Description: The ‘Wigner’s Friend’ is a thought experiment proposed by physicist Eugene Wigner in 1961, illustrating the complexities of the measurement problem in quantum mechanics. In this experiment, a scenario is considered where an observer, the ‘friend’, performs a quantum measurement on a system while a second observer, Wigner, remains outside the system and does not interact with it. The paradox arises when analyzing the difference between the reality of the system from the friend’s perspective, who has made the measurement and collapsed the wave function, and Wigner’s perspective, who still considers the system in a state of superposition. This thought experiment highlights the subjective nature of measurement in quantum mechanics and raises questions about the interpretation of quantum reality. Through this scenario, concepts such as decoherence and the role of the observer in determining the state of a quantum system are explored. ‘Wigner’s Friend’ is not just a theoretical exercise but also invites reflection on the philosophical implications of quantum mechanics and the nature of reality itself, challenging our intuitive understanding of measurement and observation in the quantum world.
History: The ‘Wigner’s Friend’ thought experiment was proposed by Eugene Wigner in 1961 as part of his work on the interpretation of quantum mechanics. Wigner, a Hungarian-American physicist, was one of the pioneers in studying quantum mechanics and its philosophical implications. His experiment was developed in a context where the paradoxes of quantum mechanics were already being discussed, such as the famous double-slit experiment and Heisenberg’s uncertainty principle. Over the years, ‘Wigner’s Friend’ has been the subject of numerous debates and analyses within the scientific community, contributing to discussions about the Copenhagen interpretation and other quantum theories.
