I used this link which work in one column Latex document, why it does not work with two column  Latex document?
\begin{figure*}
     \centering
     \begin{subfigure}[t]{0.49\textwidth}
         \centering
    \includegraphics[width=\textwidth]{diract=0.png}
         \caption{$f_k(z)$ and  $f_b(z)$ representations of the states $| f\rangle $ and $\langle f |$ at $t=0$.}
        % which at $t=0$ is given in the Eq(27).}
         \label{fig:y equals x}
     \end{subfigure}
     \hfill
     \begin{subfigure}[t]{0.50\textwidth}
         \centering
         \includegraphics[width=\textwidth]{diracexamle2kbnonperiodict=1.png}
         \caption{$f_k(z)$ and $f_b(z)$ representations of the states $|f\rangle $
        and $\langle f |$ at $t=1$.}
         % which at $ t=0 $ is given in the Eq(81), by using Hamiltonian in Eq(101) that has the eigenvalues -5.7091, 0.0478, 3.6612, $t=1$.}
         \label{fig:three sin x}
     \end{subfigure}
     \hfill
     \begin{subfigure}[t]{0.49\textwidth}
         \centering
         \includegraphics[width=\textwidth]{diracexamle2kbnonperiodict=2.png}
         \caption{$f_k(z)$ and $f_b(z)$ representations of the states $|f\rangle $
         and $\langle f |$ at  $t=2$.}
         % which at $ t=0 $ is given in the Eq(81), by using Hamiltonian in Eq(6.46) that has the eigenvalues -5.7091, 0.0478, 3.6612, $t=2$.}
         \label{fig:five over x}
     \end{subfigure}
     \hfill
     \begin{subfigure}[t]{0.49\textwidth}
         \centering
         \includegraphics[width=\textwidth]{diracexamle2kbnonperiodict=pi.png}
         \caption{$f_k(z)$ and $f_b(z)$ representations of the states $|f \rangle$ and $\langle f |$ at $t=\pi$.}
         % which at $ t=0 $ is given in the Eq(81), by using Hamiltonian in Eq(6.46) that has the eigenvalues -5.7091, 0.0478, 3.6612, $t=\pi$}
         \label{fig:three sin x}
     \end{subfigure}
     \hfill
     \begin{subfigure}[t]{0.49\textwidth}
         \centering
         \includegraphics[width=\textwidth]{diracexamle2kbnonperiodict=2pi.png}
         \caption{$f_k(z)$ and $f_b(z)$ representations of the states $|f\rangle $
         and $\langle f |$ at $t=2\pi$}
         % which at $ t=0 $ is given in the Eq(81), by using Hamiltonian in Eq(101) that has the eigenvalues -5.7091, 0.0478, 3.6612, $t=2\pi$. As we can see, the figures do not return to initial position at $t=0$ because the system is not periodic}
         \label{fig:three sin x}
     \end{subfigure}
 \caption{ Time evolution of the $\mathcal{H}_{(2j+1)}$ system is described by the movement of the magnitude and the phase of Dirac contour representation
functions $f_k(z)$ and $f_b(z)$  of the states $|f \rangle$, 
     which at $ t=0 $ is given in the Eq(6.45), and $\langle f |$ by using Hamiltonian in Eq(6.44) that has the eigenvalues -5.7091, 0.0478, 3.6612.}
        \label{fig:three graphs}
        % \caption{Three simple graphs}
        % \label{fig:three graphs}
\end{figure*}
I appreciate any help

