Improve equation formatting and text clarity

Updated the formatting of the equation and clarified the description of the transverse field in the text.

Author: marcusr2ML

content/en/tutorials/ed/ed04.md

@@ -15,7 +15,7 @@ $$
 H=J_{z} \sum_{\langle i,j \rangle} S^i_z S^j_z + \Gamma \sum_i S^i_x
 $$
 
-Here, the first sum runs over pairs of nearest neighbours. $\Gamma$ is referred to as transverse field; the system becomes critical for $\Gamma/J=\frac{1}{2}$. For $\Gamma=0$, the ground state is antiferromagnetic for $J\gt 0$ and ferromagnetic for $J \lt 0$. The system is exactly solvable ([P. Pfeuty, Annals of Physics 57, 79 (1970)](https://doi.org/10.1016/0003-4916(70)90270-8)).
+Here, the first sum runs over pairs of nearest neighbours. $\Gamma$ is referred to as transverse field; the system becomes critical for $\Gamma/J=\tfrac{1}{2}$. For $\Gamma=0$, the ground state is antiferromagnetic for $J\gt 0$ and ferromagnetic for $J \lt 0$. The system is exactly solvable ([P. Pfeuty, Annals of Physics 57, 79 (1970)](https://doi.org/10.1016/0003-4916(70)90270-8)).
 
 In the above equation, $\Delta$ refers to the scaling dimension of that field. The scaling fields occur in groups: the lowest one, referred to as primary field, comes with an infinite number of descendants with scaling dimension $\Delta + m$, $m \in \lbrace 1, 2, 3, ... \rbrace$.