Eigenvectors eigenvalues and constant of motion

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SUMMARY

The discussion focuses on the Hamiltonian for a particle in three-dimensional space, defined as H = Hx + Hy + Hz, where Hx, Hy, and Hz represent the kinetic and potential energy terms. Participants confirm that the standard angular momentum operator Lx is a constant of motion by checking the commutation relation with the Hamiltonian. Additionally, the ground state wavefunction Y0(x,y,z) is derived as a product of Gaussian functions, specifically Y0(x,y,z) = e^(-x^2/2) * e^(-y^2/2) * e^(-z^2/2), demonstrating the separation of variables in quantum mechanics.

PREREQUISITES
  • Understanding of Hamiltonian mechanics
  • Familiarity with angular momentum operators in quantum mechanics
  • Knowledge of wavefunctions and their normalization
  • Concept of commutation relations in quantum theory
NEXT STEPS
  • Study the Heisenberg equation of motion for further insights into constants of motion
  • Learn about the separation of variables in quantum mechanics
  • Explore the implications of commutation relations on physical observables
  • Investigate the normalization of wavefunctions in quantum mechanics
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Students and professionals in physics, particularly those studying quantum mechanics, as well as educators looking for examples of Hamiltonian systems and wavefunction analysis.

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Homework Statement



a.) The motion of a particle in the 3-dimensional space is described by the Hamiltonian H = Hx+Hy+Hz, where

Hx=1/2*(px2+x2), Hy=1/2*(py2+y2), Hz=1/2*(pz2+z2)

Check that the standard angular momentum operators Lx, is a constant of motion.

b.) By knowing that the ground state wavefunction for Hx is proportional to e-x2/2, write the wavefunction Y0(x,y,z) representing the ground state for H (you are not required to fix the normaliszation of the wavefunctions in this problem).

Homework Equations





The Attempt at a Solution



a.) Do you need to check if L and H commute?
b.) I really don't have a clue any tips?
 
Last edited:
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umagongdi said:

Homework Statement



a.) The motion of a particle in the 3-dimensional space is described by the Hamiltonian H = Hx+Hy+Hz, where

Hx=1/2*(px2+x2), Hy=1/2*(py2+y2), Hz=1/2*(pz2+z2)

Check that the standard angular momentum operators Lx, is a constant of motion.

b.) By knowing that the ground state wavefunction for Hx is proportional to e-x2/2, write the wavefunction Y0(x,y,z) representing the ground state for H (you are not required to fix the normaliszation of the wavefunctions in this problem).

Homework Equations


The Attempt at a Solution



a.) Do you need to check if L and H commute?
b.) I really don't have a clue any tips?
a.) Do you need to check if L and H commute?

Can you relate that commutator to the equations of motions. HINT: Look up the Heisenberg equation of motion.

b.) I really don't have a clue any tips?

Assume the wave function can be separated in its variables.
 
G01 said:
Assume the wave function can be separated in its variables.

Oh i think i get it now thanks. You can just separate the wave function like this?

Y0(x,y,z)=e-x2/2+e-y2/2+e-z2/2
 

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