Master students in the footsteps of Nobel laureates
Some 25 years after the first production of the Bose–Einstein condensate, Master's students in the Department of Physics at ETH Zurich now work in this field. With an exciting experiment, they trace the steps of the three physicists who won the Nobel Prize for their work in 2001.
Behind the inconspicuous door to the quantum optics laboratory, a surprise is waiting for the visitor: A world of lasers, vacuum pumps, mirrors and colourful cable bundles. In the physics laboratory of ETH professor Tilman Esslinger, atoms are trapped and fundamental experiments in many-body physics are carried out. Master's student Simon Hertlein, together with fellow students, is taking the first step towards building an experiment that will ultimately make them understand the production of a Bose–Einstein condensate in practice that led to the 2001 Nobel Prize in Physics.
By students for students
The students are setting up a magneto-optical trap, or MOT for short. Dr. Andrea Morales and Joaquin Minguzzi in the research group of Prof. Tilman Esslinger assisted various generations of students in the design and construction of the MOT, a preliminary stage on the way to the Bose–Einstein condensate. The students completed the trap in February 2019, and it got integrated into the Physics Lab of the Department of Physics, where students are already experimenting with it. Master's students set up the experiment for subsequent students and will expand in the future. In doing so, they learn a lot about the practical side of quantum physics in basic research.
Research-oriented Master's degree at ETH Zurich
Before Simon Hertlein came to ETH Zurich, he completed his Bachelor's degree at the Ludwig Maximilian University in Munich. For several reasons, he had decided to pursue a Master's degree at ETH Zurich, which lasted one and a half years: The opportunity to work in the quantum optics laboratory – something he explicitly applied for – was the most important aspect to come to Zurich for him. He does not regret it. He is enthusiastic about the MOT project and the collaboration with fellow students and the research group in which he feels well integrated and whose active support he appreciates. Another decisive factor in his choice was the ETH ESOP scholarship he had applied for.
Excellence Scholarships
With the Excellence Scholarship & Opportunity Programme (ESOP), ETH Zurich promotes the best students of their Master's degree programme. The scholarship allows Simon Hertlein to focus entirely on his work. He says that he benefits from being able to eat in the canteen from time to time, instead of having to cook or to depend on a part-time job. In addition, ESOP fosters networking with fellow students and industry.
Meet the Talent
On behalf of ETH Rector Prof. Sarah Springman, the patron of the ESOP programme, the ETH Foundation invites ESOP donors to the annual external page“Meet the Talent” event, a meeting between donors and sponsored students. Around twenty students from ten departments of ETH Zurich attended on 10 April 2019. Simon Hertlein presented his Master's thesis “Capturing and ultra-cold cooling of neutral atoms”. This event also offers networking opportunities across generations. external page(Video)
Why ultracold atoms?
It is not easy to trap atoms in the MOT he helped constructing, explains Simon Hertlein. At room temperature, atoms move at hundreds of meters per second. However, the goal is to bring them virtually to a standstill. Using ion pumps, lasers and magnetic fields, the students cool the rubidium atoms in the experiment to extremely low temperatures – less than one thousandth of a degree above absolute zero, which is at -273.15 °C. Although lasers are better known for generating substantial heat and cutting material, in the MOT lasers are used for cooling.
What are the atoms doing in the trap?
In order to be able to adjust the many combinations of lasers and magnetic fields until the atoms in the trap bundle into a dense cloud, students have to fully grasp the underlying concepts. The worst thing, says Simon Hertlein, is when the pump suddenly disengages during this process. If everything works, however, the cloud of atoms shines up in the laser light and can thus be seen with the naked eye! The first step on the route to condensation is achieved.
Motivation boost
Simon Hertlein sees the competitive environment in which Master's students usually find themselves as a positive challenge. In addition to the exciting experimental work in the laboratory and the successful cooperation of the students on the MOT project, he does not want to neglect theory. After all, there will be exams soon. However, the project also gets integrated into teaching: Simon Hertlein proudly recalls that Prof. Esslinger played the video of the luminous atoms created by the students during the lecture.