Circular Polarization and Quantum Spin: A Unified Real-Space Picture of Photons and Electrons

We recently performed experiments on the transfer of photon spin to electron orbital angular momentum. For an interpretation of the experimental results we used a classical electrodynamic model of the photon as a propagating electromagnetic solitary wave which is developed in detail here. A linearly polarized monochromatic photon is considered as a propagating solitary electromagnetic wave of finite energy hf which carries an angular momentum h/2pi with the frequency f and Pl...

This simple analysis shows that photon-like particles are not strange within the conceptual framework of the classical electromagnetic field theory. Circular polarized waves lead to photons. Thus, light quantum hypothesis is not necessary.

In the description of electron spin obtained through the conventional Copenhagen interpretation of quantum mechanics, the concrete picture of rotation was replaced by an abstract mathematical representation; visualization or visualisability was entirely lost. The work described here takes a step towards restoring this.

A simple real-space model for the free-electron wavefunction with spin is proposed, based on coherent vortices on the scale of h/mc, rotating at mc^2/h. This reproduces the proper values for electron spin and magnetic moment. Transformation to a moving reference frame turns this into a wave with the de Broglie wavelength. The mapping of the real two-dimensional vector phasor to the complex plane satisfies the Schrodinger equation. This suggests a fundamental role for spin in ...

Exact stationary solutions of the wave equation are obtained to describe the interaction between magnetic moment of elementary particle and circularly polarized photons. The obtained solutions substantially modify the conventional model of field-matter interaction. It follows from them that magnetic moment couples to photons, and this coupling leads to bound particle-photon states with different energies for different orientations of magnetic moment. As a consequence, the int...

We show that when an electron or photon propagates in a cylindrically symmetric waveguide, its spin angular momentum (SAM) and its orbital angular momentum (OAM) interact. Remarkably, we find that the dynamics resulting from this spin-orbit interaction are quantitatively described by a single expression applying to both electrons and photons. This leads to the prediction of several novel rotational effects: the spatial or time evolution of either particle's spin/polarization ...

A plane, monochromatic electromagnetic wave propagating in free space can have a certain amount of spin angular momentum but cannot possess any orbital angular momentum. Even the spin angular momentum of the plane-wave is difficult to evaluate without resort to certain mathematical limit arguments. Both spin and orbital angular momenta can be computed for a wavepacket of finite duration and finite cross-sectional area using standard methods of classical electrodynamics. Exten...

We theoretically demonstrate for the first time that a single free electron in circular/spiral motion emits twisted photons carrying well defined orbital angular momentum along the axis of the electron circulation, in adding to spin angular momentum. We show that, when the electron velocity is relativistic, the radiation field contains harmonic components and the photons of l-th harmonic carry lhbar total angular momentum for each. This work indicates that twisted photons are...

The comparison of the polarization and spin of light is presented in the paper. It is shown that it is more easier and clearer to use the polarization of the light to explain the effect of the interaction of light and atoms than that of spin of the light. The paper also gives rise to the question whether or not the concept of spin for photon have any essence for its existence.

An antisymmetric tensor, the photon tensor, is defined for the description of the photon as a massless relativistic particle. The photon can be visualized as an essentially two dimensional rotating object. The quantum mechanical description of a single photon is presented and it is shown that it is wrong to associate the quantum states of a photon with the macroscopic electromagnetic fields. This work is part of a series devoted to the attempt to understand the quantum of ele...