Quantum mechanics (angular momentum)

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SUMMARY

The discussion focuses on calculating the probabilities of angular momentum states for a particle described by the wave function \( \Psi (\rho, \phi) = A e^{-\rho^2/2 \Delta^2} (\cos(\phi))^2 \). The probabilities derived are \( P(l_z = 0) = \frac{2}{3} \), \( P(l_z = 2\hbar) = \frac{1}{6} \), and \( P(l_z = -2\hbar) = \frac{1}{6} \). The user references the use of the state \( \Phi_m(\phi) = \frac{1}{\sqrt{2\pi}} e^{i m \phi} \) to express the cosine term, indicating a need for clarity on how to calculate these probabilities from the wave function.

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  • Study the derivation of angular momentum eigenstates in quantum mechanics.
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icelevistus
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A particle is described by the wave function

\[CapitalPsi] (\[Rho], \[Phi]) =
AE^(-\[Rho]^2/2 \[CapitalDelta]^2) (Cos[\[Phi]])^2

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P (Subscript[l, z] = 0) = 2/3
P (Subscript[l, z] = 2 h) = 1/6
P (Subscript[l, z] = -2 h) = 1/6





I have already used

Subscript[\[CapitalPhi], m] (\[Phi]) = 1/Sqrt[2 \[Pi]] E^Im\[Phi]

as the problem suggests to express the cos^2 as PHI(sub m) states




I am simply brickwalled at how to calculate these probabilities. The only way I remember to calculate probabilities given a wavefunction is for position (probability of measuring the particle within a certain region). Or also, I remember how to find the probability of a wavefunction collapsing to a particular state if it is written as a linear combination of states. Can someone point me to the relevant equation or idea?
 
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Sorry, looks like that Mathematica code was no good.

Is it still legible?
 

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