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arXiv:2604.24871

Six textbook mistakes in quantum field theory

Alexandros Gezerlis

physics.ed-phhep-thnucl-thquant-phSubmitted Apr 27, 2026• Announced Apr 29, 2026
arXivHTMLPDF

Abstract

This article discusses incorrect statements appearing in textbooks on quantum field theory (QFT); some of these mistakes also appear in the research literature. The focus is not on errors made by an individual author, but on conceptual muddledness that is widespread in introductory textbooks. We start from a bare-bones summary of QFT, meant to establish the notation. We then turn to our six paradigmatic themes, in each case quoting a specific example of the textbook mistake, a summary of material that is known to experts but is frequently mishandled in introductory works, pointers to authoritative references where the relevant concept is handled properly, as well as a concise correction that rectifies any issues. The goal of this work is to warn readers of the existence of several pitfalls and thereby stop these errors from further propagating in the literature on QFT.

Comments
13 pages, 2 figures

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This article discusses incorrect statements appearing in textbooks on quantum field theory (QFT); some of these mistakes also appear in the research literature. The focus is not on errors made by an individual author, but on conceptual muddledness that is widespread in introductory textbooks. We start from a bare-bones summary of QFT, meant to establish the notation. We then turn to our six paradigmatic themes, in each case quoting a specific example of the textbook mistake, a summary of material that is known to experts but is frequently mishandled in introductory works, pointers to authoritative references where the relevant concept is handled properly, as well as a concise correction that rectifies any issues. The goal of this work is to warn readers of the existence of several pitfalls and thereby stop these errors from further propagating in the literature on QFT.
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Abstract Based on a series of courses taught by the authors, this theoretical-physics textbook takes the reader on a journey from the beginnings of quantum theory in the early twentieth century to the realm of quantum-information processing in the twenty-first. It provides an introductory text on quantum mechanics and quantum information theory for undergraduate students in physics and related subjects, but also serves as a resource for graduate students who want to engage with more advanced topics, while offering a collection of derivations, proofs, technical methods, and references for graduate students and more experienced readers engaged with teaching and active research.