137 - Arthur I. Miller [154]
“It is reasonable to inquire”: Eddington (1968), p. 319. See Miller (2005) for more on Eddington.
“What do you think of Eddington’s latest article”: Bohr to Pauli, January 8, 1929: PLC1 [213].
“on Eddington (??)”: Pauli to Bohr, January 16, 1929: PLC1 [214].
“for romantic poets and not for physicists”: Pauli to Klein, February 18, 1929: PLC1 [216].
“it makes no sense”: Pauli to Sommerfeld, May 16, 1929: PLC1 [225].
“‘Atomistik’ of the electric charge”: Pauli to Heisenberg, February 7, 1934: PLC1 [352].
“a deep unification of foundations”: Pauli (1933), p. 204. See Miller (1995) for more on Heisenberg’s and Pauli’s research on quantum electrodynamics during the 1930s.
relativity theory which deals with the universe: It is in the realms of imagination for the speed of light and also Planck’s constant to change; but the fine structure constant can never change because it is found in nature (the spacing between the fine structure of spectral lines—as found in the laboratory—is determined by 1/137).
This shows yet another meaning of the fine structure constant—the closeness of the bond between the worlds of quantum theory and of relativity that dramatically exhibits itself when scientists talk about moving between the everyday world and the worlds of relativity and quantum theory.
The only way to move back from the worlds of relativity and quantum theory to our daily world would be by making the speed of light infinite and Planck’s constant zero. Increasing the speed of light to infinity would make the relativity of time disappear. Reducing Planck’s constant to zero would do the same to the quantum qualities of the uncertainty relations and the wave-particle duality. We could then re-enter our everyday world where your time is the same as mine and things can be either particles or waves but not both. (In the quantum world, of course, electrons and light can be particles and waves at the same time.) But what physicists tend to forget in making these journeys between worlds is that the speed of light and Planck’s constant are both in the bottom line of the fraction for the fine structure constant: 2e2/hc. But the denominator in a fraction can never become zero because the result would be infinity, which is impossible in physics. Nor can we set the speed of light as infinite, which would make the fine structure constant zero, because it isn’t, it’s always 1/137. Both the speed of light and Planck’s constant have to be altered at once to ensure that the fine structure constant remains unchanged.
The fine structure constant, written by Niels Bohr on the blackboard in the physicist Edward M. Purcell’s office at Harvard University, 1961. Purcell, Norman Ramsey (another physicist at Harvard), and Bohr were discussing the subtleties in moving from the quantum to the classical world, when Bohr commented, “People say that classical mechanics is the limit of quantum mechanics when h goes to zero.” He shook his finger, walked to the blackboard and wrote the fine structure constant. As he underlined h three times, Bohr turned and said, “You see, h is in the denominator.”
“Everything will become beautiful”: Pauli to Heisenberg, April 17, 1934: PLC2 [369].
“I have been musing over the great question”: Pauli to Heisenberg, June 14, 1934: PLC2 [373].
“an interpretation of the numerical value”: Pauli (1934), p. 104.
“The Mysterious Number 137”: Born (1935).
“the central problem of natural philosophy”: Born (1935), p. 545.
“main problems of theoretical physics”: Enz (1997), p. 194, as recalled by a former student, Wilhelm Frank.
“a magic number that comes to us with no understanding by man”: Feynman (1985), p. 129.
additional spectral lines—a fine structure: As a result of Sommerfeld’s discovery of the fine structure constant, the quantity 2.7 × 10-11 ergs from Bohr’s original theory was re-expressed