>...6502 microprocessor from 1975. Since this processor uses transistors, and transistors work by using quantum effects, a 6502 is as much a quantum device as is a D-Wave “quantum computer”.
I'm not sure that is true in the way it is intended. The NMOS transistors used in the 6502 were quite large and worked on the basis of electrostatic charges ... as opposed to bipolar transistors that are inherently quantum in operation.
Of course it is now understood that everything that does anything is at some level dependent on quantum effects. That would include the dog...
jfengel 8 minutes ago [-]
The intention is to say that the D-Wave isn't a quantum computer at all. The comparison isn't quite literally true, but it's definitely the case that what D-Wave does is very different from the general purpose qubits that we mean when we say "quantum computer".
Arcorann 8 hours ago [-]
Somewhat related is the work done in "Falling with Style: Factoring up to 255 “with” a Quantum Computer" published in the proceedings of SIGBOVIK 2025 [1]. The author, Craig Gidney [2], successfully factored all odd composite numbers up to 255 using Shor's algorithm, even though the quantum circuits involved were such that any meaningful output would be overwhelmed by noise (and indeed, performance was maintained when the circuits were replaced by a random number generator).
> To my knowledge, no one has cheated at factoring in this way before. Given the shenanigans pulled by past factoring experiments, that’s remarkable.
[2] Who has previous experience in cheating at quantum factoring: see "Factoring the largest number ever with a quantum computer", posted April Fools' Day 2020 at https://algassert.com/post/2000
wasabi991011 3 hours ago [-]
God, I've heard Gidney's name so many times in the QC conference I'm attending, and in my research the last few months.
I really hope he eventually gets the recognition he deserves, outside of just experts in the field.
qualeed 11 hours ago [-]
I remember Peter Gutmann posting about this on the metzdowd cryptography mailing list in March. Fun to see this a few months later.
"Just as a thought experiment, what's the most gutless device that could
perform this "factorisation"? There's an isqrt() implementation that uses
three temporaries so you could possibly do the square root part on a ZX81, but
with 1k of RAM I don't think you can do the verification of the guess unless
you can maybe swap the values out to tape and load new code for the multiply
part. A VIC20 with 4k RAM should be able to do it... is there a programmable
calculator that does arbitrary-precision maths? A quick google just turns up
a lot of apps that do it but not much on physical devices.
Peter."
remcob 10 hours ago [-]
You can verify in limited memory by repeatedly verifying modulo a few small integers. If that works, then by Chinese remainder theorem the main result also holds.
tromp 10 hours ago [-]
> In the Callas Normal Form, the factors are integers p = 2^{n-1}
and q = 2^{m+1}, where n ≤ m, and p and q are ideally prime, but don’t have to be.
The paper's formatting clearly went wrong here, as it should have read p = 2^n - 1 and q = 2^m + 1.
The "Proposed Quantum Factorisation Evaluation Criteria" are excellent, but for measuring progress, the required minimum factor size of 64 bits is too large. A good milestone would be a quantum circuit that can factor the product of any pair of 5-bit primes {17,19,23,29,31}.
adgjlsfhk1 12 minutes ago [-]
I think 8 bit primes is probably a better minimum. 5 bits is still small enough that randomly choosing a 5 bit factor will succeed 40% of the time.
wasabi991011 11 hours ago [-]
Yeah there's a reason that the quantum computing field has moved away from attempting factorisations. Not that there's not still hype and misleading claims being punished, but the hardware has improved a ton since 2001 and ever closer to actual useful quantum computation (such as large size quantum chemistry calculations).
thrance 5 hours ago [-]
Are those useful computations in the room with us right now? No, but seriously, I feel like factorization is the one application that could justify those massive investments QC is receiving (even though it would probably make the world strictly worse...).
