By Sai from Tokyo 5 months ago Completed

This course starts with an introduction to quantum mechanics, develops theory about quantum circuits, and finally explains Shor's algorithm that factors an integer in polynomial time (a threat to RSA cryptography??). The course information page says it does not assume any prior background in quantum mechanics but I think it is an overstatement. Without it, be prepared to do some study on your own. The course does provide a brief introduction but quantum mechanics is so unintuitive that if you understand it solely from this course, I would say you are a genius! In addition, understanding of linear algebra over complex numbers and Euler's formula is necessary. Having said that, this course provides a unique opportunity to learn about quantum computation--I suspect very few universities in the world are offering such course. This course is not for everyone but it shows the great strength of MOOC in matching short supply and distributed demand in education. Here is some course statistics copied from the forum:

- number of people signed up for the course: 26K
- number of people that watched the first lecture: 12K
- number of people who turned in the first assignment: 6K
- number of people who turned in the fourth assignment (midpoint): 3K
- number of people who took the final: 2104
- number of certificates: 1523
- number of certificates with distinction: 373

By Hugh Pearce from Yeovil, England 2 months ago Completed

Found material too brief and poorly explained- seemed to be more interested in saying how mysterious and great the fantastic the concepts where rather than an practical help to explain and understanding them -presentation needed more substance less style. The videos were too brief and notes too dense only occupying a couple of hours a week. The additional material was presented in a scatter gun approach and 90 % of no help or relevance to understanding the course. Comparing this with the solid state chemistry on EDX where the material is expained in videos with student interaction and is 10 times more understandable and comprehensive even though I've never studied chemistry before where as I've studied computing and quantum mechanics to Hons degree/MSc level

By Ethan Berl from Princeton, New Jersey 6 months ago Completed

This course is an excellent introduction to anyone who is interested in what quantum computing really is and has a slightly technical background. I took a course which covered the same material in person at Princeton a year earlier and there were some things I thought this course made much clearer (quantum FFT for example). If you take this course you will learn a lot about functional aspects of the nature of quantum systems and quantum mechanics in general, without having to get your hands too dirty with wave equations. You will get a sense of how quantum algorithms work and where the promise of their exponential speed ups stem from as well as understanding the most significant algorithms discovered so far. I thought that the homeworks and tests were actually very good tests of skill which were right on the border of challenging and possible so that with focus you really learned something.

There were two things that this course could do better but neither was a very big detractor. Vazirani assumed a certain background knowledge of math and certain conventions which I and a lot of others just didn't have -- nothing conceptually difficult, just facts which I didn't know. This could have easily been fixed with a 10 minute math review video at the start of the course but instead I had to dig around the forums and find out that the problems relied on you knowing some facts about a convention in complex fields or certain differential equations, etc. It wasn't a big set back, but it was annoying that I had to spend a few hours teaching myself when it could have been a ten minute video.

The other issue was that we never really talked very much about how quantum computers could actually be implemented. The whole course we just assumed that if it became possible for quantum circuits to be built that these are the properties and algorithms which could be run on them. I think I would have very much enjoyed a week of lectures on the most promising current approaches and more explanation of the problems which have prevented them from being a reality so far. At any rate, my rating reflects the material which was there not the material which could have been there and this course was excellent.

By Chris Simmons from Vancouver 7 months ago Completed

This course was difficult but interesting. If I had more of a physics background, I think I would have taken more from it, but it was still worth my time (if only to prove to myself that I can still do math).

I think the prerequisites were a bit understated. They mention linear algebra, but as in all math there are different levels of knowledge. I've done a couple of university-level linear algebra classes, but I hadn't touched on tensors. I also hadn't done as much with complex numbers as the course assumed, although I caught up by the end.

Understanding the math, or at least being interested in learning it, is key here. There are other forums where you can learn the weird and wonderful ways of quantum mechanics (and to a lesser extent, computation) without having to do all the equations yourself.