00. Preface

Preface¶

Welcome to the Berkeley Physics 221A Quantum Mechanics course notes.

These notes cover the graduate-level quantum mechanics sequence at UC Berkeley. The notes were originally written in Plain TeX by Professor Robert Littlejohn and have been converted to MyST Markdown for web publishing.

About This Course¶

Physics 221A is the first part of the graduate quantum mechanics sequence (221A/221B) at UC Berkeley. The course covers:

• Mathematical formalism of quantum mechanics (Hilbert spaces, operators, bras and kets)

• Postulates of quantum mechanics

• Density operator and mixed states

• Spatial degrees of freedom

• Time evolution

• Approximation methods (perturbation theory, variational method)

• Identical particles

• Scattering theory

• Relativistic quantum mechanics (Klein-Gordon and Dirac equations)

About These Notes¶

These lecture notes were developed over many years of teaching Physics 221A/B at UC Berkeley. They are designed to be self-contained and include:

• Detailed derivations and proofs

• Numerous examples and applications

• Exercises and problems at the end of each chapter

• Cross-references to related topics

• Appendices covering mathematical background

Course Information¶

Instructor: Professor Robert Littlejohn
Office: 449 Birge Hall
Office Hours: Fridays 10:30am – 11:30am, 397 Physics North

Lecture Time: Tuesday & Thursday, 6:30pm – 8:00pm
Location: 166 Social Sciences Building

Course Website: https://bohr.physics.berkeley.edu/classes/221/

How to Use These Notes¶

Each chapter is self-contained and covers a specific topic in quantum mechanics. The notes include:

1. Derivations: Step-by-step mathematical derivations

2. Examples: Worked-out examples illustrating key concepts

3. Problems: Exercises at the end of each chapter

4. Cross-references: Links to related topics in other chapters

5. Appendices: Mathematical background material

• All the students who have taken the course over the years

• The teaching assistants who have helped improve the notes

• The UC Berkeley Physics Department for supporting this educational effort

Technical Notes¶

These notes were originally written in Plain TeX and have been converted to MyST Markdown for web publishing. The conversion process preserves:

• Mathematical equations (rendered with KaTeX)

• Cross-references between chapters

• Figure placeholders (original figures available separately)

• Problem sets at the end of each chapter

License¶

These notes are made available for educational purposes. Please respect copyright and acknowledge the source when using these materials.

Last updated: June 2026