What is the purpose of quantum computing?

Source please.

nevermind i figured it out

>being such a brainlet you need to be spoonfed

They will never replace normal desktop CPUs. They aren't meant to. They're specialty parts that can solve a very specific set of problems very quickly, when a conventional cpu would choke on them.

STOP THE PRESSES!!!!!!

QUANTUM COMPUTING IS DEAD!!!!!!

IT DOESN'T WORK!!!! (sic)

Quantum system simulations
people.eecs.berkeley.edu/~christos/classics/Feynman.pdf
Quatum system on traditional computing need 2^N bits to save N states making exponentially computing problem, Qubit means way encode quantum system using just N qubit for calculus.

smbc-comics.com/comic/the-talk-3

But Quantum computing don't means exponential fast general computing just tiny algortihms subset.

t.NSA

Quantum computing is actually quite subtle. A lot of people say that it doesn't work by doing every classical computation on every combination of inputs at the same time, by using a quantum superposition. But actually, this is precisely how some parts of quantum algorithms work. The catch is that just because you can compute a quantum state that "represents" the output of every possible classical computation, you can't necessarily do something useful with that. In particular there is no quantum measurement that will tell you "did any of these inputs lead to a 1 being computed".

You can 'store' extra information in the 'between' state that isn't available with conventional computing. This allows you to perform certain types of functions more efficiently. For example, in some cases were brute-forcing would be necessary, the quantum state allows you to avoid that.

This is a pretty good video, walks through an example of a quantum algorithm.
youtu.be/wUwZZaI5u0c

This is not true.

the way I understand it is that a quantum variable holds a probability distribution (pd) over all of its values instead of holding one concrete value. when you perform operations between them you are generating the pd of the output in a single operation (a classical algorithm would need to perform the operation for every possible assignment of the input variables and compute the output pd). at the end you collapse the pd and get a result that may or may not be what you're looking for. here is where quantum error correction, to maximize the chance that you get the output that you want. the idea of quantum algorithms is to compute a pd that has the highest probability for the answer you want to get.

this is where I got this explanation from: vimeo.com/180284417

>being a brainlet on an infinitely complex new topic
I'd say it's fair. So, no sources, right?

>>being such a brainlet you need to be spoonfed
"Yes your honor, that man over there stole my car"
"Where is your evidence, sir?"
"Being such a brainlet you need to be spoonfed"

Actually, the vectors do span it. It's called a Bloch sphere, look it up.

So, they surveil the shit out of everyone, collect everything ina database, quantum entanglement across space-time to the future, and they have foreknowledge of everything collected by the surveillance state in the future. It’s about knowing the future.

Quantum computers are slower for basic logic and faster for hard problems. For example, predicting an outcome based on tons of data will be faster, but doing math is slower. Public quantum computers still down have the "quantum advantage" but it's very likely the military/government already has that technology. Im not going to waste time on how it works since if you really wanted to know and had the prerequisite knowledge you'd have researched it instead of asking Jow Forums. Most people that write about quantum computers do not understand how they work. Watch some Feynman lectures, learn about computational theory, then when you grasp that stuff move on to quantum computing theory. There are different implementations, but they all use the same principles.

No news source explains quantum computing correctly because to actually understand it you need a good grasp of multiple advanced subjects. Most people are stuck on shit like the double slit experiment and how a transistor works, or they think Schrodinger's cat was meant literally rather than being a rough metaphor

OP here nvm I figured it out

It's impossible because quantum decoherence happens as soon as the qbit passes through a quantum logic gate

I has to do with extrapolation of quantized events to determine probabilities.

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>> What are quantum error correcting codes

smbc-comics.com/comic/the-talk-3

Fuck Jow Forums for not supporting the resolution of this comic

Lmfao

There is a thing called indirect information decoupling that doesn't result in state decoherence.

I don't think consumers will get their hands on qbits until photonic computation and cheap subatomic tools get mass produced.

This comic is one of the best introductions to why quantum computers are good imho.

Bloch sphere is just an illustration and visual tool, retard.

Lmao even python has an any() function. Quantards on suicide watch.

To cure homosexuality.

fuck she's cute

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>algorithms can create true random

>she's
huh

No. Just no. There is no "quantum" anything, this isn't poorly understood near magic effects of some mythical theoretical particle. This is simply electrons being so small they can move through any material at the path of least resistance, because nothing can exert 100% perfect electrical control over them. It is current leakage. It is nothing but current leakage. It is current leakage in short channel devices, and it happens at literally every feature size, it is not exclusive to small FinFET devices like upcoming 5nm EUV FinFETs. Even planar devices have extremely high degrees of leakage through their channels, directly under the gates, electrons still leak out. Yet despite this the transistors still function.

Quantum tunneling is a meme regurgitated by people who know nothing about the field of FETs.

The short story is, you can designs algorithms that can give you a solution to a problem with far fewer queries.
A classic but artificial example/problem is the Deutsch-Josza algorithm, that can give an answer to the eponymous problem with a single query.
Another classical but still a bit artificial example is Simon's algorithm.

But this speedup doesn't come for free. First of all, you have to find a clever way to come up with an algorithm that takes advantage of the interference effects (or mathematically, the properties of tensor products, orthonormal vectors and Hadamard+unitary transformations), to simply and cancel out many of the computations.
Without that crucial step, a quantum algorithm might as well be slower than a classical one.

