4 ms·
But why can't Alice keep rolling the die until it gets to a state that she and Bob agree is a part of an encoding scheme? Is it because she needs to read the nu
by TechBro8615 3y ago
But why can't Alice keep rolling the die until it gets to a state that she and Bob agree is a part of an encoding scheme? Is it because she needs to read the number on the die to know whether to stop rolling it, but by reading (measuring) the number, she is effectively re-rolling (collapsing) it, so she could never know when to stop rolling it? In other words, she could stop after she measures a state, but the current state of the system is N, she'd be stopping after N-1, and there is no way to coordinate with Bob to know the difference?
The link I posted downthread seemed to suggest that the No Cloning Theorem is the constraint that makes this impossible. Any chance you can try to explain that within the context of the dice analogy?
- nwallin 3y agoYou can only roll the die once. Alice and Bob have a dozen dice. They agree that if they roll a 4, that's the signal for "attack at dawn" and Alice has decided that she wants Bob to attack at dawn. Alice rolls the 12 dice, and at the agreed upon time, Bob also rolls his 12 dice. The sequence they get is 1,5,3,2,2,4,6,5,1,2,1,6. The 6th die is a 4, which is the signal that Alice wants to send. How does Alice signal to Bob that she wants him to look at the 6th die? If Alice can send a signal to say, "look at the 6th die", why wouldn't she just send a signal that says, "attack at dawn"?
- TechBro8615 3y agoThanks for the explanation. :) It makes sense, at least insofar as any of this can possibly make sense...