Quantum Mechanics Lecture Notes - Spring 2013

Introduction

• Course 804, taught by Assistant Professor Alan Adams.
• Focus on quantum mechanics and its applications.
• Recitation Instructors: Barton Zweibach and Matt Evans.
• Teaching Assistant: Paolo Glorioso.

Course Objectives

• Develop intuition for quantum phenomena, not just calculations.
• Solve problems as a way to develop understanding.
• Emphasize collaboration on problem sets while writing them independently.

Course Structure

• Problem Sets: Due Tuesdays by 11 AM, no late submissions accepted. One lowest score dropped.
• Exams: Two midterms and one final exam.
• Clickers required for participation and concept questions.
• Textbooks: No specific required textbook; recommendations provided on Stellar.

Key Concepts in Quantum Mechanics

Measurement and Properties of Electrons

• Electrons exhibit two properties: color (black or white) and hardness (hard or soft).
• Both properties are binary and can be measured using specific devices (color and hardness boxes).
• Repeatability: If an electron is observed as white/soft, future measurements will yield the same results.

Correlation of Properties

• Measured properties (color and hardness) are independent; knowing one does not inform about the other.
• Both color and hardness are uncorrelated.

Experimental Insights

Key Experiments

1. Color and Hardness Measurement: Predicts 50% for each outcome when measuring hardness after color measurement.
2. Color Measurement After Hardness: Produces similar predictions.
3. Barrier Experiment: With barriers in place, interference with measurement outcomes; electrons don't seem to follow classical logic.

Superposition

• Quantum superposition: an electron can exist in multiple states (hard/soft) at once until measured.
• Every electron behaves according to quantum mechanics, not classical intuition.
• The concept of superposition is crucial; it challenges classical ideas of definite properties.

Conclusion

• Understanding quantum mechanics requires moving beyond classical intuition to grasp the implications of superposition and measurement.
• The course will focus on building an intuition for how quantum phenomena operate.
• Next lecture will delve deeper into these concepts.