And secondly, you have many restrictions when dealing with quantum algorithms. Like, you measured a string of qubits? Now they're gone, can't use them anymore for any further steps of your algorithms. So you can't do the traditional "if it's equal/greater to this value, then apply those rules/tranformations etc.". The philosophy is to find a way, through a steps of transformations, so a single measurement at the end will be enough to determine everything you wanted to.

Also, you want to clone a string? Like say, turn |0011> to |00110011>, for error correcting? Impossible. No "we don't know yet" but "we've proven it to be impossible, through the cloning theorem".

So, quantum computation is very subtle and has tons of limitations (apart from being probabilistic), and those limitations are just on the design level of the algorithms, not even considering the hardware yet.
So the only reason to work against these limitations, is if you found a very clever way, to exploit interference effects, and using those you end up reducing calculation complexity, *despite* the limitations of quantum algorithms.

I have an introductory (to people who haven't done CS but have maths background) text in quantum computing if you want.

Are you telling me that quantum computing isn't the second coming of the Christ and won't make my video games run better?
I am so disappointed, I was expecting a quantum accelerator expansion card in my rig within 10 years and in my phone 5 years later

A hoax.

Collapsing qubits into shortest pathways and thus decrypting everything almost instantly

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I'm saying we're in the stupidly early stages of quantum computing.
In classical computing terms, we're figuring what 0's and 1's do and how you can build AND, XOR, etc. gates. We're at this stage. Imagine how primitive that is compared to clever, modern optimisations like fast square root etc..

Great things will come, but not what people expect. On the upside, some things will turn up that people didn't even think about, so it's gonna be an interesting time.

Of course all that is dependent on actually being able to build the hardware, which is not a given at all.
Right now there's no way to test in practice some more advanced quantum algorithms by simulation, because current (classical) computer are capable of simulating at most 20-25 qubits, and the (processing) power requirement increases exponentially with the number of qubits simulated. Like, it's a physical impossibility to simulate, say, 100 qubits even using all the atoms in the universe to build a mega processor.
And current quantum hardware is also very limited.

In the end, a wholly new type of thinking has to be developed, and a new kind of intuition, to make quantum algorithms. And new hardware to test them.
Experience in classical software engineering could very well be a hindrance when developing for quantum. Because many things developers take for granted, are *impossible* to work. And many things could work, that developers would never think about, because it's a totally different line of thinking that cannot be used for classical algorithms.

I was attending a masters class, introduction to quantum computing, that was open to Maths, Physics and CS students. The people with CS background, would need more time to adjust, because they had some muscle memory doing things that are "forbidden" in quantum algorithms (like cloning bits, measuring/querying a value in the middle of the algorithm to determine further steps, etc.).

What about mathematicians?

based

Ah, thought I'll find this retard here.
lmao

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Very interesting, user. Could you please, share that text about quantum computing?

quantum computer will not work. why? in the quantum world things move around too much...

So is this pasta or what?

>What about mathematicians?
When asked about how to do overcome an unfamiliar obstacle, for half the people the first response would be something similar to the classical methods. But when explained why this can't be done, then they were quite less likely to do it again, since they don't have the muscle memory of the "wrong" method.
Also they're more comfortable working with transformations (unitary matrices mostly, since that's what you need for quantum), and probability distributions, expectations etc. .

>Very interesting, user. Could you please, share that text about quantum computing?
Sure.
>homepages.cwi.nl/~rdewolf/qcnotes.pdf
(Let me know if it's behind a sign-in wall).

There's also another PDF on quantum information theory. It's more theoretical (and mathematical) and examines what is possible with quantum algorithms, how information is preserved/lost etc., rather than specific concrete algorithms.

Quantum computers can "solve" some quantum mechanical systems in P time, which a classical computer might require NP time to solve. Implying that quantum computers enable us to solve some problems that otherwise might be considered impossible, possible. That's it.

Classical computers will shit on quantum computers in the domain of problems they can handle, but quantum computers might make some algorithms that was thought unfeasible, feasible.

Saved this pdf
would appreciate that another pdf too
Probably will fail to understand most of the things, but will certainly, try

>but the picture makes it look like |0> is -|1>
Because 2 state QM systems tend to be spin-up and spin-down systems :^)

in games like counterstrike, esp hacks will be impossible because player positions will be represented by qbits, meaning when the are obscured and not drawn on screen, they might be there and they might not be

youtube.com/watch?v=QuR969uMICM

UvA?

Nondeterminism. Learn what a finite state automaton is and you'll understand why that suddenly makes many algorithms feasible.

3pbp

So would it be wrong to think of it like a coprocessor for specific operations like an ALU vs an FPU?

They outperform classical computing in niche applications, typically regarding cryptography.

>They outperform classical computing in niche applications
Hello, time traveler

no, that's exactly what most people expect it to be

they change reality using hadron collider
and talk to demons using quantim computer

any digital computer can simulate a quantum computer. In quantum computing the state of each bit is not important. What is important is whether the bit holds any significance in any particlular state. The sum of possible states is unimportant what is being measured or captured is only significant states. Simple Example
10110010101 in quantum computers can also imply 01001101010 but what is important is whether either state is significant

how do u tell if its significant

I was expecting GCC, but same thing.

>No news source can tell me why.

Because all "journalists" are fucking retards with degrees in women's studies or sociology.

Read scientific papers, don't waste your time reading the news which is bullshit most of the time anyways.