According to the principles of quantum mechanics, when two particles are entangled, their quantum states are linked regardless of the distance between them. This means that if the quantum state of one particle is measured or changed, the state of the other particle will instantaneously be affected, regardless of the separation between them, even if it is light years apart. This phenomenon is commonly referred to as "quantum entanglement" and has been experimentally observed in various systems.
However, it's important to note that the instantaneous influence of entanglement does not violate the principle of causality or allow for faster-than-light communication. The entanglement itself does not transmit information or allow for direct control or communication between the particles. Instead, it establishes a correlation between their states, and any measurement or interaction with one of the particles will determine the outcome of that particular measurement, while the state of the other particle becomes instantaneously correlated but indeterminate until measured independently.
This property of entanglement has been extensively studied and verified experimentally through various tests, including the violation of Bell's inequalities. It plays a significant role in quantum information processing and quantum communication protocols such as quantum teleportation and quantum cryptography.