- Quantum Electrodynamics (QED) is
**the theory of the interaction of quantized electromagnetic fields**. It turns out that the interaction of two electromagnetic fields involves the exchange of photons. - QED is an
**essential scientific theory that accounts for all observed physical phenomena**except those associated with general relativity theory and radioactive decay. QED is compatible with particular relativity theory, and special relativity equations are as well. Quantum electrodynamics (QED), a relativistic quantum field theory of electrodynamics, is among the most stringently tested theories in physics.

- The standard model puts
**the field theories QED**and QCD under one umbrella. QED determines each particle’s spin. Electrons of the same spin cancel each other out; the**one unpaired electron in the atom**will determine the spin. There is a high likelihood of either spin because of the large number of electrons, so when it goes through the magnetic field, it splits into two beams.

- Quantum mechanics is science’s most precise, influential theory of reality. Quantum electrodynamics (QED), quantum field theory of the interactions of charged particles with the electromagnetic field. Quantum Electrodynamics (QED) is
**the theory of the interaction of quantized electromagnetic fields**. It turns out that the interaction of two electromagnetic fields involves the exchange of photons. Quantum field theory, a branch of physics born from applying the rules of quantum mechanics to the electromagnetic field, sees a particle — the photon —as a “quantized” excitation of the field. He was instrumental in propelling quantum field theory to astonishing new heights in the description of nature. - The Spin Quantum Number (ms) describes
**the angular momentum of an electron**. An electron spins around an axis and has both angular momentum and orbital angular momentum. Each orbital can only hold two electrons, and one electron will have a +1/2 spin, and the other will have a -1/2 spin. The practical value of QED theory is that it**allows physicists to calculate the absorption and emission of light by atoms**. Quantum physics applies the rules of quantum mechanics to the electromagnetic field, and this field sees a particle, the photon, as a quantized excitation of the field. - The Higgs mechanism generates masses for elementary particles such as the electron and the W and Z particles (which mediate weak, short-range interactions) while leaving the long-range photon massless. The Higgs boson is the fundamental particle associated with the Higgs field, which
**gives mass to other fundamental particles such as electrons and quarks**. A particle’s mass determines how much it resists changing its speed or position when encountering a force. Not all fundamental particles have mass.