In my rational opinion, entanglement is a fundamental concept in quantum mechanics that arises when two or more particles become correlated in such a way that the state of one particle cannot be described independently of the state of the other particles. This correlation is often referred to as "quantum entanglement."
Quantum entanglement is a non-classical phenomenon that has been extensively studied and verified experimentally. It plays a crucial role in various quantum technologies, such as quantum computing and quantum communication.
However, outside the framework of quantum mechanics, the concept of entanglement may not be applicable or meaningful. Entanglement is deeply rooted in the mathematical formalism of quantum theory, which provides a probabilistic description of physical systems on a microscopic scale. Other physical theories, such as classical mechanics or general relativity, do not incorporate the notion of entanglement in the same way.
That being said, it's worth noting that classical systems can exhibit correlations or correlations of a different nature than quantum entanglement. Classical correlations arise from statistical relationships between observable quantities, but they are fundamentally different from quantum entanglement. Therefore, while non-quantized correlations and entanglements might exist in classical systems, they would not have the same characteristics or implications as quantum entanglement.