σ(t) =
±1
∆U
λ(t) = ±1 B 0 < γ a
0
W
0
(σ, λ) = a
0
exp
−
∆U + σλ B
D
.
d
dt
p(σ λ) = −W
0
(σ, λ) p(σ, λ) + W
0
(−σ, λ) p(−σ, λ)
+ γ [p(σ, −λ) − p(σ, λ)] .
s(t) = A cos(Ωt + ϕ
0
)
Ω < γ a
0
) A ∆U − B
W (σ, λ) = W
0
exp
−
A σ
D
cos(Ωt + ϕ
0
)
≈ W
0
1 −
A σ
D
cos(Ωt + ϕ
0
)
.
∝ (A/D)
2