Understanding Quantum Computers: A Beginner's Guide

[jhus96]

I'm new to physics and absolutely love it so far. I've always loved theoretical physics and the like, so, I've also heard about a thing called quantum computers. What are these? How do they work? Why are they so special and different from past computing processes? (I've just began learning classical physics so try to dumb down quantum terminology if possible, if not, don't worry about it I have google)

 

[phinds]

I'm new to physics and absolutely love it so far. I've always loved theoretical physics and the like, so, I've also heard about a thing called quantum computers. What are these? How do they work? Why are they so special and different from past computing processes? (I've just began learning classical physics so try to dumb down quantum terminology if possible, if not, don't worry about it I have google)

Have you done any research on this? Something as simple as a Google search will give you a wealth of information.

 

[jhus96]

I thought it would be easier to ask here first to get a rough idea. I've watched a show on it but it is confusing.

 

[phinds]

Well, I'm sure one of our members will might be willing to give you a tutorial on quantum computers but the forum works best if you have a more specific question.

 

[jhus96]

Ok, thanks, if you couldn't already tell I'm new so I'll do a little research as you suggest and come back with any questions.

 

[Strilanc]

Quantum Computing for the Determined (youtube video series by a co-author of the de-facto standard textbook in quantum computing)

Quantum Computing Since Democritus (scroll to the bottom for the lecture notes, which are more like dialogues than notes)

 

[glaucousNoise]

i would be curious to learn more too, quantum computers seem vaporware-ish ala graphene applications or confinement fusion, is there any hope that this isn't the case?

 

[Strilanc]

i would be curious to learn more too, quantum computers seem vaporware-ish ala graphene applications or confinement fusion, is there any hope that this isn't the case?

Timelines are on the order of 10-20 years for anything really practical. Noticeable progress is happening year by year. Parts of error correcting strategies are being demonstrated. Qubit reliabilities are going up. It doesn't seem like there's anything fundamental in the way, just the hard engineering slog. UCSB is hoping to double the number of qubits every year. But the really useful computational stuff requires millions of qubits to beat existing supercomputers, so it might be awhile before we feel the effect.

I guess if the reliability got really high then they might be an interesting experimental tool even with a few dozen qubits. Maybe you could use them to beat bell tests, crush quantum teleportation records, create photons in interesting entangled states, perform measurements in a strange basis, etc.

 

[glaucousNoise]

how many qubits can be coordinated currently? can you describe some of the current hurdles or point to a nice review? fusion has been 10-20 years around the corner for 60+ years now so I'm a bit skeptical

 

[Strilanc]

It depends a lot on the type of qubit. Some are more stable, some have faster operations, some are bad now but theoretically could be better in the future, etc. I think the frontrunners right now are ion traps and superconducting qubits. Ion traps can hold more qubits at the moment (tens?) and take longer to decohere, but superconducting qubits fit well with existing semiconductor manufacturing capabilities and operate faster.

But I'm really talking outside of what I know at this point. All the above is basically third-hand and half-remembered instead of something I really know about. Watch the google quantum computing tech talks and you'll know about as much as I do about the state of the research.

 

[DennisN]

I'm new to physics and absolutely love it so far. I've always loved theoretical physics and the like, so, I've also heard about a thing called quantum computers. What are these? How do they work? Why are they so special and different from past computing processes? (I've just began learning classical physics so try to dumb down quantum terminology if possible, if not, don't worry about it I have google)

Hi jhus96, and welcome to PF!
I posted this clip in another thread on this forum some time ago. It is an informative and entertaining part of a lecture, which includes some quantum mechanics/experiments/applications, maybe it is of interest to you...
"Anton Zeilinger - Quantum Information and Entanglement"


The entire lecture is here.

EDIT:
By the way, since you said

(I've just began learning classical physics so try to dumb down quantum terminology if possible...)

I'd like to say that the clip I posted above may seem challenging and weird to you (in fact I expect it to be ), but you may find it interesting nevertheless .

 

[Heinera]

how many qubits can be coordinated currently? can you describe some of the current hurdles or point to a nice review? fusion has been 10-20 years around the corner for 60+ years now so I'm a bit skeptical

Umh, fusion has not been around the corner; it has been very much here for the last 60+ years. E.g, H-bombs.

 

[rootone]

Yes, but the aim of an H bomb isn't to produce a reliable and economically viable power source!
I am quite optimistic for the ITER project though, which is basically a scaled up version of currently existing fusion reactors.
Fusion reactors do exist right now, just not ones which can sustain a reaction that generates more power than it consumes.

Edit:
Oh I just realized the topic is quantum computing, and yes I think like fusion, the problems to be overcome are mainly engineering ones and it'll be several years before the engineering is good enough to compete with the best conventional supercomputers.
I believe it likely though that we will see both of these technologies developed and in general use well before the end of the current century

 

[glaucousNoise]

I guess nobody can know for sure. I just feel burned by all the hype around fusion/graphene/superconducting transmission lines and wanted to know if I should risk getting my hopes up for this stuff or not.