Is quantum field theory the return of the ether?

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SUMMARY

Quantum field theory (QFT) is not a reinvention of the ether but rather a distinct framework that incorporates relativistic principles. QFT is built on the foundation of relativistic covariance, aligning with representations of the Lorentz group. The vacuum state in QFT acts as a relativistic ether, where light waves are excitations, yet it remains invariant for all observers moving at constant velocity, distinguishing it from classical ether concepts.

PREREQUISITES
  • Understanding of quantum field theory (QFT)
  • Familiarity with the Lorentz group and relativistic covariance
  • Knowledge of vacuum states in quantum mechanics
  • Basic concepts of light waves as excitations in a medium
NEXT STEPS
  • Study the principles of relativistic covariance in quantum mechanics
  • Explore the representations of the Lorentz group in physics
  • Investigate the role of vacuum states in quantum field theory
  • Learn about the differences between classical ether theories and modern physics concepts
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Physicists, students of theoretical physics, and anyone interested in the foundations of quantum mechanics and the implications of quantum field theory.

lucid
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Hi,

My question is about why quantum fields are used.

Are quantum fields just a reinvention of the ether? It seems like something superimposed on spacetime (from which theoretically spacetime should emerge in the case of gravity) from which particles can pop in and out of.

How wrong is it to call quantum field theory a reinvention of the ether?
 
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no. quantum fields are manifestly relativistically covariant, since they belong to a certain representation of the Lorentz group by construction.
 
Quantum fields can be said to have a relativistic aether (the "vacuum state") - in the sense that light waves are excitations of the vacuum state. However the vacuum state is the same for all observers moving at constant velocity, and in this way it is different from the non-relativistic aether.
 

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