THE WEAK INTERACTION: ITS HISTORY AND IMPACT ON PHYSICS

2001 ◽  
Vol 16 (22) ◽  
pp. 3633-3658 ◽  
Author(s):  
T. D. LEE
Keyword(s):  
Field Theory ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Transition Period ◽  
Weak Interactions ◽  
Coupling Constant ◽  
Β Decay ◽  
Fermi Interaction ◽  
Modern Period ◽  
History Of

It is a pleasure and an honor for me to give this lecture in honor of Oscar Klein who made major contributions to field theory, quantum electrodynamics and particle physics, including weak interactions. He was the first one to observe that the μ decay and the β decay could be described by the same interaction with the same coupling constant; this led to the discovery of the Universal Fermi Interaction. Perhaps I should begin my discussion of the history of weak interactions by separating it into three periods: (1) Classical Period, 1898–1949. (2) Transition Period, 1949–1956. (3) Modern Period, 1956–.

scholarly journals Dynamical Symmetries of the H Atom, One of the Most Important Tools of Modern Physics: SO(4) to SO(4,2), Background, Theory, and Use in Calculating Radiative Shifts

Symmetry ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1323 ◽  
Author(s):  
G. Jordan Maclay
Keyword(s):  
Hydrogen Atom ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Bound States ◽  
Integrated Treatment ◽  
Invariance Group ◽  
Elementary Particle Physics ◽  
Background Theory ◽  
Modern Physics ◽  
History Of

Understanding the hydrogen atom has been at the heart of modern physics. Exploring the symmetry of the most fundamental two body system has led to advances in atomic physics, quantum mechanics, quantum electrodynamics, and elementary particle physics. In this pedagogic review, we present an integrated treatment of the symmetries of the Schrodinger hydrogen atom, including the classical atom, the SO(4) degeneracy group, the non-invariance group or spectrum generating group SO(4,1), and the expanded group SO(4,2). After giving a brief history of these discoveries, most of which took place from 1935–1975, we focus on the physics of the hydrogen atom, providing a background discussion of the symmetries, providing explicit expressions for all of the manifestly Hermitian generators in terms of position and momenta operators in a Cartesian space, explaining the action of the generators on the basis states, and giving a unified treatment of the bound and continuum states in terms of eigenfunctions that have the same quantum numbers as the ordinary bound states. We present some new results from SO(4,2) group theory that are useful in a practical application, the computation of the first order Lamb shift in the hydrogen atom. By using SO(4,2) methods, we are able to obtain a generating function for the radiative shift for all levels. Students, non-experts, and the new generation of scientists may find the clearer, integrated presentation of the symmetries of the hydrogen atom helpful and illuminating. Experts will find new perspectives, even some surprises.

scholarly journals On the development of effective field theory

2021 ◽  
Author(s):  
Steven Weinberg
Keyword(s):  
Field Theory ◽  
Effective Field Theory ◽  
Particle Physics ◽  
Effective Field ◽  
Early History ◽  
First Century ◽  
Field Theories ◽  
Theory Approach ◽  
Seminar Series ◽  
History Of

AbstractEditor’s note: One of the most important developments in theoretical particle physics at the end of the 20th century and beginning of the twenty-first century has been the development of effective field theories (EFTs). Pursuing an effective field theory approach is a methodology for constructing theories, where a set of core principles is agreed upon, such as Lorentz symmetry and unitarity, and all possible interactions consistent with them are then compulsory in the theory. The utility of this approach to particle physics (and beyond) is wide ranging and undisputed, as evidenced by the recent formation of the international seminar series All Things EFT (Talks in the series can be viewed at https://www.youtube.com/channel/UC1_KF6kdJFoDEcLgpcegwCQ (accessed 21 December 2020).) which brings together each week the worldwide community of EFT practitioners. The text below is a lightly edited version of the talk given by Prof. Weinberg on September 30, 2020, which inaugurated the series. The talk reviews some of the early history of EFTs from the perspective of its pioneer and concludes with a discussion of EFT implications for future discovery.

Large-momentum behaviour in quantum field theory (QFT)

2021 ◽  
pp. 593-606
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Field Theory ◽  
Fixed Point ◽  
Fixed Points ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Large Momentum ◽  
Quantum Field ◽  
Four Dimensions ◽  
Free Theory ◽  
Electron Positron Annihilation

Renormalization group (RG) equations are used to characterize the large momentum behaviour of renormalized quantum field theories (QFT), assuming implicitly that such a universal large momentum physics can be defined, something which, beyond perturbation theory is not obvious. Since the initial effective QFT is valid only up to an energy-momentum scale much smaller than some cut-off, large momentum means much larger than the renormalization scale, but still much smaller than the cut-off scale. The existence of this large momentum physics implies the existence of a crossover scale between low and large momentum physics. One theoretic reason for discussing the large momentum behaviour is the apparent connection between the existence of consistent interacting renormalized QFTs and the presence of ultraviolet (UV) fixed points. The absence of identified UV fixed points in infrared-free QFTs, like the φ4 field theory or quantum electrodynamics (QED), leads to the triviality issue. The physics reason is that in collisions it is observed that quarks, fundamental particles of the Standard Model (SM) of particle physics, behave like free particles at the shortest distances presently accessible (the property of asymptotic freedom). This property can be explained by RG arguments if the free theory is an attractive UV fixed point. Therefore, the identification of QFTs where the free theory is an UV fixed point is important, and this has led to examine the large momentum behaviour of all QFTs renormalizable in four dimensions. It is shown that only theories having a non-Abelian gauge symmetry can be asymptotically free. As an application, the total cross section of electron–positron annihilation into hadrons at large momentum is calculated.

