Timeline of quantum mechanics

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This timeline of quantum mechanics shows the key steps, precursors and contributors to the development of quantum mechanics, quantum field theories and quantum chemistry.[1][2]

19th century[edit]

Image of Becquerel's photographic plate which has been fogged by exposure to radiation from a uranium salt. The shadow of a metal Maltese Cross placed between the plate and the uranium salt is clearly visible.
  • 1859 – Kirchhoff introduces the concept of a blackbody and proves that its emission spectrum depends only on its temperature.[1]
  • 1860–1900 – Ludwig Eduard Boltzmann, James Clerk Maxwell and others develop the theory of statistical mechanics. Boltzmann argues that entropy is a measure of disorder.[1]
  • 1877 – Boltzmann suggests that the energy levels of a physical system could be discrete based on statistical mechanics and mathematical arguments; also produces the first circle diagram representation, or atomic model of a molecule (such as an iodine gas molecule) in terms of the overlapping terms α and β, later (in 1928) called molecular orbitals, of the constituting atoms.
  • 1887 – Heinrich Hertz discovers the photoelectric effect, shown by Einstein in 1905 to involve quanta of light.
  • 1888 – Hertz demonstrates experimentally that electromagnetic waves exist, as predicted by Maxwell.[1]
  • 1888 – Johannes Rydberg modifies the Balmer formula to include all spectral series of lines for the hydrogen atom, producing the Rydberg formula which is employed later by Niels Bohr and others to verify Bohr's first quantum model of the atom.
  • 1895 – Wilhelm Conrad Röntgen discovers X-rays in experiments with electron beams in plasma.[1]
  • 1896 – Antoine Henri Becquerel accidentally discovers radioactivity while investigating the work of Wilhelm Conrad Röntgen; he finds that uranium salts emit radiation that resembled Röntgen's X-rays in their penetrating power. In one experiment, Becquerel wraps a sample of a phosphorescent substance, potassium uranyl sulfate, in photographic plates surrounded by very thick black paper in preparation for an experiment with bright sunlight; then, to his surprise, the photographic plates are already exposed before the experiment starts, showing a projected image of his sample.[1][3]
  • 1896 – Pieter Zeeman first observes the Zeeman splitting effect by passing the light emitted by hydrogen through a magnetic field.
  • 1896–1897 Marie Curie (née Skłodowska, Becquerel's doctoral student) investigates uranium salt samples using a very sensitive electrometer device that was invented 15 years before by her husband and his brother Jacques Curie to measure electrical charge. She discovers that rays emitted by the uranium salt samples make the surrounding air electrically conductive, and measures the emitted rays' intensity. In April 1898, through a systematic search of substances, she finds that thorium compounds, like those of uranium, emitted "Becquerel rays", thus preceding the work of Frederick Soddy and Ernest Rutherford on the nuclear decay of thorium to radium by three years.[4]
  • 1897 – Ivan Borgman demonstrates that X-rays and radioactive materials induce thermoluminescence.
  • 1897 – J. J. Thomson's experimentation with cathode rays led him to suggest a fundamental unit more than a 1,000 times smaller than an atom, based on the high charge-to-mass ratio. He called the particle a "corpuscle", but later scientists preferred the term electron.
  • 1899 to 1903 – Ernest Rutherford, 1st Baron, Lord Rutherford of Nelson, of Cambridge, OM, FRS: During the investigation of radioactivity he coins the terms alpha and beta rays in 1899 to describe the two distinct types of radiation emitted by thorium and uranium salts. Ernest Rutherford is joined at McGill University in 1900 by Frederick Soddy and together they discover nuclear transmutation when they find in 1902 that radioactive thorium is converting itself into radium through a process of nuclear decay and a gas (later found to be 4
    ); they report their interpretation of radioactivity in 1903.[5] Sir Ernest Rutherford becomes known as the "father of nuclear physics": with his nuclear atom model of 1911 he leads the exploration of nuclear physics.[6]

20th century[edit]


