PHYM001 Statistical Physics 2023-24
Dr W. Moebius
Delivery Weeks: T1:01-11
Level: 7 (NQF)
Credits: 15 NICATS / 7.5 ECTS
Enrolment: 70 students (approx)


This module builds upon the PHY2023 Thermal Physics module taken by students at Stage 2. It emphasises four aspects of statistical physics by applying them to a number of physical systems in equilibrium. Firstly, it is shown that a knowledge of the thermodynamic state depends upon an enumeration of the accessible quantum states of a physical system; secondly, that statistical quantities such as the partition function can be found directly from these states; thirdly, that thermodynamic observables can be related to the partition function, and fourthly, that the theoretical results relate to experimental observations.

Module Aims

This module aims to give students an understanding of how the time-symmetric laws of quantum mechanics obeyed by all systems can be linked, through a chain of statistical and thermodynamic reasoning, to the (apparently time-asymmetric) natural processes occurring in macroscopic systems. It also furnishes the theoretical background in statistical mechanics that can be drawn on in other modules e.g. PHYM003 Condensed Matter II.

Intended Learning Outcomes (ILOs)

A student who has passed this module should be able to:

Syllabus Plan

  1. Introduction
    aims and methods of thermodynamics and statistical mechanics; differences between thermodynamics and mechanics
  2. Thermodynamic equilibrium
    internal energy; hydrostatic and chemical work; heat; the first law of thermodynamics
  3. Reversible, irreversible and quasistatic processes
    entropy; the Clausius and Kelvin statements of the second law
  4. Criteria for equilibrium
    enthalpy; the Helmholtz and Gibbs free energies; the grand potential
  5. Statistical mechanics
    microstates and macrostates; assumption of equal a priori probabilities
  6. The canonical ensemble and the Boltzmann distribution
    partition functions; derivation of thermodynamic quantities
  7. Systems in contact with a heat bath
    vacancies in solids; paramagnetism
  8. Reversible quasistatic processes
    statistical meaning of heat and work; Maxwell's relations; the generalised Clausius inequality; Joule-Thomson effect; the thirdlaw of thermodynamics
  9. Heat capacity of solids
    the Einstein and Debye models
  10. Partition function for ideal gas
    validity of classical statistical mechanics; Maxwell velocity distribution; kinetic theory; approach to equilibrium
  11. Diffusion of particles between systems
    the grand canonical ensemble; the grand partition function; application to the ideal gas; chemical reactions
  12. Quantum gases
    Bose-Einstein, Fermi-Dirac and Boltzmann statistics; Black-body radiation; Bose-Einstein condensation; The degenerate electron gas
  13. A selection of more-advanced topics:
    phase equilibria; Monte Carlo methods; mean-field theory of second-order phase transitions; the kinetics of growth

Learning and Teaching

Learning Activities and Teaching Methods

Description Study time KIS type
20×1-hour lectures 20 hours SLT
2×1-hour problems/revision classes 2 hours SLT
5×6-hour self-study packages 30 hours GIS
4×4-hour problem sets 16 hours GIS
Reading, private study and revision 82 hours GIS


Weight Form Size When ILOS assessed Feedback
0% Guided self-study 5×6-hour packages Fortnightly 1-13 Discussion in tutorials
0% 4 × Problems sets 4 hours per set Fortnightly 1-13 Solutions discussed in problems classes.
100% Final Examination 2 hours 30 minutes January 1-10 Mark via MyExeter, collective feedback via ELE and solutions.


The following list is offered as an indication of the type & level of information that students are expected to consult. Further guidance will be provided by the Module Instructor(s).

Core text:

Supplementary texts:


Further Information

Prior Knowledge Requirements

Pre-requisite Modules Thermal Physics (PHY2023)
Co-requisite Modules none


Re-assessment is not available except when required by referral or deferral.

Original form of assessment Form of re-assessment ILOs re-assessed Time scale for re-assessment
Whole module Written examination (100%) 1-10 August/September assessment period

Notes: See Physics Assessment Conventions.

KIS Data Summary

Learning activities and teaching methods
SLT - scheduled learning & teaching activities 22 hrs
GIS - guided independent study 128 hrs
PLS - placement/study abroad 0 hrs
Total 150 hrs
Summative assessment
Coursework 0%
Written exams 100%
Practical exams 0%
Total 100%


IoP Accreditation Checklist
  • Not applicable to this module.
Availability MPhys only
Distance learning YES (see PHYM011)
Keywords Physics; Statistical Mechanics; Thermodynamics; Heat; Einstein; Quantum states; Partition function.
Created 01-Oct-10
Revised 18-Feb-14