Schrödinger’s work laid the foundation for developing quantum field theory, which describes the behavior of fundamental particles like quarks and leptons. One of Schrödinger’s most famous contributions is the concept of entanglement, which he introduced in 1935. Entanglement refers to the phenomenon where two or more particles become correlated so that the state of one particle cannot be described independently of the others, even when large distances separate them. This concept has been experimentally verified numerous times and is now recognized as a fundamental aspect of quantum mechanics. Schrödinger’s work on entanglement was motivated by his desire to understand the nature of reality at the atomic level. He was troubled by the implications of quantum mechanics, which seemed to suggest that the act of measurement itself could influence the outcome of a measurement. This led him to propose the thought experiment “Schrödinger’s cat,” in which a cat is placed in a box with a radioactive atom with a 50% chance of decaying within a certain time frame.