Einstein, in 1905, when he wrote the Annus Mirabilis papers
  • 1900 – To explain black-body radiation (1862), Max Planck suggests that electromagnetic energy could only be emitted in quantized form, i.e. the energy could only be a multiple of an elementary unit E = hν, where h is Planck's constant and ν is the frequency of the radiation.
  • 1902 – To explain the octet rule (1893), Gilbert N. Lewis develops the "cubical atom" theory in which electrons in the form of dots are positioned at the corner of a cube. Predicts that single, double, or triple "bonds" result when two atoms are held together by multiple pairs of electrons (one pair for each bond) located between the two atoms.
  • 1903 – Antoine Becquerel, Pierre Curie and Marie Curie share the 1903 Nobel Prize in Physics for their work on spontaneous radioactivity.
  • 1904 – Richard Abegg notes the pattern that the numerical difference between the maximum positive valence, such as +6 for H2SO4, and the maximum negative valence, such as −2 for H2S, of an element tends to be eight (Abegg's rule).
  • 1905 – Albert Einstein explains the photoelectric effect (reported in 1887 by Heinrich Hertz), i.e. that shining light on certain materials can function to eject electrons from the material. He postulates, as based on Planck's quantum hypothesis (1900), that light itself consists of individual quantum particles (photons).
  • 1905 – Einstein explains the effects of Brownian motion as caused by the kinetic energy (i.e., movement) of atoms, which was subsequently, experimentally verified by Jean Baptiste Perrin, thereby settling the century-long dispute about the validity of John Dalton's atomic theory.
  • 1905 – Einstein publishes his Special Theory of Relativity.
  • 1905 – Einstein theoretically derives the equivalence of matter and energy.
  • 1907 to 1917 – Ernest Rutherford: To test his planetary model of 1904, later known as the Rutherford model, he sent a beam of positively charged alpha particles onto a gold foil and noticed that some bounced back, thus showing that an atom has a small-sized positively charged atomic nucleus at its center. However, he received in 1908 the Nobel Prize in Chemistry "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances",[7] which followed on the work of Marie Curie, not for his planetary model of the atom; he is also widely credited with first "splitting the atom" in 1917. In 1911 Ernest Rutherford explained the Geiger–Marsden experiment by invoking a nuclear atom model and derived the Rutherford cross section.
  • 1909 – Geoffrey Ingram Taylor demonstrates that interference patterns of light were generated even when the light energy introduced consisted of only one photon. This discovery of the wave–particle duality of matter and energy is fundamental to the later development of quantum field theory.
  • 1909 and 1916 – Einstein shows that, if Planck's law of black-body radiation is accepted, the energy quanta must also carry momentum p = h / λ, making them full-fledged particles.


