It promises such lovely possibilities as quick solutions to NP-complete problems, and I’m not entirely sure the mechanism couldn’t also be used to do arbitrary amounts of computation in finite time. Certainly worth a read.
However, I don’t understand quantum mechanics well enough to tell how sane the paper is, or what the limits of what they’ve discovered are. I’m hoping one of you does.
If this worked, Harry could use it to recover any sort of answer that was easy to check but hard to find. He wouldn’t have just shown that P=NP once you had a Time-Turner, this trick was more general than that. Harry could use it to find the combinations on combination locks, or passwords of every sort. Maybe even find the entrance to Slytherin’s Chamber of Secrets, if Harry could figure out some systematic way of describing all the locations in Hogwarts. It would be an awesome cheat even by Harry’s standards of cheating.
Harry took Paper-2 in his trembling hand, and unfolded it.
Paper-2 said in slightly shaky handwriting:
DO NOT MESS WITH TIME
Harry wrote down “DO NOT MESS WITH TIME” on Paper-1 in slightly shaky handwriting, folded it neatly, and resolved not to do any more truly brilliant experiments on Time until he was at least fifteen years old.
To put this into my own words “The more information you extract from the future, the less you are able to control the future from the past. And hence, the less understanding you can have about what those bits of future-generated information are actually going to mean.”
I wrote that before actually looking at the paper you linked. I don’t understand much QM either, but now that I have looked it seems to me that figure 2 of the paper backs me up on my interpretation of Harry’s experiment.
Even if it’s written by Eliezer, that’s still generalizing from fictional evidence. We don’t know what the laws of physics are supposed to be there..
Well. You probably can’t use time-travel to get infinite computing power. But that’s not to say you can’t get strictly finite power out of it; in Harry’s case, his experiment would probably have worked just fine if he’d been the sort of person who’d refuse to write “DO NOT MESS WITH TIME”.
Playing chicken with the universe, huh? As long as scaring Harry is easier than solving his homework problem, I’d expect the universe to do the former :-) Then again, you could make a robot use the Time-Turner...
I found an interesting paper on Arxiv earlier today, by the name of Closed timelike curves via post-selection: theory and experimental demonstration.
It promises such lovely possibilities as quick solutions to NP-complete problems, and I’m not entirely sure the mechanism couldn’t also be used to do arbitrary amounts of computation in finite time. Certainly worth a read.
However, I don’t understand quantum mechanics well enough to tell how sane the paper is, or what the limits of what they’ve discovered are. I’m hoping one of you does.
It won’t work, as is clearly explained here.
To put this into my own words “The more information you extract from the future, the less you are able to control the future from the past. And hence, the less understanding you can have about what those bits of future-generated information are actually going to mean.”
I wrote that before actually looking at the paper you linked. I don’t understand much QM either, but now that I have looked it seems to me that figure 2 of the paper backs me up on my interpretation of Harry’s experiment.
Even if it’s written by Eliezer, that’s still generalizing from fictional evidence. We don’t know what the laws of physics are supposed to be there..
Well. You probably can’t use time-travel to get infinite computing power. But that’s not to say you can’t get strictly finite power out of it; in Harry’s case, his experiment would probably have worked just fine if he’d been the sort of person who’d refuse to write “DO NOT MESS WITH TIME”.
Playing chicken with the universe, huh? As long as scaring Harry is easier than solving his homework problem, I’d expect the universe to do the former :-) Then again, you could make a robot use the Time-Turner...