Curvilinear Coordinates and Vector Calculus

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SUMMARY

The discussion focuses on verifying operator identities involving the vector calculus operator \(\nabla\) and the angular momentum operator \(\vec{L}\) defined as \(\vec{L} = -i\vec{r} \times \nabla\). The identities to verify are \(\nabla = \hat{r}\frac{\partial }{\partial \vec{r}} - i\frac{\vec{r} \times \vec{L}}{r^{2}}\) and \(\vec{r} \nabla^2 - \nabla(1 + \vec{r}\frac{\partial }{\partial \vec{r}}) = i \nabla \times \vec{L}\). Participants noted the complexity of the equations and suggested using spherical coordinates and the double vector product identity for simplification.

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  • Understanding of vector calculus and operators
  • Familiarity with spherical coordinates
  • Knowledge of angular momentum in quantum mechanics
  • Proficiency in manipulating vector identities
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  • Study the derivation of the nabla operator in spherical coordinates
  • Learn about the double vector product identity and its applications
  • Explore the properties of angular momentum operators in quantum mechanics
  • Investigate the implications of operator identities in vector calculus
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Homework Statement



With [itex]\vec{L}[/itex] = -i[itex]\vec{r}[/itex] x [itex]\nabla[/itex], verify the operator identities

[itex]\nabla = \hat{r}\frac{\partial }{\partial \vec{r}}-i\frac{\vec{r}\times\vec{L}}{r^{2}}[/itex]
and
[itex]\vec{r} \bigtriangledown ^2 - \bigtriangledown (1+\vec{r}\frac{\partial }{\partial \vec{r}})=i\bigtriangledown \times \vec{L}[/itex]

Homework Equations


The Attempt at a Solution



... I tried to expand it, and use some identities... But the equation becomes super complicated... Help!
 
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I don't see other way to do it other than expanding and writing the nabla operator in spherical coordinates...The only identity you need is the one for double vector product

[tex]\vec{A}\times \left(\vec{B}\times\vec{C}\right) = \ ...[/tex]
 

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