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Ralph Kronig
Ralph Kronig (10 March 1904 – 16 November 1995) 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. Background Ralph Kronig (later Ralph de Laer Kronig) was born on 10 March 1904 to German parents (Harold Theodor Kronig, Augusta de Laer) in Dresden, Germany. He died in Zeist on 16 November 1995 at the age of 91. Kronig received his primary and high-school education in Dresden and went to New York City to study at Columbia University where he received his PhD in 1925 and subsequently became instructor (1925) and assistant professor (1927). Early in Kronig's career he had encountered Paul Ehrenfest who, while visiting America in 1924, had advised the young physicist Ralph Kronig to revisit Europe. Kronig left for that continent later in 1924 and paid visits to the important centers for theoret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Dresden
Dresden (; ; Upper Saxon German, Upper Saxon: ''Dräsdn''; , ) is the capital city of the States of Germany, German state of Saxony and its second most populous city after Leipzig. It is the List of cities in Germany by population, 12th most populous city of Germany, the fourth largest by area (after Berlin, Hamburg, and Cologne), and the third-most populous city in the area of former East Germany, after Berlin and Leipzig. Dresden's urban area comprises the towns of Freital, Pirna, Radebeul, Meissen, Coswig, Saxony, Coswig, Radeberg, and Heidenau and has around 790,000 inhabitants. The Dresden metropolitan area has approximately 1.34 million inhabitants. Dresden is the second largest city on the River Elbe after Hamburg. Most of the city's population lives in the Dresden Basin, Elbe Valley, but a large, albeit very sparsely populated, area of the city east of the Elbe lies in the West Lusatian Hill Country and Uplands (the westernmost part of the Sudetes) and thus in Lusatia. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Paul Ehrenfest
Paul Ehrenfest (; 18 January 1880 – 25 September 1933) was an Austrian Theoretical physics, theoretical physicist who made major contributions to statistical mechanics and its relation to quantum physics, quantum mechanics, including the theory of phase transition and the Ehrenfest theorem. He befriended Albert Einstein on a visit to Prague in 1912 and became a professor in Leiden, where he frequently hosted Einstein. Suffering from depression, in 1933 Ehrenfest killed his disabled son, Wassik, and then himself. Biography Paul Ehrenfest was born on 18 January 1880 in Vienna to Ashkenazi Jews, Jewish parents, who were originally from Loštice in Moravia (now part of the Czech Republic). His parents, Sigmund Ehrenfest and Johanna Jellinek, managed a grocery store. Although the family was not overly religious, Paul studied Hebrew language, Hebrew and Jewish history. Later, he always emphasized his Jewish ancestry. Ehrenfest excelled in grade school but did not do well at the Akad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Zürich
Zurich (; ) is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zurich. It is in north-central Switzerland, at the northwestern tip of Lake Zurich. , the municipality had 448,664 inhabitants. The Urban agglomeration, urban area was home to 1.45 million people (2020), while the Zurich Metropolitan Area, Zurich metropolitan area had a total population of 2.1 million (2020). Zurich is a hub for railways, roads, and air traffic. Both Zurich Airport and Zürich Hauptbahnhof, Zurich's main railway station are the largest and busiest in the country. Permanently settled for over 2,000 years, Zurich was founded by the Roman Empire, Romans, who called it '. However, early settlements have been found dating back more than 6,400 years (although this only indicates human presence in the area and not the presence of a town that early). During the Middle Ages, Zurich gained the independent and privileged status of imperial immediacy and, in 1519 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
London
London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Western Europe, with a population of 14.9 million. London stands on the River Thames in southeast England, at the head of a tidal estuary down to the North Sea, and has been a major settlement for nearly 2,000 years. Its ancient core and financial centre, the City of London, was founded by the Roman Empire, Romans as Londinium and has retained its medieval boundaries. The City of Westminster, to the west of the City of London, has been the centuries-long host of Government of the United Kingdom, the national government and Parliament of the United Kingdom, parliament. London grew rapidly 19th-century London, in the 19th century, becoming the world's List of largest cities throughout history, largest city at the time. Since the 19th cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Matrix Mechanics
Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925. It was the first conceptually autonomous and logically consistent formulation of quantum mechanics. Its account of quantum jumps supplanted the Bohr model's electron orbits. It did so by interpreting the physical properties of particles as matrices that evolve in time. It is equivalent to the Schrödinger wave formulation of quantum mechanics, as manifest in Dirac's bra–ket notation. In some contrast to the wave formulation, it produces spectra of (mostly energy) operators by purely algebraic, ladder operator methods. Relying on these methods, Wolfgang Pauli derived the hydrogen atom spectrum in 1926, before the development of wave mechanics. Development of matrix mechanics In 1925, Werner Heisenberg, Max Born, and Pascual Jordan formulated the matrix mechanics representation of quantum mechanics. Epiphany at Helgoland In 1925 Werner Heisenberg w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Rigid Rotor
