Quantum mechanics of electron–photon interaction

Gefen Baranes, Ron Ruimy, Alexey A. Gorlach +1 more

Abstract Entanglement of photons is a fundamental feature of quantum mechanics, which stands at the core of quantum technologies such as photonic quantum computing, communication, and sensing. An ongoing challenge in all these is finding an efficient and controllable mechanism to entangle photons. Recent experimental developments in electron microscopy enable to control the quantum interaction between free electrons and light. Here, we show that free electrons can create entanglement and bunching of light. Free electrons can control the second-order coherence of initially independent photonic states, even in spatially separated cavities that cannot directly interact. Free electrons thus provide a type of optical nonlinearity that acts in a nonlocal manner, offering a way of heralding the creation of entanglement. Intriguingly, pre-shaping the electron’s wavefunction provides the knob for tuning the photonic quantum correlations. The concept can be generalized to entangle not only photons but also photonic quasiparticles such as plasmon-polaritons and phonons.

Helmut Schwarz

Johan Hansson

We propose that the mechanism responsible for the ``collapse of the wave function" (or "decoherence" in its broadest meaning) in quantum mechanics is the nonlinearities already present in the theory via nonabelian gauge interactions. Unlike all other models of spontaneous collapse, our proposal is, to the best of our knowledge, the only one which does not introduce any new elements into the theory. Indeed, unless the gauge interaction nonlinearities are not used for exactly this purpose, one must then explain why the violation of the superposition principle which they introduce does not destroy quantum mechanics. A possible experimental test of the model would be to compare the coherence lengths for, e.g., electrons and photons in a double-slit experiment. The electrons should have a finite coherence length, while photons should have a much longer (in principle infinite) coherence length.

Puru Jena, Pavankumar Naik, T. Pradhan

Liudmila Borisovna Boldyreva

The aim of the work is to show that the study of following properties of electrons in atoms: stability of motion, the Pauli exclusion principle; the effect of electrons state (singlet or triplet) in hydrogen atoms on creating from them of the hydrogen molecule, - can be carried out based on concepts of classical mechanics (forces, moments). The contemporary investigation of topic “The Properties of Electrons in Atoms” is based on concepts of quantum mechanics, in particular on notions of electron wave function having probabilistic character. However, it is very difficult to perform the exact description of deterministic processes from the standpoint of probability theory. It has been proven in this work that description of properties of electrons in atom may be performed with using the concept of virtual photons created by the considered electrons. The concept of virtual photons was developed by Nobel Prize winner R. Feynman in 1949; one of the main properties of virtual photons is their ability to interact with each other by electric dipole interaction. The virtual photon is a unique object: except deterministic characteristic-(electric dipole moment) it has one of the attributes of wave function of the quantum object that created the virtual photon: the size of virtual photon equals the wavelength of this quantum object wave function. This is the reason why the description of properties of electrons in atom based on the concept of virtual photon created by atomic electrons is in accordance with some conclusions of quantum mechanical description of those properties.

N L Chuprikov