Quantum_ Einstein, Bohr and the Great Debate About the Nature of Reality - Manjit Kumar [188]
April: Heisenberg delivers a two-hour lecture on matrix mechanics attended by Einstein and Planck. Afterwards Einstein invites the young turk back to his apartment where the two of them discuss, Heisenberg recalled later, 'the philosophical background of my recent work'.
May: Heisenberg is appointed Bohr's assistant and lecturer at Copenhagen University. As Bohr recovers from a severe case of flu, Heisenberg begins using wave mechanics to account for the spectral lines of helium.
June: Dirac receives his PhD from Cambridge University with a thesis entitled 'Quantum Mechanics'.
July: Born puts forward the probability interpretation of the wave function. Schrödinger delivers a lecture in Munich and during the question-and-answer session, Heisenberg complains about the shortcomings of wave mechanics.
September: Dirac goes to Copenhagen and during his stay develops transformation theory, which shows that Schrödinger's wave mechanics and Heisenberg's matrix mechanics are special cases of a more general formulation of quantum mechanics.
October: Schrödinger visits Copenhagen. He, Bohr and Heisenberg fail to reach any sort of accord over the physical interpretation of either matrix or wave mechanics.
1927
January: Clinton Davisson and Lester Germer obtain conclusive evidence that wave-particle duality also applies to matter as they succeed in diffracting electrons.
February: After months of trying, tempers fray as Bohr and Heisenberg are no closer to developing a coherent physical interpretation of quantum mechanics. Bohr leaves on a month-long skiing holiday in Norway. In Bohr's absence, Heisenberg discovers the uncertainty principle.
1927
May: The uncertainty principle is published after arguments between Heisenberg and Bohr over its interpretation.
September: The Volta conference at Lake Como, Italy. Bohr presents his principle of complementarity and the central elements of what later became known as the Copenhagen interpretation of quantum mechanics. Born, Heisenberg and Pauli are among those present, but not Schrödinger or Einstein.
October: At the fifth Solvay conference in Brussels, the Einstein-Bohr debate begins over the foundations of quantum mechanics and the nature of reality. Schrödinger succeeds Planck as professor of theoretical physics at Berlin University. Compton is awarded the Nobel Prize for the discovery of the 'Compton effect'. Heisenberg, aged only 25, is appointed to a professorship at Leipzig University.
November: George Thomson, son of J.J. Thomson, the discoverer of the electron, reports the successful diffraction of electrons employing a different technique than Davisson and Germer.
1928
January: Pauli is appointed professor of theoretical physics at the ETH in Zurich.
February: Heisenberg delivers his inaugural lecture as professor of theoretical physics at Leipzig University.
1929
October: De Broglie receives the Nobel Prize for the discovery of the wave nature of the electron.
1930
October: The sixth Solvay conference in Brussels, the second round of the Einstein-Bohr debate as Bohr refutes Einstein's 'clock-in-the-box' thought experiment challenging the consistency of the Copenhagen interpretation.
1931
December: The Danish Academy of Sciences and Letters selects Bohr as the next occupant of the Aeresbolig, 'The House of Honour', a mansion built by the founder of the Carlsberg breweries.
1932
John von Neumann's book The Mathematical Foundations of Quantum Mechanics is published in German. It contains his famous 'impossibility proof' – no hidden variables theory can reproduce the predictions of quantum mechanics. Dirac is elected Lucasian Professor of Mathematics at Cambridge University – a post once held by Isaac Newton.
1933
January: The Nazis seize power in Germany. Luckily, Einstein is in