Deriving the needed wavefunction transformation for gauge symmetry?

In summary, the conversation discusses determining the transformation for \Psi that corresponds to the gauge transformation A\rightarrow A +\nabla F and \phi \rightarrow \phi - \frac{\partial F}{\partial t}. The speaker mentions being familiar with the transformation, but not knowing how to work from it to get the necessary operator for \Psi \rightarrow \Psi\prime. The other speaker suggests assuming a function psi that satisfies the Schrodinger equation with the un-transformed A and phi, and then determining what psi' needs to be to satisfy the equation with the transformed A' and phi'.
  • #1
quarky2001
34
0

Homework Statement


Take the Schrodinger equation for a point particle in a field:

[tex] i\hbar \frac{\partial \Psi}{\partial t} = \frac{1}{2m}(-i\hbar\nabla - q\vec{A})^2\Psi + q\phi\Psi [/tex]

I'm supposed to determine what the transformation for Psi is that corresponds to the gauge transformation [itex] A\rightarrow A +\nabla F [/itex] and [itex] \phi \rightarrow \phi - \frac{\partial F}{\partial t} [/itex]

The Attempt at a Solution



I know what the transformation should be, since these transformations are actually derived the other way around in most textbooks, but I have no idea how to work from these transformations to get the necessary operator for [itex] \Psi \rightarrow \Psi\prime [/itex].
 
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  • #2
Assume you have a function psi that satisfies the Schrodinger equation with the un-transformed A, phi, then ask what psi' needs to be to satisfy the Schrodinger equation with the transformed A', phi'.
 

1. What is the purpose of deriving the needed wavefunction transformation for gauge symmetry?

The purpose of deriving the needed wavefunction transformation for gauge symmetry is to ensure that a physical theory is invariant under local gauge transformations. This allows for the description of fundamental forces, such as electromagnetism and the strong and weak nuclear forces, in a consistent and mathematically rigorous manner.

2. What is gauge symmetry and why is it important in physics?

Gauge symmetry refers to the invariance of a physical theory under local transformations of its fields. It is important in physics because it allows us to describe fundamental forces in a unified and consistent way, and it also plays a crucial role in the development of quantum field theories.

3. How is the wavefunction transformation derived for gauge symmetry?

The wavefunction transformation for gauge symmetry is derived by imposing the condition of gauge invariance on the Lagrangian density of a physical theory. This involves introducing gauge fields and gauge covariant derivatives, and then finding the appropriate transformation properties for the fields under local gauge transformations.

4. What are the consequences of not properly accounting for gauge symmetry in a physical theory?

If gauge symmetry is not properly accounted for in a physical theory, it can lead to inconsistencies and contradictions within the theory. This can result in incorrect predictions and a breakdown of the mathematical framework that describes the theory.

5. Are there any real-life applications of gauge symmetry?

Yes, there are many real-life applications of gauge symmetry. For example, it is used in the Standard Model of particle physics to describe the fundamental forces and particles of the universe. It is also used in the development of quantum field theories, which have applications in fields such as condensed matter physics and materials science.

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