Hendrik Anthony Kramers
2 February 1894
|Died||24 April 1952 58) (aged|
|Alma mater||Leiden University|
|Known for|| Kramers–Heisenberg formula |
Kramers model for polymer chains
Kramers' degeneracy theorem
Kramers' opacity law
|Awards|| Lorentz Medal (1947)|
Hughes Medal (1951)
|Doctoral advisor|| Niels Bohr |
|Doctoral students|| Dirk ter Haar |
Nico van Kampen
Hendrik Anthony "Hans" Kramers (2 February 1894 – 24 April 1952) was a Dutch physicist who worked with Niels Bohr to understand how electromagnetic waves interact with matter and made important contributions to quantum mechanics and statistical physics.
Hans Kramers was born in Rotterdam.the son of Hendrik Kramers, a physician, and Jeanne Susanne Breukelman.
In 1912 Hans finished secondary education (HBS) in Rotterdam, and studied mathematics and physics at the University of Leiden, where he obtained a master's degree in 1916. Kramers wanted to obtain foreign experience during his doctoral research, but his first choice of supervisor, Max Born in Göttingen, was not reachable because of the first world war. Because Denmark was neutral in this war, as was the Netherlands, he travelled (by ship, overland was impossible) to Copenhagen, where he visited unannounced the then still relatively unknown Niels Bohr. Bohr took him on as a Ph.D. candidate and Kramers prepared his dissertation under Bohr's direction. Although Kramers did most of his doctoral research (on intensities of atomic transitions) in Copenhagen, he obtained his formal Ph.D. under Ehrenfest in Leiden, on 8 May 1919.
Kramers greatly enjoyed music and could play the cello and the piano.
He worked for almost ten years in Bohr's group, becoming an associate professor at the University of Copenhagen. He played a role in the ill-fated BKS theory of 1924-5 BKS theory. Kramers left Denmark in 1926 and returned to the Netherlands. He became a full professor in theoretical physics at Utrecht University, where he supervised Tjalling Koopmans. In 1934 he left Utrecht and succeeded Paul Ehrenfest in Leiden. From 1931 until his death he held also a cross appointment at Delft University of Technology.
Kramers was one of the founders of the Mathematisch Centrum in Amsterdam.
In 1925, with Werner Heisenberg he developed the Kramers–Heisenberg dispersion formula. He is also creditedwith introducing in 1948 the concept of renormalization into quantum field theory, although his approach was nonrelativistic. He is also credited for the Kramers–Kronig relations with Ralph Kronig which are mathematical equations relating real and imaginary parts of complex functions constrained by causality. One further refers to a Kramers turnover when the rate of thermally activated barrier crossing as a function of the damping goes through a maximum, thereby undergoing a transition between the energy diffusion and spatial diffusion regimes.
On 25 October 1920 he was married to Anna Petersen. They had three daughters and one son.
Kramers became member of the Royal Netherlands Academy of Arts and Sciences in 1929, he was forced to resign in 1942. He joined the Academy again in 1945.Kramers won the Lorentz Medal in 1947 and Hughes Medal in 1951.
The Copenhagen interpretation is a collection of views about the meaning of quantum mechanics principally attributed to Niels Bohr and Werner Heisenberg. It is one of the oldest of numerous proposed interpretations of quantum mechanics, as features of it date to the development of quantum mechanics during 1925–1927, and it remains one of the most commonly taught.
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research.
Wolfgang Ernst Pauli was an Austrian theoretical physicist and one of the pioneers of quantum physics. In 1945, after having been nominated by Albert Einstein, Pauli received the Nobel Prize in Physics for his "decisive contribution through his discovery of a new law of Nature, the exclusion principle or Pauli principle". The discovery involved spin theory, which is the basis of a theory of the structure of matter.
Paul Ehrenfest was an Austrian and Dutch theoretical physicist, who made major contributions to the field of statistical mechanics and its relations with quantum mechanics, including the theory of phase transition and the Ehrenfest theorem.
Hendrik Antoon Lorentz was a Dutch physicist who shared the 1902 Nobel Prize in Physics with Pieter Zeeman for the discovery and theoretical explanation of the Zeeman effect. He also derived the transformation equations underpinning Albert Einstein's special theory of relativity.
In physics, hidden-variable theories are proposals to provide explanations of quantum mechanical phenomena through the introduction of unobservable 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 at a deterministic description of quantum mechanics, to avoid quantum indeterminacy, but at the expense of requiring the existence of nonlocal interactions.
George Eugene Uhlenbeck was a Dutch-American theoretical physicist.
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. An example of such a pair is position and momentum. Bohr considered one of the foundational truths of quantum mechanics to be the fact that setting up an experiment to measure one quantity of a pair, for instance the position of an electron, excludes the possibility of measuring the other, yet understanding both experiments is necessary to characterize the object under study. In Bohr's view, the behavior of atomic and subatomic objects cannot be separated from the measuring instruments that create the context in which the measured objects behave. Consequently, there is no "single picture" that unifies the results obtained in these different experimental contexts, and only the "totality of the phenomena" together can provide a completely informative description.
Hendrik Brugt Gerhard Casimir ForMemRS was a Dutch physicist best known for his research on the two-fluid model of superconductors in 1934 and the Casimir effect in 1948.
In particle physics, the history of quantum field theory starts with its creation by Paul Dirac, when he attempted to quantize the electromagnetic field in the late 1920s. Major advances in the theory were made in the 1940s and 1950s, and led to the introduction of renormalized quantum electrodynamics (QED). QED was so successful and accurately predictive that efforts were made to apply the same basic concepts for the other forces of nature. By the late 1970s, these efforts successfully utilized gauge theory in the strong nuclear force and weak nuclear force, producing the modern standard model of particle physics.
Dirk Coster, was a Dutch physicist. He was a Professor of Physics and Meteorology at the University of Groningen.
The Solvay Conferences have been devoted to outstanding preeminent open problems in both physics and chemistry. They began with the historic invitation-only 1911 Solvay Conference on Physics, considered a turning point in the world of physics, and continue to the present day.
Ralph Kronig was a German physicist. He is noted for the discovery of particle spin and for his theory of X-ray absorption spectroscopy. His theories include the Kronig–Penney model, the Coster–Kronig transition and the Kramers–Kronig relations.
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.
Paul Sophus Epstein was a Russian-American mathematical physicist. He was known for his contributions to the development of quantum mechanics, part of a group that included Lorentz, Einstein, Minkowski, Thomson, Rutherford, Sommerfeld, Röntgen, von Laue, Bohr, de Broglie, Ehrenfest and Schwarzschild.
David Mathias Dennison was an American physicist who made contributions to quantum mechanics, spectroscopy, and the physics of molecular structure.
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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.
Nicolaas 'Nico' Godfried van Kampen was a Dutch theoretical physicist, who worked mainly on statistical mechanics and non-equilibrium thermodynamics.
Hendrika Johanna van Leeuwen was a Dutch physicist known for her early contributions to the theory of magnetism. She studied at Leiden University under the guidance of Hendrik Antoon Lorentz, obtaining her doctorate in 1919. Her thesis explained why magnetism is an essentially quantum mechanical effect, a result now referred to as the Bohr–van Leeuwen theorem. She continued to investigate magnetic materials at the "Technische Hogeschool Delft", first as "assistant" between September 1920 and April 1947, and then she was promoted to "lector in de theoretische en toegepaste natuurkunde".
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