deletions | additions       diff --git a/With_some_derivations_we_can__.tex b/With_some_derivations_we_can__.tex  index a20e315..32c7d60 100644  --- a/With_some_derivations_we_can__.tex  +++ b/With_some_derivations_we_can__.tex 
...
With some derivations, we can show that the winding number in the SSH model is exactly the Berry phase of the system. The winding number can be defined in a more general form. The integral of the Berry curvature of the energy eigenstate on the surface of k-space is called "Chern number", which is defined as following  \begin{equation}  Q^(n)=-\frac{1}{2\pi}\oint_{S}\textbf{b_{n}}dS Q^(n)=-\frac{1}{2\pi}\oint_{S}\textbf{b_n}dS  \end{equation}