Difference between spin and polarisation?

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SUMMARY

The discussion clarifies the distinction between "spin" and "polarization," emphasizing that polarization is a classical concept related to various wave types, including electromagnetic and mechanical waves. In contrast, spin is a quantum mechanical property associated with particles, denoted by "s," which can only take integer or semi-integer values. The relationship between the two concepts is established through the quantization of classical waves into particles, such as photons and phonons, where photons exhibit spin +1 and two possible spin states, while electromagnetic waves have two polarization states.

PREREQUISITES
  • Understanding of classical wave concepts, including electromagnetic and mechanical waves.
  • Familiarity with quantum mechanics terminology, particularly "spin" and "quantization."
  • Knowledge of quantum field theory (QFT) and the Lorentz group representations.
  • Basic grasp of particle physics and the relationship between particles and their wave counterparts.
NEXT STEPS
  • Research the concept of "quantization of waves" in quantum mechanics.
  • Study the properties of photons, including their spin and polarization states.
  • Explore the implications of spin in quantum field theory (QFT).
  • Learn about the representation of the Lorentz group in particle physics.
USEFUL FOR

Students and professionals in physics, particularly those focusing on quantum mechanics and wave-particle duality, as well as educators seeking to clarify these fundamental concepts.

tozhan
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can someone explain to me the difference between spin and polarisation?? someone told me they were the same thing and now I am getting confussed.

:confused:
Tom
 
Science news on Phys.org
It's simple."Polarization" is a classical concept,u meet it when discussing any form of waves:electromagnetic,mechanical (sound waves in solids for example),thermal,gravitational.The concept of "spin" is entirely quantum.In QM it is the ratio for the spin angular momentum and is denoted by "s" and can take only integer and semiinteger values;in QFT is the dimension of the irreductible (for 0 and 1/2)/reductible (for 1,3/2,2,...) representation of the restricted Lorentz group.The connection between the two notions is realized by quantizing each classical wave:the electromagnetic->photon,the gravitational->graviton,the sound waves and the thermal waves in solids->phonon.The particles (quanta) have "spin",while the classical waves have "polarization".The photon has spin +1 and has 2 possible spin states.The electromagnetic wave has 2 possible polarization states.

Daniel.
 

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