A schematic diagram of the apparatus for Millikan's refined oil drop experiment.
  • 1911 – Lise Meitner and Otto Hahn perform an experiment that shows that the energies of electrons emitted by beta decay had a continuous rather than discrete spectrum. This is in apparent contradiction to the law of conservation of energy, as it appeared that energy was lost in the beta decay process. A second problem is that the spin of the Nitrogen-14 atom was 1, in contradiction to the Rutherford prediction of ½. These anomalies are later explained by the discoveries of the neutrino and the neutron.
  • 1911 – Ștefan Procopiu performs experiments in which he determines the correct value of electron's magnetic dipole moment, μB = 9.27×10−21 erg·Oe−1 (in 1913 he is also able to calculate a theoretical value of the Bohr magneton based on Planck's quantum theory).
  • 1912 – Victor Hess discovers the existence of cosmic radiation.
  • 1912 – Henri Poincaré publishes an influential mathematical argument in support of the essential nature of energy quanta.[8][9]
  • 1913 – Robert Andrews Millikan publishes the results of his "oil drop" experiment, in which he precisely determines the electric charge of the electron. Determination of the fundamental unit of electric charge makes it possible to calculate the Avogadro constant (which is the number of atoms or molecules in one mole of any substance) and thereby to determine the atomic weight of the atoms of each element.
  • 1913 – Ștefan Procopiu publishes a theoretical paper with the correct value of the electron's magnetic dipole moment μB.[10]
  • 1913 – Niels Bohr obtains theoretically the value of the electron's magnetic dipole moment μB as a consequence of his atom model
  • 1913 – Johannes Stark and Antonino Lo Surdo independently discover the shifting and splitting of the spectral lines of atoms and molecules due to the presence of the light source in an external static electric field.
  • 1913 – To explain the Rydberg formula (1888), which correctly modeled the light emission spectra of atomic hydrogen, Bohr hypothesizes that negatively charged electrons revolve around a positively charged nucleus at certain fixed "quantum" distances and that each of these "spherical orbits" has a specific energy associated with it such that electron movements between orbits requires "quantum" emissions or absorptions of energy.
  • 1914 – James Franck and Gustav Hertz report their experiment on electron collisions with mercury atoms, which provides a new test of Bohr's quantized model of atomic energy levels.[11]
  • 1915 – Einstein first presents to the Prussian Academy of Science what are now known as the Einstein field equations. These equations specify how the geometry of space and time is influenced by whatever matter is present, and form the core of Einstein's General Theory of Relativity. Although this theory is not directly applicable to quantum mechanics, theorists of quantum gravity seek to reconcile them.
  • 1916 – Paul Epstein[12] and Karl Schwarzschild,[13] working independently, derive equations for the linear and quadratic Stark effect in hydrogen.
  • 1916 – Gilbert N. Lewis conceives the theoretical basis of Lewis dot formulas, diagrams that show the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule.[14]
  • 1916 – To account for the Zeeman effect (1896), i.e. that atomic absorption or emission spectral lines change when the light source is subjected to a magnetic field, Arnold Sommerfeld suggests there might be "elliptical orbits" in atoms in addition to spherical orbits.
  • 1918 – Sir Ernest Rutherford notices that, when alpha particles are shot into nitrogen gas, his scintillation detectors shows the signatures of hydrogen nuclei. Rutherford determines that the only place this hydrogen could have come from was the nitrogen, and therefore nitrogen must contain hydrogen nuclei. He thus suggests that the hydrogen nucleus, which is known to have an atomic number of 1, is an elementary particle, which he decides must be the protons hypothesized by Eugen Goldstein.
  • 1919 – Building on the work of Lewis (1916), Irving Langmuir coins the term "covalence" and postulates that coordinate covalent bonds occur when two electrons of a pair of atoms come from both atoms and are equally shared by them, thus explaining the fundamental nature of chemical bonding and molecular chemistry.


A plaque at the University of Frankfurt commemorating the Stern–Gerlach experiment.


