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Updated: Jul 8, 2026
11:21
Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Probing Bardeen-Cooper-Schrieffer Pairing and Quasiparticle Formation in Ultracold Gases by Rydberg Atom
Emilio Ramos Rodríguez1,2, Marcel Gievers3, Richard Schmidt1
1Universität Heidelberg, Institut für Theoretische Physik, 69120 Heidelberg, Germany.
Physical Review Letters
|July 7, 2026
Summary
This study introduces Rydberg impurities as a novel method to probe pairing in ultracold fermionic superfluids. This technique directly measures the superfluid gap and reveals Cooper pair states in strongly correlated matter.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Condensed Matter Physics
- Quantum Many-Body Systems
Background:
- Probing pairing in fermionic superfluids at various scales presents significant challenges.
- Ultracold paired fermions exhibit complex strongly correlated states.
- Rydberg impurities offer a potential new avenue for local spectroscopic sensing.
Purpose of the Study:
- To investigate the use of Rydberg impurities as a spectroscopic sensor for ultracold paired fermions.
- To develop a method for directly measuring the superfluid gap in fermionic superfluids.
- To determine the state of Cooper pairs (broken or intact) using Rydberg spectroscopy.
Main Methods:
- Utilizing Rydberg impurities to interact with and sense the surrounding ultracold paired fermions.
- Analyzing the optical absorption spectrum of the Rydberg impurity.
- Employing the functional determinant approach to interpret spectral shifts.
Main Results:
- The optical absorption spectrum of Rydberg impurities directly encodes many-body properties of the fermionic superfluid.
- Frequency shifts of dimer and trimer peaks provide a direct measure of the superfluid gap.
- The spectra distinguish between broken and intact Cooper pairs, revealing pairing signatures.
Conclusions:
- Rydberg atom spectroscopy is established as a powerful local probe for strongly correlated matter.
- This method allows for detailed characterization of pairing in fermionic superfluids.
- The formation of polaron quasiparticles is linked to the superconducting gap and suppressed orthogonality catastrophe.
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