4 ms·

I'm in the same boat. A qubit can have more than the two states that a transistor can have, got it. Okay, now what can we do with that? "crack encryption by s

I'm in the same boat. A qubit can have more than the two states that a transistor can have, got it. Okay, now what can we do with that? "crack encryption by simulating a state!" yeah but what? is that something I should be concerned about now? "hahaha no no no silly normie we'd need two thousand qubits for that, this machine only has 53!" oooookay, and you did that number in your head, how??? "we just solved the first unsolvable problem that a mere bit bound supercomputer couldn't solve, look at this math formula!" but that didn't explain "we are celebrating, are you not celebrating" There just seems to be a lack of non-introductory but non-PhD level information. Where is the "explain it like I've been accepted into college at all".

rmidthun 7y ago
Since we're looking at Scott Aaronson, you might want to check out "Quantum Computing Since Democritus". It gives a good explanation of the math behind qubits and how they can be used. Best intro I know of.
- rolltiide 7y ago
  thank you for that and not trying to explain it in an additional convoluted way
rini17 7y ago
Schrodinger's cat in unopened box is 1 qubit = it's alive and dead at the same time. When the box is opened to observe the result, the quantum state "decoheres" - decays to 1 bit result. Now imagine 53 such boxes, interconnected by quantum gates. The 53 qubits combined are in all of 2^53 states at once. The gates can be set up such that some combinations like "cat 1 alive", "cat 2 dead", etc. are much more likely result than others, after the boxes are opened. And all this computation is done in one step, whereby the classical computer must do 2^53 steps to get the same result. To have 53 cats all undisturbed in these dead/alive states so that computation is done without errors is very technically challenging :)
- drdeca 7y ago
  I don’t think the cat thing helps to explain this, especially with the finality association of “dead”.
  - rini17 7y ago
    It can't really be explained, we kind of accept it works like it has been in both states at once until the box was opened. Similarly, we don't really know how to explain how particles travel by both slits at once in the double-slit experiment.
    - drdeca 7y ago
      Idk, it seems to me like https://www.smbc-comics.com/comic/the-talk-3 https://www.smbc-comics.com/comic/the-talk-3 is a pretty good explanation. “A new ontological category”. What’s the problem?
      - rolltiide 7y ago
        satire and educational this has been the best thing I've seen so far
- buboard 7y ago
  Here .. finding the circuit that saves more cats from death is already a useful thing. Of course, i dont see an obvious algorithm to search for that circuit so it would have to be brute force. but now this computer makes even brute force possible
drdeca 7y ago
Do you know linear algebra? If you have a collection of n qubits, the state of those corresponds to a unit vector in a 2^n dimensional space over the field of complex numbers. You can do certain linear operations (iirc, only unitary ones. I wouldn’t claim all unitary ones either) to change the state. You can also do a measurement, which has a random outcome, following the Born rule. So, it isn’t really just “each of them has more than 2 possible states”. That can be the case with something classical, and has been done before (there have been ternary computers. Binary computers won out. Ternary computers (or quaternary, etc. etc.) wouldn’t be particularly special.) You can’t just think of each of the qubits as having a state always entirely independent of the rest of the qubits.

rmidthun 7y ago

Since we're looking at Scott Aaronson, you might want to check out "Quantum Computing Since Democritus". It gives a good explanation of the math behind qubits and how they can be used. Best intro I know of.

rolltiide 7y ago
thank you for that and not trying to explain it in an additional convoluted way

rini17 7y ago

Schrodinger's cat in unopened box is 1 qubit = it's alive and dead at the same time. When the box is opened to observe the result, the quantum state "decoheres" - decays to 1 bit result. Now imagine 53 such boxes, interconnected by quantum gates. The 53 qubits combined are in all of 2^53 states at once. The gates can be set up such that some combinations like "cat 1 alive", "cat 2 dead", etc. are much more likely result than others, after the boxes are opened. And all this computation is done in one step, whereby the classical computer must do 2^53 steps to get the same result. To have 53 cats all undisturbed in these dead/alive states so that computation is done without errors is very technically challenging :)

drdeca 7y ago
I don’t think the cat thing helps to explain this, especially with the finality association of “dead”.
- rini17 7y ago
  It can't really be explained, we kind of accept it works like it has been in both states at once until the box was opened. Similarly, we don't really know how to explain how particles travel by both slits at once in the double-slit experiment.
  - drdeca 7y ago
    Idk, it seems to me like https://www.smbc-comics.com/comic/the-talk-3 https://www.smbc-comics.com/comic/the-talk-3 is a pretty good explanation. “A new ontological category”. What’s the problem?
    - rolltiide 7y ago
      satire and educational this has been the best thing I've seen so far
buboard 7y ago
Here .. finding the circuit that saves more cats from death is already a useful thing. Of course, i dont see an obvious algorithm to search for that circuit so it would have to be brute force. but now this computer makes even brute force possible

drdeca 7y ago

Do you know linear algebra? If you have a collection of n qubits, the state of those corresponds to a unit vector in a 2^n dimensional space over the field of complex numbers. You can do certain linear operations (iirc, only unitary ones. I wouldn’t claim all unitary ones either) to change the state. You can also do a measurement, which has a random outcome, following the Born rule. So, it isn’t really just “each of them has more than 2 possible states”. That can be the case with something classical, and has been done before (there have been ternary computers. Binary computers won out. Ternary computers (or quaternary, etc. etc.) wouldn’t be particularly special.) You can’t just think of each of the qubits as having a state always entirely independent of the rest of the qubits.