Skip to main content
University Quantum Mechanics I

University Quantum Mechanics I · The Quantum Harmonic Oscillator · 9.05

The ground state: a Gaussian with no nodes

ψ₀ = (m ω / π ℏ)¹⁄⁴ exp(−m ω x² / 2 ℏ), normalised by a Gaussian integral.

Course-map guide · not a complete lesson or simulation

Scope & orientation

What this subsection covers

ψ₀ = (m ω / π ℏ)¹⁄⁴ exp(−m ω x² / 2 ℏ), normalised by a Gaussian integral.

A strong response uses parabolic well with its level ladder drawn in 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 a finite-difference diagonalisation of the quadratic well and a truncated ladder-operator matrix return the same Eₙ, and where does each route fail first?

Read the complete note

Do a finite-difference diagonalisation of the quadratic well and a truncated ladder-operator matrix return the same Eₙ, and where does each route fail first? Useful evidence includes grid eigenvalues against (n + 1/2) ℏ ω, the same spectrum from truncated a and a-dagger matrices, node count and parity per eigenvector, convergence in spacing and box size, and the top-of-basis truncation error..

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 ground state: a Gaussian with no nodes

ψ₀ = (m ω / π ℏ)¹⁄⁴ exp(−m ω x² / 2 ℏ), normalised by a Gaussian integral.

Read the complete note

ψ₀ = (m ω / π ℏ)¹⁄⁴ exp(−m ω x² / 2 ℏ), normalised by a Gaussian integral. Its length scale is a = √(ℏ/m ω), so δ-x = a/√(2) = √(ℏ/2 m ω), and about 16 percent of its probability lies beyond the classical turning points. Being stationary, it does not oscillate.

02 · RepresentationThe subsection's claim

Model, evidence, and boundary

03 · TestPrediction before measurement

What is the strongest test of a claim about The ground state: a Gaussian with no nodes?

04 · Evidence & boundaryDecide, then qualify

Do a finite-difference diagonalisation of the quadratic well and a truncated ladder-operator matrix return the same Eₙ, and where does each route fail first?

Read the complete note

Do a finite-difference diagonalisation of the quadratic well and a truncated ladder-operator matrix return the same Eₙ, and where does each route fail first? Useful evidence includes grid eigenvalues against (n + 1/2) ℏ ω, the same spectrum from truncated a and a-dagger matrices, node count and parity per eigenvector, convergence in spacing and box size, and the top-of-basis truncation error..

Interactive diagram for The ground state: a Gaussian with no nodes: 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

What is the strongest test of a claim about The ground state: a Gaussian with no nodes?

Quick check

Test the reasoning, not recall

What is the strongest test of a claim about The ground state: a Gaussian with no nodes?

Choose an answer to test the model.