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Observation of Massless and Massive Collective Excitations with Faraday Patterns in a Two-Component Superfluid
R Cominotti1, A Berti1, A Farolfi1
1INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, and Trento Institute for Fundamental Physics and Applications, INFN, 38123 Povo, Italy.
Physical Review Letters
|June 10, 2022
Summary
Researchers measured collective excitation modes in ultracold bosonic atoms. Coherent coupling between components reduced phase symmetry, giving spin modes a finite mass.
Area of Science:
- Atomic physics
- Quantum fluids
- Condensed matter physics
Background:
- Ultracold atomic gases provide a versatile platform for studying quantum phenomena.
- Two-component superfluids exhibit rich collective excitation dynamics.
Purpose of the Study:
- To experimentally measure the dispersion relation of density and spin collective modes.
- To investigate the effect of inter-component coherent coupling on these modes.
Main Methods:
- Parametric spectroscopy utilizing external modulation of transverse confinement.
- Formation of density and spin Faraday waves.
- Experimental setup with an elongated two-component Bose-Einstein condensate.
Main Results:
- Successfully measured the dispersion relation for both density and spin excitations.
- Observed the emergence of density and spin Faraday waves under modulated confinement.
- Demonstrated that coherent coupling between the two components breaks phase symmetry.
Conclusions:
- Coherent coupling between components imparts a finite mass to spin modes.
- The findings offer insights into the fundamental properties of multi-component superfluids.
- Experimental control over collective excitations in ultracold atomic systems is achieved.
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