The development of the vector meson theory in Britain and Japan (1937–38)

1991 ◽  
Vol 24 (4) ◽  
pp. 405-433 ◽  
Author(s):  
Laurie M. Brown ◽  
Helmut Rechenberg
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Quantum Electrodynamics ◽  
Real Field ◽  
Electronic Charge ◽  
Quantum Field ◽  
Nuclear Forces ◽  
Β Decay ◽  
Meson Theory ◽  
Exchange Character

In order to formulate a fundamental quantum field theory of nuclear forces that explains their strength, range, and exchange character, while at the same time accounting for the weak β-decay interaction, Hideki Yukawa introduced a new kind of quantum field. In contrast to the real field of quantum electrodynamics (QED), which he took as his model, Yukawa's U-field was complex, and in contrast to the neutral massless photon of QED, the U-field's ‘heavy’ (i.e. massive) quanta were charged, carrying the electronic charge (positive and negative). The theory was proposed in November 1934 and published a few months later; however, its advantages were ignored, and for more than two years it went unnoticed, probably because there was no direct experimental evidence for the existence of U-quanta.

Abelian gauge theories: The framework of quantum electrodynamics (QED)

2021 ◽  
pp. 507-547
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Field Theory ◽  
Gauge Theory ◽  
Vector Field ◽  
Scalar Field ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Gauge Theories ◽  
Abelian Gauge ◽  
Four Dimensions ◽  
Gauge Fixing

This chapter is devoted Abelian gauge theory, whose physical realization is quantum electrodynamics (QED). Since many textbooks deal extensively with QED, the chapter focusses mainly on the more formal properties of Abelian gauge theories. First, the free massive vector field is considered, because its quantization does not immediately follow from the quantization of the scalar field, and thus requires a specific analysis. If the vector field is coupled to a conserved current, it is possible to construct a field theory with fermion matter renormalizable in four dimensions. In this case, a massless vector limit can be defined, and the corresponding field theory is gauge invariant. To directly quantize a gauge theory starting directly from first principles, it is necessary to introduce gauge fixing. The formal equivalence between different gauges is established. The Abelian gauge symmetry, broken by gauge-fixing terms, leads to a set of Ward–Takahashi (WT) identities which are used to prove the renormalizability of the quantum field theory (QFT). Renormalization group (RG) equations follow, and the RG β-function is calculated at leading order. As an introduction to the Standard Model of particle physics, the Abelian Landau–Ginzburg–Higgs model is described, where the gauge field is coupled to a complex scalar field with a non-zero expectation value, leading to a model that classically also describes a superconductor in a magnetic field.

Introduction to Quantum Field Theory

2019 ◽  
Author(s):  
Horatiu Nastase
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Cross Sections ◽  
Quantum Electrodynamics ◽  
Particle Physics ◽  
Vector Fields ◽  
Quantum Field ◽  
Fermionic Fields ◽  
Key Aspects ◽  
Scattering Cross Sections

Quantum Field Theory provides a theoretical framework for understanding fields and the particles associated with them, and is the basis of particle physics and condensed matter research. This graduate level textbook provides a comprehensive introduction to quantum field theory, giving equal emphasis to operator and path integral formalisms. It covers modern research such as helicity spinors, BCFW construction and generalized unitarity cuts; as well as treating advanced topics including BRST quantization, loop equations, and finite temperature field theory. Various quantum fields are described, including scalar and fermionic fields, Abelian vector fields and Quantum ElectroDynamics (QED), and finally non-Abelian vector fields and Quantum ChromoDynamics (QCD). Applications to scattering cross sections in QED and QCD are also described. Each chapter ends with exercises and an important concepts section, allowing students to identify the key aspects of the chapter and test their understanding.

scholarly journals Beta functions in the quantum field theory

2022 ◽  
Vol 70 (1) ◽  
pp. 157-168
Author(s):  
Nikola Fabiano
Keyword(s):  
Field Theory ◽  
Quantum Electrodynamics ◽  
Beta Function ◽  
Coupling Constants ◽  
Field Theories ◽  
Asymptotic Freedom ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Coupling Constant ◽  
High Energies

Introduction/purpose: The running of the coupling constant in various Quantum Field Theories and a possible behaviour of the beta function are illustrated. Methods: The Callan-Symanzik equation is used for the study of the beta function evolution. Results: Different behaviours of the coupling constant for high energies are observed for different theories. The phenomenon of asymptotic freedom is of particular interest. Conclusions: Quantum Electrodynamics (QED) and Quantum Chromodinamics (QCD) coupling constants have completely different behaviours in the regime of high energies. While the first one diverges for finite energies, the latter one tends to zero as energy increases. This QCD phenomenon is called asymptotic freedom.

