Artificial Dynamical Effects in Quantum Field Theory

TL;DR

This paper explores how artificial dynamical effects arise in relativistic quantum field theory when Poincaré invariance is violated, and demonstrates that light-front quantization avoids these issues, simplifying the analysis of strong interactions.

Contribution

It highlights the emergence of artificial effects in non-invariant frameworks and advocates for light-front quantization as a solution to maintain Poincaré invariance in QFT.

Findings

Canonical quantization can lead to subjective descriptions due to pseudoforces.

Light-front quantization preserves Poincaré invariance and avoids spurious effects.

Examples include the GDH relation and the non-measurable impact of Lorentz contraction.

Abstract

In Newtonian mechanics, inertial pseudoforces - or fictitious forces - appear in systems studied in non-Galilean reference frames; e.g., a centrifugal force seems to arise if the dynamics is analyzed in a rotating reference frame. The equivalent of Galilean invariance for relativistic kinematics is Poincar\'e invariance; analogous artificial effects may arise in relativistic quantum field theory (QFT) if a system is studied in a framework violating Poincar\'e invariance. We highlight how such issues complicate the traditional canonical quantization of QFTs and can lead to a subjective description of natural phenomena. In fact, if the system involves the strong interaction, obtaining objective results can become an intractable problem using canonical quantization because the pseudoforces are essentially nonperturbative. In contrast, the treatment of the same problem using light-front (LF) quantization is free of spurious pseudoeffects because Poincar\'e invariance is manifest; thus the treatment of strong interaction problems becomes simpler. These statements are illustrated using several examples: the Gerasimov-Drell-Hearn (GDH) relation, a fundamental feature of QFT; the absence of any measurable impact of Lorentz contraction in high-energy collisions; and the fictitious character of vacuum fluctuation contributions to the cosmological constant.