# Tilman Enss | Teaching — Theory of Ultracold Atoms

as of 20 Sep 2017

## Theory of Ultracold Atoms (MVSpec)

#### Winter term 2017/18

The field of ultracold atomic gases has undergone a remarkable development over the past few years and is now a key area of many-body physics at the interface to condensed matter, atomic and nuclear physics. This course introduces the theoretical concepts and methods of ultracold quantum gases and covers many timely examples, as seen in current experiments also in Heidelberg. Many of the topics that we discuss for cold atoms (Bose-Einstein condensation, superfluidity, fermion pairing, quantum phase transitions, thermalization) are at the same time more general paradigms of many-body physics and are used also in other areas of physics. The exercises also show how to compute experimental observables.

#### Contents

**Strongly interacting fermions: the BCS-BEC crossover**- Scattering theory and Feshbach resonances
- BCS theory of superconductivity
- Bose-Einstein condensation and superfluidity
- Unitary Fermi gas and scale invariance
- Contact density and Tan relations
- Fermi polarons and spectroscopy

**Bosons in optical lattices: the Mott Insulator—Superfluid transition**- Optical lattices
- Bose-Hubbard model
- Mott Insulator—Superfluid transition
- Excitations and Higgs mode
- Quantum Simulation

**Real-time dynamics and transport**- Nonequilibrium dynamics and thermalization
- Heavy impurity dynamics
- Collective modes
- Hydrodynamic transport

#### Dates and Location

Lecture Tuesday and Thursday 09.15-11.00h, Philosophenweg 19, SR
[LSF] (starting Oct 17),

Exercise Monday 11.15-13.00h, Philosophenweg 19, SR (first exercise Oct 23).

Please register for the course at this URL
for notifications and/or for taking part in the exam; you may
unregister yourself before January 30.

#### Prerequisites

- Quantum Mechanics (PTP4)
- Theoretical Statistical Physics (MKTP1)

#### Literature

- Ketterle and Zwierlein,
*Making, probing and understanding ultracold Fermi gases*, Varenna lecture notes (2008) - Pitaevskii and Stringari,
*Bose-Einstein Condensation*, Clarendon Press 2003 - Bloch, Dalibard, and Zwerger,
*Many-body physics with ultracold gases*, Rev. Mod. Phys. 80, 885 (2008) - Zwerger (ed.),
*The BCS-BEC Crossover and the Unitary Fermi Gas*, Springer Lecture Notes in Physics 836 (PDF available from the university library) - Diehl,
*Many-Body Physics with Cold Atoms*, Innsbruck lecture notes (2013)

#### Exam

The written exam will be held on **Tuesday, 6 February 2018, from 09:15-10:45h.** The
exam will be graded, those who pass will get 6 credit points.
In order to participate in the exam you will need to register for the
course at this
URL; you may unregister yourself before January 30.