- Home
- Publications
- News
- Ultracold gallery
- Group Videos
- Research
- People/Contact
- Courses/Outreach
- Physics Courses
- Spring 2022 P334
- Autumn 2021 P238
- Summer 2021 P334
- Spring 2021 P143
- Spring 2021 P334
- Spring 2020 P143
- Spring 2020 P334
- Spring 2019 P226
- Autumn 2018 P238
- Spring 2018 P226
- Autumn 2017 P452
- Spring 2017 P226
- Fall 2016 P154
- Spring 2016 P334
- Spring 2016 P226
- Spring 2015 P334
- Spring 2014 (ETH Zürich)
- Autumn 2013
- Winter 2013
- Autumn 2012
- Winter 2012
- Spring 2011
- Winter 2010
- Spring 2009
- Autumn 2008
- Spring 2008
- Autumn 2007
- Winter 2007
- Autumn 2006
- Spring 2006
- SMART program
- Physics Courses
- Open Positions
- Collaborative project
- Internal
Fermion-Mediated Interactions Between Bosonic Atoms
In our ultracold mixture of atomic gases, the Cs atoms form a Bose-Einstein condensate (BEC) which is completely immersed in a much larger degenerate Fermi gas of Li atoms. Theorists have long predicted that such a system should permit an interesting new type of interaction, where bosons interact through density fluctuations of the Fermi sea. We have recently been able to show for the first time that these fermion-mediated interactions indeed exist in a quantum gas mixture!
We performed the experiment by very carefully measuring the size of our BEC as a function of the Cs-Cs interaction strength. We were able to measure a small additional attraction felt between the Cs atoms only when they were immersed in the Fermi sea. This effect is consistent with the existence of fermion-mediated interactions. Finally, we showed that the Li atoms are capable of rendering the Cs BEC unstable and causing it to fracture into previously unobserved "Bose-Fermi solitons".
These fermion-mediated interactions are predicted to be long-ranged and oscillatory, analogous to the RKKY (Ruderman-Kittel-Kasuya-Yosida) interaction in magnetic materials. We are excited about the prospect of exploring such a novel interaction in ultracold atomic systems, and are currently working to learn more about the way these fermion-mediated interactions behave.