A Dimension of \lambda constant in \delta potential

Click For Summary
In the context of the time-independent Schrödinger equation with a delta potential, the potential is defined as V(x) = -λδ(x), where λ > 0. The dimension of the potential V(x) is established as ML²T⁻². The wave function ψ(x) has a dimension of L⁻½, while the delta function δ(x) is determined to have a dimension of L⁻¹ based on the integral property ∫ dx δ(x) = 1. Consequently, the dimension of λ can be derived from these relationships, leading to a clear understanding of its dimensionality in the context of the delta potential. This analysis highlights the interplay between the dimensions of the potential, wave function, and delta function in quantum mechanics.
LagrangeEuler
Messages
711
Reaction score
22
Time independent Schroedinger equation in ##\delta## potential ##V(x)=-\lambda \delta(x)##, where ##\lambda >0## is given by
-\frac{\hbar^2}{2m}\frac{d^2}{d x^2}\psi(x)-\lambda \delta(x)\psi(x)=E\psi(x).
How to find dimension of ##\lambda##? Dimension of ##V(x)## is
[V(x)]=ML^2T^{-2}.
Because it is one dimensional problem dimension of ##\psi(x)## is
[\psi(x)]=L^{-\frac{1}{2}}.
Is then also
[\delta(x)]=L^{-\frac{1}{2}}?
 
Physics news on Phys.org
The dimension of ##\psi## is irrelevant. From ##\int dx\,\delta(x)=1## it follows that the dimension of ##\delta## is ##L^{-1}##. From that, the dimension of ##\lambda## should be easy.
 
  • Like
Likes LagrangeEuler
Demystifier said:
The dimension of ##\psi## is irrelevant. From ##\int dx\,\delta(x)=1## it follows that the dimension of ##\delta## is ##L^{-1}##. From that, the dimension of ##\lambda## should be easy.
Thank you very much.
 
  • Like
Likes Demystifier
For the quantum state ##|l,m\rangle= |2,0\rangle## the z-component of angular momentum is zero and ##|L^2|=6 \hbar^2##. According to uncertainty it is impossible to determine the values of ##L_x, L_y, L_z## simultaneously. However, we know that ##L_x## and ## L_y##, like ##L_z##, get the values ##(-2,-1,0,1,2) \hbar##. In other words, for the state ##|2,0\rangle## we have ##\vec{L}=(L_x, L_y,0)## with ##L_x## and ## L_y## one of the values ##(-2,-1,0,1,2) \hbar##. But none of these...

Similar threads

  • · Replies 0 ·
Replies
0
Views
1K
  • · Replies 21 ·
Replies
21
Views
3K
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
59
Views
4K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 10 ·
Replies
10
Views
2K
Replies
1
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K