Overview of The Structure of Physics Where do






















- Slides: 22
Overview of The Structure of Physics: Where do Statistical &Thermal Physics fit in to the structure & organization?
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.
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 17 th & 18 th Centuries. Still useful in the 21 st Century!!
Physics Structure 1. Classical Electromagnetism & Optics (Newton, Coulomb, Gauss, Ampere, Faraday, Maxwell, . . ) The Physics of the 18 th & 19 th centuries. Still useful in the 21 st Century!
Physics Structure 1. Classical Electromagnetism & Optics (Newton, Coulomb, Gauss, Ampere, Faraday, Maxwell, . . ) The Physics of the 18 th & 19 th centuries. Still useful in the 21 st Century! 2. High Speeds (v ≤ ~ c) Special (& General) Relativity (Einstein, . . ) 20 th & 21 st Century Physics!
Physics Structure 3. Small Size (atomic & smaller): Quantum Mechanics (Bohr, Schrödinger, Heisenberg…. ) 20 th & 21 st Century physics!
Physics Structure 3. Small Size (atomic & smaller): Quantum Mechanics (Bohr, Schrödinger, Heisenberg…. ) 20 th & 21 st Century physics! 4. Relativity + Quantum Mechanics: Relativistic Quantum Mechanics (Dirac, …) 20 th & 21 st Century physics! Quantum Field Theory (Feynman, Schwinger, . . ) 20 th & 21 st Century physics!
“Mechanics” • HOW objects move (behave) under given forces. • (Usually) Does not deal with the sources of 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!
The 4 Fundamental Forces of Nature The sources of the forces, in order of decreasing strength
The 4 Fundamental Forces of Nature The sources of 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 4 Fundamental Forces of Nature The sources of 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 4 Fundamental Forces of Nature The sources of 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 4 Fundamental Forces of Nature The sources of 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….
The 4 Fundamental Forces of Nature The sources of the forces, in order of decreasing strength
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 Force were combined into one theory. This was done by S. Weinberg & A. Salaam. For this work, they received the 1979 Nobel Prize in Physics!
The Standard Model of Particle Physics “Periodic Table for Elementary Particles”! Quantum Chromodynamics (QCD) & the Electroweak Theory Protons & Neutrons consist of 3 Quarks each.
The Standard Model
The Standard Model
The Standard Model
The Rest of Physics! • What we’ve mentioned so far is all of physics except: Statistical Mechanics (& Thermodynamics) (This course ≡ “Stat Mech” ) “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 BOTH the Classical & the Quantum worlds! 3. Is the major link between microscopic & macroscopic physics! 4. Contains Thermodynamics as a sub-theory!
The Most Important Point: Statistical Mechanics is important because it is the major link between microscopic & macroscopic physics!