History of Ardalānids (1590-1810) by Sharaf al-Dīn bin Shams al-Dīn

2017 ◽  
Vol 5 (1) ◽  
pp. 56-79
Author(s):  
Sara Zandi Karimi
Keyword(s):  
Early Modern ◽  
Early Modern Period ◽  
Historical Narrative ◽  
Modern Period ◽  
History Of ◽  
Critical Translation

This article is a critical translation of the “History of the Ardalānids.” In doing so, it hopes to make available to a wider academic audience this invaluable source on the study of Iranian Kurdistan during the early modern period. While a number of important texts pertaining to the Kurds during this era, most notably the writings of the Ottoman traveler Evliya Chalabi, focus primarily on Ottoman Kurdistan, this piece in contrast puts Iranian Kurdistan in general and the Ardalān dynasty in particular at the center of its historical narrative. Thus it will be of interest not only to scholars of Kurdish history but also to those seeking more generally to research life on the frontiers of empires.Keywords: Ẕayl; Ardalān; Kurdistan; Iran.ABSTRACT IN KURMANJIDîroka Erdelaniyan (1590-1810)Ev gotar wergereke rexneyî ya “Dîroka Erdelaniyan” e. Bi vê yekê, merema xebatê ew e ku vê çavkaniya pir biqîmet a li ser Kurdistana Îranê ya di serdema pêş-modern de ji bo cemawerê akademîk berdest bike. Hejmareke metnên girîng li ser Kurdên wê serdemê, bi taybetî nivîsînên Evliya Çelebî yê seyyahê osmanî, zêdetir berê xwe didine Kurdistana di bin hukmê Osmaniyan de. Lê belê, di navenda vê xebatê de, bi giştî Kurdistana Îranê û bi taybetî jî xanedana Erdelaniyan heye. Wisa jî ew dê ne tenê ji bo lêkolerên dîroka kurdî belku ji bo ewên ku dixwazin bi rengekî berfirehtir derheq jiyana li ser tixûbên împeretoriyan lêkolînan bikin jî dê balkêş be.ABSTRACT IN SORANIMêjûy Erdellan (1590-1810)Em wutare wergêrranêkî rexneyî “Mêjûy Erdellan”e, bew mebestey em serçawe girînge le ser Kurdistanî Êran le seretakanî serdemî nwê bixate berdest cemawerî ekademî. Jimareyek serçawey girîng le ser kurdekan lew serdeme da hen, diyartirînyan nûsînekanî gerîdey ‘Usmanî Ewliya Çelebîye, ke zortir serincyan le ser ‘Kurdistanî ‘Usmanî bûwe. Em berheme be pêçewanewe Kurdistanî Êran be giştî, we emaretî Erdelan be taybetî dexate senterî xwêndinewekewe. Boye nek tenya bo twêjeranî biwarî mêjûy kurdî, belku bo ewaney le ser jiyan le sinûre împiratoriyekan twêjînewe deken, cêgay serinc debêt.

Riemann–Weyl in Deleuze's Bergsonism and the Constitution of the Contemporary Physico-Mathematical Space

2015 ◽  
Vol 9 (1) ◽  
pp. 59-87 ◽  
Author(s):  
Martin Calamari
Keyword(s):  
Field Theory ◽  
Gauge Field ◽  
Fibre Bundle ◽  
History Of Mathematics ◽  
Gauge Field Theory ◽  
Contemporary Science ◽  
Explicit Mention ◽  
History Of ◽  
Key Features ◽  
Bernhard Riemann

In recent years, the ideas of the mathematician Bernhard Riemann (1826–66) have come to the fore as one of Deleuze's principal sources of inspiration in regard to his engagements with mathematics, and the history of mathematics. Nevertheless, some relevant aspects and implications of Deleuze's philosophical reception and appropriation of Riemann's thought remain unexplored. In the first part of the paper I will begin by reconsidering the first explicit mention of Riemann in Deleuze's work, namely, in the second chapter of Bergsonism (1966). In this context, as I intend to show first, Deleuze's synthesis of some key features of the Riemannian theory of multiplicities (manifolds) is entirely dependent, both textually and conceptually, on his reading of another prominent figure in the history of mathematics: Hermann Weyl (1885–1955). This aspect has been largely underestimated, if not entirely neglected. However, as I attempt to bring out in the second part of the paper, reframing the understanding of Deleuze's philosophical engagement with Riemann's mathematics through the Riemann–Weyl conjunction can allow us to disclose some unexplored aspects of Deleuze's further elaboration of his theory of multiplicities (rhizomatic multiplicities, smooth spaces) and profound confrontation with contemporary science (fibre bundle topology and gauge field theory). This finally permits delineation of a correlation between Deleuze's plane of immanence and the contemporary physico-mathematical space of fundamental interactions.

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