Physics:Quantum mechanics/Timeline/Quantum field theory era
Quantum field theory (QFT) is a framework in theoretical physics that combines field theory, special relativity, and quantum mechanics.[1]Template:Rp It forms the foundation of modern particle physics and underlies the Standard Model of particle physics.
Introduction
Quantum field theory extends quantum mechanics to systems consistent with relativity. Instead of particles alone, physical reality is described in terms of fields, whose excitations correspond to particles. This framework allows the creation and annihilation of particles and successfully describes three of the four fundamental interactions.
Early development (1920s–1940s)
The origins of QFT lie in attempts to describe interactions between light and electrons. In 1927, Paul Dirac formulated quantum electrodynamics (QED), the first quantum field theory, explaining emission and absorption of radiation.
A major challenge emerged: calculations produced infinities. These difficulties temporarily cast doubt on the validity of QFT.
Renormalization and QED (1940s–1950s)
A breakthrough came with the development of renormalization, allowing infinities to be systematically removed. Key contributors included Julian Schwinger, Richard Feynman, and Shinichiro Tomonaga.
Feynman introduced Feynman diagrams, providing a visual and computational method for particle interactions. QED became one of the most precise theories in physics.
Gauge theories and unification (1950s–1970s)
The development of gauge theory extended QFT beyond electromagnetism. In 1954, Chen-Ning Yang and Robert Mills introduced non-Abelian gauge theories.
In the 1960s, Sheldon Glashow, Abdus Salam, and Steven Weinberg developed the electroweak theory, unifying electromagnetic and weak interactions. The introduction of spontaneous symmetry breaking and the Higgs boson allowed particles to acquire mass.
Quantum chromodynamics and the Standard Model (1970s)
The strong interaction was described by quantum chromodynamics (QCD), a gauge theory based on the symmetry group SU(3). Discoveries such as asymptotic freedom by David Gross, Frank Wilczek, and Hugh David Politzer enabled accurate high-energy predictions.
Together, QED, electroweak theory, and QCD form the Standard Model of particle physics, which successfully describes all known fundamental interactions except gravity.
Modern developments
Quantum field theory continues to evolve. It is applied in:
Despite its success, challenges remain, including the incorporation of gravity and establishing full mathematical rigor.
See also
Table of contents (185 articles)
Index
Full contents
References
- ↑ Peskin, M.; Schroeder, D. (1995). An Introduction to Quantum Field Theory. Westview Press. ISBN 978-0-201-50397-5.
Source attribution: Physics:Quantum field theory