Fifty years ago: The birth of quantum mechanics

Kristian Camilleri

Linus Carl Pauling

P. C. W. Davies, David S. Betts

This chapter presents the basic physical ideas that underpin the quantum theory. Historians place the beginnings of the quantum theory at 1900. That year Max Planck published his famous formula for the distribution of energy as a function of frequency in black-body radiation. Curiously, although radiation theory gave birth to quantum mechanics, the interaction of matter and electromagnetic radiation is a rather advanced topic in quantum mechanics and it took almost fifty years for an acceptable formulation to be achieved. One reason for this is that photons are quanta of the electromagnetic field, and the quantum theory of fields requires a relativistic treatment to be entirely successful. The corpuscular nature of light was only half of the input that gave birth to quantum mechanics. The other half concerns matter. Given that the discreteness of photons manifests itself during the emission and absorption process, it is not surprising to find that quantum oddities afflict the behaviour of material particles too.

Субхон Джомирзоев

The hundred and fifty years ago, I.Newton, in his corpuscular classic mechanics (CCM), introduced mass as an initial quantity, and, an its basis, defined other corpuscular quantities of CCM. And a hundred years ago, the corpuscular-wave properties of microparticles testified to the inherent corpuscular-wave quantities (CWQ), which as the initial value had the product of mass and wavelength. Accordingly, just as Newton’s CCM was based on corpuscular quantities, corpuscular-wave mechanics (CWM) should have been based on CWQ in the same way. But a hundred years ago, Plank’s and Einstein, to describe the corpuscular-wave properties of the photon, used hybrid of corpuscular quantities Newton’s CCM and wave quantities of wave optics, which a priori, by their definition, were insufficient to describe the CWQ of the photon. Subsequently, de Broglie and Schrödinger applied the method of Planck and Einstein to the case of a non-relativistic electron (NE), and obtained wave quantum mechanics (WQM). But the WQM he obtained turned out to be a real puzzle, and now, a hundred years later, l was able to discover that in reality WQM is an incomplete version of the CWM NE. The campaign managed to find out that Newton’s CCM arises in the form of a special case of the CWM macroscopic body. In this regard, now, l seem to be a Tajikistan physicist who discovered CWQ and CWM physics.

N. H. March

Quantum Mechanics, A Half Century Later: Papers of a Colloquium on Fifty Years of Quantum Mechanics, held at the University Louis Pasteur, Strasbourg, 2–4 May 1974 (Episteme 5), N H March