Electron microscope constructed by Ernst Ruska in 1933.
  • 1930 – Dirac hypothesizes the existence of the positron.[1]
  • 1930 – Dirac's textbook Principles of Quantum Mechanics is published, becoming a standard reference book that is still used today.
  • 1930 – Erich Hückel introduces the Hückel molecular orbital method, which expands on orbital theory to determine the energies of orbitals of pi electrons in conjugated hydrocarbon systems.
  • 1930 – Fritz London explains van der Waals forces as due to the interacting fluctuating dipole moments between molecules
  • 1930 – Pauli suggests in a famous letter that, in addition to electrons and protons, atoms also contain an extremely light neutral particle which he calls the "neutron." He suggests that this "neutron" is also emitted during beta decay and has simply not yet been observed. Later it is determined that this particle is actually the almost massless neutrino.[1]
  • 1931 – John Lennard-Jones proposes the Lennard-Jones interatomic potential
  • 1931 – Walther Bothe and Herbert Becker find that if the very energetic alpha particles emitted from polonium fall on certain light elements, specifically beryllium, boron, or lithium, an unusually penetrating radiation is produced. At first this radiation is thought to be gamma radiation, although it is more penetrating than any gamma rays known, and the details of experimental results are very difficult to interpret on this basis. Some scientists begin to hypothesize the possible existence of another fundamental particle.
  • 1931 – Erich Hückel redefines the property of aromaticity in a quantum mechanical context by introducing the 4n+2 rule, or Hückel's rule, which predicts whether an organic planar ring molecule will have aromatic properties.
  • 1931 – Ernst Ruska creates the first electron microscope.[1]
  • 1931 – Ernest Lawrence creates the first cyclotron and founds the Radiation Laboratory, later the Lawrence Berkeley National Laboratory; in 1939 he awarded the Nobel Prize in Physics for his work on the cyclotron.
  • 1932 – Irène Joliot-Curie and Frédéric Joliot show that if the unknown radiation generated by alpha particles falls on paraffin or any other hydrogen-containing compound, it ejects protons of very high energy. This is not in itself inconsistent with the proposed gamma ray nature of the new radiation, but detailed quantitative analysis of the data become increasingly difficult to reconcile with such a hypothesis.
  • 1932 – James Chadwick performs a series of experiments showing that the gamma ray hypothesis for the unknown radiation produced by alpha particles is untenable, and that the new particles must be the neutrons hypothesized by Fermi.[1]
  • 1932 – Werner Heisenberg applies perturbation theory to the two-electron problem to show how resonance arising from electron exchange can explain exchange forces.
  • 1932 – Mark Oliphant: Building upon the nuclear transmutation experiments of Ernest Rutherford done a few years earlier, observes fusion of light nuclei (hydrogen isotopes). The steps of the main cycle of nuclear fusion in stars are subsequently worked out by Hans Bethe over the next decade.
  • 1932 – Carl D. Anderson experimentally proves the existence of the positron.[1]
  • 1933 – Following Chadwick's experiments, Fermi renames Pauli's "neutron" to neutrino to distinguish it from Chadwick's theory of the much more massive neutron.
  • 1933 – Leó Szilárd first theorizes the concept of a nuclear chain reaction. He files a patent for his idea of a simple nuclear reactor the following year.
  • 1934 – Fermi publishes a very successful model of beta decay in which neutrinos are produced.
  • 1934 – Fermi studies the effects of bombarding uranium isotopes with neutrons.
  • 1934 – N. N. Semyonov develops the total quantitative chain chemical reaction theory, later the basis of various high technologies using the incineration of gas mixtures. The idea is also used for the description of the nuclear reaction.
  • 1934 – Irène Joliot-Curie and Frédéric Joliot-Curie discover artificial radioactivity and are jointly awarded the 1935 Nobel Prize in Chemistry[22]
  • 1935 – Einstein, Boris Podolsky, and Nathan Rosen describe the EPR paradox which challenges the completeness of quantum mechanics as it was theorized up to that time. Assuming that local realism is valid, they demonstrated that there would need to be hidden parameters to explain how measuring the quantum state of one particle could influence the quantum state of another particle without apparent contact between them.[23]
  • 1935 - Schrödinger develops the Schrödinger's cat thought experiment. It illustrates what he saw as the problems of the Copenhagen interpretation of quantum mechanics if subatomic particles can be in two contradictory quantum states at once.
  • 1935 – Hideki Yukawa formulates his hypothesis of the Yukawa potential and predicts the existence of the pion, stating that such a potential arises from the exchange of a massive scalar field, as it would be found in the field of the pion. Prior to Yukawa's paper, it was believed that the scalar fields of the fundamental forces necessitated massless particles.
  • 1936 – Alexandru Proca publishes prior to Hideki Yukawa his relativistic quantum field equations for a massive vector meson of spin-1 as a basis for nuclear forces.
  • 1936 – Garrett Birkhoff and John von Neumann introduce Quantum Logic[24] in an attempt to reconcile the apparent inconsistency of classical, Boolean logic with the Heisenberg Uncertainty Principle of quantum mechanics as applied, for example, to the measurement of complementary (noncommuting) observables in quantum mechanics, such as position and momentum;[25] current approaches to quantum logic involve noncommutative and non-associative many-valued logic.[26][27]
  • 1936 – Carl D. Anderson discovers muons while he is studying cosmic radiation.
  • 1937 – Hermann Arthur Jahn and Edward Teller prove, using group theory, that non-linear degenerate molecules are unstable.[28] The Jahn-Teller theorem essentially states that any non-linear molecule with a degenerate electronic ground state will undergo a geometrical distortion that removes that degeneracy, because the distortion lowers the overall energy of the complex. The latter process is called the Jahn-Teller effect; this effect was recently considered also in relation to the superconductivity mechanism in YBCO and other high temperature superconductors. The details of the Jahn-Teller effect are presented with several examples and EPR data in the basic textbook by Abragam and Bleaney (1970).
  • 1938 – Charles Coulson makes the first accurate calculation of a molecular orbital wavefunction with the hydrogen molecule.
  • 1938 – Otto Hahn and his assistant Fritz Strassmann send a manuscript to Naturwissenschaften reporting they have detected the element barium after bombarding uranium with neutrons. Hahn calls this new phenomenon a 'bursting' of the uranium nucleus. Simultaneously, Hahn communicate these results to Lise Meitner. Meitner, and her nephew Otto Robert Frisch, correctly interpret these results as being a nuclear fission. Frisch confirms this experimentally on 13 January 1939.
  • 1939 – Leó Szilárd and Fermi discover neutron multiplication in uranium, proving that a chain reaction is indeed possible.


