**PH-616 Statistical Physics **

- Intensive and extensive quantities, thermodynamic variables, thermodynamic limit, thermodynamic transformations.
- Classical ideal gas, first law of thermodynamics, application to magnetic systems, heat and entropy, Carnot cycle.
- Second law of thermodynamics, absolute temperature, temperature as integrating factor, entropy of ideal gas.
- Conditions for equilibrium, Helmholtz free energy, Gibbs potential, Maxwell relations, chemical potential. First-order phase transition, condition for phase coexistence.
- The statistical approach: phase space, distribution function, microcanonical ensemble, the most probable distribution, Lagrange multipliers.
- Maxwell-Boltzmann distribution: pressure of an ideal gas, equipartition of energy, entropy, relation to thermodynamics, fluctuations, Boltzmann factor.
- Transport phenomena: collisionless and hydrodynamic regimes, Maxwell’s demon, non-viscous hydrodynamics, sound waves, diffusion, conduction, viscosity.
- Quantum statistics: thermal wavelength, identical particles, Fermi and Bose statistics, pressure, entropy, free energy, equation of state, Fermi gas at low temperatures, application to electrons in solids and white dwarfs.
- The Bose gas: photons, phonons, Debye specific heat, Bose-Einstein condensation, equation of state, liquid helium.
- Canonical and grand canonical ensembles, partition function, connection with thermodynamics, fluctuations. minimization of free energy, photon fluctuations, pair creation.
- The order parameter, Broken symmetry, Ising spin model, Ginsburg – Landau theory, mean-field theory, critical exponents, fluctuation-dissipation theorem, correlation length, universality.

** Recommended texts: **

*Introduction to Statistical Physics*, Kerson Huang, (Taylor and Francis, 2001).*Statistical Mechanics*, Raj Kumar Pathria, second edition (India, 1996).