Projective measurements of quantum processor

  • #1
EightBells
11
1
Homework Statement:
The quantum processor will provide information about the final state of
the system by performing projective measurement |1><1|. What are possible outcomes of
this measurement and what are the probabilities for this outcomes for each state listed
in Eq. (2). Explain, how you can perform projective measurements for states |±x> and
|±y> using the processor equipped with the standard single qubit gates and the projective
measurements |1><1|.
Relevant Equations:
Eq. 2 gives the six states: |0>, |1>, |±x>=(1/sqrt(2))*(|0>±|1>), |±y>=(1/sqrt(2))*(|0>±i*|1>)
Am I correct in thinking that the system measures the probability |<f|1>|^2 for some state <f|? Then the probabilities for each of the six states would be:

|<0|1>|^2= 0
|<1|1>|^2= 1
|<+x|1>|^2= |(1/√2)|^2 = 1/2
|<-x|1>|^2= |(-1/√2)|^2 = 1/2
|<+y|1>|^2= |(-i/√2)|^2 = 1/2
|<-y|1>|^2= |(i/√2)|^2 = 1/2

However, what, specifically, is the question asking for when it asks for the possible outcomes of the measurements?

Performing projective measurements in|±x> and|±y>, am I looking for the probabilities |<f|±x>|^2 and |<f|±y>|^2, but in terms of state |1> which is done using the qubit gates? I know ZH|1> = |+x>, H|1> = |-x>, and SH|1> = |-y>, but I can't find a gate or series of gates that transforms |1> to |+y>, and I'm not sure how to use this to calculate the probabilities |<f|±x>|^2 and |<f|±y>|^2.
 

Attachments

  • Gates.png
    Gates.png
    14.9 KB · Views: 79

Answers and Replies

Suggested for: Projective measurements of quantum processor

  • Last Post
Replies
4
Views
500
Replies
1
Views
346
Replies
9
Views
651
Replies
2
Views
341
Replies
3
Views
457
  • Last Post
Replies
1
Views
610
Replies
3
Views
564
Replies
8
Views
599
Replies
22
Views
826
Top