A brief discussion on the connection between classical theory and quantum mechanics

This paper first reviews several issues in the history of quantum mechanics development, briefly explaining the main contents of the "EPR paradox" and "Schrödinger's cat." It then introduces the efforts scientists have made in recent years in studying the relationship between classical and quantum theory through the "ghost imaging" experiment. Furthermore, by introducing "Ohm's law in the quantum world" and "the connection between photosynthesis and quantum mechanics," it illustrates the relevance of quantum mechanics to our daily lives. Finally, the paper analyzes and summarizes the problems that still exist in quantum mechanics today, concluding that quantum mechanics urgently needs further development.