Overview of The Structure of Physics :

1. Overview ofThe Structure of Physics:

2. The Structure of Physics Classical Physics is The Foundation of pure & applied (macroscopic) physics & engineering! Newton’s Laws+ Electromagnetism +Statistical Mechanics+ Thermodynamics. (The Latter Topics are what this course is about!) These together give a good description of most of the macroscopic world.

3. The Structure of Physics Classical Physics is The Foundation of pure & applied (macroscopic) physics & engineering! Newton’s Laws+ Electromagnetism +Statistical Mechanics+ Thermodynamics. (The Latter Topics are what this course is about!) These together give a good description of most of the macroscopic world. Classical Mechanics (Newton, Lagrange, Hamilton,..) The Physics of the 17th & 18th Centuries. Still useful in the 21st Century!!

4. Physics Structure 1. Classical Electromagnetism & Optics (Newton, Coulomb, Gauss, Ampere, Faraday, Maxwell,..) The Physics of the 18th & 19th centuries. Still useful in the 21st Century!

5. Physics Structure 1. Classical Electromagnetism & Optics (Newton, Coulomb, Gauss, Ampere, Faraday, Maxwell,..) The Physics of the 18th & 19th centuries. Still useful in the 21st Century! 2. High Speeds(v ≤ ~ c)  Special (& General) Relativity (Einstein, ..) 20th & 21st Century Physics!

6. Physics Structure 3. Small Size(atomic & smaller): Quantum Mechanics (Bohr,Schrödinger, Heisenberg….) 20th & 21st Century physics!

7. Physics Structure 3. Small Size(atomic & smaller): Quantum Mechanics (Bohr,Schrödinger, Heisenberg….) 20th & 21st Century physics! 4. Relativity + Quantum Mechanics: Relativistic Quantum Mechanics (Dirac,…) 20th & 21st Century physics! Quantum Field Theory (Feynman,Schwinger, ..) 20th & 21st Century physics!

8. “Mechanics” • HOW objects move (behave) under given forces. • (Usually) Does not deal with the sourcesof forces. Answers the question: Given the forces, how do objects move? • Forces in the universe are classified into 4 types: The 4 Fundamental Forces Of Nature! Some version of Mechanics applies to all four!

9. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength

10. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength The Strong Nuclear Force: Binds nuclei together. Explained by the “Standard Model” & Quantum Chromodynamics. Still being researched.

11. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength The Strong Nuclear Force: Binds nuclei together. Explained by the “Standard Model” & Quantum Chromodynamics. Still being researched. The Electromagnetic Force: E&M phenomena. Chemical forces. Most everyday forces. Maxwell, Coulomb, Ampere, Faraday, ...

12. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength The Strong Nuclear Force: Binds nuclei together. Explained by the “Standard Model” & Quantum Chromodynamics. Still being researched. The Electromagnetic Force: E&M phenomena. Chemical forces. Most everyday forces. Maxwell, Coulomb, Ampere, Faraday, ... The Weak Nuclear Force: Nuclear decay. Fermi, Bethe, others. Electroweak Theory.

13. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength The Strong Nuclear Force: Binds nuclei together. Explained by the “Standard Model” & Quantum Chromodynamics. Still being researched. The Electromagnetic Force: E&M phenomena. Chemical forces. Most everyday forces. Maxwell, Coulomb, Ampere, Faraday, ... The Weak Nuclear Force: Nuclear decay. Fermi, Bethe, others. Electroweak Theory. The Gravitational Force: Newton (classical mechanics), Einstein (general relativity), Hawking….

14. The 4 Fundamental Forces of NatureThe sourcesof the forces, in order of decreasing strength

15. The Four Fundamental Forces The “Electro-Weak” Force Since ~ the late 1960’s, in some sense, the 4 fundamental forces have been reduced to 3! The Electromagnetic Force& the Weak Nuclear Forcewere combined into one theory. This was done by S. Weinberg & A. Salaam. For this work, they received the 1979 Nobel Prize in Physics!

16. The Standard Model of Particle Physics “Periodic Table for Elementary Particles”!Quantum Chromodynamics (QCD) & the Electroweak Theory Protons & Neutrons consist of 3 Quarks each.

17. The Standard Model

18. The Standard Model

19. The Standard Model

21. The Rest of Physics! • What we’ve mentioned so far is  all of physics except: Statistical Mechanics(& Thermodynamics) “Stat Mech” is the mechanics of systems of huge numbers (>> ~ 1023) of particles. Stat Mech: 1. Uses Probability & Statistics to calculate macroscopic properties from microscopic force laws. 2. Applies to BOTHthe Classical & the Quantum worlds! 3. Is the major linkbetween microscopic & macroscopic physics! 4. Contains Thermodynamicsas a sub-theory!

22. The Most Important Point: Statistical Mechanics is important because it is the major link between microscopic & macroscopic physics!