Artificial magnetic fields

Magnetic phenomena play an essential role in quantum physics. Concepts and phenomena as varied as gauge invariance, the quantum Hall effect, spin-orbit coupling, the Aharonov-Bohm effect and topological insulators all originate in the interaction between moving charges and a magnetic field. The study of magnetism with cold atoms is therefore an important part of the general quantum simulation program based on these new gases. However, the electrical neutrality of the atoms requires the use of " artifices " - for example, light beams of well-chosen frequencies and directions - to achieve situations equivalent to those encountered in the electron fluids of ordinary matter.
This year's lecture and seminars will take stock of this very active research, both theoretically and experimentally. We'll start with the key elements of magnetism, such as the Lorentz force and gauge symmetry. We'll then show how a rotating field or a geometric phase, such as the Berry phase appearing in an adiabatic transformation, can be used to simulate orbital magnetism for neutral particles. Finally, we'll give some examples of the phases of matter likely to appear under the effect of this artificial magnetism, from vortex networks to strongly correlated states reminiscent of the quantum Hall effect.