Generation of quasiparticles by particle-antiparticle mixing and limitations of quantum mechanics

TL;DR

This paper demonstrates that quantum field theory reveals limitations of quantum mechanics in describing neutral particle-antiparticle mixing, impacting predictions of decay processes and CP violation.

Contribution

It fully analyzes particle-antiparticle mixing within quantum field theory, showing quantum mechanics is not its proper non-relativistic limit and highlighting discrepancies affecting observable predictions.

Findings

Quantum mechanics does not accurately describe particle-antiparticle mixing in certain cases.

Discrepancies between quantum mechanics and quantum field theory can significantly alter decay width predictions.

Implications for neutral meson mixing and CP violation in particle decays.

Abstract

The mixing of a neutral unstable particle and its antiparticle has been usually discussed in the framework of quantum mechanics in the literature. In this paper, the particle-antiparticle mixing is discussed fully in the quantum field theory, and it is shown that quantum mechanics is not the proper non-relativistic limit of the quantum field theory in the presence of such mixing. Moreover, it is also shown that a discrepancy indeed exists between the results from quantum mechanics and the quantum field theory, which can sometimes make big differences in theoretical predictions of observables such as decay widths. This result has an implication for the mixing of neutral mesons and the CP violation in their decays.