1. Nanoelectronics Chapter 2 Classical Particles, Classical Waves, and Quantum Particles 1Q.Li@Physics.WHU@2015.3

2. Electron Double-Slit Experiment Q.Li@Physics.WHU@2015.32

3. 2.1 Comparison of Classical and Quantum Systems Classical physics is to describe the exact state of a particle, how fast it will travel at a certain instant of time. Quantum mechanics: it is impossible to measure precisely both the position and momentum of a particle, theoretically impossible. Quantum theory is truly a probabilistic theory. Q.Li@Physics.WHU@2015.33

4. 2.2 Origins of Quantum Mechanics Photoelectric effect: if light is incident on a metal, some energy carried by the light can be transferred to electrons at the metal’s surface, and the electrons gain enough energy to escape from the metal. Kinetic energy of photo-emitted electrons does not increase as the intensity of light increases. When the frequency of light increases, more energetic electrons were emitted. Q.Li@Physics.WHU@2015.34

5. 2.3 Light as a Wave, Light as a Particle Q.Li@Physics.WHU@2015.35

6. Young’s Experiment Q.Li@Physics.WHU@2015.36 r j is the distance from jth slit to observation location on the screen

7. Finally, Light as a Quantum Particle Young’s Experiment – one slit at a time Q.Li@Physics.WHU@2015.37

8. 8 Finally, Light as a Quantum Particle

9. Young’s Experiment – A very strange result concerning interference Light exhibits bot wave-like and particle-like behavior, is clearly neither a classical wave not a classical particle. We call this a quantum particle. Q.Li@Physics.WHU@2015.39

10. 2.4 Electrons as Particles, Electrons as Waves Q.Li@Physics.WHU@2015.310

11. Electrons as Waves Q.Li@Physics.WHU@2015.311

12. 2.4.3 Further Development of Quantum Mechanics Q.Li@Physics.WHU@2015.312

13. 2.5 Wavepackets and Uncertainty Q.Li@Physics.WHU@2015.313

14. 2.5 Wavepackets and Uncertainty Q.Li@Physics.WHU@2015.314 Wavepacket can change shape

15. 2.6 Main Points Classical particles Quantum particle’s position and momentum Electron’s wavelength Idea of spin and Pauli exclusion principle Fermions and bosons Wavepacket concepts: phase velocity and group velocity Q.Li@Physics.WHU@2015.315

16. 2.7 Problems 2, 3, 4, 11, 12 Q.Li@Physics.WHU@2015.316