The phrase "Einstein's spooky action at a distance" refers to Albert Einstein's skepticism regarding the non-locality implied by quantum entanglement. Einstein famously used this term to express his discomfort with the instantaneous correlations that occur between entangled particles.
On the other hand, Niels Bohr, one of the pioneers of quantum mechanics, embraced the concept of entanglement and argued that it was an inherent feature of the quantum world. Bohr's viewpoint, known as the Copenhagen interpretation, emphasized the probabilistic nature of quantum mechanics and rejected the idea of hidden variables that could explain the correlations observed in entangled systems.
Since the time of Einstein and Bohr, the understanding and interpretation of quantum entanglement have continued to evolve. Various theoretical models and interpretations have been proposed to account for entanglement and reconcile different perspectives. Here are a few notable examples:
Many-worlds interpretation: Proposed by Hugh Everett, this interpretation suggests that when particles become entangled, the universe splits into multiple branches, each corresponding to a different outcome of the entanglement. In this view, the apparent non-locality arises from our limited perspective within a particular branch of the multiverse.
Pilot-wave theory: Also known as de Broglie-Bohm theory, this model suggests that particles have definite positions and velocities, but their behavior is influenced by a hidden guiding wave. In this interpretation, the entanglement is maintained through the guiding wave, which determines the correlated behavior of the entangled particles.
Quantum information theory: This framework focuses on the mathematical description and manipulation of quantum information. It treats entanglement as a valuable resource for various quantum tasks, such as quantum communication and computation, without necessarily delving into the underlying ontological interpretation.
It's important to note that while these models provide alternative ways to think about and describe entanglement, the interpretation of quantum mechanics remains an open and actively debated area of research. The experimental evidence for entanglement and its practical applications are well-established, but the philosophical and conceptual understanding of its nature continues to be explored by physicists and philosophers.