Slashdot Mirror
Is Quantum Computing Impossible? (ieee.org)
"Quantum computing is complex and it's not all it's cracked up to be," writes Slashdot reader nickwinlund77, pointing to this new article from IEEE Spectrum arguing it's "not in our foreseeable future":
Having spent decades conducting research in quantum and condensed-matter physics, I've developed my very pessimistic view. It's based on an understanding of the gargantuan technical challenges that would have to be overcome to ever make quantum computing work.... Experts estimate that the number of qubits needed for a useful quantum computer, one that could compete with your laptop in solving certain kinds of interesting problems, is between 1,000 and 100,000. So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2**1,000, which is to say about 10**300. That's a very big number indeed. How big? It is much, much greater than the number of subatomic particles in the observable universe. To repeat: A useful quantum computer needs to process a set of continuous parameters that is larger than the number of subatomic particles in the observable universe. At this point in a description of a possible future technology, a hardheaded engineer loses interest....
[I]t's absolutely unimaginable how to keep errors under control for the 10300 continuous parameters that must be processed by a useful quantum computer. Yet quantum-computing theorists have succeeded in convincing the general public that this is feasible.... Even without considering these impossibly large numbers, it's sobering that no one has yet figured out how to combine many physical qubits into a smaller number of logical qubits that can compute something useful. And it's not like this hasn't long been a key goal.... On the hardware front, advanced research is under way, with a 49-qubit chip (Intel), a 50-qubit chip (IBM), and a 72-qubit chip (Google) having recently been fabricated and studied. The eventual outcome of this activity is not entirely clear, especially because these companies have not revealed the details of their work...
I believe that, appearances to the contrary, the quantum computing fervor is nearing its end. That's because a few decades is the maximum lifetime of any big bubble in technology or science. After a certain period, too many unfulfilled promises have been made, and anyone who has been following the topic starts to get annoyed by further announcements of impending breakthroughs. What's more, by that time all the tenured faculty positions in the field are already occupied. The proponents have grown older and less zealous, while the younger generation seeks something completely new and more likely to succeed.
He advises quantum computing researchers to follow the advice of IBM physicist Rolf Landauer. Decades ago Landauer warned quantum computing's proponents that they needed a disclaimer in all of their publications.
"This scheme, like all other schemes for quantum computation, relies on speculative technology, does not in its current form take into account all possible sources of noise, unreliability and manufacturing error, and probably will not work."
[I]t's absolutely unimaginable how to keep errors under control for the 10300 continuous parameters that must be processed by a useful quantum computer. Yet quantum-computing theorists have succeeded in convincing the general public that this is feasible.... Even without considering these impossibly large numbers, it's sobering that no one has yet figured out how to combine many physical qubits into a smaller number of logical qubits that can compute something useful. And it's not like this hasn't long been a key goal.... On the hardware front, advanced research is under way, with a 49-qubit chip (Intel), a 50-qubit chip (IBM), and a 72-qubit chip (Google) having recently been fabricated and studied. The eventual outcome of this activity is not entirely clear, especially because these companies have not revealed the details of their work...
I believe that, appearances to the contrary, the quantum computing fervor is nearing its end. That's because a few decades is the maximum lifetime of any big bubble in technology or science. After a certain period, too many unfulfilled promises have been made, and anyone who has been following the topic starts to get annoyed by further announcements of impending breakthroughs. What's more, by that time all the tenured faculty positions in the field are already occupied. The proponents have grown older and less zealous, while the younger generation seeks something completely new and more likely to succeed.
He advises quantum computing researchers to follow the advice of IBM physicist Rolf Landauer. Decades ago Landauer warned quantum computing's proponents that they needed a disclaimer in all of their publications.
"This scheme, like all other schemes for quantum computation, relies on speculative technology, does not in its current form take into account all possible sources of noise, unreliability and manufacturing error, and probably will not work."
Quantum computing is simultaneously both possible and impossible.
