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/sci/ - Science & Math

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6384379 No.6384379 [Reply] [Original]

Is quantum computing a promising field? or just a passing useless fad?

>> No.6384391

Bump for interest. There is so much bullshit about this out there. One expert says they have quantum computers now. Others say they don't really and wont' for a long time.

What the hell?

>> No.6384397

Bump for interest

>> No.6384533

Interesting as a theoretical exercise, nearly a waste of time as an experimental research.

>> No.6384544

>>6384391
>>6384379

Quantum Computing is real and promising but not for the reasons retarded pop-sci sites will tell you. Stop reading pop-sci, it is making you dumb.

There are problems out there that can be solved with classical computers and problems that cannot be solved with classical computers. Similarly there are problems that can be solved with quantum computers and problems that can't be solved with quantum computers. Where everyone seems to fuck up is in explaining that not every problem that can be solved with classical computers can be solved with quantum computers, similarly, not every problem that can be solved with quantum computers can be solved with classical computers.

Basically they're a new technology that won't replace the technology we currently have, but it will allow us to resolve some problems we couldn't resolve before. It will also make some problems easier to solve. We will probably only ever use them in combination with classical computers.

Furthermore, since there's no requirement on how big or powerful a quantum computer needs to be before it can be called a quantum computer then there's obviously some disagreement over whether or not "we" (consumers?, the industry? the military? research scientists?) "have" (as in they exist? as in we have full deployment? as in they're in our phones right now?) "them" (just some qubits? an entire machine?).

>> No.6384564

>>6384544

wat

>> No.6384566

>>6384379
It's a promising field but it's where computing was in world war II (actually it's behind that even). Right now qubits have decoherence problems and issues with coupling to other qubits/the environment that may alter the result a qubit gives. This is manageable with error correcting designs (like the surface code) but you need a bunch more qubits (2-10) to do one operation. Using the surface code you would need something like 40000 qubits to break AES-128 which isn't very feasible right now and would still probably take forever.

>> No.6384593

>>6384564
to summarize what he's saying, quantum computing might have some applications in things normal computers aren't good at.

But in contrast, normal computers have tasks that a quantum computer isn't good at, either.

>> No.6384608

Of course its promising. The potential to use a 3 bit system over a 2 bit would make processing so much more powerful

>> No.6384615

>>6384608
I... just... what? Weirdest b8 I've seen today.

>> No.6384614

>>6384608
This is not why it's promising. Stop being retarded.

>> No.6384623

>>6384614
>>6384615
so what reasons?

>>6384544
what are quantum computing problems? Preferably one that wouldnt be possible with classic computing

>> No.6384626

>>6384608
>The potential to use a 3 bit system over a 2 bit would make processing so much more powerful

You've got a couple things wrong here.

For one thing, a "bit" is like a decimal place, that can have a value of 0 or 1. If something is "two bits" that means it can be 00, 01, 10, or 11. And so on. It doesn't just mean binary.

Second, a quantum computer is not simply one that can have 0, 1, or 2. That would be a) pointless, and b) not require anything "quantum" about it. A quantum computer is one that uses qubits instead of bits, which can still only have two values, but it can also have a superposition of those values instead of a definite one or the other.

>> No.6384633

Isn't technically any statistical planning for multiple possible outcomes quantum computing?

>> No.6384638

>>6384626
>which can still only have two values, but it can also have a superposition of those values instead of a definite one or the other.
so in other words 3 positions. 1, 0, 1/0 which under perfect conditions you could have 3^n possible states rather than 2^n

>> No.6384645

>>6384638
>so in other words 3 positions.

No.

https://en.wikipedia.org/wiki/Qubit

>> No.6384658

>>6384623
not him, but shor's algorithm to find prime factors.

>> No.6384670

>>6384379
Quantum Computers: yes
Quantum Engineering: yes
Quantum Computing: no

>> No.6384680

>>6384379
Even if we are unable to produce large scale quantum computers like the kind needed to obsolete RSA, what we learn in the process of trying to do so will be more than worth it.

>> No.6384682
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6384682

>>6384615
Probably not b8. CS majors have this weird idea that 3bit computers would be magical and a massive paradigm shift.

>> No.6384767

>>6384682
It's not their fault. America does not want people to have 256-bit computers because that shit would be too hard to decode.

So, they want people to believe that multiple cores are better than greater power.

>> No.6384799

bump

>> No.6384868

TIME is super sensationalist

>> No.6384886

>>6384868
TIME is JEWS.

Fixed for truth.

>> No.6384996

>>6384544
This was remarkable uninformative. I'd do better reading pop-sci

>> No.6385023

>>6384544

This. If we (home consumers) see anything out of quantum computing, I imagine it would be a board you can integrate into a normal PC which handles the "quantum tasks", ie those which benefit from quantum parallelism.

The general speedup of quantum computing is due to Grover's algorithm, which guarantees a brute force search through some input space of size n will take sqrt(n) time, as opposed to n in classical computing. Time will tell if this will be important enough of a speedup to warrant a quantum system in every home, or if people will opt for quantum systems based on their computing needs.

>> No.6385094

Jesus Crisco people, do these things exist or not? And if they do, to what extent?