All those other applications, no matter how neat, I feel are quite niche. Like, "simulate pairs of electrons in the Ising model". Cool. Is that a multi-billion dollars industry though?
rgbforge 4 hours ago [-]
If results from methods with higher electronic structure accuracy than DFT (MP2, couple cluster) can be made cheap enough, it would hugely disrupt industrial chemistry, medical experimentation, pharmaceuticals, the energy sector, etc.
wasabi991011 3 hours ago [-]
Ground state and activation energy estimation for chemistry would be really useful. I know chemists are looking specifically at nitrogen fixation as one useful example.
Or as another example, I'm currently at a conference listening to a PhD student's research on biomolecular structure prediction (for protein design).
DoctorOetker 2 hours ago [-]
Energy levels and activation energies can be acquired much more simply from Fourier Transform - Ion Cyclotron Resonance - Mass Spectroscopy...
Its a device that makes and analyzes at the same time, check out this primer:
Factorization could have number theory implications I suppose. Using quantum effects to break cryptography wouldn't have any real long term advantages unless you aspired to be some sort of a supervillain.
LeftHandPath 2 hours ago [-]
> Using quantum effects to break cryptography wouldn't have any real long term advantages unless you aspired to be some sort of a supervillain.
It's of interest to governments, for national security reasons. Quantum computing is an arms race.
fcpguru 14 hours ago [-]
this was great. I had no idea quantum factorisation was cooking their books!
The dog is funny but it just means, pick actually "random" numbers from a bigger range than the staged phony numbers quantum factorisation uses.
jojobas 11 hours ago [-]
>We use the UK form “factorise” here in place of the US variants “factorize” or “factor” in order to avoid the 40% tariff on the US term
Brilliant.
3 hours ago [-]
neuroelectron 11 hours ago [-]
This is probably one of the first academic papers I've ever read completely from beginning to end in one go.
Rendered at 16:38:35 GMT+0000 (Coordinated Universal Time) with Vercel.
I'm not sure that is true in the way it is intended. The NMOS transistors used in the 6502 were quite large and worked on the basis of electrostatic charges ... as opposed to bipolar transistors that are inherently quantum in operation.
Of course it is now understood that everything that does anything is at some level dependent on quantum effects. That would include the dog...
> To my knowledge, no one has cheated at factoring in this way before. Given the shenanigans pulled by past factoring experiments, that’s remarkable.
[1] https://sigbovik.org/2025/; standalone paper is also available in the code repository https://github.com/strilanc/falling-with-style
[2] Who has previous experience in cheating at quantum factoring: see "Factoring the largest number ever with a quantum computer", posted April Fools' Day 2020 at https://algassert.com/post/2000
I really hope he eventually gets the recognition he deserves, outside of just experts in the field.
It starts here: https://www.metzdowd.com/pipermail/cryptography/2025-Februar...
This part is from farther down thread:
"Just as a thought experiment, what's the most gutless device that could perform this "factorisation"? There's an isqrt() implementation that uses three temporaries so you could possibly do the square root part on a ZX81, but with 1k of RAM I don't think you can do the verification of the guess unless you can maybe swap the values out to tape and load new code for the multiply part. A VIC20 with 4k RAM should be able to do it... is there a programmable calculator that does arbitrary-precision maths? A quick google just turns up a lot of apps that do it but not much on physical devices.
Peter."
The paper's formatting clearly went wrong here, as it should have read p = 2^n - 1 and q = 2^m + 1.
The "Proposed Quantum Factorisation Evaluation Criteria" are excellent, but for measuring progress, the required minimum factor size of 64 bits is too large. A good milestone would be a quantum circuit that can factor the product of any pair of 5-bit primes {17,19,23,29,31}.
All those other applications, no matter how neat, I feel are quite niche. Like, "simulate pairs of electrons in the Ising model". Cool. Is that a multi-billion dollars industry though?
Or as another example, I'm currently at a conference listening to a PhD student's research on biomolecular structure prediction (for protein design).
Its a device that makes and analyzes at the same time, check out this primer:
https://warwick.ac.uk/fac/sci/chemistry/research/oconnor/oco...
It's of interest to governments, for national security reasons. Quantum computing is an arms race.
The dog is funny but it just means, pick actually "random" numbers from a bigger range than the staged phony numbers quantum factorisation uses.
Brilliant.