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New silicon structure opens the gate to quantum computers

princeton.edu

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Re: New silicon structure opens the gate to quantum computers

#21

Post by badspeler »

propter_hoc wrote: post #9

I did graduate research in an area of experimental physics that was quite close to state of the art quantum computing research. It was very exciting, but all the research was pretty much in extreme conditions that aren't really usable for a realistic computing device (ultra-high vacuum, nanokelvin temperatures, high magnetic fields or laser trap confinement, etc.). From the looks of it this paper is in the same vein.…

That's true but once Science conquers something, engineering isn't very far behind. The apparatus to build Bose-Einstein Condensates was a fucking monster of vacuums and quantum optics but now we can fit a Bose-Einstein Condensate on a microchip. https://arxiv.org/abs/0912.0553

Re: New silicon structure opens the gate to quantum computers

#22

Post by mercutio2 »

sytelus wrote: post #19
tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

Here's my rather crude understanding of what QC can do (please feel free to comment if this is correct): Let's say you have a problem that requires examining 2^N different possibilities. So the brute force solution would have O(2^N) runtime. QC can potentially help to solve this problem in O(2^(sqrt(N))) time instead. This can make a world of difference. For example, if N=1024 and examining each possibility took 1 na…

Utterly unimportant to your point, but 2^32 nanoseconds is not a microsecond...

Re: New silicon structure opens the gate to quantum computers

#23

Post by Sniffnoy »

sytelus wrote: post #19
tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

Here's my rather crude understanding of what QC can do (please feel free to comment if this is correct): Let's say you have a problem that requires examining 2^N different possibilities. So the brute force solution would have O(2^N) runtime. QC can potentially help to solve this problem in O(2^(sqrt(N))) time instead. This can make a world of difference. For example, if N=1024 and examining each possibility took 1 na…

I'm afraid you're a bit off. A quantum computer can search N possibilities (such as when, say, looking up data in a database, though I doubt you'd go to the trouble of using a QC for that) in time O(sqrt(N)). So for 2^N things, that's 2^(N/2), not 2^(sqrt(N)). Obviously still a big improvement.

Re: New silicon structure opens the gate to quantum computers

#24

Post by asddkk »

TrinaryWorksToo wrote: post #15
NhanH wrote: post #13

Earlier quoted context omitted.

Quantum annealing can be used for optimization of functions. Shor’s algorithm of integer factorization would solve (and cause) a whole host of problems for us. But in general, quantum computer is not strictly a superset of improvement over Turing machine. It’s just different. And while it might reduces your database query time, unless you are already working at that abstraction it might probably be invisible changes…

From what I gathered, it's similar to how a CPU and GPU compare: different complexity classes, different problems it's efficient on.

The CPU-GPU analogy is very good for all sorts of reasons. For some things there's no speedup, for some important things there's a huge speedup, for other things there's some significant speedup, but not game-changing.

I tend to think of applications where you might want to brute-force search or simulate over some large set as being where quantum computing will be most significant, but I say that very vaguely and timidly.

This gives a number of applications and algorithms; I found some of the references in it really interesting to read:

http://math.nist.gov/quantum/zoo/

Re: New silicon structure opens the gate to quantum computers

#25

Post by Mizza »

tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

Your bank could give you a quantum keyfob. All of your encrypted transactions are now entangled, so you know that nobody has spied on them: the act of observation modifies the result.

Re: New silicon structure opens the gate to quantum computers

#26

Post by Sniffnoy »

Mizza wrote: post #25
tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

Your bank could give you a quantum keyfob. All of your encrypted transactions are now entangled, so you know that nobody has spied on them: the act of observation modifies the result.

It sounds like you're describing quantum cryptography, which doesn't require a quantum computer and in fact already exists commerically.

Re: New silicon structure opens the gate to quantum computers

#27

Post by gaze »

tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

We don't know. If someone manages to find an algorithm to do such things, it'll be helpful for that. It's as if we're rediscovering the computer itself from the beginning and we're still not sure what it's good for, but the things we've managed to find algorithms for it appears to be really really good at.

Basically, don't worry too much about it, unless you wish to hunt for such algorithms yourself.

The one thing it's definitely promising for is simulating quantum mechanics... something classical computers are very bad at, and has serious practical use. For this, they will always be very useful.

Re: New silicon structure opens the gate to quantum computers

#28

Post by comstock »

Sniffnoy wrote: post #26
Mizza wrote: post #25

Earlier quoted context omitted.

Your bank could give you a quantum keyfob. All of your encrypted transactions are now entangled, so you know that nobody has spied on them: the act of observation modifies the result.

It sounds like you're describing quantum cryptography, which doesn't require a quantum computer and in fact already exists commerically.

To be honest it sounds like they’re describing the plot of the next mission impossible film rather than anything that exists in our reality.

Re: New silicon structure opens the gate to quantum computers

#29

Post by frik »

tim-- wrote: post #10

My biggest pet peeve about quantum computing is that no one can answer me the question of "what can quantum computing do for me?". The answer I hear is that it helps solve the traveling salesman in record time, and that's all great and everything, but how will quantum computing be able to do things such as decrease the time it takes to train a RNN, or look up data in a database?

Can the idea of quantum computing be simplified/abstracted to say instead of doing binary (0 1) calculations, it do does calculation on arbitrary base? E.g. base 16 (hex) or base 1024?

If this is true, it would be easier to code, and compilers could spit out very efficient machine code.

Re: New silicon structure opens the gate to quantum computers

#30

Post by ryacko »

Sniffnoy wrote: post #23
sytelus wrote: post #19

Earlier quoted context omitted.

Here's my rather crude understanding of what QC can do (please feel free to comment if this is correct): Let's say you have a problem that requires examining 2^N different possibilities. So the brute force solution would have O(2^N) runtime. QC can potentially help to solve this problem in O(2^(sqrt(N))) time instead. This can make a world of difference. For example, if N=1024 and examining each possibility took 1 na…

I'm afraid you're a bit off. A quantum computer can search N possibilities (such as when, say, looking up data in a database, though I doubt you'd go to the trouble of using a QC for that) in time O(sqrt(N)). So for 2^N things, that's 2^(N/2), not 2^(sqrt(N)). Obviously still a big improvement.

But wouldn't it have to be stored as qubits? A database in qubits would be expensive.
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