MIT 8.372 - Quantum Information Science 3

Fall 2024

Lecture: TR2:30-4, Room 3-370

Instructor: Aram W Harrow
Office hours: Thursday 1:30-2:30pm and Friday 2-3pm, Room 6-318

TA: Yuanjie (Collin) Ren
Office hours: Monday 3-5pm, Room 4-251

This is a third class in the MIT QIS sequence, following 8.370 and 8.371. It ran before in Fall 2020 [as 8.S372/18.S996] and in Fall 2022.

Psets and lecture notes will be made public. Registered students (including listeners) can access the canvas site and Piazza discussion boards. Any content only for registered students (such as pset solutions) will be labeled by the MIT icon.

Syllabus

This is a third course in quantum information and computing theory, focused on special topics that may change from year to year. This year the focus is on quantum information theory, both understanding the core theory of the field, as well as application to physics.

The first part of the course will introduce the main questions and tools of quantum information theory, such as entropies, capacities, hypothesis testing, decoupling, random states and unitaries, symmetry, and entanglement. The second part will apply these tools, along with those from quantum complexity theory and error correction, to questions in many-body physics.

The grade will be 50% homework, 10% scribing, 30% final paper and 10% presentation.

Assignments

Problem sets are due by 9pm on Tuesdays. Click on the due date to upload your completed homework.

Assignment Due Date Solutions Topic
Problem set 1 Tues, Sep 17 solutionsMIT Bit commitment and metrics on states
Problem set 2 Tues, Sep 24 solutionsMIT Gentle measurement and types
Problem set 3 Tues, Oct 1 solutionsMIT Relative entropy, Gibbs distributions, and compression
Problem set 4 Tues, Oct 8 solutionsMIT Mutual information and capacity
Problem set 5 Wed, Oct 16 Entanglement-assisted capacity and Fisher information
Problem set 6 Tues, Oct 22 Pinsker and more entanglement-assisted capacities
Problem set 7 Tues, Oct 29
Problem set 8 Tues, Nov 5
Project Proposal Tues, Nov 12
Problem set 9 Tues, Nov 19
Problem set 10 Tues, Dec 3
Project Presentation Mon, Dec 9 (11:59pm)
Project Paper Wed, Dec 11 (11:59pm)
Late policy: You can turn in two assignments up to three days late each for any reason. These no-questions-asked late days are meant for things under your control, like other work taking higher priority. For things out of your control like illness, family emergency, etc. then talk to us (plus SSS if you're an undergrad) and this won't count against your two free extensions. This policy is only for the homeworks, not the project. For the project, extensions are only possible due to circumstances like illness, and may result in a grade of I given how close the end of term is to the grading deadline. This being said, the deadlines are meant to keep you on track and not to make your life difficult, so don't hesitate to reach out if you're having trouble.

Lectures

  1. Sep 5, 2024: introduction, purifications, bit commitment (tablet notes, scribed notes)
    Review material: 8.371 lectures on density matrices, quantum operations
    Related reading: Chap 5 of [Wilde].

  2. Sep 10, 2024: trace distance, fidelity, metrics (tablet notes, scribed notes)
    Review material: Chap 9 of [Wilde], Section 3.2 of [Wat]
    Related reading: early review of the bit-commitment no-go paper.

  3. Sep 12, 2024: classical information theory: entropy, compression and channel coding (scribed notes)
    Review material: Chap 10 of [Wilde]
    Related reading: C. Shannon, A Mathematical Theory of Communication, Bell System Technical Journal, 1948. Shannon, The Bandwagon, IRE Transactions on Information Theory, 1956.

  4. Sep 17, 2024: quantum entropy and compression. (tablet notes, scribed notes)
    Review material: Chap 11 of [Wilde]
    Related reading: algorithmic cooling on wikipedia.

  5. Sep 19, 2024: relative entropy (tablet notes, scribed notes)
    Review material: Chaps 10 and 11 of [Wilde]
    Related reading: Robin Blume-Kohout, Patrick Hayden. Accurate quantum state estimation via "Keeping the experimentalist honest", arXiv:quant-ph/0603116, 2006. Masanori Ohya, Dénes Petz. Quantum Entropy and Its Use, 1993.

