Lectures

Lecture 1: Failure of classical statistical mechanics

• Example: Planck theory of black-body radiation.

Additional references

• Black-body radiation curves

Lecture 2: Mixed states in quantum mechanics and the density operator

• Example: Proper mixed states in spintronics.
• Example: Improper mixed states in decoherence of qubits and von Neumann entropy.
• Example: Proper mixed states for quantum systems in thermal equilibrium and density matrix for microcanonical, canonical, and grand canonical ensembles via correspondence with classical statistical mechanics.
• Example: Density matrix and quantum partition function for a single particle in a box in the quantum canonical ensemble.
• Example: Density matrix and quantum partition function for a linear harmonic oscillator in the quantum canonical ensemble.

Additional references

• J. K. Gamble and J. F. Lindner, Demystifying decoherence and the master equation of quantum Brownian motion, Am. J. Phys. 77, 244 (2009). [PDF]
• A. Ekert and P. L. Knight, Entangled quantum systems and the Schmidt decomposition, Am. J. Phys. 63, 415 (1995). [PDF]

Lecture 3: Many-particle wave functions and the Hilbert space of identical particles

• Example: Wave functions of 3 fermions and 3 bosons.

Lecture 4: Quantum partition function for many-particle systems in equilibrium

• Example: Quantum partition function for two bosons and two fermions and comparison with classical statistical mechanics.
• Example: "Effective force" between noninteracting bosons and fermions due to Pauli principle.
• Quantum partition function for non-interacting bosons and fermions in the grand canonical ensemble.
• Example: Equation of state for non-degenerate bosons and fermions.

Additional references

• W. J. Mullin and G. Blaylock, Quantum statistics: Is there an effective fermion repulsion or boson attraction?, Am. J. Phys. 71, 1223 (2003). [PDF]
• G. Cook and R. H. Dickerson, Understanding the chemical potential, Am. J. Phys. 63, 737 (1995). [PDF]

Lecture 5: Degenerate fermions in equilibrium

• Example: Heat capacity of electrons in solids.
• Example: Pauli paramagnetism.
• Example: Landau diamagnetism.
• Example: Stoner ferromagnetism.
• Example: Neutron stars and black holes.

Additional references

• R. Balian and J.-P. Blaizot, Stars and statistical physics: A teaching experience, Am. J. Phys. 67, 1189 (1999). [PDF]
• Stelar evolution: The life and death of stars

Lecture 6: Degenerate bosons in equilibrium

• Example: Heat capacity of phonons in solids.
• Example: Cosmic microwave background radiation.
• Example: Magnons in the Heisenberg model of magnetism.
• Example: BEC for free noninteracting bosons.
• Example: BEC for trapped ultracold atom gases.

Additional references

• G. Scharf, On Bose–Einstein condensation, Am. J. Phys. 61, 843 (1993). [PDF]
• W. J. Mullin, The loop-gas approach to Bose–Einstein condensation for trapped particles, Am. J. Phys. 68, 120 (2000). [PDF]

Lecture 7: Magnetic systems

• Example: Noninteracting spins.
• Thermodynamics of magnetism.
• Example: Partition function of the Ising model in one-dimension.
• Example: Onsager solution and computer simulations of the Ising model in two-dimensions.

Lecture 9: Abrupt vs. continuous phase transitions

• Example: Phase diagrams of liquid-gas and paramagnet-ferromagnet systems.
• Thermodynamic equation of state near phase transitions.

Lecture 10: Mean-field theory of phase transitions

• Example: Mean-field theory of the Ising model of magnetism.
• Example: Mean-field theory of the Heisenberg model of magnetism and upper critical dimensionality.
• Example: Landau theory and the origin of its failure for two-dimensional Ising model.

Lecture 11: Critical phenomena and renormalization group (RG)

• Universality and scaling relations
• Example: Percolation as geometrical phase transition.
• Example: RG for percolation.
• Example: RG for 1D Ising model.
• Example: Niemeijer-van Leeuwen RG in real space for 2D Ising model.
• Additional references:
  • M. E. Fisher, Renormalization group theory: Its basis and formulation in statistical physics, Rev. Mod. Phys. 70, 653 (1998). [PDF]

Lecture 12: Boltzmann (semiclassical) theory of linear response

• Example: Conductivity of massless Dirac fermions in 2D graphene.

Lecture 13: Kubo (quantum) theory of linear response

• Example: Conductivity of electrons in metals.

Lecture 15: Introduction to quantum phase transitions

• PDF

Additional references

• S. Sachdev and B. Keimer, Quantum criticality, Physics Today 64(2), 29 (2011). [PDF]