Hacker News new | ask | show | jobs
by jptman 3295 days ago
Can someone explain the computation the article talks about further? All it says is that the array will go into a chaotic state and produce seemingly random output.
5 comments

I believe they talk about the computational task described in [1] (published in 2016). Note that this is somewhat contrived: it's a task defined specifically so that it is very difficult for classical computers and relatively easy for quantum computers. It is also defined in a way that ensures that a quantum computer necessary to demonstrate quantum supremacy is relatively small in terms of the number of qubits.

The task is that of generating output samples from pseudo-random quantum circuits. The paper shows that the task has exponential computational complexity on classical computers and that it can be used to demonstrate quantum supremacy using a quantum computer with approximately 50 qubits.

Now, the IEEE Spectrum article indicates that the team has now built a 49-qubit quantum computer and plan to use it to demonstrate quantum supremacy.

EDIT: Replaced direct pdf link with the article page link.

[1] https://arxiv.org/abs/1608.00263

Am I right to read this as "the classical computer and quantum computer compete at the task of being that particular quantum computer?" Scott Aaronson is probably preparing to denounce this experiment already.
Not really "that particular", but more like performing a trick explicitly designed to be feasible even for low-qubit quantum computers but unfeasible even for very powerful conventional computers attempting to emulate quantum computing.

Performing such a trick demonstrates that you have a working device that can perform arbitrary quantum computations - unlike, say, the much hyped D-wave quantum annealing device.

If you'd checked the article, you would see that actually he's solidly in favor.

But yes, it's basically "represent a quantum computer of this size", which we legitimately can't do classically beyond a certain size. It's not hugely useful but it's legitimate quantum supremacy, if it works.

I don't know a good link to a discussion of this system, but the idea of establishing quantum supremacy has been much discussed in optical systems under the title of boson sampling.

https://en.wikipedia.org/wiki/Boson_sampling

It wasn't clear to me either. Demonstrated "supremacy" over conventional general-purpose CPUs, as described in the article, does certainly read like hyperbole.
"Supremacy" is a technical term used by people in the field, albeit sometimes in different ways.

https://twitter.com/quantum_graeme/status/849317195599556609

Interesting, I assumed they meant the term colloquially.
Here's an educational video on the subject that explains it in a way that everyone can understand. https://www.youtube.com/watch?v=JhHMJCUmq28
This video doesn't discuss quantum supremacy, so it does nothing to answer his question.
It does however establish the background material. Inability to make the connection is a failure of intellect and imagination.
Here is another link that, while being a tiny bit mathematically rigourous, made me have an "a ha" moment about how quantum computtattion works.

PBS Digital Studios is truly a treasure and really shows what's possible with eduxation when you truly take advantage of internet video.

You mentioned a link to another educational video, however; you provided no links in your comment. Would you mind editing your content to include the link? I'm quite interested.
You also read my mind.
It is indeed
I hate posting from my phone. Here it is:

https://www.youtube.com/watch?v=IrbJYsep45E

I tried to find it im the PBS Digital Studios YouTube channel and failed. But I did learn about PBS Digital Studios!
Also, I'm glad you became a fan! Some people mock anything that is government funded and reflexively assume private enterprise always makes a superior product.

One exception of many to this I recently found is when the gf and I were watching tv and she changed the station to the Science Channel. My excitement was destroyed by my exponentially higher dissapointment: The tv show she wanted to watch was Ghost Hunters...on the frickin science channel!!!!

Some people mock anything that is government funded and reflexively assume private enterprise always makes a superior product.

I am grateful to have never knowingly met one of these people.

Specifically, it's the Infinite series. Math is so much easier to understand with animations. Something that would take me hours of dense reading of some dusty tome can to grok requires only 20 minutes with modern video production