# David Tong: Concepts in Theoretical Physics

These lectures provide bite sized introductions to a handful of topics in theoretical physics, aimed at first year undergraduates. Presentations can be downloaded below.

# Contents

**Principle of Least Action: PDF File**

Principle of least action, Unification of physics, Feynman's path integral formulation of quantum mechanics.**Quantum Mechanics PDF File**

Applications of Quantum Mechanics, The Principle of Superposition, Eigenvalue Equations and Probability, Entanglement.**Particle Physics PDF File**

Fundamental Particles, Antiparticles, Fundamental Forces, QCD and Confinement of Quarks, Higgs Boson, LHC.**General Relativity PDF File**

Equivalence Principle, Light Bending, Gravitational Redshift and Time Dilation, Gravity as Geometry, Schwarzschild solution, Geodesic motion as orbits.**Cosmology PDF File**

Composition of the Universe. History of the universe, Friedmann equations. Cosmic Microwave Background and density perturbations. Singularity problem, Quantum gravity.