How to Derive Raising and Lowering Operators from Ladder Operator Definitions?

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SUMMARY

This discussion focuses on deriving the raising and lowering operators, denoted as a and a†, from the definitions of ladder operators in quantum mechanics. The operators are defined as a=(1/2)ñ+∂n and a†=(1/2)n -∂ñ, where n and ñ are expressed in terms of the magnetic length L. Participants suggest calculating the commutator of a and a† to verify their properties, emphasizing the need to derive these operators rather than merely verify them.

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  • Knowledge of commutation relations in quantum mechanics.
  • Basic understanding of magnetic length in quantum systems.
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shinobi20
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Homework Statement


Define n=(x + iy)/(2)½L and ñ=(x - iy)/(2)½L.

Also, ∂n = L(∂x - i ∂y)/(2)½ and ∂ñ = L(∂x + i ∂y)/(2)½.

with ∂n=∂/∂n, ∂x=∂/∂x, ∂y=∂/∂y, and L being the magnetic length.

Show that a=(1/2)ñ+∂n and a=(1/2)n -∂ñ

a and a are the lowering and raising operators of quantum mechanics.

Homework Equations

3. The Attempt at a Solution [/B]
Sorry but I really don't have any idea on how start. I just know that a=(1/ (2)½) (x/x0-ip/p0) and a=(1/ (2)½) (x/x0+ip/p0) with x0=(ħ/mω)½ and p0=(ħmω)½
 
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shinobi20 said:

Homework Statement


Define n=(x + iy)/(2)½L and ñ=(x - iy)/(2)½L.

Also, ∂n = L(∂x - i ∂y)/(2)½ and ∂ñ = L(∂x + i ∂y)/(2)½.

with ∂n=∂/∂n, ∂x=∂/∂x, ∂y=∂/∂y, and L being the magnetic length.

Show that a=(1/2)ñ+∂n and a=(1/2)n -∂ñ

a and a are the lowering and raising operators of quantum mechanics.

Homework Equations

3. The Attempt at a Solution [/B]
Sorry but I really don't have any idea on how start. I just know that a=(1/ (2)½) (x/x0-ip/p0) and a=(1/ (2)½) (x/x0+ip/p0) with x0=(ħ/mω)½ and p0=(ħmω)½
Have you tried calculating the commutator of your a and ##a^\dagger##? The idea is to show that they are the same as for the raising and lowering operators.
 
nrqed said:
Have you tried calculating the commutator of your a and ##a^\dagger##? The idea is to show that they are the same as for the raising and lowering operators.
Wouldn't that just be verifying but not showing? I think the problem wants me to derive it.
 

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