Integrate Laplacian operator by parts

In summary, the Laplacian operator is a mathematical operator used in vector calculus to measure divergence and curvature. Integration by parts is a technique used in calculus to evaluate products of functions. Integration by parts is useful for simplifying the Laplacian operator, making it easier to solve problems involving it. The steps for integrating the Laplacian operator by parts involve identifying functions, applying the product rule, and simplifying the resulting integral. Applications of integrating the Laplacian operator by parts include calculating electric fields and fluid flows, solving differential equations, and image processing.
  • #1
Eric_J
2
0
upload_2016-1-18_18-33-58.png

This is the key step to transform from position space Schrodinger equation to its counterpart in momentum space.
How is the first equation transformed into 3.21?
To be more specific, how to integral Laplacian term by parts?
 
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  • #2
Do you know tensor tensor calculus or at least the Gauss-Ostrograski theorem in 3D?
 
  • #3
dextercioby said:
Do you know tensor tensor calculus or at least the Gauss-Ostrograski theorem in 3D?
upload_2016-1-18_21-6-4.png

Thanks for the hint!
 

Related to Integrate Laplacian operator by parts

1. What is the Laplacian operator?

The Laplacian operator, denoted by ∇^2, is a mathematical operator used in vector calculus to measure the divergence and curvature of a vector field. It is often used in physics and engineering to describe physical phenomena such as fluid flow and electric fields.

2. What is integration by parts?

Integration by parts is a technique used in calculus to evaluate the integral of a product of two functions. It involves rewriting the integral in terms of a different set of functions and applying the product rule of differentiation.

3. Why is integration by parts useful for the Laplacian operator?

The Laplacian operator by itself is not easily integrated, but by using integration by parts, we can simplify the integral into a more manageable form. This makes it easier to solve problems involving the Laplacian operator, such as finding the potential of an electric field or the velocity of a fluid flow.

4. What are the steps for integrating the Laplacian operator by parts?

The steps for integrating the Laplacian operator by parts are as follows:
1. Identify the functions u and v in the product ∇^2(uv).
2. Apply the product rule to rewrite the integral as ∫ u(∇^2v) dx.
3. Integrate by parts, using the formula ∫ u(dv/dx) dx = uv - ∫ v(du/dx) dx.
4. Simplify the resulting integral to solve for the original integral of ∇^2(uv).

5. What are the applications of integrating the Laplacian operator by parts?

Integrating the Laplacian operator by parts has many applications in physics and engineering, such as calculating the potential of an electric field, determining the velocity of a fluid flow, and solving differential equations in heat transfer and wave propagation. It is also useful in image processing and machine learning for feature extraction and pattern recognition.

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