deletions | additions       diff --git a/When_applied_an_electric_field__.tex b/When_applied_an_electric_field__.tex  index 791cd7d..e6e7502 100644  --- a/When_applied_an_electric_field__.tex  +++ b/When_applied_an_electric_field__.tex 
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E(t) = E_0 cos(\omega t)  \end{equation}  there will be DC and AC currents. current contributions.  The empirical DC conductance is of the form\cite{Bardeen_1979}: \begin{equation}  \sigma(E) = \sigma_a + \sigma_b exp(-E_0/E)  \end{equation}  CDW was modeled as a classical particle moving in a "wash board" potential, which was approximated by parabolic and sinusoidal potentials. The particle was overdamped and subjected to electric force $e E$.  Only when the applied DC  electric field exceeds some threshold value $E_th$ will the CDW "particle" start to "slide". This is "slide",  also known as the "depinning" process of CDW \cite{Gr_ner_1981}. The conductance Once depinned, the equation of motion can be written  in this case terms of position x or the phase shift $\phi$.   \begin{equation}  \frac{d^{2}\phi}{dt^{2}} + \Gamma \frac{d\phi}{dt} + 2k_F V_0 sin(2k_F \phi) =\frac{e E_0}{m}cos(\omega t)  \end{equation}  where \Gamma  is "diode-like". the damping coefficient determined by experiment and m is the collective mass of CDW. By