I can't be the only one here that goes to look for a bug that vanishes when I am doing any kind of problem.
Now THAT is Quantum Computing.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
A useful quantum computer needs to process a set of continuous parameters that is larger than the number of subatomic particles in the observable universe
I thought that the whole point of quantum computers was that there's no need to describe or process all possible states. And that the difficulty of practical quantum computers is that the qubits need to "work together": you can't just make 1 cubit, then make 1023 more and build yourself a 1024 cubit computer.
The guy obviously knows way more about quantum computers than I do. But I've never seen the difficulties of quantum computing described in this manner.
If construction was anything like programming, an incorrectly fitted lock would bring down the entire building...
And has been for about 2 decades or so. Even if the physical universe supports it (and that is a big if, given the exactness required and the problem of noise), it may well be impossible to build a QC of meaningful size. It does look now very much that it is either infeasible or far, far in the future (i.e. >100 years and possibly much more).
And to all you attack dogs that cannot bear having your dreams criticized: I am not opposed to QC in any way. I just do not see it happening.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
The author makes a great point about the near impossibility of perfect, error-free quantum computation.
But this has been realized a few years back by most quantum algorithm developers, too.
Many recent algorithms assume that the quantum computation will be partially faulty.
And they work around it.
Yes, that makes these algorithms harder to design and they are less efficient compared to the ones assuming no errors, but they still seem to provide a way forward.
I would definitely not write off quantum computing yet.
We'll know when the wave equation collapses.
So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2**1,000, which is to say about 10**300. That's a very big number indeed. How big? It is much, much greater than the number of subatomic particles in the observable universe.
I am struggling to come up with some way that this part makes any sense at all. It sounds like the kind of thing someone who is definitely not an expert the area would say. He is expressing the number of possible configurations of 1,000 qubits but that is only something you care about if you are simulating a quantum computer with a classical one. The whole point of quantum computers is that you don't have to do that.
Also a simple counterexample to this sentiment is given later on, when mentioning that Google already has a 72-qubit computer. Just storing the states of a 72-qubit machine would be substantially more than the entire capacity of the internet, implying that since we somehow did it then enumerating all the states is not necessary.
No
pulls down blinds "We're closed, go home! No more quantum!"
Well, I guess we should just take their word. Just like when Wal-mart says it's doing a lot of good for local communities.
Well then. We just need to work out exactly how improbable it is, feed that figure into the finite improbability generator, give it a fresh cup of really hot tea . . . and turn it on!
I'm pretty sure that the CIA and friends would pay all of the money (*all of it*) to have a box that could crack public key encryption. How feasible is this? Is it on the horizon, or one of those things (like practical fusion) that always will be?
I think it is waste of time and money, with errors in quantum computing, this is like making an analogue computer to work.
We should focus of using the light as a signal with proper switches and keep the computers digital/binary.
I'll catch the bowl of petunias. You stand under the sperm whale.
Have gnu, will travel.
my clients/employers would ever have any kind access to/make use of. I don't know why any employee/contractor would accept that as a terms of employment
;)
As for implants for my defective eyes and/or other senses, computer interfacing, nervous system interfacing I would definitely consider it when it looks advantageous and useful.
But in reality I am probably to old (63) to get there.
Just my 2 cents
Perhaps writing the code in this way would help with the problem suggested in this article. Whats the name of that language again? lol
[($)]
If an elderly but distinguished scientist says that something is possible, he is almost certainly right; but if he says that it is impossible, he is very probably wrong. -- Arthus C. Clarke
Ha maybe in the future, but not likely in the way that has been predicted in the past. I could be wrong.
Quantum computing will be simultaneously possible in the future and impossible in the future.
1000 qubits have 2^1000 possible states, yes. That does not mean you need 2^1000 parameters to describe them. 1000 will do.
By the argument in this article, electronic computers with 1Kb of RAM are impossible.
Makes since, lots of money at stake and they only have ~5 years before quantum computers destroy their pump & dump campaign, gotta keep the suckers buying shitcoins.
