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CO 481Introduction to Quantum Information Processing

Units
0.50
Faculty
Mathematics
Subject
Combinatorics and Optimization
Cross-listed
CS 467, PHYS 467

When it runs

  1. F24
  2. W25
  3. S25
  4. F25
  5. W26
  6. S26
  7. F26
  8. W27
  9. S27

Ran in 3 of the last 7 terms. Winter 2027: scheduled, 2 lecture sections. Spring 2027: schedule not out yet.

Basics of computational complexity; basics of quantum information; quantum phenomena; quantum circuits and universality; relationship between quantum and classical complexity classes; simple quantum algorithms; quantum Fourier transform; Shor factoring algorithm; Grover search algorithm; physical realization of quantum computation; error-correction and fault-tolerance; quantum key distribution.

Prerequisites

  • Complete all of the following
    • Earned a minimum grade of 80% in at least 1 of the following:
      • MATH235 - Linear Algebra 2 for Honours Mathematics (0.50)
      • MATH245 - Linear Algebra 2 (Advanced Level) (0.50)
    • Students must be in level 3A or higher

Antirequisites

None listed.

Leads to

No course lists it as a requisite.

Winter 2027 sections

Enrolment from UW Open Data, which can trail Quest by up to two days. Instructors and rooms: Schedule of Classes.
SectionClassEnrolledMeets
LEC 00157200 / 35MW 11:30–12:50
LEC 701220916 / 9999Online or by arrangement

Reviewed on UW Flow

83% liked it10% easy67% useful

From 12 ratings and 8 comments on UW Flow. The most helpful comments, quoted as written, without names. Read them all on UW Flow.

  • This course was the most interesting course I have taken at the university. There are many unintuitive results, and even fundamental concepts such as measurement and entanglement take a long time to sink in.
    Bra-ket notation is kind of a pain coming from MATH 235, but once you get used to it it's not so bad. At the beginning of the course I was struggling to understand how the Hadamard gate sends |0> to |+>, but now it is second nature. It is also strange how once you measure, the wavefunction collapses and so any quantum advantage disappears. The fact that encoding using qubits doesn’t really give any advantage over encoding using regular bits is also very nonintuitive (modulo some…

    Apr 2026 · liked it · 1 found this helpfulOn UW FlowRemove this

  • This course was a rollercoaster and a half. Assignments took hours and hours to do, course content involved understanding of basic quantum physics, probability, and lots of linear algebra. There were lots of algorithms that you had to memorize the steps of while also understanding exactly how they worked. Avoid Ashwin Nayak if you can, our midterm did not have a passing grade average and yet he refused to curve it at all, stating that he'd see how our exam performance was and consider circling back to the midterm then. By FAR the worst prof I've ever had the displeasure of knowing at UW. Overall extremely stressful course thanks to him, I spent lots of time worrying that I would fail it and…

    Apr 2026 · liked itOn UW FlowRemove this

  • Hardest course I've ever taken. Doing assignments is a full time job. Self-taught the entire course based on Nielsen and Chuang (there's no centralized source for material covered in lectures / no lectures posted / no official course notes). Very interesting tho

    Apr 2026 · liked itOn UW FlowRemove this

  • interesting course, pinnacle of combing probability with linear algebra. regardelss of who your prof is, prepare to teach yourself a lot of the material, but especially if Ashwin Nayak is your prof

    Mar 2026 · liked itOn UW FlowRemove this

  • I really enjoyed this course with lots of interesting concepts and ideas. It can get tough if you try to understand absolutely everything. But the assignments are manageable and the exams are on the easier side. Debbie is very supportive and really wants students to succeed, she even gives an unweighted test in the first week to help assess your suitability. If you’re a mathy student into quantum info, you’ll probably find this course pretty fun.

    May 2025 · liked itOn UW FlowRemove this

Discussed on r/uwaterloo

32 posts and comments in 27 threads mention CO 481, July 2015 to December 2024. Quoted word for word, newest first; each reply sits under the post and the comment that started its branch. Search r/uwaterloo for newer posts.

Fall 2024

CO course comparison 3 points, 7 comments

u/amsyed10385: “… Options for me are: CO 444 Algebraic Graph Theory CO 481 Quantum Info CO 463 Convex Optimization CO 353 Discrete Optimization Anyone who has taken one or more of these? Preferably if you can compare two courses difficulty and how time consuming it is. …”

u/batson2002: “CO481 is horribly coordinated and such a poorly designed course. CO463 is notoriously hard. CO444 was super fun if you like graph theory and group theory (like PMATH347) or even just linear algebra. Can't comment on CO353. …”

u/amsyed10385: “thanks, do you know if CO 481 is the same contents across different professors? How hard is CO 444 compared to PMATH 347?”

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Spring 2024

CO481 5 points, 1 comment

u/EcstaticPepper37: “How is CO481 for someone who has taken PHYS 234? I know no prior quantum knowledge is required for the course but does it help if you have taken a quantum physics course before?”

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Winter 2024

cs251 usefulness 3 points, 6 comments

“Course selection coming up thinking about what courses to take on top of cs240, cs241, math239, and afm274 for 2B CFM. Debating between math235 (linalg) and cs251 and bird courses right now. …”

u/Stranger_Natural: “Cs251 was an annoying course that I learned almost nothing from. Math235 (and in particular, anything that gives you more exposure to linear algebra) is very very useful if you want to take CO 250/255/463, and from what I’ve heard, it also helps with CO 481 and CS 480.”

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Fall 2023

I don’t know what to do with my degree 1 point, 14 comments

“I'm in my 2A term as a math student and my initial plans were to get into data science, but due to my average being lower than the cutoff that did not happen. …”

u/Organic_Midnight1999: “Bro a Math degree is underrated. As the world advances the problems we face just get harder and harder. We move towards more high level, abstract, and data driven problems - guess what? …”

u/jadedwolf12: “… though 485 is more theoretical and focused on public-key, and 487 covers more breadth CO 481 - quantum algorithms (crosslisted with CS 467/PHYS 467) This is not an exhaustive list - they're just the ones I took during my undergrad.”

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Spring 2023

Most Recommended CO Courses? 22 points, 21 comments

“What are your most recommended CO courses regardless of hardness? :D Thank you\”

u/S3132: “I planned to take CO 367 but seems like no one recommends it lol? Anyone took this course before? 👀”

u/harmonyIn3rdsNot4ths: “CO 367 is an excellent course, although I've enjoyed every CO course I've taken. CO 367/456/481/487 are all fun!”

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Fall 2022

CS467 5 points, 4 comments

“How is the course? Anyone taken it recently? Is it challenging for someone who hasnt touched physics above say a phy121 level? …”

u/AHpache182: “CS 467 / CO 481 / PHYS 467 (the same course just cross-listed) is a course on quantum information processing, as the name suggests. I chatted with David Jao (CO advisor) and briefly asked about this course. …”

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Spring 2022

4xx math courses 4 points, 10 comments

“Are there any 4xx math courses that only require a 1st or second year course as a prerequisite? For example pmath340 only requires math135, but I was wondering if there are any other math classes …”

u/TheRealArjun: “AMATH 456, 475 (not sure if pmath majors usually take those Calc 4, ODE 1 prereqs), CS 467 / PHYS 467 / CO 481 (same course), CS 436, 487”

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Winter 2022

Fall 2021

Check it elsewhere for Fall 2026

Calendar versions

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