CERN Online introductory lectures on quantum computing from 6 November

Author: limist

Score: 271

Comments: 35

Date: 2020-11-05 06:11:47

Web Link

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ahelwer wrote at 2020-11-05 12:42:31:

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 wrote at 2020-11-05 16:12:40:

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 wrote at 2020-11-05 17:36:04:

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 wrote at 2020-11-05 17:24:51:

ETH Zurich has a quantum engineering masters:

https://master-qe.ethz.ch/

deeeeplearning wrote at 2020-11-05 20:48:18:

In that Vein, so does USC. MSc in Quantum Information Science

https://viterbigradadmission.usc.edu/programs/masters/msprog...

whimsicalism wrote at 2020-11-05 16:18:43:

Probably a PhD

asb3st0s wrote at 2020-11-05 13:57:36:

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!

ahelwer wrote at 2020-11-05 15:14:24:

Glad you enjoyed! I also wrote a couple of follow-up blog posts which examine quantum entanglement & quantum chemistry simulation, respectively:

https://ahelwer.ca/post/2018-12-07-chsh/

https://ahelwer.ca/post/2019-12-21-quantum-chemistry/

thijsb wrote at 2020-11-06 21:03:53:

That was incredibly insightful! Thank you sharing this!

DevX101 wrote at 2020-11-05 17:08:29:

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

cameronperot wrote at 2020-11-05 10:25:04:

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 wrote at 2020-11-05 07:37:10:

Another great introductory resource is

https://quantum.country/

by Andy Matuschak and Michael Nielsen

boniface316 wrote at 2020-11-06 21:35:49:

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

teruakohatu wrote at 2020-11-05 08:14:08:

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 wrote at 2020-11-05 17:33:26:

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 wrote at 2020-11-05 09:03:04:

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 wrote at 2020-11-05 13:18:46:

Small correction, Tang's classical algorithm considers only low rank matrices, HHL still is more efficient for higher rank matrices.

f00zz wrote at 2020-11-05 11:57:37:

Wow, that guy is 18 years old!

tephra wrote at 2020-11-05 12:06:41:

Ewin Tang is a female.

dmurray wrote at 2020-11-05 14:01:48:

Also, she's 20.

bawolff wrote at 2020-11-05 17:15:08:

She was 18 at the time she discovered this algorithm, which in context seems to be what is relevant.

kgwgk wrote at 2020-11-05 12:59:58:

> Ewin Tang is a female.

How do you define "female"?

ycombonator wrote at 2020-11-05 13:26:02:

https://www.google.com/search?q=female&ie=UTF-8&oe=UTF-8&hl=...

kgwgk wrote at 2020-11-05 13:30:06:

I know how to use google, thanks. But tephra is a) thinking of a different definition, b) used the term by mistake or c) is just wrong.

4gotunameagain wrote at 2020-11-05 14:17:02:

This is not the place for this. Maybe Ctrl+tab to twitter instead?

kgwgk wrote at 2020-11-05 14:18:36:

I was just curious about the unusual choice of words.

4gotunameagain wrote at 2020-11-05 14:23:40:

You surely must be trolling

kgwgk wrote at 2020-11-05 15:07:29:

Reading "Ewin Tang is a female" instead of "Ewin Tang is a woman" is what made me look into it, really. It seemed a deliberate choice and I wondered if it was related to a gender change from woman to man. Of course, that's completely irrelevant to the subject of quantum computing.

virattara wrote at 2020-11-05 13:10:59:

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 wrote at 2020-11-05 15:00:04:

> 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 wrote at 2020-11-05 19:10:53:

https://quantumalgorithmzoo.org/

lists algorithms, speedups, and descriptions.

jlokier wrote at 2020-11-06 15:11:37:

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 wrote at 2020-11-06 18:15:53:

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.

bsdooby wrote at 2020-11-06 18:21:54:

Can past sessions be downloaded/re-watched?

sharmaakshat wrote at 2020-11-06 06:55:23:

is anyone attending?

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

emrehan wrote at 2020-11-06 10:00:06:

I’m joining in too