Is quantum field theory the return of the ether?

In summary, quantum fields are not a reinvention of the ether, as they are manifestly relativistically covariant and have a different concept of the "vacuum state" compared to the non-relativistic aether. While they may have some similarities, quantum field theory is a distinct concept from the traditional notion of the ether.
  • #1
lucid
5
0
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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  • #2
no. quantum fields are manifestly relativistically covariant, since they belong to a certain representation of the Lorentz group by construction.
 
  • #3
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.
 

1. What is quantum field theory?

Quantum field theory is a theoretical framework that combines the principles of quantum mechanics and special relativity to describe the behavior of particles and fields at the subatomic level. It is one of the most successful and well-tested theories in physics, and it has been used to explain a wide range of phenomena, from the behavior of particles in accelerators to the properties of materials.

2. What is the "ether" in physics?

The "ether" was a concept that was proposed in the 19th century to explain the propagation of light through space. It was thought to be a medium through which light waves traveled, similar to how sound waves travel through air. However, this concept was later disproven by the theories of relativity and quantum mechanics.

3. How is quantum field theory related to the concept of the ether?

Quantum field theory is not a return of the ether, as the ether has been shown to be an outdated and incorrect concept. However, some aspects of quantum field theory, such as the concept of a field, may have similarities to the idea of the ether. But these similarities are purely conceptual and do not indicate a revival of the ether theory.

4. Are there any experiments that support the existence of the ether?

No, there are no experiments that support the existence of the ether. In fact, many experiments, such as the Michelson-Morley experiment, have shown that the ether does not exist. These experiments have been consistently replicated and have helped to disprove the concept of the ether.

5. Why do some people still believe in the existence of the ether?

Some people may still believe in the ether because it was a widely accepted concept in the 19th century and it may still be included in some outdated textbooks or teachings. Additionally, the concept of the ether may be appealing to some as it provides a physical medium for the propagation of light. However, with the advancements in modern physics, the concept of the ether has been disproven and is no longer accepted in the scientific community.

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