The Copenhagen interpretation is a collection of views about the meaning of quantum mechanics, stemming from the work of Niels Bohr, Werner Heisenberg, Max Born, and others. The term "Copenhagen interpretation" was apparently coined by Heisenberg during the 1950s to refer to ideas developed in the 1925–1927 period, glossing over his disagreements with Bohr. Consequently, there is no definitive historical statement of what the interpretation entails. Features common across versions of the Copenhagen interpretation include the idea that quantum mechanics is intrinsically indeterministic, with probabilities calculated using the Born rule, and the principle of complementarity, which states that objects have certain pairs of complementary properties that cannot all be observed or measured simultaneously. Moreover, the act of "observing" or "measuring" an object is irreversible, and no truth can be attributed to an object except according to the results of its measurement. Copenhagen-type interpretations hold that quantum descriptions are objective, in that they are independent of physicists' personal beliefs and other arbitrary mental factors.
Paul Adrien Maurice Dirac was an English theoretical physicist who is considered to be one of the founders of quantum mechanics and quantum electrodynamics. He is credited with laying the foundations of quantum field theory. He was the Lucasian Professor of Mathematics at the University of Cambridge, a professor of physics at Florida State University and the University of Miami, and a 1933 Nobel Prize in Physics recipient.
Werner Karl Heisenberg was a German theoretical physicist and one of the main pioneers of the theory of quantum mechanics. He published his work in 1925 in a major breakthrough paper. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, his matrix formulation of quantum mechanics was substantially elaborated. He is known for the uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics".
Determinism is the philosophical view that events are completely determined by previously existing causes. Deterministic theories throughout the history of philosophy have developed from diverse and sometimes overlapping motives and considerations. Like eternalism, determinism focuses on particular events rather than the future as a concept. The opposite of determinism is indeterminism, or the view that events are not deterministically caused but rather occur due to chance. Determinism is often contrasted with free will, although some philosophers claim that the two are compatible.
Louis Victor Pierre Raymond, 7th Duc de Broglie was a French physicist and aristocrat who made groundbreaking contributions to quantum theory. In his 1924 PhD thesis, he postulated the wave nature of electrons and suggested that all matter has wave properties. This concept is known as the de Broglie hypothesis, an example of wave–particle duality, and forms a central part of the theory of quantum mechanics.
An interpretation of quantum mechanics is an attempt to explain how the mathematical theory of quantum mechanics might correspond to experienced reality. Although quantum mechanics has held up to rigorous and extremely precise tests in an extraordinarily broad range of experiments, there exist a number of contending schools of thought over their interpretation. These views on interpretation differ on such fundamental questions as whether quantum mechanics is deterministic or stochastic, local or non-local, which elements of quantum mechanics can be considered real, and what the nature of measurement is, among other matters.
In philosophy, philosophy of physics deals with conceptual and interpretational issues in modern physics, many of which overlap with research done by certain kinds of theoretical physicists. Philosophy of physics can be broadly divided into three areas:
David Joseph Bohm was an American–Brazilian–British scientist who has been described as one of the most significant theoretical physicists of the 20th century and who contributed unorthodox ideas to quantum theory, neuropsychology and the philosophy of mind. Among his many contributions to physics is his causal and deterministic interpretation of quantum theory known as De Broglie–Bohm theory.
In physics, a hidden-variable theory is a proposal which seeks to explain quantum mechanical phenomena through the introduction of hypothetical entities. The existence of fundamental indeterminacy for some measurements is assumed as part of the mathematical formulation of quantum mechanics; moreover, bounds for indeterminacy can be expressed in a quantitative form by the Heisenberg uncertainty principle. Most hidden-variable theories are attempts to avoid this indeterminacy, but possibly at the expense of requiring that nonlocal interactions be allowed.
Indeterminism is the idea that events are not caused, or are not caused deterministically.
In physics, complementarity is a conceptual aspect of quantum mechanics that Niels Bohr regarded as an essential feature of the theory. The complementarity principle holds that objects have certain pairs of complementary properties which cannot all be observed or measured simultaneously, for examples, position and momentum or wave and particle properties. In modern terms, complementarity encompasses both the uncertainty principle and wave-particle duality.
Alfred Landé was a German-American physicist known for his contributions to quantum theory. He is responsible for the Landé g-factor and an explanation of the Zeeman effect.
The ensemble interpretation of quantum mechanics considers the quantum state description to apply only to an ensemble of similarly prepared systems, rather than supposing that it exhaustively represents an individual physical system.
Science and technology in Germany has a long and illustrious history, and research and development efforts form an integral part of the country's economy. Germany has been the home of some of the most prominent researchers in various scientific disciplines, notably physics, mathematics, chemistry and engineering. Before World War II, Germany had produced more Nobel laureates in scientific fields than any other nation, and was the preeminent country in the natural sciences.
Edwin Crawford Kemble was an American physicist who made contributions to the theory of quantum mechanics and molecular structure and spectroscopy. During World War II, he was a consultant to the Navy on acoustic detection of submarines and to the Army on Operation Alsos.
David Mathias Dennison was an American physicist who made contributions to quantum mechanics, spectroscopy, and the physics of molecular structure.
The Bohr–Kramers–Slater theory was perhaps the final attempt at understanding the interaction of matter and electromagnetic radiation on the basis of the so-called old quantum theory, in which quantum phenomena are treated by imposing quantum restrictions on classically describable behaviour. It was advanced in 1924, and sticks to a classical wave description of the electromagnetic field. It was perhaps more a research program than a full physical theory, the ideas that are developed not being worked out in a quantitative way. The purpose of BKS Theory was to disprove Einstein's hypothesis of the light quantum.
Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain and predict natural phenomena. This is in contrast to experimental physics, which uses experimental tools to probe these phenomena.
An index list of articles about the philosophy of science.
Jan Faye is a Danish philosopher of science and metaphysics. He is currently associate professor in philosophy at the University of Copenhagen. Faye has contributed to a number of areas in philosophy including explanation, interpretation, philosophy of the humanities and the natural sciences, evolutionary naturalism, philosophy of Niels Bohr, and topics concerning time, causation, and backward causation (Retrocausality).
