Update 4_ZPFs.md - update

src/4_ZPFs.md

@@ -24,7 +24,7 @@ import plotly.graph_objs as go
 
 
 ```
-# Lecture 4: Quantum Fluctuations, coherent states, and the quantum harmonic oscillator
+# Lecture 4: Quantum fluctuations, the quantum harmonic oscillator, and coherent states
 
 !!! success "Expected prior knowledge"
 
@@ -32,7 +32,7 @@ import plotly.graph_objs as go
 
     - write down the energy spectrum of the quantum harmonic oscillator 
     - recall that the state of a quantum object is described by the wavefunction $|\Psi\rangle$
-    - calculate the expectation value of an observable given a wave function
+    - calculate the expectation value of an observable given a wavefunction
 
 !!! summary "Learning goals"