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Cavity-mediated charge and pair-density waves in a unitary Fermi gas
Timo Zwettler1, Filip Marijanovic2, Tabea Bühler1
1Institute of Physics and Center for Quantum Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Nature Communications
|December 8, 2025
Summary
Researchers engineered simultaneous coupling of light to single atoms and fermionic pairs in a quantum gas. This interference between charge-density and pair-density waves leads to novel self-ordering phase transitions in strongly correlated matter.
Area of Science:
- Quantum optics
- Condensed matter physics
- Ultracold atomic gases
Background:
- Coherent light-matter interactions in high-finesse cavities drive self-ordering phase transitions.
- Previous studies focused on single-atom coupling, leading to charge-density or spin-density wave and superradiant order.
Purpose of the Study:
- To engineer simultaneous coupling of cavity photons to both single atoms and fermionic pairs.
- To investigate the interference between charge-density wave and pair-density wave orders.
- To explore exotic orders in strongly correlated matter using cavity quantum electrodynamics.
Main Methods:
- Utilizing a unitary Fermi gas with strong correlations.
- Engineering simultaneous coupling of cavity photons to single atoms and fermionic pairs.
- Tracking the onset of superradiance to observe interference effects.
Main Results:
- Observed interference between charge-density wave and pair-density wave orders.
- Demonstrated spontaneous spatial modulation of the short-range pair correlation function.
- Revealed constructive or destructive interference of three orders (photon, atom, pair) based on coupling strength and sign.
Conclusions:
- Cavity quantum electrodynamics can produce and observe exotic orders in strongly correlated matter.
- The study paves the way for quantum simulation of complex quantum matter using ultracold atoms.
- Interplay between light-matter and atom-atom interactions is crucial for emergent phenomena.
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