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University Quantum Mechanics I

University Quantum Mechanics I · Introduction to Three-Dimensional Quantum Mechanics · 14.06

The azimuthal equation and the quantum number m

A second separation of Y into Θ(θ) Φ(φ) leaves Phi'' = −m² Φ and Φ = exp(i m φ), with single-valuedness over 2 π forcing integer m; the operator −i ℏ d/dphi is Lz, so m ℏ is what an Lz measurement returns.

Course-map guide · not a complete lesson or simulation

Scope & orientation

What this subsection covers

A second separation of Y into Θ(θ) Φ(φ) leaves Phi'' = −m² Φ and Φ = exp(i m φ), with single-valuedness over 2 π forcing integer m; the operator −i ℏ d/dphi is Lz, so m ℏ is what an Lz measurement returns.

A strong response uses radial functions r(r) beside u = rr and states where the model stops being reliable.

Reasoning checklist

Evidence, assumptions and limits

01

Assumptions to state

State the system, observable, approximation, and conditions held fixed before using a model.

02

Evidence to collect

Do the resonances of a circular membrane sit at ratios of the Bessel zeros, and do the visible nodal circles and diameters match the two indices of the separated solution?

Read the complete note

Do the resonances of a circular membrane sit at ratios of the Bessel zeros, and do the visible nodal circles and diameters match the two indices of the separated solution? Useful evidence includes driven frequencies with nodal patterns recorded, modes labelled by nodal circles and diameters, ratios against Bessel zeros, split degenerate pairs traced to tension asymmetry, and the ideal-membrane assumption named.

03

Limits to state

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus.

Read the complete note

This GioPhysics course map is an adaptable learning sequence, not academic credit, accreditation, or a universal university syllabus. It is a first dedicated quantum-mechanics course, distinct from University Physics V, which covers quantum mechanics alongside atomic, nuclear and particle physics in twenty units: this course is narrower, slower, and teaches the linear algebra it needs rather than assuming it. Hydrogen appears here as an introduction, with the full radial derivation belonging to a second course. A midterm examination is assumed around week 8. Follow your institution's published scope, notation, laboratory programme, and assessment rules. A result should be checked against units, signs, limiting cases, and the conditions under which its model was derived.

Diagram & examples

Work the claim before choosing an equation

Interactive concept map

Follow the model from claim to evidence.

01 · Physical claimThe azimuthal equation and the quantum number m

A second separation of Y into Θ(θ) Φ(φ) leaves Phi'' = −m² Φ and Φ = exp(i m φ), with single-valuedness over 2 π forcing integer m; the operator −i ℏ d/dphi is Lz, so m ℏ is what an Lz measurement returns.

Read the complete note

A second separation of Y into Θ(θ) Φ(φ) leaves Phi'' = −m² Φ and Φ = exp(i m φ), with single-valuedness over 2 π forcing integer m; the operator −i ℏ d/dphi is Lz, so m ℏ is what an Lz measurement returns. Single-valuedness is an assumption worth naming, and this equation alone never bounds |m|.

02 · RepresentationThe subsection's claim

Model, evidence, and boundary

03 · TestPrediction before measurement

When should a model used for The azimuthal equation and the quantum number m be revised?

04 · Evidence & boundaryDecide, then qualify

Do the resonances of a circular membrane sit at ratios of the Bessel zeros, and do the visible nodal circles and diameters match the two indices of the separated solution?

Read the complete note

Do the resonances of a circular membrane sit at ratios of the Bessel zeros, and do the visible nodal circles and diameters match the two indices of the separated solution? Useful evidence includes driven frequencies with nodal patterns recorded, modes labelled by nodal circles and diameters, ratios against Bessel zeros, split degenerate pairs traced to tension asymmetry, and the ideal-membrane assumption named.

Interactive diagram for The azimuthal equation and the quantum number m: follow the physical claim through its representation, proposed test, evidence, and model boundary.

modelModel, evidence, and boundary turns the stated idea into a representation that can make a prediction.

Example questions

Try the reasoning before revealing the structure.

Diagram check

When should a model used for The azimuthal equation and the quantum number m be revised?

Quick check

Test the reasoning, not recall

When should a model used for The azimuthal equation and the quantum number m be revised?

Choose an answer to test the model.