Consider the expression for EΔh,
EΔh=∫FΔhidaψi=mc21aψi(aψf−aψi)
Differentiating with respect to aψi,
∂EΔh∂aψi=FΔhi=−mc2aψfa2ψi
And consider,
EΔh=∫FΔhfdaψf=mc21aψi(aψf−aψi)
Differentiating with respect to aψf,
∂EΔh∂aψf=FΔhf=mc21aψi
So, when both aψi and aψf are changing,
∂EΔh∂aψ=∂EΔh∂aψf+∂EΔh∂aψi=FΔhT=mc21aψi(1−aψfaψi)
And we consider the second derivative,
∂2EΔh∂a2ψ=∂∂aψ{∂EΔh∂aψf+∂EΔh∂aψi}=F′ΔhT
F′ΔhT=−mc21a2ψi+2mc2aψfa3ψi−mc21a2ψi
F′ΔhT=2mc21a2ψi(aψfaψi−1)=−k
And an approximation,
FΔhT=F′Δh.Δaψ
If such a system is prompted to oscillate,
ωn=√km=√2c√aψfa3ψi
where ωn is the natural frequency of the system. Naturally, such a system is damped as it emits photons, the loss due to damping is,
Ploss=−∂EΔh∂t=−mν(daψidt)2
where ν (rads-1) is the damping factor using the model f(x,˙x)=−kx−mν˙x and the rate at which f(x,˙x) does work is,
P=f.˙x=−kx˙x−mν˙x2=Posc+Ploss
And consider, aψi making a round trip to aψf and back in time Td=2π1ωd,
daψidt=2(aψi−aψf)Td=1π(aψi−aψf)ωd
where ωd is the damped resonance frequency. We have,
∂EΔh∂t=mν(daψidt)2=mν1π2(aψi−aψf)2ω2d
As,
∂EΔh∂t=∂EΔh∂aψfdaψfdt+∂EΔh∂aψidaψidt
Assuming daψfdt=daψidt, that the external driving force affects both equally,
mc21aψi(1−aψfaψi)=mν1π(aψi−aψf)ωd
Since, aψ at aψf loses almost all its energy, the amplitude of the wave at aψf, Af is small,
ν≈1 rads-1
then,
wd=πc21a2ψi
which is a very high frequency, (1034Hz).
At this frequency, the particle will be "resonating" with high output of photons emitted as a result of the energy state transition aψi→aψf.
If this high frequency, ωd can be achieved, we have a photon resonator that might drive that particular particle to wrap speed.
Note: What? Wrong to replace ˙x with average speed?