Quantum Computing for Computer Scientists

Quantum Computing for Computer Scientists

This talk discards hand-wavy pop-science metaphors and answers a simple question: from a computer science perspective, how can a quantum computer outperform a classical computer? Attendees will learn the following:

– Representing computation with basic linear algebra (matrices and vectors)
– The computational workings of qbits, superposition, and quantum logic gates
– Solving the Deutsch oracle problem: the simplest problem where a quantum computer outperforms classical methods
– Bonus topics: quantum entanglement and teleportation

The talk concludes with a live demonstration of quantum entanglement on a real-world quantum computer, and a demo of the Deutsch oracle problem implemented in Q# with the Microsoft Quantum Development Kit. This talk assumes no prerequisite knowledge, although comfort with basic linear algebra (matrices, vectors, matrix multiplication) will ease understanding.

See more at https://www.microsoft.com/en-us/research/video/quantum-computing-computer-scientists/


  1. Jhon A on April 16, 2020 at 3:04 pm

    Hi, my name is Jhon.
    Is there anyway to use these slides? I’m a Systems Eng. student at UNAL Bogotá and I’m preparing a brief presentation abour QC with a partner, we think that your slides are a wonderful working material.

    Thanks for the attention, and nice video.

  2. Blind Magus on April 16, 2020 at 3:04 pm

    this guy is brilliant, who knows him?

  3. logicOnAbstractions on April 16, 2020 at 3:04 pm

    It’s funny how entanglement discussed with people confronted for the first time with the concept INVARIABLY leads to a discussion along the lines of "wait – but what you go to other end of the universe and I measure my qbit… is there not a way for you to know that I have?". No, there is none, but we will forever keep on having to discuss the issue!

  4. Amin Mirakhorli on April 16, 2020 at 3:06 pm

    Nice teaching session.

  5. 34cvc on April 16, 2020 at 3:07 pm

    As someone with basically 0 knowledge about the topic this was awesome! Really good explanation, i actually feel like i learned something which is not always the case in some of these talks

  6. Wim Van Renterghem on April 16, 2020 at 3:08 pm

    At 23:20, he says "there are states where we can’t factor out the product states", does he mean that there are some 4 complex numbers (2 qubits, a 1×4 matrix) that we can’t write in the tensor product form?

  7. Heitor Santos on April 16, 2020 at 3:08 pm


  8. Antony Stevens on April 16, 2020 at 3:09 pm

    Thank you for an excellent lecture. Very helpful.

  9. justalperen on April 16, 2020 at 3:10 pm

    you can also watch kurzgesagts video instead too

  10. jagatheesan kunasaikaran on April 16, 2020 at 3:12 pm

    Thank you for this amazingly dense, informative and casual presentation! I enjoyed it! =D

  11. Christopher Moutoulas on April 16, 2020 at 3:12 pm

    this kid is actually very funny without knowing it, as well as an excellent lecturer

  12. Ramalingeswara Rao Bhavaraju on April 16, 2020 at 3:12 pm

    thank you sir

  13. googlEddy on April 16, 2020 at 3:12 pm

    "..and our language is not developed for this. Anything i trying to tell you is fundamentally a lie, except for the math." 🙂 thank you! 🙂

  14. Muhammad Shahbaz on April 16, 2020 at 3:13 pm

    thank you so much, this is the first tutorial I really understood. the way you taught maths and stuff felt easy to grab. thank you.

  15. bo j on April 16, 2020 at 3:14 pm

    21.10 "we dont use photons because they collapse too easy"
    Id love to see you write information on a massless photon.
    21 mins in ive seen 4 errors.
    Thought microsoft would have better talent.
    Quantum computers cant be applied in reality.
    So many dumb people pretending they understand any of the maths and theory behind the qbit science fiction.
    I hope someone can come back to this comment and prove me wrong one day. Highly doubt it though.

  16. ilko derez on April 16, 2020 at 3:14 pm

    This is one of the best introductions to quantum computing that I’ve seen. Other teachers should use this presentation as a template to expand on. <insert J++ joke> Thanks to whoever that guy is, he’s a good (nifty) instructor!

  17. Cesar U on April 16, 2020 at 3:15 pm

    Annnnnnnnndddddd in 2020 quantum computing is nowhere near "supremacy"…Nice try kid.

  18. Andrew Casper on April 16, 2020 at 3:21 pm

    "drac vector notation" 5:24

    You have angered the physicists.

  19. chaospage on April 16, 2020 at 3:21 pm

    This taught me more than ever about this topic – bravo!

    But that "outperform" argument seems weak (what am I missing?)
    34:43 “Blackbox – you can try inputs and observe outputs … how many queries to determine if function is constant or variable?”
    On classical box with one wire going in and one wire going out the tester must take 2 measures – ok, no problem.
    On quantum box the tester takes one measure (turns around ensuring no one else is looking), ignores the Output completely and measures that other wire supposedly added for reversibility purpose – which conveniently happens to have the answer we are looking for (umm)
    Me: adds a second outgoing wire to the classical box that is 0 if function is constant and 1 if function is variable and calls the competition a tie.

  20. oldartguy on April 16, 2020 at 3:22 pm

    The arrow of time is running back ward at the Quatum level.

  21. Lemon Lady on April 16, 2020 at 3:23 pm

    Really enjoying this, in terms I can easily understand. I am not a physicist, but CS, yes!

