QMat Student Seminars
The QMat Student Seminars are courses organized by QMat students at the Faculty of Physics and Engineering, in partnership with the Tutoring Division of the ARIANE, the GeQS group and the Strasbourg Students Physical Letters.
They are intended to foster a better understanding of quantum sciences among physics students. When not stated otherwise, all seminars are held at the Institut de Physique in Strasbourg, and the proceedings are published in the 2SPL.
For more information regarding the QMat Student Seminars, please contact Loris DELAFOSSE.
2025-2026 Second Semester
16th February (16h-18h): But what is spin, really?
Target audience: L3
Room 103
Starting from the importance of classical angular momentum, we will undertake a journey motivated by history towards an intuitive understanding of the necessity for an intrinsic angular momentum (or spin) of particles. The procedure of quantisation of angular momentum and the main conceptual interests of the operators that arise from it will be outlined, and evidence of the existence of half integer quantum numbers will be presented. Most of the seminar will then be spent deriving and exploring Pauli’s theory of spin in depth, while we learn to let go of our classical understanding of the quantum realm in favour of an intuition for the seemingly nonsensical. Finally, consequences of this new intrinsic degree of freedom will be explored by studying the symmetrization postulate and its origins in the spin-statistics theorem, giving rise to the well known properties of Fermions and Bosons.
2nd March (14h-15h30): EPR paradox, Bell's inequalities and entanglement: Violation of locality?
Target audience: L3
Room 111
Locality in a physical theory posits that an object is directly influenced only by its immediate surroundings, implying that physical systems separated in space should possess independent realities. That is, the information of the system is contained locally. In this seminar, we will revisit the foundational Einstein-Podolsky-Rosen (EPR) paper, which states that if one demands a description of reality that is both local and real, Quantum Mechanics must be deemed incomplete. Afterwards, we will mathematize this argument will Bell's inequalities and see how they were violated in the 1980s. Finally, we will discuss the profound implications of these results: specifically, how quantum non-locality coexists with relativity, manifesting as "spooky action at a distance" that nonetheless prohibits faster-than-light communication.
13th March (16h-18h): Green functions and propagators in physics
Target audience: L3-M1
Room 103
Green functions are among the most powerful tools at the physicist’s disposal. Their main role being the characterisation of the response of a system to a perturbation, they are naturally ubiquitous in theoretical physics, from diffusion problems to quantum field theory.
This seminar is aimed at giving an introductory view at their importance in classical systems. First, the example of the heat equation will be explored, then advanced and retarded Green functions will be intuitively introduced in the case of the simple harmonic oscillator, before investigating the manifestation of time irreversibility in open systems. In the second part, we will establish a relationship between Green functions and susceptibility, first for the case of the harmonic oscillator, then for a magnetic system, in order to show their central role in the theoretical calculation of observables in an interacting system.
26th March (13h-15h): Classical field theory II - Gauge theories
Target audience: M1-M2
Room 130 (SAP Master Classroom), Building 26, IPHC, Cronenbourg campus
We introduce gauge theories as a very general procedure allowing us to extend the perimeter of some field theories. Several examples are discussed, and gauge theories are shown to be the current best mathematical description of fundamental interactions in particle physics. The relation of classical field theory with relativistic quantum mechanics and general relativity is discussed, although no previous knowledge of these domains is assumed. Attendance at the first seminar is not required to understand the notions discussed here, since general results on field theories and Noether's theorem will be recalled at the beginning (it helps, though).
9th April (10h-12h): Path integrals for quantisation
Target audience: L3-M2
Room 113
Path integrals are one of the most popular formulations of quantum mechanics. Their success is due both to their natural physical interpretation and to their explicit dependence on the classical action, which makes them a formalism of quantisation rather than of some particular quantum theory. Indeed, path integrals can in principle be written from any classical action, allowing to formally quantise any classical theory. Thus it becomes possible to produce general, "action-agnostic", theorems that remain valid even for theories whose exact quantisation is still unknown. In this seminar, path integrals are introduced as symbolic objects whose behaviour is governed by several calculation rules. Mathematical issues in functional integration are mentioned, but the seminar concentrates on the symbolic manipulation of path integrals, illustrated with examples from many-body physics, chromodynamics and string theory. Physical discussion of these examples leads to a better understanding of the quantum realm and the quantisation procedure.
To be announced: Experimental platforms in condensed matter physics
Target audience: ...
Room ...
Various experimental platforms are used in condensed matter physics, and students are often not aware of their existence, let alone how they work and how they perform measurements. This seminar will be given by a series of PhD students who will present the experimental platforms they work with.