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PX441 - Quantum Theory of Interacting Particles

  • Module code: PX441
  • Module name: Quantum Theory of Interacting Particles
  • Department: Physics
  • Credit: 15

Content and teaching | Assessment | Availability

Module content and teaching

Principal aims

To cover some theoretical models and mathematical methods important in theoretical physics.

Principal learning outcomes

At the end of this module you should: understand interactions between electrons in atoms and molecules; be able to work with quantum fields; be prepared for postgraduate research in quantum theory of many-body systems.

Timetabled teaching activities

30 Lectures (equivalent)

Departmental link

Other essential notes

At the quantum level, systems of identical particles are always interacting particle systems even if there is no direct interaction between particles. This is because the wavefunction has to satisfy a symmetry condition imposed by quantum statistics - Pauli statistics for fermions and Bose-Einstein statistics for bosons. In atoms and molecules this leads to the familiar rule about never occupying a single-particle level with more than one electron. This module looks at phenomena found in such interacting particle systems. It will start by looking at the properties of interacting electrons in molecules using ideas you have met before. In parallel we introduce the idea of a quantum field. This is where the wavefunctions of matter/light themselves are quantized (made into operators). Although not strictly necessary for the description of atoms and molecules or systems with fixed particle number, the theory of quantum fields automatically builds the correct fermionic/bosonic statistics into the description of a many-particle system and is the natural theory for discussing the properties of such systems. We will go on to look at Landau's theory of the Fermi liquid, the effect of dimensionality on the stability of ordered states and how, in ultracold trapped atomic gases, the properties can be controlled by tuning the interaction itself.

Module assessment

Assessment group Assessment name Percentage
15 CATS (Module code: PX441-15)
B (Examination only) 2 hour examination (Summer) 100%

Module availability

This module is available on the following courses:



Optional Core


  • Undergraduate Physics (BSc MPhys) (F304) - Year 4
  • Undergraduate Mathematics and Physics (BSc MMathPhys) (FG33) - Year 4