komplementaarisuusperiaatetta

The komplementaarisuusperiaate, commonly referred to as the principle of complementarity, is a foundational concept in quantum physics formulated primarily by Niels Bohr in the early 20th century. It states that phenomena at the quantum level cannot be fully described by a single classical framework; instead, multiple, seemingly mutually exclusive experimental arrangements or theoretical descriptions are required to fully capture the behavior of quantum systems. For instance, the wave and particle aspects of light and electrons are complementary: they cannot be observed simultaneously in the same experiment, but together provide a complete picture of quantum behavior.

Bohr introduced the principle to explain the apparent contradictions between wave-like interference and particle-like trajectory observations. He emphasized that the choice of experimental apparatus determines which property of a quantum system will be revealed, and that these choices are intrinsic complements in the sense that they cannot be combined into a single classical model. This idea was later generalized as a philosophical stance: that all observations are contingent on the context and that classical concepts are only useful within their valid domains.

The principle has influenced interpretations of quantum mechanics, such as the Copenhagen interpretation, and has guided experimental approaches in quantum optics and information science. It underscores the necessity of acknowledging limits in our classical intuition when dealing with quantum reality.