A Feynman diagram showing the radiation of a gluon when an electron and positron are annihilated.



The baryon decuplet of the Eightfold Way proposed by Murray Gell-Mann in 1962. The
particle at the bottom had not yet been observed at the time, but a particle closely matching these predictions was discovered[41] by a particle accelerator group at Brookhaven, proving Gell-Mann's theory.
  • 1961 – Clauss Jönsson performs Young's double-slit experiment (1909) for the first time with particles other than photons by using electrons and with similar results, confirming that massive particles also behaved according to the wave–particle duality that is a fundamental principle of quantum field theory.
  • 1961 – Anatole Abragam publishes the fundamental textbook on the quantum theory of Nuclear Magnetic Resonance entitled The Principles of Nuclear Magnetism;[42]
  • 1961 – Sheldon Lee Glashow extends the electroweak interaction models developed by Julian Schwinger by including a short range neutral current, the Z_o. The resulting symmetry structure that Glashow proposes, SU(2) X U(1), forms the basis of the accepted theory of the electroweak interactions.
  • 1962 – Leon M. Lederman, Melvin Schwartz and Jack Steinberger show that more than one type of neutrino exists by detecting interactions of the muon neutrino (already hypothesised with the name "neutretto")
  • 1962 – Murray Gell-Mann and Yuval Ne'eman independently classify the hadrons according to a system that Gell-Mann called the Eightfold Way, and which ultimately led to the quark model (1964) of hadron composition.
  • 1962 – Jeffrey Goldstone, Yoichiro Nambu, Abdus Salam, and Steven Weinberg develop what is now known as Goldstone's Theorem: if there is a continuous symmetry transformation under which the Lagrangian is invariant, then either the vacuum state is also invariant under the transformation, or there must be spinless particles of zero mass, thereafter called Nambu-Goldstone bosons.
  • 1962 to 1973 – Brian David Josephson, predicts correctly the quantum tunneling effect involving superconducting currents while he is a PhD student under the supervision of Professor Brian Pippard at the Royal Society Mond Laboratory in Cambridge, UK; subsequently, in 1964, he applies his theory to coupled superconductors. The effect is later demonstrated experimentally at Bell Labs in the USA. For his important quantum discovery he is awarded the Nobel Prize in Physics in 1973.[43]
  • 1963 – Eugene P. Wigner lays the foundation for the theory of symmetries in quantum mechanics as well as for basic research into the structure of the atomic nucleus; makes important "contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles"; he shares half of his Nobel prize in Physics with Maria Goeppert-Mayer and J. Hans D. Jensen.
  • 1963 – Maria Goeppert Mayer and J. Hans D. Jensen share with Eugene P. Wigner half of the Nobel Prize in Physics in 1963 "for their discoveries concerning nuclear shell structure theory".[44]
  • 1963 – Nicola Cabibbo develops the mathematical matrix by which the first two (and ultimately three) generations of quarks can be predicted.
  • 1964 – Murray Gell-Mann and George Zweig independently propose the quark model of hadrons, predicting the arbitrarily named up, down, and strange quarks. Gell-Mann is credited with coining the term quark, which he found in James Joyce's book Finnegans Wake.
  • 1964 – François Englert, Robert Brout, Peter Higgs, Gerald Guralnik, C. R. Hagen, and Tom Kibble postulate that a fundamental quantum field, now called the Higgs field, permeates space and, by way of the Higgs mechanism, provides mass to all the elementary subatomic particles that interact with it. While the Higgs field is postulated to confer mass on quarks and leptons, it represents only a tiny portion of the masses of other subatomic particles, such as protons and neutrons. In these, gluons that bind quarks together confer most of the particle mass. The result is obtained independently by three groups: François Englert and Robert Brout; Peter Higgs, working from the ideas of Philip Anderson; and Gerald Guralnik, C. R. Hagen, and Tom Kibble.[45][46][47][48][49][50][51]
