Trying to get my head round quantum computers

rubberduck · 27 Mar 2018 at 10:12

Have watched some youtube vids etc on this and think I get the general gist that the superposition state of qubits gives the computer the opportunity to exist in an exponetially increasing number of states simultaneously as more qubits are added. Conversely, a conventional computer can only exist in one state at once but it can obviously cycle through states incredibly quickly (number crunching). What I do not understand is how you use use these superposition states in a beneficial way in terms of an algorithm to solve the optimisation and modelling problems that quantum computers are supposed to be able to tackle. Can someone explain it in as simple terms as possible?

rubberduck · 27 Mar 2018 at 11:00

So post #2 is a superposition of trolling and serious answer? Thanks cupcake!

Edit - upon inspecting the quantum field state of post 2 it's wavefunction collapsed and upon analysis of the corresponding eigenvectors I determined it was troll.

/reported

rubberduck · 27 Mar 2018 at 19:28

QlimaxUK said:
The question everyone want to know.. when will these be ready for the domestic market?

now I know these things are big, complex and require crazy low cooling to work at all so will be a long long way off so are we talking 20 30 40+ years.. or never? make your predictions now!

I don't think you would actually want one, even if they could be prodced to a point where they could be purchased by the end user. The cost of the cooling would be prohibitively expensive but furthermore they just wouldnt be able to run applications or games - and even if they could they would be slower than a conventional computer. They are only useful for solving specific problems where conventional number crunching is ridiculously inefficient to the point of almost requiring infinite computational power. Outside of these specific problems they would fail badly. I doubt if they could even run Crysis maxed.

rubberduck · 27 Mar 2018 at 22:46

So how do you write code for a quantum computer then?

rubberduck · 28 Mar 2018 at 22:50

Hello, thanks for the input. It seems "Grover's Algorithm" is what I was after to better understand quantum computers - plenty of youtube videos out there ranging in quality.

Out of interest. Can you overclock a quantum computer? I would assume yes but wanted to check.

rubberduck · 28 Mar 2018 at 23:07

Rroff said:
I don't think you understand how it would work.

Well it still needs to execute operations and thus I would assume that there can be variability in speed of operation based on the architecture of the quantum computer. After all, the resolution of the wave function is not the limiting step in speed as I believe this happens essentially instantaneously.... Even at a distance as per Eistein's famous EPR paper which tried to discount such a principle but was later discredited by Bell's inequality through theory initially and more recently multiple experiments to discount the 'hidden information' theory favoured by Einstein et al.

So the question remains, can you overclock a quantum computer, please explain your answer and rationale.

rubberduck · 7 Apr 2018 at 21:26

Hello again. I have been trying to dig in to (watch youtube videos on) Pilot wave theory / Bohmian mechanics. While I get the basic principle (or at least I think I do) I do not understand how this theory explains how the interference pattern from the double slit experiment disappears should a detection device be place after the slits. Surely the whole pilot wave cannot collapse can it? And if so is it really that much different from Copenhagen interpretation?

rubberduck · 24 Apr 2018 at 21:37

Hello again... In my efforts to expand my brain I stumbled on a youtube channel called 'PBS Space Time'... It is fantastic for the armchair physicist... I need to watch some videos multiple times, do background reading and even then dont 100% understand but there are some great videos on there.

rubberduck · 24 Apr 2018 at 21:54

itchy said:
Its easy its basic computational maths.

The is 1 and 0 with quantum computing the is a 3rd bit 0 and 1 combined so the is 3 bits as opposed to 2 bits.

3 bits don't go into 10 so binary base 10 goes a bit wobbly that's all it is, I can understand how its hard to comprehend but you need to look at the bigger picture.

You are wrong... I used to think that way but it is not as simple as computers being able to switch to base 3 number processing as opposed to binary... It is more than that in terms of problem solving.

rubberduck · 24 Apr 2018 at 23:15

No, I don't think that is right m8.