It just comes down to Cost vs Benefit vs bragging rights e.g. Fusion power while there are cheaper energy sources it is no rush to make fusion power except bragging rights at the moment same goes with Quantum computing if the benefit could be defined as giving a nation a really good advantage it would have lots of money thrown at it which would then attract more people to work on it
Your'e all thinking it, I just said it for you
... i want to know when the Positronic Brain will be perfected!
The author makes a significant error which falsies his entire line of reasoning. The number of continuous variables in a 1000 qubit register is 2000, not 2^1000. Furthermore, the least technically difficult application of a qubit is to create an ALU operating on two qubit based registers. In that system the only entanglement is between the two electrons in a cubit, something that has been accomplished. The number of discrete states which can be held by each qubit depends on how noise free the system is, which is where much focus is at now. The advantage of this system over a conventional computer is that only a small number of qubits are needed to store the integer values of a 1000 bit conventional register. As a consequence, factorization of the large primes in a 1000 bit encryption key can be accomplished more efficiently. Presently, you need a BigNum like representation in conventional computers, which is primarily a software process. The real value of a qubit ALU is more aparent in factorization of the 2048 and 4096 bit keys of RSA or other public key encryption systems. The integer value represented by a 4096 bit key requires 64 registers on a 64-bit machine. Most 64 bit machines do not have 64 registers available for extended mathematical operations and so most of the work must be accomplished in software, and as a consequence it is very slow.
Pretty sure that that person was simply expressing his informed views of the current state of quantum computing and doesn't have some sort of evil agenda to prevent QC from ever becoming a thing.
WT actual F is going on in the comments section right now?! In the last few days I've had to raise my filter from -1 up to 1, and the quality of discussion is still basically trash. The apk impersonator spam in first doesn't help, but even that's just the tip of the iceberg.
If ever there were a potential application for quantum computing, I'd say that's it's in /. moderation!
Maybe I should actually log in for a change and accrue some mod points to tackle this.
is another AI winter? https://en.wikipedia.org/wiki/...
Great for getting all possible mil and gov funding.
Domestic spying is now "Benign Information Gathering"
Then a Quantum Blockchain Coin. Or Quantum VR. Or Quantum NOSQL databases. C'mon people, think out of your comfy Einstein inspired box! OK, not really. Fusion reactors. Self driving cars. Quantum computing. Sometimes the last 10% or 5% or 1% of development is where the rubber doesn't always meet the road and the whole thing, no matter how promising/life changing/world saving (pick any two) finally just doesn't work in the real world with real world requirements and expectations.
"Don't you understand English you arse, we're not at home!".
By his logic... my very first computer was an RCA VIP, it came with a whopping 2K of RAM. That's a measly 16384 bits - not counting internal registers, flags, etc.So to actually model all the possible internal states of just the RAM is 2^16384 which is roughly 10^500. I'm sure you know how the rest of the argument goes.
A thousand qubits is simply 1000 mutually interacting particles. You're not trying to represent every possible state (and as the possible states are infinite, you couldn't). His argument is complete nonsense and tells you nothing at all.
Quantum physics is always teasing us with almosts: almost instantaneous communication, almost energy out of nowhere, almost backward time travel, etc.
After all these teases, I'd bet on quantum computing having an inherent flaw nobody has discovered yet.
Schrodinger Lucy is holding the football again...
Table-ized A.I.
My pub is my home
And the other pub is my living room!
You insensitive clod!
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Quantum computer is more like a test tube than a computer. In the sense that the best way to find out how a chemical reaction will run is to do it in a test tube, instead of trying to simulate in on a classical computer. Quantum computer is just more generic than that and you can reduce wider range of problems down to quantum algorithms.
A writer of fiction's opinion on cutting edge scientist is as good as the scientist's fiction writing skills.
Expertise is non-transferable.
They gave up trying to make the Field Effect Transistor in the '30s until the right technology came along...
