Timeline for How are qubits better than classical bit if they collapse to a classical state after measurement?
Current License: CC BY-SA 3.0
9 events
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| Sep 14, 2015 at 18:54 | comment | added | Ellie | @AlexL Clear and fun, +1. Interesting webpage too, been checking it out. BTW this recent post may interest you. | |
| May 5, 2013 at 21:58 | comment | added | Alex L | @kansi Yes, I was talking about entanglement. The two qubits are in the state $\frac{\left| 00 \right> + \left| 11 \right>}{\sqrt{2}}$, so if you measure 0 your friend will measure 0. To get to 0.85 probability of winning you have to each measure your qubits in a basis which depends on your own input. I don't know how to explain this intuitively, but the math shows that doing this lets you correlate your answers slightly better than classically. | |
| May 5, 2013 at 21:52 | comment | added | kansi | @AlexL first of all Thanx for replies :) ... u said: "On the other hand, if only you and your friend each had one qubit ..." i think u are talking about entanglement, can u elaborate on that. | |
| May 5, 2013 at 21:33 | comment | added | Alex L | @kansi The amplitude amplification process doesn't require measurements. Only at the very end do you measure to get your answer. | |
| May 5, 2013 at 21:32 | comment | added | kansi | in the computation section: if you make a measurement then the "n" qubits will collapse into the state that u observed. So the next time u make a measurement u know wat to expect, because the measurement u just made collapsed the qubits into one of the states and this is wat u would observe the next time. So how would u get to the answer if u didnt get the right string, the first time? | |
| May 5, 2013 at 21:24 | comment | added | Alex L | @kansi Yes, you save all measurements until the end, otherwise you collapse the state. | |
| May 5, 2013 at 21:24 | comment | added | Martin Ender | Just a little nitpicking: NP-complete is a specific class, where checking a solution has polynomial time-complexity, while finding one has exponential time-complexity (for all we know!) - and there are often approaches that are better than trying every single candidate solution, but they are still exponential. However, there are other complexity classes, where checking a solution is significantly faster than finding one - so this applies to all of these. | |
| May 5, 2013 at 20:53 | history | edited | Alex L | CC BY-SA 3.0 |
added 61 characters in body
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| May 5, 2013 at 20:45 | history | answered | Alex L | CC BY-SA 3.0 |