  22. ALEXANDER BRONAUGH on April 16, 2020 at 3:23 pm


  23. Frank Erdman on April 16, 2020 at 3:24 pm

    more slides, less shots of guy drinking soda and telling us how simple it all is, lol

  24. morthim on April 16, 2020 at 3:26 pm

    "i think i did an okay job of explaining it" you are in a superposition of being a good and unemployed.

  25. Yicheng Wu on April 16, 2020 at 3:27 pm

    Why are the students so old

  26. Salim Huerta on April 16, 2020 at 3:28 pm

    Around 1:10:00 the question he was trying to get at is that you can’t prove that each time you are doing the distribution of measurements of creating q bits and collapsing them that each time they have a probability of collapsing to both. But rather that they had decided to collapse on one value prior each time a new pair was created. We know that the information was correlated but we don’t know if it just so happens that any arbitrary sum of entangled bits will be correlated to 0 or 1 in a 50% distribution when in actuality each specific pair never had a probability of collapsing to the other value than it collapsed to. Which is actually aiming as something very deep in quantum mechanics which is that these bits may be entangled with the future state of pairs. So say you test 1000 bits right and 498 are 1 502 are 0, if you had planned to collapse 10,000 bits instead of 1000 then maybe some of those that had collapsed to 1 would have collapsed to 1 anyway and the ones for 0 also or maybe they wouldn’t have, in order to maintain the distribution as 50% under the conditions of 10,000 pair collapses. In this case the bits have to worry about how large your sample size in your distribution, because they’re somehow dependent on the number of entangled future bits. At least that is how I interpreted his question.

  27. Gaming Kalakar on April 16, 2020 at 3:29 pm

    1000th Comment

  28. ה David L. Montoya on April 16, 2020 at 3:30 pm

    wow the reaity will change and also the language beacuse it is not quamtum

  29. morthim on April 16, 2020 at 3:30 pm

    should have showed the slide more than the guy

  30. Hartmut P. on April 16, 2020 at 3:30 pm

    Great motivating talk, thank You so much!!

  31. tariqboost on April 16, 2020 at 3:30 pm

    very solemnly do I thank the youtube algorithms

  32. Ghost Banned on April 16, 2020 at 3:30 pm


  33. James Shelburn on April 16, 2020 at 3:34 pm


  34. Romarain Games on April 16, 2020 at 3:34 pm

    "So, faster than light coordination okay, but faster than light communication not okay. Okay ?"
    Okay ! Message received 5/5, in both states ! No, wait…

  35. Claudio Reyes on April 16, 2020 at 3:36 pm

    Teoría de cuerdas en minuto 1:03:00

  36. Unkown on April 16, 2020 at 3:37 pm

    Guys kinda hot

  37. Salim Huerta on April 16, 2020 at 3:40 pm

    Also, seeing as Google has performed Quantum Supremacy even without applying a real algorithm yet…I wonder if there was an exponential error term how exactly it grew?

  38. DENisVali on April 16, 2020 at 3:40 pm

    You make try youself in 2020 https://www.tensorflow.org/quantum

  39. in briefs on April 16, 2020 at 3:40 pm

    Why do you keep cutting away from a useful slide to watch him pretend to drink, so annoying.

  40. ಪೂರ್ಣಿಮಾ ಎ.ಮ್ on April 16, 2020 at 3:43 pm

    Can you give your mail id

  41. Marvin PhiRatio on April 16, 2020 at 3:44 pm

    bull shit no photon…no i wont tell so shut up tired of the lies….

  42. Keith King on April 16, 2020 at 3:49 pm

    So I didn’t quite grasp the practical application of quantum teleportation due to the lack of the trigger for the receiving end.

    Would one such practical application Be to stream cubits to remote locations for long-term storage with the intent of massive instantaneous data transfers with a light speed trigger such as a laser.

    Basically high-speed instantaneous bulk data transfer by using a laser as the trigger to indicate the states have been collapsed and retrieve the data remotely?

    If so I could see how that would help locally as in Earth to Mars and vice versa. Tiny lightspeed synchronization signal with instantaneous bulk transfer?

  43. pep on April 16, 2020 at 3:50 pm

    This is literally the best video on quantum mechanics, how could 275 people dislike it?

  44. Devan Walsh on April 16, 2020 at 3:53 pm

    This is therapeutic 🥴

  45. Jack Stewart on April 16, 2020 at 3:55 pm

    So the Hadamard gate is a tensor transformation law which represents a change of basis in a quantum computing state, and the intrinsic abilities of a tensor—that is, its ability to perform forward and reverse transformations to end up where you started, as it were—make reversible computing possible? Or is that just complete gobbledygook?

  46. Azeddine Wizert on April 16, 2020 at 3:55 pm

    Difficult to understand the concept of 2 in 1 perhaps for Christians who believe in 3 in 1 without could explaining it

  47. Josicler Leme Silva on April 16, 2020 at 3:57 pm

    Thanks you excellent video!!!

  48. Twisted on April 16, 2020 at 3:59 pm

    wooohooooo . . . we used 2 bits on a quantum computer to qualify 4 states which out performed a classic computer trying to identify 4 states with 1 bit . . . .now thats spooky action

  49. Ahmad Fahmy Abdul Latib on April 16, 2020 at 4:00 pm

    Just like me during my presentation, I tired to be funny but no body laughing. Keep it up

  50. MrSonny6155 on April 16, 2020 at 4:01 pm

    It’s funny because the EPR paradox incident is more like a trend than a once off. Examples include the story of the Poisson Spot or Millikan’s oil drop experiment. The irony of attempts to discredit a theory actually proving the theory is clearly not lost on history.