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Multiple choice
A VQE parameter starts at
θ
=
0.4
\theta = 0.4
θ
=
0.4
. A parameter-shift gradient gives energies
E
(
+
)
=
0.6
E(+) = 0.6
E
(
+
)
=
0.6
and
E
(
−
)
=
0.2
E(-) = 0.2
E
(
−
)
=
0.2
, so
g
r
a
d
=
(
E
(
+
)
−
E
(
−
)
)
/
2
\mathrm{grad} = (E(+) - E(-))/2
grad
=
(
E
(
+
)
−
E
(
−
))
/2
. With learning rate
0.1
0.1
0.1
, the gradient-descent update
θ
new
=
θ
−
0.1
g
r
a
d
\theta_{\text{new}} = \theta - 0.1\,\mathrm{grad}
θ
new
=
θ
−
0.1
grad
equals what?
0.40
0.38
0.42
0.36
Check answer