport, NATO ASI Series, pp. 105–214 (1997).
- L. P. Kouwenhoven, D. G. Austing, and S. Tarucha, “Few-electron quantum dots,” Reports on Progress in Physics 64, 701–736 (2001).
- W. G. van der Wiel, S. De Franceschi, J. M. Elzerman, T. Fujisawa, S. Tarucha, and L. P. Kouwenhoven, “Electron transport through double quantum dots,” Reviews of Modern Physics 75, 1 (2003).
- R. Hanson, L. P. Kouwenhoven, J. R. Petta, S. Tarucha, and L. M. K. Vandersypen, “Spins in few-electron quantum dots,” Reviews of Modern Physics 79, 1217 (2007).
- G. Burkard, T. D. Ladd, A. Pan, J. M. Nichol, and J. R. Petta, “Semiconductor spin qubits,” Reviews of Modern Physics 95, 025003 (2023).
Additional research papers may be assigned throughout the term for journal-club discussions. These papers will be chosen to connect the foundational material to current research in gate-defined quantum dots, semiconductor spin qubits, quantum control, readout, decoherence, and scaling.
The following textbooks may be useful as background references, but are not required:
- M. H. Levitt, Spin Dynamics: Basics of Nuclear Magnetic Resonance, Wiley, 2001.
- D. A. Neamen, Semiconductor Physics and Devices, 3rd ed., McGraw-Hill, 2003.
- Y. V. Nazarov and Y. M. Blanter, Quantum Transport: Introduction to Nanoscience, Cambridge University Press, 2009.
- S. Datta, Electronic Transport in Mesoscopic Systems, Cambridge University Press, 1995.
Evaluation
There is no final exam. Evaluation will be based on preparation, in-class problem solving, participation in paper discussions, and a course project. The course alternates between lectures, research-paper discussions and problem solving “boot camp” sessions. Students are expected to come prepared, participate actively, and develop the ability to explain core concepts and calculations clearly at the board.
The approximate grade breakdown is:
In-class problem work 35%
Reading, journal-club discussion, paper presentation 25%
Course Project 30%
Short preparation assignments 10%
In-class problem work — 35%
Problems will be posted in advance and assigned to specific students. Assigned students will present their solutions at the board during class. Evaluation will emphasize physical understanding, clarity of explanation, correct use of notation, ability to make reasonable approximations, and ability to respond to questions from the group.
Students are not expected to deliver polished lectures. The goal is to practice explaining relevant physics in the style needed for comprehensive exams, thesis defences, group meetings, and research presentations. Other students are expected to engage with the solution, ask questions, and help identify unclear assumptions or missing steps.
Reading, discussion, and paper presentation — 25%
Students are expected to read assigned review articles and research papers before class and be prepared to discuss them. Each student will present at least one paper during the term. Paper presentations should explain the motivation, main experimental or theoretical result, essential methods, connection to the course material, and open questions or limitations.
Participation in paper discussions will be assessed based on preparation and engagement, not on already being an expert in the topic.
Short preparation assignments — 10%
Short preparation assignments will replace most traditional homework. These may include one or two warm-up problems, a short derivation, a sketch of an energy diagram, or a brief written response to an assigned paper. The purpose is to prepare students for the next class, not to create a heavy weekly homework load.
These assignments will normally be graded for reasonable effort and completion. They should help students arrive ready to participate in the boot camp or journal-club discussion.
Course project — 30%
Each student will complete a course project on a topic related to semiconductor quantum dots, spin qubits, quantum transport, control, readout, decoherence, or scaling. There are two possible formats:
- a focused research-style project involving a calculation, simulation, data analysis, or theoretical model; or
- a literature-review project that synthesizes an important topic or recent research direction.
The topic must be approved by the instructor. The final submission should be a clear and concise write-up, approximately 5–10 pages, preferably prepared in LaTeX, with properly formatted references. Students will also give a short final presentation on their project.
To keep the project on track, students will submit a brief project proposal by the middle of the term and a short progress update before the final presentation.
Lab/Project
TBA
Schedule
- Tue: 11:00 am - 12:20 pm in QNC 1201
- Thu: 11:00 am - 12:20 pm in QNC 1201
