OVERVIEW

The main goal of the course is to give to the students a basic introduction to advanced techniques used in the framework of statistical physics of fields. These techniques are useful to comprehend physical phenomena which are subject of research in modern physics, spanning from condensed matter to high energy physics.

AIMS AND CONTENT

LEARNING OUTCOMES

Verify and stimulate the basic knowledge on statistical physics. To take on recent arguments in the simplest possible context so to stimulate interest for the recent deveopments of statistical mechanics.

AIMS AND LEARNING OUTCOMES

During the course, the student will acquire the following skills:

• Understanding the concepts of symmetry and scale of magnitude for deriving effective models in field theory.
• Learning to describe and understand critical phenomena and phase transitions in terms of scale-invariant effective theories.
• Learning to use the path integral method in field theory and becoming familiar with the concept of renormalization group and its implications in the study of fixed points.
• Gaining a deep understanding of the concepts of spontaneous symmetry breaking and the description of the spontaneously broken phase in terms of effective theories of Goldstone bosons.
• Learning to describe physical phenomena using effective field theories.

PREREQUISITES

The topics covered in the course will be presented in a self-contained manner. Therefore, no specific prerequisites are required from students other than the skills acquired during their bachelor's degree.

TEACHING METHODS

Blackboard lectures and exercise sessions.

SYLLABUS/CONTENT

1. The Ising model:
   •  Description in terms of spins
   • Mean field approximation: from spins to fields
2. The Landau approach to phase transitions:
   • Continuous phase transitions
   • First order phase transitions
   • The concept of "Universality"
3. The Ginzburg-Landau theory:
   • applications to the ferromagnetic and superconducting phase transitions
4. The path integral:
   • defining the thermodynamical quantities using the path integral
   • The Gaussian path integral
   • Correlation length and critical dimension
   • Analogies with quantum field theory
5. The renormalization group:
   • Scale transformations and critical exponents
   • The Gaussian fixed point
   • Relevant, marginal and irrelevant perturbations at the fixed point
   • Interactions and renormalization group: Beta functions and Feynman diagrams
6. Continuous symmetries
   • Continuous symmetries and phase transitions
   • Spontaneous symmetry breaking and Goldstone bosons
   • O(N) models
   • Sigma models
   • The Kosterlitz-Thouless phase transition
7. Effective field theory and the Fermi surface
   • The renormalization group applied to the Fermi liquid theory and the superconductive instability
8. Introduction to conformal field theories and their application to the description of critical points

Where possible the symbolic calculus program Mathematica will be used to illustrate applications of the techniques explained during the course.

RECOMMENDED READING/BIBLIOGRAPHY

• Nigel Goldenfeld, Phase Transitions and the Renormalization Group
• Mehran Kardar, Statistical Physics of Fields
• John Cardy, Scaling and Renormalisation in Statistical Physics
• Chaikin and Lubensky, Principles of Condensed Matter Physics
• Shankar, Quantum Field Theory and Condensed Matter
• Alexey Polyakov, Gauge Fields and Strings
• Philippe Di Francesco and Pierre Mathieu, Conformal Field Theory

TEACHERS AND EXAM BOARD

Exam Board

ANDREA AMORETTI (President)

NICOLA MAGGIORE

NICODEMO MAGNOLI (President Substitute)

DANIEL KEITH BRATTAN (Substitute)

GIOVANNI RIDOLFI (Substitute)

PAOLO SOLINAS (Substitute)

LESSONS

EXAMS

EXAM DESCRIPTION

Oral exam about the topics of the syllabus.

ASSESSMENT METHODS

The oral exam will last for about 40 minutes and the student will be asked to present two arguments from the syllabus. One argument will be chosen by the student while the second will be chosen  by the exam commetee during the examination. Moreover, exersise sheets will be provided during the course.

Exam schedule

FURTHER INFORMATION

Students who have valid certification of physical or learning disabilities on file with the University and who wish to discuss possible accommodations or other circumstances regarding lectures, coursework and exams, should speak both with the instructor and with Professor Sergio Di Domizio (sergio.didomizio@unige.it), the Department’s disability liaison.