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Guilherme Mazui

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What is the Difference Between QED and QCD?

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The key difference between QED (Quantum Electrodynamics) and QCD (Quantum Chromodynamics) lies in the particles they describe and the forces they account for.

QED is a quantum field theory that describes the interactions of charged particles, such as electrons and positrons, with each other and with photons. It is the quantum field theory of the electromagnetic force. In QED, there is only one type of electric charge, which can be positive or negative, and the photons exchanged carry no charge.

On the other hand, QCD is a quantum field theory that describes the interactions between quarks and gluons. It is the theory that explains the behavior of quarks in terms of the strong force. In QCD, there are three different types of color charges, each of which can occur as color or anticolor. Gluons, the particles that carry the strong force, also carry color charges. This difference in charge types and carriers leads to distinct properties and behaviors in QED and QCD.

In summary:

  • QED describes the interactions of charged particles and is the quantum field theory of the electromagnetic force.
  • QCD describes the interactions between quarks and gluons and is the quantum field theory of the strong force.
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  • What is the Difference Between QED and QCD?
  • Comparative Table: QED vs QCD

    • Comparative Table: QED vs QCD

    Here is a table comparing the key differences between Quantum Electrodynamics (QED) and Quantum Chromodynamics (QCD):

    Property QED QCD
    Description QED is the quantum theory of electromagnetism, explaining the interactions of charged particles. QCD is the quantum theory of the strong nuclear force, explaining the interactions between quarks and gluons.
    Field Electromagnetism Strong nuclear force
    Particles Describes the interactions of charged particles (electrons, positrons, photons). Describes the interactions between quarks and gluons.
    Gluons Photons in QED cannot interact with each other. Gluons in QCD can interact with each other, allowing for the apparent confinement of quarks.
    Confinement No confinement of particles. Quarks are confined and found only in bound composites, such as protons and neutrons.
    Symmetry Abelian symmetry, meaning photons carry no electric charge. Non-Abelian symmetry, meaning gluons carry color charge.

    Both QED and QCD are quantum field theories that describe the behavior of subatomic particles. QED focuses on the interactions of charged particles, such as electrons and photons, while QCD deals with the interactions between quarks and gluons, which are responsible for the strong nuclear force holding quarks together to form protons and neutrons.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.