diff --git a/README.md b/README.md
index 0b6580c..6f69f95 100644
--- a/README.md
+++ b/README.md
@@ -85,6 +85,7 @@ Feel free to explore, contribute, and share your insights!
      
    - **Contribution**: Formalized quantum theory, especially the description of quantum states and the mathematical interpretation of wave function collapse.
 
+   - **Formula**: $\huge \color{DeepSkyBlue}\langle \psi | \hat{A} | \psi \rangle \$ 
   
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