I swear 99% of what I read sounds like the same vaporware nonsense from Blacklight Power and other crackpottery

>> No.6385127

quantum computer are not even promising right now because quantum mechanics are too hard, even now.

the amount of math is just so enormous compared to other fields, it's a huge barrier of entry.

The mass of people doing math is just not big enough, and I think that's the first reason. Doing experience with quantum is very expensive too, so it's even harder.

>> No.6385155
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6385155

>>6384379
>nobody knows how it actually works

>> No.6385181

>>6385094
The DWave machine is a form of quantum computer, it is just not a complete quantum computer as it can't, for example, implement Shor's algorithm. As for more...complete schemes, we have managed to link several qubits and get them to factor some numbers. When last I had heard, IBM held the record with a quantum computer finding all the factors of 15. So, quantum computers exist "right now" in that there are machines that do quantum computations, but they do not yet exist in a useful way [though the DWave is good for search type stuff and the travelling salesman IIRC].

>> No.6385588

>>6385181
Is the debate about DWave over? Experts were pretty skeptical before. Has that changed?

>> No.6385594

>>6385127
It's just fucking group theory. Stop being a babby.

>> No.6385617

>>6384379
>quantum computing
>>>/x/

>> No.6385621

>>6384379
It's sensationalist bullshit.

>> No.6385632

could these in theory basically brute force most passwords/security mechanisms

>> No.6385673

>>6384638

No. This is incorrect. So many people think this is correct, did you all watch the same (wrong) youtube video or something??

A Quibit (through quantum superposition) can be expressed as a linear combination of two classical states:

For classical states [0] and [1], one quibit is:

a[0] + b[1] where a,b are in R

A two qubit system can be expressed as:

a[00] + b[10] + c[01] + d[11]

as you can see, a single qubit contains 2 pieces of information (a & b) and a two qubit system contains 4 pieces of information (a & b & c & d). Whereas a single (classical) bit system contains 1 piece of information and a two bit system contains 2 pieces of information.

So for N qubits, you have 2^N pieces of information.

Whereas for classical bits, N bits have N pieces of information.

So if you have a 64 qubit systems, suddenly you can manipulate 2^64 = 1.84 x10^19 pieces of information. Pretty neat huh.

>> No.6385686

>>6385632

Yes, see http://en.wikipedia.org/wiki/Shors_algorithm

Shors algorithm allows integer factorisation to be completed far more quickly with a quantum system. Hence, asymmetric key encryption becomes a lot easier to brute force.

>> No.6385710
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6385710

>>6385621

>> No.6385738

>>6384996

read this >>6385673 buttmuncher.

>> No.6385741

Here's a bunch of quantum computing videos for people interested in how qubits and the logic gates work.

http://michaelnielsen.org/blog/quantum-computing-for-the-determined/

>> No.6385752
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6385752

>>6384533
>>6384564
>>6384608
>>6384638
>>6385094
>>6384886
>>6385127
>>6385617
>>6385621

>mfw /sci/ is this casual

>> No.6385754

>>6385673

Good post, thanks for not being retarded.

>> No.6385761

>>6385752
Oh, Mike. Saddest scene ever.

>> No.6385775

>>6385761

>complains about casuals
>attracts attention of casuals

;_;

>> No.6385815

>>6385741
>http://michaelnielsen.org/blog/quantum-computing-for-the-determined/

Wow! Thanks for the link anon!

>> No.6385852
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6385852

>>6385155

>> No.6385909

>>6385752
Are you me? Shit like this is why I dont go on /sci/ very often. There is a big difference between 3 possible states and superposition of two states exponented by the number of qbits (which can basically be any number of qbits if you build a large enough quantum computer)

I dont even know if exponented is a word

>> No.6385932

>>6385909

I have heard that "quantum computers have 3 states instead of two" so many times. Do all these guys watch discovery channel and then come post on /sci/. So many casuals it's unbelieveable.

>> No.6385936
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6385936

>>6384608

>3 bit system over 2 bit system

So does that make Windows 64bit super-quantum? Come on son...

>> No.6386050

>>6384379
I don't see quantum computing ever being needed for personal home computers. No average computer user does anything interesting enough to require a computer that can do calculations that quickly. I would say quantum computing is purely for scientific/computing research, where it would save time on long winded calculations.

>> No.6387199

>>6386050
>who will ever need more than 20 GB of hard disk space, 256 MB of RAM, or anything more than a single core CPU running at 900 MHz?

I mean, you're pretty much right for the time being. But wait until porn comes out for the RealSim7 (now with more realistic saliva).

>> No.6387236

How can Boolean logic be real if the Berry phase of our bits isnt real?

>> No.6387244

>>6387236


in other words:


completely redesign the logic gate for ternary logic.
no.
casuals ask a similar question for why we dont use superconductors to make computer chips, with the answer being that transistors fundamentally depend on the physics of semiconductors and there is no such thing as a superconducting FET.

there are alternative ways of performing logic with superconductors, but none of them are as compact or high performance as traditional semiconductor based logic gates composed of transistors.

>> No.6387376

>>6385127
>>quantum mechanics are too hard
>>the amount of math is just so enormous compared to other fields, it's a huge barrier of entry
>>The mass of people doing math is just not big enough

And CS majors ask why we hate them