David Tong: Statistical Physics

David Tong: Lectures on Statistical Physics

This is an introductory course on Statistical Mechanics and Thermodynamics given to final year undergraduates. They were last updated in May 2012. Full lecture notes come in around 190 pages. Individual chapters and problem sets can also be found below.

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A second course on statistical mechanics, covering non-equilibrium phenomena, can be found here. A third course on statistical mechanics, covering critical phenomena, can be found here.


  • 1. Fundamentals of Statistical Mechanics:   PDF
    Introduction; Microcanonical Ensemble; Entropy and the Second Law; Temperature; Two-State Spin System; First Law of Thermodynamics; Canonical Ensemble; Energy Fluctuations; Chemical Potential; Grand Canonical Ensemble.
  • 2. Classical Gases:   PDF
    Classical Partition Functions; Ideal Gas; Equipartition; Maxwell Distribution; Diatomic Gas; Interactions; van der Waals Equation of State; Cluster Expansion; Debye-Huckel model.
  • 3. Quantum Gases:   PDF
    Density of States; Blackbody Radiation; Debye Model of Vibrations in a Solid; Diatomic Gas Revisted, Bose-Einstein Distribution and Bose-Einstein Condensation; Fermi-Dirac Distribution and Fermi Gas; White Dwarfs; Pauli Paramagnetism; Landau Diamagnetism.
  • 4. Classical Thermodynamics:   PDF
    Temperature and the Zeroth Law; The First Law; The Second Law; Carnot Cycles; Entropy; Adiabatic Surfaces; Maxwell Relations; The Third Law.
  • 5. Phase Transitions:   PDF
    van der Waals equation Revisited; Phase Equilibrium; Maxwell Construction; Clausius-Clapyron Equation; Critical Point; Ising Model; Mean Field Theory; Critical Exponents; Ising Chain; Low Temperature Expansion and Peierls Droplets; High Temperature Expansion; Kramers-Wannier Duality; Landau Theory; Lee-Yang Zeros; Landau-Ginzburg Theory; Fluctuations and Correlations.

Problem Sheets

  • Problem Sheet 1:   Postscript    PDF    Ensembles   

  • Problem Sheet 2:   Postscript    PDF    Classical and Quantum Gases   

  • Problem Sheet 3:   Postscript    PDF    Bosons and Fermions   

  • Problem Sheet 4:   Postscript    PDF    Thermodynamics and Phase Transitions

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