Albert Einstein did express his opinion on the possibility of faster-than-light communication using quantum entanglement. He was skeptical of the concept and famously referred to it as "spooky action at a distance."
Einstein's skepticism stemmed from his deep commitment to the theory of relativity, which posits that nothing can travel faster than the speed of light in a vacuum. Quantum entanglement, on the other hand, is a phenomenon where two particles become linked in such a way that the state of one particle instantaneously affects the state of the other, regardless of the distance between them.
Einstein, along with Boris Podolsky and Nathan Rosen, proposed a thought experiment known as the Einstein-Podolsky-Rosen (EPR) paradox in 1935 to challenge the completeness of quantum mechanics. The EPR paradox was designed to show what they believed were inherent inconsistencies in the quantum theory's description of reality.
In a letter to physicist Max Born in 1947, Einstein expressed his doubts about the possibility of using entanglement for faster-than-light communication. He argued that the phenomenon did not involve the transfer of physical signals and suggested that any such communication would violate the principles of causality and special relativity.
It's worth noting that subsequent experiments, such as the Bell tests, have supported the predictions of quantum mechanics and provided evidence for the non-local nature of entanglement. However, the question of whether faster-than-light communication is possible using quantum entanglement remains a topic of debate and ongoing research in the field of quantum physics.