14 research outputs found
On the Gravitational Field Produced by Light
Expressions are obtained, in accordance with Einstein's approximate solution of the equations of general relativity valid in weak fields, for the effect of steady pencils and passing pulses of light on the line element in their neighborhood. The gravitational fields implied by these line elements are then studied by examining the velocity of test rays of light and the acceleration of test particles in such fields. Test rays moving parallel to the pencil or pulse do so with uniform unit velocity the same as that in the pencil or pulse itself. Test rays moving in other directions experience a gravitational action. A test particle placed at a point equally distant from the two ends of a pencil experiences no acceleration parallel to the pencil, but is accelerated towards the pencil by twice the amount which would be calculated from a simple application of the Newtonian theory. The result is satisfactory from the point of view of the conservation of momentum. A test particle placed at a point equally distant from the two ends of the track of a pulse experiences no net integrated acceleration parallel to the track, but experiences a net acceleration towards the track which is satisfactory from the point of view of the conservation of momentum
Knowledge of past and future in quantum mechanics
It is well known that the principles of quantum mechanics limit the possibilities of exact prediction as to the future path of a particle. It has sometimes been supposed, nevertheless, that the quantum mechanics would permit an exact description of the past path of a particle.
The purpose of the present note is to discuss a simple ideal experiment which shows that the possibility of describing the past pathof one particlewould lead to the predictions as to the future behaviour of a second particle of a kind not allowed in the quantum mechanics. It will hence be concluded that the principles of quantum mechanics actually involve an uncertainty in the description of past events which is analogous to the the uncertainty in the prediction of future events. And it will be shown for the case in hand, that this uncertainty in the description of the past arises from a limitation of the knowledge that can be obtained by measurement of momentum
Classical diamagnetism, magnetic interaction energies, and repulsive forces in magnetized plasmas
The Bohr-van Leeuwen theorem is often summarized as saying that there is no
classical magnetic susceptibility, in particular no diamagnetism. This is
seriously misleading. The theorem assumes position dependent interactions but
this is not required by classical physics. Since the work of Darwin in 1920 it
has been known that the magnetism due to classical charged point particles can
only be described by allowing velocity dependent interactions in the
Lagrangian. Legendre transformation to an approximate Hamiltonian can give an
estimate of the Darwin diamagnetism for a system of charged point particles.
Comparison with experiment, however, requires knowledge of the number of
classically behaving electrons in the sample. A new repulsive effective
many-body force, which should be relevant in plasmas, is predicted by the
Hamiltonian.Comment: added references, revise
The Dispersion by Hydrogen-Like Atoms in Wave Mechanics
In view of the recent experimental determination of the dispersion by atomic hydrogen it seems interesting to apply the theory of dispersion developed by Schrodinger to this case. In this paper we restrict ourselves to an approximation in which terms of the order of relativistic correction are neglected. For this purpose it is simpler to obtain our wave equation by the operational method of Schrodinger and Eckart, as extended by Epstein, for in this way we immediately obtain an equation free of relativistic terms.
In what follows, in order to preserve a continuity of the discussion, details of calculations are omitted from the main text and are given as Supplementary Notes at the end of the paper. References will be found immediately preceding the Supplementary Notes.</p
On King's Classical Theory of Radiation
In his paper, "Gyromagnetic Electrons and a Classical Theory of Atomic Structure and Radiation," [1] Louis V. King endeavors to give a physical image of the quantum mechanism. Ever since quantum phenomena became definitely recognized many attempts were made to picture their mechanism [2]. In the case of King's theory there is an additional appeal to a scientific mind in the fact that his picture seems to unify the quantum phenomena with the classical electro-magnetic theory of Maxwell-Lorentz. Briefly stated the essentials of King's theory are as follows:
An electron is assumed to be a rigid sphere carrying a surface charge uniformly distributed and rigidly attached to the surface.
The electron is assumed spinning with constant intrinsic angular velocity Ω, the same for all electrons. The shape of the electron is assumed unchanged by rotation
The Dispersion by Hydrogen-Like Atoms in Undulatory Mechanics
In view of the recent experimental determination of the dispersion by atomic hydrogen [1] it seems interesting to apply the theory of dispersion developed by Schrödinger [2] to this case. In this paper we restrict ourselves to an approximation in which terms of the order of relativistic correction are neglected. For this purpose it is simpler to obtain our wave equation by the operational method of Schrödinger [3] and Eckart [4], as extended by Epstein [5], for in this way we immediately obtain an equation free of relativistic terms