Quantum_mechanics_and_its_interpretation EPR_paradox

since twentieth century, quantum theory has proved successful in describing accurately physical reality of mesoscopic , microscopic world, in multiple reproducible physics experiments.

quantum mechanics developed aim of describing atoms , explaining observed spectral lines in measurement apparatus. although disputed in twentieth century, has yet challenged. philosophical interpretations of quantum phenomena, however, matter: question of how interpret mathematical formulation of quantum mechanics has given rise variety of different answers people of different philosophical persuasions (see interpretations of quantum mechanics).

quantum theory , quantum mechanics not provide single measurement outcomes in deterministic way. according understanding of quantum mechanics known copenhagen interpretation, measurement causes instantaneous collapse of wave function describing quantum system eigenstate of observable measured. einstein characterized imagined collapse in 1927 solvay conference. presented thought experiment in electrons introduced through small hole in sphere inner surface serves detection screen. electrons contact spherical detection screen in dispersed manner. electrons, however, individually described wave fronts expand in directions point of entry. wave understood in everyday life paint large area of detection screen, electrons found impact screen @ single points , form pattern in keeping probabilities described identical wave functions. einstein asks makes each electron s wave front collapse @ respective location. why electrons appear single bright scintillations rather dim washes of energy across surface? why single electron appear @ 1 point rather alternative point? behavior of electrons gives impression of signal having been sent possible points of contact have nullified 1 of them, or, in other words, have preferentially selected single point exclusion of others.