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Physics World

Light beats quantum mechanics

John Jeffers

Published Nov 1, 2000• 1 citation
Publisher

Abstract

The mathematics of quantum theory is based on operators rather than numbers. In optics this simple fact allows statistical quantities, such as the fluctuations in the electric field of a light beam, to be smaller than is allowed by classical physics. Experiments that measure these quantities can generally be divided into two types, depending on whether they measure the wave or the particle properties of light. This is in line with the "complementarity principle" of quantum mechanics, which states that the wave and particle aspects of a system cannot be observed at the same time.

DOI
10.1088/2058-7058/13/11/28

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The mathematics of quantum theory is based on operators rather than numbers. In optics this simple fact allows statistical quantities, such as the fluctuations in the electric field of a light beam, to be smaller than is allowed by classical physics. Experiments that measure these quantities can generally be divided into two types, depending on whether they measure the wave or the particle properties of light. This is in line with the "complementarity principle" of quantum mechanics, which states that the wave and particle aspects of a system cannot be observed at the same time.
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The paper contains a quantum theoretical analysis of laser beam fluctuations and of the light beat experiments with two lasers. With the help of experimental results on photon counting fluctuations in a single-mode laser field, some correlation properties of the field are derived. It is shown that the correlation equations are satisfied by states of the field which are much more general than "coherent" states. The equations lead directly to the spectral density of the intensity operator in the light beat experiments, which can be obtained from photoelectric measurements. The resulting expression is practically identical to that found by Forrester for light having thermal statistical properties. The reasons for this are discussed by a comparison of the corresponding probability distributions of photon counts and of the classical wave amplitude.
New insight on the principles of the quantum physics development is given. The quite different behavior of quantum microworld mechanical systems in comparison with classical mechanical macroworld systems is attributed to the drastical change of the role of the gravitation field on the dynamics of microworld mechanical systems, for which it seems to be vanishing in com- parison with the role of the gravitation field on the dynamics of macroworld mechanical systems, for which it is decisive. The conclusion on the status of the second main postulate of quantum mechanics is given. Its formulation in all textbooks has to be represented in the form of the proved statement, since the hypothesis of Schrödinger on the existence of the field scalar function, being to be observable quantity, just charge density, is strictly mathematically proved. It is shown, that the field scalar function, being to be the solution of the corresponding nonstationary in general case Schrödinger equation and being to be the function the only of coordinates and time, actually describes the state of the atomic system, more strictly its corpuscular aspect. The atomic system is considered from the positions of the field theory, that is, it is the association of elementary particles with corresponding fields. The given fields being to be the media for the particles’ propagation are responsible for the wave aspect in the characteristic of atomic systems. The wave aspect is described by the independent scalar wave-function which was also introduced in quantum physics by Schrödinger, althogh the given fact seems to be unknown to the wide circle of the readers. The second main postulate being to be mathematically strictly grounded in Schrödinger formulation of quantum nechanics, in the popular probabilistic form of quantum nechanics cannot be proved for the general case, although the probabilistic theatise, proposed by Born is true in a number of special cases, quite correctly indicated by Dirac. The possible ways of the development of quantum theory, based on clear understanding of the origin of corpuscular-wave dualism and based on the fundamental both now mathemtically grounded main postulates are analysed.