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CERN Online introductory lectures on quantum computing from 6 November

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277 points by limist 5 years ago · 39 comments

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ahelwer 5 years ago

If anyone is interested I've also created a short 1.5 hour lecture on quantum computing aimed specifically at software engineers & computer scientists, which has proven popular: https://youtu.be/F_Riqjdh2oM

I'd love to answer any questions people have. In quantum computation, state behaves like a vector and logic gates behave like matrices that multiply the vector to get a new state value. It doesn't get too much more complicated than that.

  • mendeza 5 years ago

    Any advice on breaking into the industry? Would be really neat to work as a quantum research engineer, or software engineer on quantum computers!

    • ahelwer 5 years ago

      Google, Amazon, IBM, and Microsoft all have quantum programs which use "regular" software engineers in various roles - for example, writing software to support researchers working in the labs. That's what I did for Microsoft. If you want to work on actual research yourself though, you'll probably need a PhD. There are some non-PhD positions that do research-adjacent work like simulating, implementing & refining researcher findings for the specific hardware the company is developing, but those are quite competitive/difficult to get (I tried!)

      Microsoft also has a fairly large team working on Q# and the Microsoft Quantum Development Kit. That would also involve research-adjacent things like efficiently compiling programs to specific quantum device layouts with appropriate error correction schemes, etc.

    • erej 5 years ago

      ETH Zurich has a quantum engineering masters: https://master-qe.ethz.ch/

    • whimsicalism 5 years ago

      Probably a PhD

  • asb3st0s 5 years ago

    Just wanted to say I watched your lecture on YouTube a while back and thought it was very well-done and informative. I learned a lot. Thank you!

  • DevX101 5 years ago

    Nice! This seems to fit my learning style well. I prefer to understand why something matters, than progressively probe backwards into the theory.

  • thijsb 5 years ago

    That was incredibly insightful! Thank you sharing this!

cameronperot 5 years ago

For anyone interested in additional resources, MIT has some courses taught by Peter Shor and Isaac Chuang on quantum information science [1-6].

[1] https://www.edx.org/course/quantum-information-science-i-par...

[2] https://www.edx.org/course/quantum-information-science-i-par...

[3] https://www.edx.org/course/quantum-information-science-i-par...

[4] https://www.edx.org/course/quantum-information-science-ii-qu...

[5] https://www.edx.org/course/quantum-information-science-ii-ef...

[6] https://www.edx.org/course/quantum-information-science-ii-ad...

z3phyr 5 years ago

Another great introductory resource is https://quantum.country/ by Andy Matuschak and Michael Nielsen

teruakohatu 5 years ago

This is probably a dumb question but are there any data sciencey or tensorflowy things that can be done faster on a quantum computer?

  • _8091149529 5 years ago

    I think your question is excellently phrased. The answer for anything data science-y is "no." The bottleneck will be transferring the input data onto the quantum CPU.

    For algorithms like HHL that have superclassical performance, a complex superposition encoding the data needs to be created first. This state is subsequently "consumed" by the algorithm. The no-cloning theorem forbids creating copies of the encoded state, and hence the encoding step needs to be repeated every time the algorithm is run.

    For another example, consider Grover's search that is sub-linear in calls to an oracle function. If the oracle references a linear array of data, for example, it needs to work on superpositions of array indices. In other words, the entire dataset needs to fit in "quantum" memory.

    Using a quantum cpu can only be sensible for computationally difficult problems where the hard problem instances can be specified by a relatively small number of bits.

  • bawolff 5 years ago

    I dont super follow this area, so i might be totally off base, but i think lots of the hopes for that sort of thing was based around the HHL algorithm, but then Tang showed that normal computers can be just as fast doing that problem, so now its up in the air a bit how applicable wuantum computers are

    But i really dont know much about this area, might be totally wrong. I'm kind of basing this off this blog post https://www.scottaaronson.com/blog/?p=3880

  • virattara 5 years ago

    There are some basic linear algebra subroutines (Matrix inversion, finding eigenvalues & eigenvectors) that can be performed with an exponential speedup on a quantum computer in theory, that's why there is so much interest in Quantum Machine Learning. If you are asking about the current hardware level, then no, current quantum computers can not solve any practical problem faster than a classical computer.

    In theory classical computers are also not limited to have better solutions to problems where quantum computers claim superiority like prime factorisation or like Tang's quantum inspired classical algorithm that beats HHL for low rank matrices.

    • jlokier 5 years ago

      > There are some basic linear algebra subroutines (Matrix inversion, finding eigenvalues & eigenvectors) that can be performed with an exponential speedup on a quantum computer in theory

      Eh... those particular subroutines have polynomial time algorithms already on a classical computer.

      You can't exponentially speed up something that's polynomial time already.

      • westurner 5 years ago

        https://quantumalgorithmzoo.org/ lists algorithms, speedups, and descriptions.

        • jlokier 5 years ago

          That's a great list, thanks!

          (Though for the benefit of readers here, the list doesn't include any "basic linear algebra subroutines (Matrix inversion, finding eigenvalues & eigenvectors)").

          • westurner 5 years ago

            The "linear systems" and "machine learning" algorithm paragraphs under "Optimization, Numerics, & Machine Learning" reference a number of resources in regards to currently understood limits of and applications for quantum computers and linear optimization.

boniface316 5 years ago

Am I the only one who is having issues seeing the recorded session?

bsdooby 5 years ago

Can past sessions be downloaded/re-watched?

sharmaakshat 5 years ago

is anyone attending? They given time for GMT 6:30 AM..still waiting for the feed to start

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