- #1
Francis
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- TL;DR Summary
- Dear fellas, I am reading a quantum physics tutorial to understand Grover's algorithm and I am stuck with a (very simple) deduction.
I have the pdf attached page 23 at the top.
I am trying to understand the following deduction:
"The conditional phase shift can be represented by the unitary operator 2|0> <0| - I:"
for eq. 4a) I was expecting to be:
[2 |0><0| - I] |0> =
2 |0> <0|0> - I|0> = 2|0> - |0> =
|0>
as for eq. 4b I can't understand it at all. Why does the author considers I|0> = I and I|x> = I? What am I missing?
"The conditional phase shift can be represented by the unitary operator 2|0> <0| - I:"
[2 |0><0| - I] |0> =
2 |0> <0|0> - I|0> = 2|0> - |0> =
|0>
as for eq. 4b I can't understand it at all. Why does the author considers I|0> = I and I|x> = I? What am I missing?