Modular localization and the holistic structure of causal quantum theory, a historical perspective

TL;DR

This paper explores the concept of modular localization in quantum field theory (QFT), revealing its holistic structure, historical context, and implications for gauge theories, the crossing property, and the Higgs mechanism.

Contribution

It provides a new holistic perspective on localization in QFT, clarifies the Einstein-Jordan conundrum, and proposes alternative approaches to gauge theories and symmetry breaking.

Findings

Localization causes thermal behavior in QFT vacuum states

Revises the conceptual origin of the crossing property in particle theory

Suggests alternative solutions for gauge theories using string-local fields

Abstract

Recent insights into the conceptual structure of localization in QFT ("modular localization") led to clarifications of old unsolved problems. The oldest one is the Einstein-Jordan conundrum which led Jordan in 1925 to the discovery of quantum field theory. This comparison of fluctuations in subsystems of heat bath systems (Einstein) with those resulting from the restriction of the QFT vacuum state to an open subvolume (Jordan) leads to a perfect analogy; the globally pure vacuum state becomes upon local restriction a strongly impure KMS state. This phenomenon of localization-caused thermal behavior as well as the vacuum-polarization clouds at the causal boundary of the localization region places localization in QFT into a sharp contrast with quantum mechanics and justifies the attribute "holstic". In fact it positions the E-J Gedankenexperiment into the same conceptual category as the cosmological constant problem and the Unruh Gedankenexperiment. The holistic structure of QFT resulting from "modular localization" also leads to a revision of the conceptual origin of the crucial crossing property which entered particle theory at the time of the bootstrap S-matrix approach but suffered from incorrect use in the S-matrix settings of the dual model and string theory. The new holistic point of view, which strengthens the autonomous aspect of QFT, also comes with new messages for gauge theory by exposing the clash between Hilbert space structure and localization and presenting alternative solutions based on the use of stringlocal fields in Hilbert space. Among other things this leads to a radical reformulation of the Englert-Higgs symmetry breaking mechanism.