  6. Sep 24, 2024: quantum relative entropy (tablet notes, scribed notes)
    Proof presented in class: Igor Bjelakovic, Rainer Siegmund-Schultze, Quantum Stein's lemma revisited, inequalities for quantum entropies, and a concavity theorem of Lieb, quant-ph/0307170, 2012.
    Original proof: Fumio Hiai, Dénes Petz. The proper formula for relative entropy and its asymptotics in quantum probability. Comm. Math. Phys. 143(1): 99-114 (1991). Tomohiro Ogawa, Hiroshi Nagaoka. Strong Converse and Stein's Lemma in the Quantum Hypothesis Testing, arXiv:quant-ph/9906090, IEEE Trans. Inf. Th., Vol. 46, No. 7, 2428-2433 (2000).
    Bonus application: Robin Blume-Kohout and Patrick Hayden. Accurate quantum state estimation via “Keeping the experimentalist honest”. arXiv:quant-ph/0603116 (2006).

  7. Sep 26, 2024: Noisy channel coding (tablet notes, scribed notes)
    Review material: Chapters 2, 16 and 20 of [Wilde]

  8. Oct 1, 2024: Classical messages over quantum channels. Fano and Fannes inequality. Conditional mutual information. (tablet notes, scribed notes)
    Review material: Chapters 16 and 20 of [Wilde]
    Related reading: Tomohiro Ogawa, Hiroshi Nagaoka; A New Proof of the Channel Coding Theorem via Hypothesis Testing in Quantum Information Theory. arXiv:quant-ph/0208139, IEEE Trans. Inf. Th. 2002. Jingliang Gao. Quantum union bounds for sequential projective measurements. Phys. Rev. A 92, 052331, 2015, arXiv:1410.5688. Andreas Winter. Coding Theorem and Strong Converse for Quantum Channels. 1409.2536. IEEE Trans. Inf. Th. 1999

  9. Oct 3, 2024: HSW converse and application to random-access coding (tablet notes, scribed notes)
    Related reading: Ashwin Nayak. Optimal lower bounds for quantum automata and random access codes. quant-ph/9904093. FOCS 1999.

  10. Oct 8, 2024: state learning and tomography (tablet notes)
    Related reading: Scott Aaronson. The Learnability of Quantum States. quant-ph/0608142. Proc. Roc. Soc. A. 2007. Jeongwan Haah, Aram W. Harrow, Zhengfeng Ji, Xiaodi Wu, Nengkun Yu. Sample-optimal tomography of quantum states. 1508.01797. STOC 2016 and IEEE Trans. Inf. Th. 2017.

  11. Oct 10, 2024: quantum sensing and Fisher information (tablet notes)
    Review article: Jasminder S. Sidhu, Pieter Kok. A Geometric Perspective on Quantum Parameter Estimation. arXiv:1907.06628, AVS Quantum Sci. 2, 014701 (2020).
    Connection to fidelity: Sisi Zhou, Liang Jiang. An exact correspondence between the quantum Fisher information and the Bures metric. arXiv:1910.08473.

  12. Oct 17, 2024: Random states and entanglement
    Related reading: 18.S997 High-dimensional statistics. Chapter 1: Sub-Gaussian Random Variables. Spring 2015 OCW notes. A. W. Harrow, The Church of the Symmetric Subspace, arXiv:1308.6595

  13. Oct 22, 2024:

  14. Oct 24, 2024:

  15. Oct 29, 2024:

  16. Oct 31, 2024:

  17. Nov 5, 2024:

  18. Nov 7, 2024:

  19. Nov 12, 2024:

  20. Nov 14, 2024:

  21. Nov 19, 2024:

  22. Nov 21, 2024:

  23. Nov 26, 2024:

  24. Dec 3, 2024:

  25. Dec 5, 2024:

  26. Dec 10, 2024: Student presentations

References