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I use mathematica 12.3

(*单位约定:时间\[LongDash]s; 频率\[LongDash]MHz;长度-m*)
Clear["Global`*"]
cc = 300;(*光速*)
\[Omega] = 2*\[Pi]*351.722*10^6;(*光频*)

k = [Omega]/cc;(光波矢) L = 1010^(-3);(铯泡长度*)

NN = 410^15;(25摄氏度时铯原子的原子数密度) [HBar] = 1.05510^(-34);(约化普朗克常量) [Epsilon] = 8.85410^(-12);(真空介电常数) [Sigma] = 4.6410^(-29);(铯原子D1线的偶极矩阵元)

m = 2.20710^(-25);(铯原子质量,单位:kg*)

kB = 1.38110^(-35);(玻尔兹曼常量,已换算成我们的单位制) T = 273.15 + 25;(温度*)

Subscript[[CapitalGamma], 1] = 0; Subscript[[CapitalGamma], 2] = 2[Pi]5.2;(2态的decay rate)

Subscript[[CapitalGamma], 3] = 2[Pi]0.03; Subscript[[Gamma], 21] = (Subscript[[CapitalGamma], 2] + Subscript[[CapitalGamma], 1])/2;(2态和1态之间的off-diagonal decay rate)

Subscript[[Gamma], 31] = (Subscript[[CapitalGamma], 3] + Subscript[[CapitalGamma], 1])/2; Subscript[[CapitalOmega], c] = 2[Pi]10;(耦合光的拉比频率)

Subscript[[CapitalOmega], p] = 2[Pi]3;(探针光的拉比频率)

v = 10^(-6)[Mu];
Subscript[[Delta], p] = 0; Subscript[[Delta], c] = 2
[Pi][Nu]; Subscript[[CapitalDelta], p] = Subscript[[Delta], p] + kv; Subscript[[CapitalDelta], c] = Subscript[[Delta], c] - kv; [Chi] = ( I(NN[Sigma]^2)/([Epsilon][HBar])10^(-6))/((Subscript[[Gamma]
, 21] - I
Subscript[[CapitalDelta], p]) + (!( *SubsuperscriptBox[([CapitalOmega]), (c), (2)]/ 4))/(Subscript[[Gamma], 31] - I(Subscript[[CapitalDelta], p] + Subscript[[CapitalDelta], c])));(极化率*)

Im[Chi] = FullSimplify[Im[[Chi]], Assumptions -> {Subscript[[Delta], c] [Element] Reals, [Mu] [Element] Reals}]; f = 10^(-6)(m/(2[Pi]kBT))^(1/2)* Exp[(-mv^2)/(2kB*T)];(麦克斯韦速度分布) [Mu]M = 500;(原子速度,计算范围)

d[Mu] = 0.5;(原子速度,计算步长)

DIm[Chi] = Sum[Im[Chi]f, {[Mu], -[Mu]M, [Mu]M, d[Mu]}]d[Mu]; FT = Exp[-DIm[Chi]kL];(透射光强) [Nu]M = 10;(作图范围) ITMin = 0; a = Plot[FT, {[Nu], -[Nu]M, [Nu]M}, PlotRange -> {{-[Nu]M, [Nu]M}, {0, 1}}, AxesOrigin -> {-[Nu]M, ITMin}]; Show[a, Frame -> True, FrameStyle -> Thick, FrameTicksStyle -> Directive[Black, 20, Thick], FrameLabel -> {Coupling frequency detuning @MHz, Free space Transmission@arb . units }, LabelStyle -> Directive[Black, 20, Thick]]

get this

enter image description here

but I use mathematica 10.3 can get complete

enter image description here

To figure out why, I notice that the core of this diagram is Exp[-DIm\[Chi]*k*L],So I use Table and ListPlot

Table[Exp[-DIm\[Chi]*k*L], {\[Nu], -10, 10, 0.01}] // ListPlot[#, PlotRange -> All] &

get this

enter image description here

You can see that the dots in the middle are very sparse,How do I deal with that in 12.3?

我心永恒
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1 Answers1

6

If you replace your definition of Im\[Chi] with

Im\[Chi] = 
  FullSimplify[Im[\[Chi]], 
   Assumptions -> {Subscript[\[Delta], c] \[Element] 
      Reals, \[Mu] \[Element] Reals}] // ComplexExpand;

then it will work. All I did was to add // ComplexExpand at the end.

user293787
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