Thank God someone other than Scott Aaronson is publishing this kind of content. Shetl Optimized is too much of a vanity project to serve as a mainstream resource.
Meanwhile, the author of the foreward is none other than…
What You Shouldn't Know About Quantum Computers
51–60 of 104 posts
Re: What You Shouldn't Know About Quantum Computers
#52Earlier quoted context omitted.
I thought the error rate has stayed pretty exponential in terms of the number of physical qubits needed to express a logical qubit and it’s not actually known if we’re any closer on that metric vs other more easily achieved metrics. Additionally, I was under the impression that not all QCs being built are able of executing Shor’s algorithm which added additional challenges that aren’t solved. My final impression is t…
A QC that can't run Shor's algorithm is not a QC, as much as D-Wave screams and stamps their feet that it's not fair.
I'm a complete layman when it comes to Quantum Computing, but I thought Shor's algorithm is effectively the most basic usecase example of Quantum Computers?
I'm confused here.
Re: What You Shouldn't Know About Quantum Computers
#53It's a better use of your time just learning quantum mechanics than reading this book. Even if you give up, you'll at least learn some linear algebra along the way.
Re: What You Shouldn't Know About Quantum Computers
#54> Researchers like Jaime Sevilla and Jess Riedel support this timeline, publishing a report in late 2020 that claimed a 90% confidence of RSA-2048 being factored before 2060. I am skeptical. 36 years is a long time, but in the past 10 years there hasn't been much progress: year 2001: factorization of 15 (IBM) year 2012: factorization of 21 (University of Bristol) year 2019: factorization of 35 attempt, failed (IBM) h…
> I am skeptical. 36 years is a long time, but in the past 10 years there hasn't been much progress:
36 years ago we didn't even know shor's algorithm existed, and didn't know quantum computers could non-exponentially factor integers at all.
So in a certain sense, we have made infinite progress in the last 36 years. Who knows what could happen in the next 36.
More generally, i think making science predictions that far out is basically impossible.
Re: What You Shouldn't Know About Quantum Computers
#55The article suffers from skipping between layers of abstraction in an attempt to make a point, and in the end in doing so fails to make the initial point. In the first "Myth" section, that "nobody understands this quantum stuff", the example is used of the transistor. It's true that we have no way of making a classical model of a transistor, and our understanding of how transistors work relies on quantum mechanics. B…
>I am in the camp that believes that quantum computing is not possible in any useful sense; in particular a quantum computer will not be capable of being significantly more powerful than a classical computer, in the quantum supremacy sense.
Could you elaborate on that? I was under the impression that some companies are using Quantum Computers because quantum supremacy has been demonstrated (such as in molecular modeling for drug discovery or materials science) - but I'm a complete novice here, and would love to learn more. I'm probably quite wrong, and happy to be corrected.
Also, by not possible in a useful sense, do you mean that QCs as they are now versus in N years, or just in general?
Re: What You Shouldn't Know About Quantum Computers
#56You have to get to page 25 before it starts being honest about the fact quantum computing is a con. Important Nuance: the research is real, the science is real, but the narrative being sold about the future of quantum computing to ensnare investors is not a reasonable prediction and is a con.
To be fair, that doesn't really distinguish it from the rest of the industry. I would say the same thing about AI and (especially) blockchain.
Re: What You Shouldn't Know About Quantum Computers
#57Earlier quoted context omitted.
Not the size, but the temperature. If you have to cool to a microkelvin for a certain number of qbits to retain coherence, how low do you need to go to add one more qbit, and how much energy will that require? My thermodynamic instinct says that the cooling effort required rises with the resolving power — which is exponential with the number of qbits. But it's just instinct, not grounded very well in science or engin…
It's plausible to me that cooling becomes exponentially harder as you aim for lower temperatures but I don't understand why you think you need lower temperatures for more qbits? The whole point of quantum error correction is that ones you reach a constant threshold you can use more iterations of error correction to decrease you logical error rate without decreasing your physical error rate.
They're not talking about lower temperatures, but greater volume.
Re: What You Shouldn't Know About Quantum Computers
#58Earlier quoted context omitted.
Surface area is squared, volume is cubed, a larger object has to get hotter to expell the same amount of heat. Per unit of volume, your body produces more heat than the sun, exactly because it is an exponential function.
Huh? What are you saying is an exponential function? x^3 is not an exponential function, in the sense relevant here.
You aren't thinking about the exponential decay of emissivity near absolute zero. It isn't linear like we get to assume to make the math easier.
Thus why IBMs largest refrigerator can only dissipate tiny amounts when cold.
> enabling close to ~10 mW at 100 mK cooling power, and over 24 W of cooling power at 4 K temperatures. Finally, the weight of the entire system — 6.7 metric tons
They aren't building single huge quantum processors, but networks of easy to cool parts.
IBM hopes that one GoldenEye refrigerator may be able to hold a million qbits but that isn't enough to break RSA.
RAND estimated 890 MWh per key to be broken.
It will be horizontal sprawl, not vertical integration.
Larger objects simply have to get hotter to expell the same watts per volume or increase surface area.
That is problematic for quantum computers.
Re: What You Shouldn't Know About Quantum Computers
#59Chris Ferrie also writes great books about science for babies. https://www.csferrie.com/books https://www.amazon.com/Quantum-Computing-Babies-Baby-Univers...
At first I saw that this was downvoted and assumed maybe it was a different Chris Ferrie, but from the looks of the blog it's the same person.[0] Maybe other people thought this didn't add much to the discussion, but I found it interesting. [0] I am Chris Ferrie, father of four and happy husband. My day job is academic research where I follow my curiosity through the world of quantum physics. My passion for communica…
It is for sure the same Chris Ferrie, it's even in the foreword of the paper:
Yet in all that time I never thought to write, much less did I actually write, a pithy book called “What You Shouldn't Know About Quantum Computers.” My colleague Chris Ferrie did. He's the same guy who coauthored the surprise bestseller “Quantum Computing for Babies.” Now he's back, with something for those babies to read when they're slightly older.
I enjoy his kids' books and read almost all of them to my kids. They aren't "perfect" (whatever that means for a kids' book), but my kids love them and they start to wrap their brains around otherwise inaccessible topics for their age.