101.school
CoursesAbout
Search...⌘K
Generate a course with AI...

    Quantum Field Theory

    Receive aemail containing the next unit.
    • Introduction to Quantum Mechanics
      • 1.1Historical Background
      • 1.2Introduction to Quantum Concepts
      • 1.3Quantum States and Observables
    • Wave-Particle Duality
      • 2.1The Double Slit Experiment
      • 2.2Heisenberg's Uncertainty Principle
      • 2.3Quantum Superposition and Entanglement
    • The Schrödinger Equation
      • 3.1Time-Dependent Equation
      • 3.2Stationary States
      • 3.3Square Well Potential
    • Quantum Operators and Measurement
      • 4.1Quantum Operators
      • 4.2The Measurement Postulate
      • 4.3Complex Probability Amplitudes
    • Quantum Mechanics of Systems
      • 5.1Quantum Harmonic Oscillator
      • 5.2Quantum Angular Momentum
      • 5.3Particle in a Box
    • The Dirac Equation
      • 6.1Wave Equations
      • 6.2The Dirac Sea
      • 6.3Hole Theory
    • Introduction to Quantum Electrodynamics (QED)
      • 7.1Electromagnetic Field
      • 7.2Feynman Diagrams
      • 7.3QED Interactions
    • Path Integrals and Quantum Mechanics
      • 8.1Feynman’s Approach
      • 8.2Action Principle
      • 8.3Quantum Oscillator Problem
    • Symmetries in Quantum Field Theory
      • 9.1Gauge Symmetry
      • 9.2Poincaré Symmetry
      • 9.3Global and Local Symmetries
    • Quantum Chromodynamics
      • 10.1Color Charge
      • 10.2Quark Model
      • 10.3Confinement and Asymptotic Freedom
    • The Higgs Mechanism
      • 11.1Electroweak Symmetry Breaking
      • 11.2The Higgs Boson
      • 11.3Implication for Mass of Known Particles
    • Quantum Field Theory in Curved Space-Time
      • 12.1The Concept of Spacetime
      • 12.2Quantum Effects in Curved Spaces
      • 12.3Hawking Radiation
    • Quantum Cosmology and Conclusion
      • 13.1Big Bang Theory
      • 13.2Cosmic Inflation
      • 13.3Looking Ahead: Frontiers in Quantum Mechanics

    Introduction to Quantum Electrodynamics (QED)

    Understanding the Electromagnetic Field in Quantum Electrodynamics

    Abelian gauge theory describing quantum interactions of the electromagnetic field with matter

    Abelian gauge theory describing quantum interactions of the electromagnetic field with matter.

    Quantum Electrodynamics (QED) is the quantum field theory of electromagnetism. It describes how light and matter interact and is one of the key components of the Standard Model of particle physics. In this unit, we will delve into the fundamental concept of the electromagnetic field in QED.

    The Concept of the Electromagnetic Field

    The electromagnetic field is a physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. In classical physics, the electromagnetic field is described by Maxwell's equations. However, in the quantum realm, we need to understand it in terms of quantum field theory.

    The Role of Photons in the Electromagnetic Field

    In QED, the electromagnetic field is quantized, meaning it is made up of discrete packets of energy called quanta. These quanta of the electromagnetic field are what we know as photons. Photons are massless, chargeless particles that travel at the speed of light. They are the force carriers for the electromagnetic force, meaning they mediate interactions between charged particles.

    The Quantum Description of the Electromagnetic Field

    In the quantum description, the electromagnetic field is represented by a quantum field, a mathematical entity that has a value at every point in space and time. The quantum field can be thought of as an ocean of virtual photons, constantly being created and annihilated. These virtual photons mediate the electromagnetic interactions between charged particles.

    The Interaction of Charged Particles with the Electromagnetic Field

    When a charged particle, such as an electron, interacts with the electromagnetic field, it can absorb or emit photons, changing its energy, momentum, and other properties. This interaction is described by the rules of quantum mechanics and is represented visually by Feynman diagrams.

    In conclusion, the electromagnetic field is a fundamental concept in QED. It is the field through which light and matter interact, mediated by the exchange of photons. Understanding the electromagnetic field is crucial for understanding the behavior of particles in the quantum realm.

    Test me
    Practical exercise
    Further reading

    Hey there, any questions I can help with?

    Sign in to chat
    Next up: Feynman Diagrams