  • 1964 – Sheldon Lee Glashow and James Bjorken predict the existence of the charm quark. The addition is proposed because it allows for a better description of the weak interaction (the mechanism that allows quarks and other particles to decay), equalizes the number of known quarks with the number of known leptons, and implies a mass formula that correctly reproduced the masses of the known mesons.
  • 1964 – John Stewart Bell puts forth Bell's theorem, which used testable inequality relations to show the flaws in the earlier Einstein–Podolsky–Rosen paradox and prove that no physical theory of local hidden variables can ever reproduce all of the predictions of quantum mechanics. This inaugurated the study of quantum entanglement, the phenomenon in which separate particles share the same quantum state despite being at a distance from each other.
  • 1964 – Nikolai G. Basov and Aleksandr M. Prokhorov share the Nobel Prize in Physics in 1964 for, respectively, semiconductor lasers and Quantum Electronics; they also share the prize with Charles Hard Townes, the inventor of the ammonium maser.
  • 1967 – Steven Weinberg and Abdus Salam publish a paper in which he describes Yang–Mills theory using the SU(2) X U(1) supersymmetry group, thereby yielding a mass for the W particle of the weak interaction via spontaneous symmetry breaking.
  • 1968 – Stanford University: Deep inelastic scattering experiments at the Stanford Linear Accelerator Center (SLAC) show that the proton contains much smaller, point-like objects and is therefore not an elementary particle. Physicists at the time are reluctant to identify these objects with quarks, instead calling them partons — a term coined by Richard Feynman. The objects that are observed at SLAC will later be identified as up and down quarks. Nevertheless, "parton" remains in use as a collective term for the constituents of hadrons (quarks, antiquarks, and gluons). The existence of the strange quark is indirectly validated by the SLAC's scattering experiments: not only is it a necessary component of Gell-Mann and Zweig's three-quark model, but it provides an explanation for the kaon (K) and pion (π) hadrons discovered in cosmic rays in 1947.
  • 1969 to 1977 – Sir Nevill Mott and Philip Warren Anderson publish quantum theories for electrons in non-crystalline solids, such as glasses and amorphous semiconductors; receive in 1977 a Nobel prize in Physics for their investigations into the electronic structure of magnetic and disordered systems, which allow for the development of electronic switching and memory devices in computers. The prize is shared with John Hasbrouck Van Vleck for his contributions to the understanding of the behavior of electrons in magnetic solids; he established the fundamentals of the quantum mechanical theory of magnetism and the crystal field theory (chemical bonding in metal complexes) and is regarded as the Father of modern Magnetism.
  • 1969 and 1970 – Theodor V. Ionescu, Radu Pârvan and I.C. Baianu observe and report quantum amplified stimulation of electromagnetic radiation in hot deuterium plasmas in a longitudinal magnetic field; publish a quantum theory of the amplified coherent emission of radiowaves and microwaves by focused electron beams coupled to ions in hot plasmas.
  • 1970 – Glashow, John Iliopoulos and Luciano Maiani predict the charmed quark that is subsequently found experimentally and share a Nobel prize for their theoretical prediction.



