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Multiple choice
Two qubits are measured along axes separated by angle
θ
=
π
/
3
\theta = \pi/3
θ
=
π
/3
. The correlation is
E
=
P
(
same
)
−
P
(
opposite
)
E = P(\text{same}) - P(\text{opposite})
E
=
P
(
same
)
−
P
(
opposite
)
, with
P
(
same
)
=
sin
2
(
θ
/
2
)
P(\text{same}) = \sin^2(\theta/2)
P
(
same
)
=
sin
2
(
θ
/2
)
and
P
(
opposite
)
=
cos
2
(
θ
/
2
)
P(\text{opposite}) = \cos^2(\theta/2)
P
(
opposite
)
=
cos
2
(
θ
/2
)
. What is
E
E
E
?
🔬 try it before you answer
0
0
0
−
1
/
2
=
−
0.5
-1/2 = -0.5
−
1/2
=
−
0.5
+
1
/
2
=
0.5
+1/2 = 0.5
+
1/2
=
0.5
−
3
/
2
≈
−
0.866
-\sqrt{3}/2 \approx -0.866
−
3
/2
≈
−
0.866
Check answer