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Multiple choice
Two amplitude-damping channels are applied in sequence to
ρ
=
∣
1
⟩
⟨
1
∣
\rho = |1\rangle\langle 1|
ρ
=
∣1
⟩
⟨
1∣
: first with
g
1
=
0.2
g_1 = 0.2
g
1
=
0.2
, then with
g
2
=
0.5
g_2 = 0.5
g
2
=
0.5
. What is the surviving excited-state population
⟨
1
∣
E
(
ρ
)
∣
1
⟩
\langle 1|E(\rho)|1\rangle
⟨
1∣
E
(
ρ
)
∣1
⟩
after both?
🔬 try it before you answer
0.4
0.3
0.7
0.1
Check answer