  • 1980 to 1982 – Alain Aspect verify experimentally the quantum entanglement hypothesis; his Bell test experiments provide strong evidence that a quantum event at one location can affect an event at another location without any obvious mechanism for communication between the two locations.[59][60]
  • 1982 to 1997 – Tokamak Fusion Test Reactor (TFTR) at PPPL, Princeton, USA: Operated since 1982, produces 10.7MW of controlled fusion power for only 0.21s in 1994 by using T-D nuclear fusion in a tokamak reactor with "a toroidal 6T magnetic field for plasma confinement, a 3MA plasma current and an electron density of 1.0×1020 m−3 of 13.5 keV" [61]
  • 1983 – Carlo Rubbia and Simon van der Meer, at the Super Proton Synchrotron, see unambiguous signals of W particles in January. The actual experiments are called UA1 (led by Rubbia) and UA2 (led by Peter Jenni), and are the collaborative effort of many people. Simon van der Meer is the driving force on the use of the accelerator. UA1 and UA2 find the Z particle a few months later, in May 1983.
  • 1983 to 2011 – The largest and most powerful experimental nuclear fusion tokamak reactor in the world, Joint European Torus (JET) begins operation at Culham Facility in UK; operates with T-D plasma pulses and has a reported gain factor Q of 0.7 in 2009, with an input of 40MW for plasma heating, and a 2800-ton iron magnet for confinement;[62] in 1997 in a tritium-deuterium experiment JET produces 16 MW of fusion power, a total of 22 MJ of fusion, energy and a steady fusion power of 4 MW which is maintained for 4 seconds.[63]
  • 1985 to 2010 – The JT-60 (Japan Torus) begins operation in 1985 with an experimental D-D nuclear fusion tokamak similar to the JET; in 2010 JT-60 holds the record for the highest value of the fusion triple product achieved: 1.77×1028 K·s·m−3 = 1.53×1021 keV·s·m−3.;[64] JT-60 claims it would have an equivalent energy gain factor, Q of 1.25 if it were operated with a T-D plasma instead of the D-D plasma, and on May 9, 2006 attains a fusion hold time of 28.6 s in full operation; moreover, a high-power microwave gyrotron construction is completed that is capable of 1.5MW output for 1s,[65] thus meeting the conditions for the planned ITER, large-scale nuclear fusion reactor. JT-60 is disassembled in 2010 to be upgraded to a more powerful nuclear fusion reactor—the JT-60SA—by using niobium-titanium superconducting coils for the magnet confining the ultra-hot D-D plasma.
  • 1986 – Johannes Georg Bednorz and Karl Alexander Müller produce unambiguous experimental proof of high temperature superconductivity involving Jahn-Teller polarons in orthorhombic La2CuO4, YBCO and other perovskite-type oxides; promptly receive a Nobel prize in 1987 and deliver their Nobel lecture on December 8, 1987.[66]
  • 1986 – Vladimir Gershonovich Drinfeld introduces the concept of quantum groups as Hopf algebras in his seminal address on quantum theory at the International Congress of Mathematicians, and also connects them to the study of the Yang–Baxter equation, which is a necessary condition for the solvability of statistical mechanics models; he also generalizes Hopf algebras to quasi-Hopf algebras, and introduces the study of Drinfeld twists, which can be used to factorize the R-matrix corresponding to the solution of the Yang–Baxter equation associated with a quasitriangular Hopf algebra.
  • 1988 to 1998 – Mihai Gavrilă discovers in 1988 the new quantum phenomenon of atomic dichotomy in hydrogen and subsequently publishes a book on the atomic structure and decay in high-frequency fields of hydrogen atoms placed in ultra-intense laser fields.[67][68][69][70][71][72][73]
  • 1991 – Richard R. Ernst develops two-dimensional nuclear magnetic resonance spectroscopy (2D-FT NMRS) for small molecules in solution and is awarded the Nobel Prize in Chemistry in 1991 "for his contributions to the development of the methodology of high resolution nuclear magnetic resonance (NMR) spectroscopy."[74]
  • 1977 to 1995 – The top quark is finally observed by a team at Fermilab after an 18-year search. It has a mass much greater than had been previously expected — almost as great as a gold atom.
  • 1995 – Eric Cornell, Carl Wieman and Wolfgang Ketterle and co-workers at JILA create the first "pure" Bose–Einstein condensate. They do this by cooling a dilute vapor consisting of approximately two thousand rubidium-87 atoms to below 170 nK using a combination of laser cooling and magnetic evaporative cooling. About four months later, an independent effort led by Wolfgang Ketterle at MIT creates a condensate made of sodium-23. Ketterle's condensate has about a hundred times more atoms, allowing him to obtain several important results such as the observation of quantum mechanical interference between two different condensates.
  • 1998 – The Super-Kamiokande (Japan) detector facility reports experimental evidence for neutrino oscillations, implying that at least one neutrino has mass.
  • 1999 to 2013 – NSTX—The National Spherical Torus Experiment at PPPL, Princeton, USA launches a nuclear fusion project on February 12, 1999 for "an innovative magnetic fusion device that was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle"; NSTX is being used to study the physics principles of spherically shaped plasmas.[75]