I think this article really overestimates the drive for quantum computing on a grand scale, and I don't think it was ever sold to use by the experts as something that we would actually see in "the foreseeable future". As such, that makes the author's premise disingenuous.
I always assumed we'd have optical computers long, LONG before a general-purpose quantum computer, and I don't think it's unreasonable to stand by that statement. That said, I don't think that warrants slowing down any resaerch towards quantum computers, no matter how daunting the scope.
Let's compare quantum computing to nuclear fusion: I doubt I'll see sustainable, controlled fusion in my lifetime. That doesn't negate the investment of billions upon billions of dollars into it, nor should it, but fusion's just as "foreseeable" as quantum computers.
To my understanding these are the core arguments of the article:
1) The feasibility of quantum computing is based on the assumption, that the effort (e.g. for error correction) scales with the number of qbits (in the example 1000), not the dimension of the superimposable state vector (2^1000). According to the author it is not yet proven that that is the case.
2) For a useful quantum computer it must be possible to manipulate qbits (with quantum gates) at will, i.e. move them around and "process" them like we do with classical bits in a classical computer nowadays.
3) In theoretical concepts of quantum computers perfect quantum gates are assumed, but quantum gates are physical devices. Rotating a spin by 90 deg might be achieved by applying a magnetic field of a given strength for a precise length of time. But in the physical world the precision of such manipulations is always finite, so maybe the result is somewhere between an 89 and 91 deg rotation and the axis might be slightly off too. Such imprecision might even occur when storing or transferring qbits (the information) in/between their physical storage. In lengthier calculations such errors add up, a bit like in analog computers. That would (severely?) limit the usefulness of quantum computers.
This is very unlike classical logical gates where anything above a certain voltage is interpreted as "1", anything below as "0" and logical gates consist of voltage controlled switches (transistors) in either "on" or "off" state that is clearly defined and leaves a wide error margin in terms of voltage.
To summarize: The physical world is far messier than the theoretical concepts of quantum computing and it has yet to be shown, that error correction mechanisms to control that "messiness" are feasible.
These problems are not new, and AFAIK there are theoretical as well as experimental efforts made to counter them. The article presents a very disillusioned view of the advances in that respect and suggests that it might be even impossible to overcome the problems. Sadly, instead of making the points by giving examples of the efforts and the advances or non-advances that were made, a lot of space in the article is simply wasted by pointless comparisons of the number of superimposable quantum states to the number of particles in the universe and the like. The question is not how big that number is but if it really represents the size of the obstacle/necessary effort on the way to quantum computing.
OTOH it should be noted, that even the theoretical concepts of quantum computing, i.e. quantum information theory, broadened our understanding of quantum mechanics. E.g. experiments on entangled states like EPR, delayed quantum eraser or "quantum teleportation" (which should really be named "quantum state teleportation") can be viewed from a new perspective.
"By the way if anyone here is in advertising or marketing... kill yourself." -- Bill Hicks
About time we heard some sense instead of constant cheerleading. Just because scientists and engineers say something is doable and should be done, it doesn't mean there is any reality to the thing. Let's hear more actual opposition based on real science and math to easy plans and projects . I'm sick of hearing breathless pie-in-the-sky schemes that are given the imprimatur of science and tech that are just manipulations for money, position, or fame.
E Proelio Veritas.
So it is not as easy as those ass hats in Personel implied. Get back to work.
QC may be impossible (we won't know if we don't try), but for sure not for the misconceived reasons stated in the OP.
* The point in QC is that to control 2^300 states you need to control 300 qubits, and for Quantum error correcting sequences
* People started to think about quantum error correction about 2 decades ago, and have come great lengths in reducing the overhead since then
* The big question is not if it is technologically feasible (would be in latest 20 years from now), but if highly entangled Quantum systems actually behave like we imagine they do (zero guarantee for that)
The ultimate consequence of this quote always seems to me that everything is very probably possible.
Maybe