Quantum Mechanics: Understanding Probability and Current Flow

Click For Summary
SUMMARY

The discussion centers on the relationship between quantum current density (J) and the wave function in quantum mechanics. The user grapples with understanding how substituting the wave function into the equation for current density yields a result of J=1, which suggests that one particle passes through a unit area per second. The confusion arises from the cancellation of units and the interpretation of J as a measure of particle flux. The user seeks clarification on whether this simplification accurately represents the flow of particles.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with wave functions and their properties
  • Knowledge of current density and its units
  • Basic grasp of particle flux concepts
NEXT STEPS
  • Explore the derivation of current density in quantum mechanics
  • Study the implications of wave function normalization
  • Learn about the continuity equation in quantum mechanics
  • Investigate the relationship between flux and probability density
USEFUL FOR

Students and researchers in physics, particularly those focusing on quantum mechanics, as well as educators seeking to clarify concepts related to current density and wave functions.

physicsjock
Messages
84
Reaction score
0
quantum current question

Hey,

I've been trying to work out this question and I'm really struggling to work out what to do.

http://img36.imageshack.us/img36/9759/afasp.jpg

I know that the units of current density is flow per unit area but I can't see a way to use that to prove the wave function has units such that exactly one particle passes per second.

When I sub the wave function into j I get j=1, all the units and everything cancel out.

Does getting j=1 mean only 1 particle flows through a unit area each second?

Substituting the wave function straight in seems too simple to answer the question,

Is there something I have missed?

Thanks in advanced
 
Last edited by a moderator:
Physics news on Phys.org
I've been looking around and reading around,

I found this, haha off wiki, it's consistent with some lecture slides I found online aswell.

http://en.wikipedia.org/wiki/Flux#Quantum_mechanics

"Then the number of particles passing through a perpendicular unit of area per unit time is J"

The thing that has me stumped is that its supposed to be flux right? Why do all the units cancel out? Is J just supposed to represent the NUMBER of particles?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 11 ·
Replies
11
Views
2K
Replies
4
Views
2K
Replies
12
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 7 ·
Replies
7
Views
1K
Replies
12
Views
2K