cohomologo

Note this is version 2 of the Arxiv posting. The first version claims a proof of Collatz, which appears to be effectively withdrawn by the update.

Physicist here:

Just gave it a cursory look, but looks like crank nonsense to me. The paper makes no effort to give any context on what an informaton at a level that physicists would understand.

True, but as someone who works on quantum physics using classical computers and loves to see classical computers simulating increasingly hard quantum problems, these "crushings" were still only done on classical computers in a way that would scale exponentially with the number of qubits.

Even then, I believe the classical simulations to beat google's 53 qubit device were never actually performed -- it was shown that they could be performed quickly with petascale memory but actually doing it would be a huge expense. Add a dozen more qubits and even the hypothetical classical challengers fall off quickly...

I research QC. Feel free to explain how my skills could be used to meaningfully contribute to the problem of world hunger or renewable energy while also keeping me employed --- going back to college to train in a different field isn't feasible. If it's not so easy, then perhaps it's logical that QC researchers and AI researchers and software devs aren't all jumping ship to work on "more important topics"...

You may just be spouting off, but I genuinely am asking. If someone else dissing QC research wants to make a pitch for a concrete plan on how to make a difference in the world with a physics PhD and years of experience in scientific computing, drop me a message.

No, but the quantum groups are making progress towards essentially making 1 logical qubit -- a common scheme uses a square grid of physical qubits, say with size 7x7, 8x8, 9x9, etc.. as a single logical qubit. This may seem like a moving target, but it is not. There is a specific, concrete error rate on the physical qubits, below which it is known that the logical qubits on increasingly large grids get _exponentially_ more accurate. Once the engineering achieves that noise level, logical qubits in the form of NxN grids where N~10-20 will ~eventually~ follow. I won't venture to predict how long, as building and controlling these grids of qubits while keeping the error rate low isn't easy. Could be years or decades.

In my experience in QC, I've yet to see many grifters. In fact, many of the people in quantum computing are quite open about the fact that we aren't that close to "useful" quantum computing, that the number of practical problems that quantum computers will beat classical computers with could be quite small, and are actively worried about over-hyping. People selling today's QCs as a solver for generic optimization problems are indeed grifting, but that is not most of the community.

Despite all these problems, myself and much of the community still think QC is worth attempting --- for my part, the applications to quantum physics is the main motivation, and one in which it's relatively certain that QC will not "become obsolete". (It's also still perfectly valid to _research_ how to make QC useful in various types of classical problems, including optimization, and it's plausible that progress _could_ be made that would open up more widespread uses of QC. The line, for me, is when people misrepresent the likelihood of success of that research.)

As far as I understand it, either two incommensurate frequencies or the Fibonacci sequence ABAAB… approach produce similar physics. The Fibonacci sequence is easier to simulate numerically on a (classical) computer because there is a recursive property to it that allows you to jump forward in time in large steps, making it nice for theorists even if the experiments are fairly similar.

I got lucky with 5 as well:

ADIEU BLAST MANOR FANNY CANNA

⬜⬜⬜⬜ ⬜⬜⬜⬜ ⬜⬜⬜ ⬜⬜

With double exponential growth, “it looks like nothing is happening, nothing is happening, and then whoops, suddenly you’re in a different world,” Neven said.

This is just a clever way to spin the fact that we are experiencing growth much slower than exponential growth now into a prediction of much faster future growth, without any evidence. Or perhaps an internal joke the physicists would make. Next time I have a really flat function, I'm going to fit it with a triple exponential like so:

  https://www.wolframalpha.com/input/?i=plot+exp(exp(exp(x))),+x%3D-20..-5,+y%3D0..5

From the ARCH foundation FAQ:

Beyond the laser based digital layer there may also be layers that require the ability to detect and decode molecular, atomic scale or subatomic scale (quantum or holographic) information. We can already encode data in this way, but reading it requires very advanced technology.

They seem so clueless that even if I bought into the underlying mission of preserving data by sending it into space, I wouldn't trust this group to do it.

I think you've got that last part backwards. When you have constituents with binding energy, that reduces the total energy of the system and reduces the mass. So it seems that the mass of the proton is quark mass + gluon kinetic energy - bonding energy, and most of the mass comes from gluon kinetic energy.

It's pretty easy. If your computer has enough ram to store a size 2^16 length complex vector (which is 2^20 bytes, or 1MB) than you can open up an ipython notebook and write code to apply quantum gates to it with no problem.

The problems start to set in if your RAM can't hold the wavefunction in memory (so around 28 qubits, which takes 2^32 bytes = 4GB of RAM.)

With specialized code and supercomputers you can get a little farther, but you will be fighting exponential growth, so not too much. The practical limit for classical computers is in the 40-50 qubit range.

I think it's more like a 6 bit number, and probably not very fast at all...

The Google group in Santa Barbara is building to a 49-qubit computer. If I understand correctly, it'll be interesting for understanding how you calibrate your quantum machine and validate that it is doing what it is supposed to. The algorithms they run on classical computers to validate that device will need a decent amount of supercomputer time. And much bigger devices would be impossible to validate with a classical computer in the same way, so in some sense you hit "the limit" of classical computation and start to move beyond.

But for the computational problems that are useful for applications, which are not very much like the problem they use for validation, 49 qubits is still far far away from beating a classical computer.