dont you think

I can barely do regular computing, that sounds terrifying.

im writing a page-long essay about it now and my head is exploding

My discrete math class nearly got our professor to drop the lecture he was giving us and tell us how a quantum computer works.

had a lecture on it last week for my Origins of Computer Science class. pretty interesting stuff

I have trouble wrapping my head around the qubit. On or off I get, but 4 states?

Basically, classical computers represent data as bits, which can either be 1 or 0. In quantum computers, we use qubits, which can be both 1 and 0 simultaneously. The problem quantum computing faces is that if a system is disrupted by the "outside world", it loses its quantumness, and as computers kinda require interaction with the outside world, that makes it difficult to build a quantum computer.

Quote from: Fedorekd™ on December 01, 2015, 01:48:20 PM

Quote from: MyNameIsCharlie on December 01, 2015, 01:43:31 PM

I have trouble wrapping my head around the qubit. On or off I get, but 4 states?

Basically, classical computers represent data as bits, which can either be 1 or 0. In quantum computers, we use qubits, which can be both 1 and 0 simultaneously. The problem quantum computing faces is that if a system is disrupted by the "outside world", it loses its quantumness, and as computers kinda require interaction with the outside world, that makes it difficult to build a quantum computer.

Yeah, I get it uses the 4 state qubit, I just don't see what we could do with it. Like a guy sitting on a horse in the old west contemplating low Earth orbit satellites.

As far as the whole quantum gobblygook goes... I'll take your word for it

well ive heard it can be useful for encrypting information and making it leagues harder to crack, but i dont know about that fully

NEEERRRRDDDDDD

Quote from: MyNameIsCharlie on December 01, 2015, 01:52:47 PM

Quote from: Fedorekd™ on December 01, 2015, 01:48:20 PM

Quote from: MyNameIsCharlie on December 01, 2015, 01:43:31 PM

I have trouble wrapping my head around the qubit. On or off I get, but 4 states?

Basically, classical computers represent data as bits, which can either be 1 or 0. In quantum computers, we use qubits, which can be both 1 and 0 simultaneously. The problem quantum computing faces is that if a system is disrupted by the "outside world", it loses its quantumness, and as computers kinda require interaction with the outside world, that makes it difficult to build a quantum computer.

Yeah, I get it uses the 4 state qubit, I just don't see what we could do with it. Like a guy sitting on a horse in the old west contemplating low Earth orbit satellites.

As far as the whole quantum gobblygook goes... I'll take your word for it

Quantum computers can solve problems faster than classical supercomputers. Quantum computers would be really useful in medicine to analyse proteins and shit so we can make better medicines. Also quantum computing has use in weather forecasting to make super accurate predictions and also artificial intelligence.
A potential problem with it is that the current method of encryption we use for electronic services would be rendered useless against quantum computers. So we need to develop some new encryption algorithms that are secure against quantum computers.

So, how does the 0 and 1 simultaneously thing make it able to process information quicker?

Quote from: Fedorekd™ on December 01, 2015, 01:58:32 PM

Quote from: MyNameIsCharlie on December 01, 2015, 01:52:47 PM

Quote from: Fedorekd™ on December 01, 2015, 01:48:20 PM

Quote from: MyNameIsCharlie on December 01, 2015, 01:43:31 PM

I have trouble wrapping my head around the qubit. On or off I get, but 4 states?

Basically, classical computers represent data as bits, which can either be 1 or 0. In quantum computers, we use qubits, which can be both 1 and 0 simultaneously. The problem quantum computing faces is that if a system is disrupted by the "outside world", it loses its quantumness, and as computers kinda require interaction with the outside world, that makes it difficult to build a quantum computer.

Yeah, I get it uses the 4 state qubit, I just don't see what we could do with it. Like a guy sitting on a horse in the old west contemplating low Earth orbit satellites.

As far as the whole quantum gobblygook goes... I'll take your word for it

Quantum computers can solve problems faster than classical supercomputers. Quantum computers would be really useful in medicine to analyse proteins and shit so we can make better medicines. Also quantum computing has use in weather forecasting to make super accurate predictions and also artificial intelligence.
A potential problem with it is that the current method of encryption we use for electronic services would be rendered useless against quantum computers. So we need to develop some new encryption algorithms that are secure against quantum computers.

So, how does the 0 and 1 simultaneously thing make it able to process information quicker?

Okay... I'll attempt to explain this.

Due to the nature of classical computers, they can only do one thing at a time. If I have a complex problem requiring millions of different equations to solve, it's going to take a while as bits can only be in one state at a time.

With a quantum computer of n qubits, however, I can have 2^n states, and so quantum computers can answer far more questions at a time, and so I can solve the problem using less operations.

Kinda iffy explanation but the actual how of it all is what computer scientists are trying to figure it out.

my head hurts

but muh ones


muh zeros

I'm wrapping up a graduate course on it this semester!

They're not an end-all solution and they actually perform worse in some use cases then classical computers do, but the algorithms used are almost magical they're so unlike those used in classical computing.

When it comes to qubits, a single qubit does NOT store one of four potential states. It only technically represents two states, the usual 0 and 1 (using Dirac/bra-ket notation, |0> and |1>), but the ability to put a qubit in a superposition is where the whole "both" thing comes from, which I personally find misleading. Basically, many quantum algorithms designed around gate computers start off with a Hadamard transformation which sets a qubit or set of qubits in an equal weighted superposition between |0> and |1>. At that point, if you measure any of them there's a 50/50 chance of getting either result. After they are superimposed, you can perform a function you are interested in/other operations on them and it effectively is equivalent to performing that operation on all the possible values that those qubits can occupy at once. Well, until you measure them. But that massive parallelization is where the power lies.

Most of the notable algorithms don't go straight for an answer in a usual computational sense. Usually they exploit relationships between the outcomes. It's pretty weird, half the time the answer you're looking for is produced in the input register rather than the output register.

It's so complicated though, I couldn't adequately express it in layman's terms if I tried. And that's in spite of the fact that the math is really pretty simple; you really only need basic calculus and linear algebra for the early quantum algorithms (i.e. up to the 1990s and 2000s). Check out Deutsch's, Simon's, Shor's, and Grover's problems/algorithms if you want real examples.