Defining quantum entanglement can be challenging because it is a concept rooted in the mathematical formalism of quantum mechanics and has properties that are not easily described in classical terms. However, I will attempt to provide a simplified explanation.
Quantum entanglement is a phenomenon in which two or more particles become correlated in such a way that the state of one particle is inseparably linked to the state of another, even when they are physically separated. These particles can be entangled through a process called quantum superposition, which allows them to exist in multiple states simultaneously.
The key aspect of entanglement is that the individual properties of the entangled particles, such as their spins or polarizations, are not well-defined until they are measured. Instead, their combined state is described by a mathematical entity called a quantum state or wave function, which encompasses all possible combinations of their properties.
When an observation or measurement is made on one of the entangled particles, it "collapses" the quantum state of the entire system, including the other entangled particles, instantaneously determining their properties as well. This instantaneous correlation between the particles, regardless of their spatial separation, is often referred to as "spooky action at a distance."
Quantum entanglement has been experimentally observed and is a fundamental aspect of quantum mechanics. It plays a crucial role in various phenomena and applications, such as quantum teleportation, quantum cryptography, and quantum computing.
While a precise and comprehensive definition of quantum entanglement requires a more rigorous mathematical framework, the basic idea is that entangled particles are deeply interconnected and exhibit correlations that defy classical intuition. It is one of the fascinating and puzzling aspects of quantum physics that continues to be explored and studied by physicists.