# FS 2015: Ultracold Atoms (4 KP)

## VV-Nr 27002-01

Lecturer | Prof. Dr. Philipp Treutlein |

Assistants | Dr. Baptiste Allard, Dr. Lucas Beguin |

Time and place | Lecture: Mondays 10:15–12:00, Klingelbergstr. 82, Alter Hörsaal 2, 1.22 Tutorial: Mondays 14:00–15:30, Klingelbergstr. 82, Seminarzimmer 4.1 |

Start Date | 16 February, 2015 |

Final Lecture | 18 May 2015 |

Language | English or German |

## Content

The invention of atomic trapping, laser cooling and evaporative cooling made it possible to cool atomic gases to nanokelvin temperatures. At such low temperatures, the atoms form Bose-Einstein condensates or degenerate Fermi gases that allow studies of quantum phenomena in very clean and controllable systems. For example, ultracold atoms in optical lattices can be used as quantum simulators for condensed matter Hamiltonians. Chip-based microtraps can be used to generate atom-atom entanglement for quantum metrology. Ultracold atoms find applications in atomic clocks and atom interferometers for precision measurement.

This lecture gives an introduction to the field of ultracold atoms. We will discuss the basic phenomena and develop the necessary theoretical tools, as well as discuss key experiments in the field. The goal is to provide a solid background for research in ultracold atoms and related fields.

## Topics

- Two-level atom interacting with laser light (semiclassical theory)
- Optical Bloch equations
- Light forces on two-level atoms (scattering force/dipole force)
- Doppler cooling, Doppler limit
- Multi-level atoms
- Sub-Doppler cooling, optical molasses
- Magneto-optical trap (MOT)
- Atomic clocks and atom interferometers
- Magnetic traps, atom chips
- Evaporative cooling, the path to BEC
- Bose-Einstein condensation: quantum statistics
- Properties of the condensate: Gross-Pitaevskii theory
- Dynamics of the condensate, vortices, atom laser
- Josephson effect with Bose-Einstein condensates
- Interference of two Bose-Einstein condensates
- Atoms in optical lattices, Mott-insulator transition
- Quantum atom optics, quantum metrology

## Problem sets and handouts

Problem sets and handouts can be downloaded from here.

## Prerequisites

Basic knowledge of quantum mechanics and atomic physics.

## Course requirements

Solving and presentation of problem sets and short talk in the journal club.

## Audience

Master of Physics, Master of Nanoscience, advanced Bachelor students.

## Literature

#### Books:

- Laser Cooling and Trapping, H. J. Metcalf and P. van der Straten, Springer-Verlag, Berlin (1999).
- Bose-Einstein Condensation in Dilute Gases, C. J. Pethick and H. Smith, 2nd edition, Cambridge University Press (2008).
- Atomic Physics, C. J. Foot, Oxford University Press (2010).

#### Review articles:

- C. S. Adams and E. Riis, "Laser cooling and trapping of neutral atoms", Progress in Quantum Electronics 21, 1 (1997).
- F. Dalfovo, S. Giorgini, L. P. Pitaevskii, and S. Stringari, "Theory of Bose-Einstein condensation in trapped gases", Reviews of Modern Physics 71, 463 (1999).
- A. J. Leggett, "Bose-Einstein condensation in the alkali gases: Some fundamental concepts", Reviews of Modern Physics 73, 307 (2001).
- S. Chu, C. Cohen-Tannoudji, W. D. Phillips, Nobel Lectures, The Nobel Prize in Physics 1997
- E. A. Cornell, W. Ketterle, C. E. Wieman, Nobel Lectures, The Nobel Prize in Physics 2001