Are equations of motion invariant under gauge transformations?

In summary, the equations of motion are not always invariant under gauge transformations. While for electrodynamics they are invariant, for Yang-Mills theories and the Einstein-Hilbert action, they are only covariant. This means that the equations of motion may change form, but their overall structure remains the same. A mathematical proof can be shown to demonstrate this.
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Baela
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We know that all actions are invariant under their gauge transformations. Are the equations of motion also invariant under the gauge transformations?

If yes, can you show a mathematical proof (instead of just saying in words)?
 
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Yes. Since the action is the same the path of least action is also the same.
 
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No, in general they are just covariant. For electrodynamics the equations of motion are invariant under gauge transformations, but for Yang-Mills theories they are just covariant. Similarly, the Einstein-Hilbert action is invariant under general coordinate transformations, but the Einstein equation of motion is just covariant.
 
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  • #4
Demystifier said:
No, in general they are just covariant. For electrodynamics the equations of motion are invariant under gauge transformations, but for Yang-Mills theories they are just covariant. Similarly, the Einstein-Hilbert action is invariant under general coordinate transformations, but the Einstein equation of motion is just covariant.
Thanks!
 
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1. What are gauge transformations?

Gauge transformations are mathematical transformations that are used to describe symmetries in physical systems. They involve changing the mathematical description of a system without affecting its physical properties.

2. What are equations of motion?

Equations of motion are mathematical equations that describe the motion of a physical system. They are typically used in classical mechanics to determine the position, velocity, and acceleration of an object at a given time.

3. How are gauge transformations related to equations of motion?

Gauge transformations are related to equations of motion because they can be used to transform the equations of motion into a different form without changing their physical meaning. This allows for different mathematical descriptions of the same physical system.

4. Are equations of motion invariant under gauge transformations?

Yes, equations of motion are invariant under gauge transformations. This means that the physical properties described by the equations of motion remain the same even after a gauge transformation is applied.

5. Why is it important to consider gauge transformations in physics?

Gauge transformations are important in physics because they allow for a more flexible and comprehensive understanding of physical systems. They also help to reveal underlying symmetries and principles that govern the behavior of these systems.

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