Coulomb Gauge vs. Lorentz Gauge transformation

In summary, the conversation discusses the methods for recognizing a Coulomb or Lorentz gauge transformation by creating an electric field and observing its form. It also mentions that there are other possible gauges and clarifies the distinction between gauge transformations and auxiliary conditions. The main question is how to determine if a given four-potential satisfies the Lorenz gauge, to which the response is to take its derivative and show that it equals zero.
  • #1
kthouz
193
0
Given a set of a scalar function V and a vector function, how does one recognize that it is a coulomb gauge or lorentz gauge transformation?
Actually there is a method that i use but i am not sure if it is always true:
what i do is to make an electric field (from that set and using known gauge transformation) and see if it has the form a coulomb electric field (static field). If it does i conclude that it is a coulomb gauge, else it is a Lorentz gauge.
Am i right?
 
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  • #2
You can find descriptions of the Coulomb and Lorentz gauge conditions here:

http://en.wikipedia.org/wiki/Gauge_fixing

(and probably in any E&M textbook at the intermediate level or above.)

If this isn't what you're looking for, please clarify...

Also note that there is in principle an infinite set of possible gauges, of which Coulomb and Lorentz are only two.
 
  • #3
The Coulomb and Lorenz gauges are not gauge transformations. They are auxiliary conditions on the four-potential that we may choose because of the fact that there is gauge freedom. If you have a given four-potential Aµ, and you want to check if it satisfies the Lorenz gauge, all you have to do is show that ∂µAµ = 0.
 
  • #4
Exactly. And how do you show this?
This is my question ...
 
  • #5
You take the derivative.
 

1. What is the difference between Coulomb Gauge and Lorentz Gauge transformation?

The Coulomb Gauge and Lorentz Gauge transformations are two different mathematical methods used to describe the electromagnetic field. The main difference between the two lies in the choice of gauge condition, which is a mathematical constraint used to simplify the equations of motion for the electromagnetic field.

2. How does the Coulomb Gauge transformation simplify the equations of motion?

The Coulomb Gauge transformation sets the divergence of the vector potential to zero, which eliminates one of the four Maxwell's equations. This simplifies the equations of motion and makes it easier to solve for the electric and magnetic fields.

3. What does the Lorentz Gauge transformation do?

The Lorentz Gauge transformation sets the divergence of the vector potential plus a time derivative to zero. This results in a different set of equations of motion, which can be more useful in certain situations, such as when dealing with moving charges.

4. When should the Coulomb Gauge be used?

The Coulomb Gauge is typically used when dealing with static or slowly varying electromagnetic fields, as it simplifies the equations of motion and makes it easier to solve for the fields.

5. In what situations is the Lorentz Gauge more useful?

The Lorentz Gauge is more useful in situations where there are moving charges or rapidly varying electromagnetic fields. It also has the advantage of being covariant under Lorentz transformations, making it useful in relativity and particle physics.

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