In rotordynamics, the rigid rotor is a mechanical model of rotating systems. An arbitrary rigid rotor is a 3-dimensional rigid object, such as a top. To orient such an object in space requires three angles, known as Euler angles. A special rigid rotor is the ''linear rotor'' requiring only two angles to describe, for example of a diatomic molecule. More general molecules are 3-dimensional, such as water (asymmetric rotor), ammonia (symmetric rotor), or methane (spherical rotor). Linear rotor The linear rigid rotor model consists of two point masses located at fixed distances from their center of mass. The fixed distance between the two masses and the values of the masses are the only characteristics of the rigid model. However, for many actual diatomics this model is too restrictive since distances are usually not completely fixed. Corrections on the rigid model can be made to compensate for small variations in the distance. Even in such a case the rigid rotor model is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Schrödinger Equation
The Schrödinger equation is a partial differential equation that governs the wave function of a non-relativistic quantum-mechanical system. Its discovery was a significant landmark in the development of quantum mechanics. It is named after Erwin Schrödinger, an Austrian physicist, who postulated the equation in 1925 and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933. Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics. Given a set of known initial conditions, Newton's second law makes a mathematical prediction as to what path a given physical system will take over time. The Schrödinger equation gives the evolution over time of the wave function, the quantum-mechanical characterization of an isolated physical system. The equation was postulated by Schrödinger based on a postulate of Louis de Broglie that all matter has an associated matter wave. The equati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Isidor Isaac Rabi
Israel Isidor Isaac Rabi (; ; July 29, 1898 – January 11, 1988) was an American nuclear physicist who received the Nobel Prize in Physics in 1944 for his discovery of nuclear magnetic resonance, which is used in magnetic resonance imaging. He was also one of the first scientists in the United States to work on the cavity magnetron, which is used in microwave radar and microwave ovens. Born into a traditional Polish-Jewish family in Rymanów, Galicia (Central Europe), Galicia, Rabi came to the United States as an infant and was raised in New York's Lower East Side. He entered Cornell University as an electrical engineering student in 1916, but soon switched to chemistry. Later, he became interested in physics. He continued his studies at Columbia University, where he was awarded his doctorate for a thesis on the magnetic susceptibility of certain crystals. In 1927, he headed for Europe, where he met and worked with many of the finest physicists of the time. In 1929, Rabi retu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Samuel Goudsmit
Samuel Abraham Goudsmit (July 11, 1902 – December 4, 1978) was a Dutch-American physicist famous for jointly proposing the concept of electron spin with George Eugene Uhlenbeck in 1925. Life and career Goudsmit was born in The Hague, Netherlands, of Dutch Jewish descent. He was the son of Isaac Goudsmit, a manufacturer of water-closets, and Marianne Goudsmit-Gompers, who ran a millinery shop. In 1943, his parents were deported to a concentration camp by the German occupiers of the Netherlands and were murdered there. Goudsmit studied physics at the University of Leiden under Paul Ehrenfest, where he obtained his PhD in 1927. After receiving his PhD, Goudsmit served as a professor at the University of Michigan between 1927 and 1946. In 1930 he co-authored a text with Linus Pauling titled ''The Structure of Line Spectra.'' During World War II he worked at the Massachusetts Institute of Technology. As scientific head of the Alsos Mission, he successfully reached a Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
George Uhlenbeck
George Eugene Uhlenbeck (December 6, 1900 – October 31, 1988) was a Dutch-American theoretical physicist, known for his significant contributions to quantum mechanics and statistical mechanics. He co-developed the concept of electron spin, alongside Samuel Goudsmit, in 1925. The formalization of Langevin equation for the Brownian motion as a stochastic process, is known as the Ornstein–Uhlenbeck process, derived in 1930 from his work with Leonard Ornstein. I. I. Rabi said that Uhlenbeck and Goudsmit's omission for the Nobel Prize in Physics "will always be a mystery to me". Background and education George Uhlenbeck was the son of Eugenius and Anne Beeger Uhlenbeck. He attended the Hogere Burgerschool (High School) in The Hague, from which he graduated in 1918. He subsequently entered Delft University of Technology as a student in chemical engineering. During the next year, he transferred to Leiden University, to study physics and mathematics, and he earned his bachelor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hans Kramers
Hendrik Anthony "Hans" Kramers (17 December 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. Background and education Hans Kramers was born on 17 December 1894 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 P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Werner Heisenberg
Werner Karl Heisenberg (; ; 5 December 1901 – 1 February 1976) was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics and a principal scientist in the German nuclear program during World War II. He published his Umdeutung paper, ''Umdeutung'' paper in 1925, a major reinterpretation of old quantum theory. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, his matrix mechanics, 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". Heisenberg also made contributions to the theories of the Fluid dynamics, hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic particles. He introduced the concept of a wave function collapse. He was also instrumental in planning the first West Germa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
