deletions | additions       diff --git a/textbf_Absence_of_back_scattering__.tex b/textbf_Absence_of_back_scattering__.tex  index b35d19a..1683e66 100644  --- a/textbf_Absence_of_back_scattering__.tex  +++ b/textbf_Absence_of_back_scattering__.tex 
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\end{equation}  We choose the propagating modes that incoming and outgoing states are related by TRS, which means that $\psi^{out}_{L}=T\psi^{in}_{L}$ and $\psi^{out}_{R}=T\psi^{in}_{R}$. So the total state outside the scattering region can be expressed as  \begin{equation}  \psi=sum_{s\in(L,R}a^{in}_{s}\psi^{in}_{s}+sum_{s\in(L,R}(Sa^{in}_{s})\psi^{in}_{s} \psi=\sum_{s\in(L,R}a^{in}_{s}\psi^{in}_{s}+\sum_{s\in(L,R}(Sa^{in}_{s})\psi^{in}_{s}  \end{equation}