21st century[edit]

Graphene is a planar atomic-scale honeycomb lattice made of carbon atoms which exhibits unusual and interesting quantum properties.

See also[edit]


  1. ^ a b c d e f g h i j k l m n o p q r s Peacock 2008, pp. 175–183
  2. ^ Ben-Menahem 2009
  3. ^ Becquerel, Henri (1896). "Sur les radiations émises par phosphorescence". Comptes Rendus. 122: 420–421. 
  4. ^ Marie Curie and the Science of Radioactivity: Research Breakthroughs (1897–1904). Aip.org. Retrieved on 2012-05-17.
  5. ^ Soddy, Frederick (December 12, 1922). "The origins of the conceptions of isotopes" (PDF). Nobel Lecture in Chemistry. Retrieved April 2012.  Check date values in: |access-date= (help)
  6. ^ Ernest Rutherford, Baron Rutherford of Nelson, of Cambridge. Encyclopædia Britannica on-line. Retrieved on 2012-05-17.
  7. ^ The Nobel Prize in Chemistry 1908: Ernest Rutherford. nobelprize.org
  8. ^ McCormmach, Russell (Spring 1967). "Henri Poincaré and the Quantum Theory". Isis. 58 (1): 37–55. doi:10.1086/350182. 
  9. ^ Irons, F. E. (August 2001). "Poincaré's 1911–12 proof of quantum discontinuity interpreted as applying to atoms". American Journal of Physics. 69 (8): 879–884. Bibcode:2001AmJPh..69..879I. doi:10.1119/1.1356056. 
  10. ^ Procopiu, Ştefan (1913). "Determining the Molecular Magnetic Moment by M. Planck's Quantum Theory". Bulletin scientifique de l'Académie Roumaine de sciences. 1: 151. 
  11. ^ Pais, Abraham (1995). "Introducing Atoms and Their Nuclei". In Brown, Laurie M.; Pais, Abraham; Pippard, Brian. Twentieth Century Physics. 1. American Institute of Physics Press. p. 89. ISBN 9780750303101. Now the beauty of Franck and Hertz's work lies not only in the measurement of the energy loss E2-E1 of the impinging electron, but they also observed that, when the energy of that electron exceeds 4.9 eV, mercury begins to emit ultraviolet light of a definite frequency ν as defined in the above formula. Thereby they gave (unwittingly at first) the first direct experimental proof of the Bohr relation! 
  12. ^ P. S. Epstein, Zur Theorie des Starkeffektes, Annalen der Physik, vol. 50, pp. 489-520 (1916)
  13. ^ K. Schwarzschild, Sitzungsberichten der Kgl. Preuss. Akad. d. Wiss. April 1916, p. 548
  14. ^ Lewis, G. N. (1916), "The Atom and the Molecule", J. Am. Chem. Soc., 38 (4): 762–85, doi:10.1021/ja02261a002 
  15. ^ H. A. Kramers, Roy. Danish Academy, Intensities of Spectral Lines. On the Application of the Quantum Theory to the Problem of Relative Intensities of the Components of the Fine Structure and of the Stark Effect of the Lines of the Hydrogen Spectrum, p. 287 (1919);Über den Einfluß eines elektrischen Feldes auf die Feinstruktur der Wasserstofflinien (On the influence of an electric field on the fine structure of hydrogen lines), Zeitschrift für Physik, vol. 3, pp. 199–223 (1920)
  16. ^ Lewis, G.N. (1926). "The conservation of photons". Nature. 118 (2981): 874–875. Bibcode:1926Natur.118..874L. doi:10.1038/118874a0. 
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  • Peacock, Kent A. (2008). "The Quantum Revolution : A Historical Perspective". Westport, Conn.: Greenwood Press. ISBN 9780313334481. 
  • Ben-Menahem, A. (2009). "Historical Encyclopedia of Natural and Mathematical Sciences" (1st ed.). Berlin: Springer: 4342–4349. ISBN 9783540688310.  |chapter= ignored (help)

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