EPR

Einstein-Podolsky-Rosen Paradox (EPR Paradox) is a thought experiment proposed by physicists Albert Einstein, Boris Podolsky, and Nathan Rosen (EPR) in 1935. It challenges the quantum mechanics' principle of quantum entanglement, arguing that it leads to physical effects not present in classical physics.

History

The EPR paradox was first published in a paper titled "Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?" in the Physical Review journal. The authors, Einstein, Podolsky, and Rosen, aimed to demonstrate that the wave function in quantum mechanics does not provide a complete description of physical reality.

Concept

The EPR paradox is based on two main concepts: locality and realism. Locality suggests that an object can only be influenced by its immediate surroundings, while realism proposes that an object has definite properties, independent of measurement.

The paradox arises when these two concepts are applied to two particles that have interacted and then separated. According to quantum mechanics, the state of the second particle can instantaneously collapse into a definite state no matter the distance, once the first particle's state is measured. This phenomenon, known as quantum entanglement, seems to violate the principle of locality.

Implications

The EPR paradox has significant implications for the interpretation of quantum mechanics. It led to the development of the concept of hidden variables theory, which suggests that quantum mechanics is incomplete and that there are hidden variables not accounted for.

The paradox also inspired John Bell to derive the Bell's theorem, which provides a testable distinction between quantum mechanical predictions and those of local hidden variable theories.

See also

• Quantum entanglement
• Bell's theorem
• Hidden variables theory
• Quantum mechanics
• Albert Einstein
• Boris Podolsky
• Nathan Rosen