The wave particle duality -- does the concept of particle make sense in quantum mechanics? Should we ask the second quantization?

TL;DR

This paper critically examines the particle concept in quantum mechanics, arguing it leads to contradictions and proposing that phenomena like wave function collapse challenge the traditional particle notion, with insights from experiments and cavity QED.

Contribution

It demonstrates that the particle concept results in contradictions in quantum experiments and explores alternative explanations involving virtual particles in cavity QED.

Findings

Particle concept leads to simultaneous localization contradictions.

Wave function collapse challenges the particle notion.

Virtual particles in cavity QED may offer solutions.

Abstract

The quantum object is in general considered as displaying both wave and particle nature. By particle is understood an item localized in a very small volume of the space, and which cannot be simultaneously in two disjoint regions of the space. By wave, to the contrary, is understood a distributed item, occupying in some cases two or more disjoint regions of the space. The quantum formalism did not explain until today the so called "collapse" of the wave function, i.e. the shrinking of the wave function to one small region of the space, when a macroscopic object is encountered. This seems to happen in "which way" experiments. A very appealing explanation for this behavior is the idea of a particle, localized in some limited part of the wave-function. The present article challenges the concept of particle. It proves in base of a variant of the Tan, Walls and Collett experiment, that this concept leads to a situation in which the particle has to be simultaneously in two places distant from one another, situation that contradicts the very definition of a particle. Another argument is based on a modified version of the Afshar experiment, showing that the concept of particle is problematic. The concept of particle makes additional difficulties when the wave-function passes through fields. An unexpected possibility to solve these difficulties seems to arise from the cavity quantum electrodynamics studies done recently by S. Savasta and his collaborators. It involves virtual particles. One of these studies is briefly described here. Though, experimental results are expected, so that it is too soon to draw conclusions whether it speaks in favor, or against the concept of particle.