Goldstone mode and pair-breaking excitations in atomic Fermi superfluids
| Autor: | Georg M. Bruun, Sascha Hoinka, Marcus Lingham, Jami J. Kinnunen, Paul Dyke, Chris J. Vale |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Atomic Physics (physics.atom-ph)
General Physics and Astronomy FOS: Physical sciences Roton 01 natural sciences 010305 fluids & plasmas Physics - Atomic Physics Superfluidity Gapless playback Condensed Matter::Superconductivity Quantum mechanics 0103 physical sciences 010306 general physics Spectroscopy Goldstone Physics Condensed Matter::Quantum Gases ta114 Condensed matter physics Condensed Matter::Other Mode (statistics) Quantum Gases (cond-mat.quant-gas) visual_art Goldstone boson visual_art.visual_art_medium Condensed Matter::Strongly Correlated Electrons Condensed Matter - Quantum Gases Fermi Gamma-ray Space Telescope |
| Zdroj: | Hoinka, S, Dyke, P, Lingham, M, Kinnunen, J, Bruun, G & Vale, C 2017, ' Goldstone mode and pair-breaking excitations in atomic Fermi superfluids ', Nature Physics . https://doi.org/10.1038/nphys4187 |
| Popis: | Spontaneous symmetry breaking is a central paradigm of elementary particle physics, magnetism, superfluidity and superconductivity. According to Goldstone's theorem, phase transitions that break continuous symmetries lead to the existence of gapless excitations in the long-wavelength limit. These Goldstone modes generally dominate the low-energy excitations, showing that symmetry breaking has a profound impact on the physical properties of matter. Here, we present the first comprehensive study of the elementary excitations in a homogeneous strongly interacting Fermi gas through the crossover from a Bardeen-Cooper-Schrieffer (BCS) superfluid to a Bose-Einstein condensate (BEC) of molecules using two-photon Bragg spectroscopy. The spectra exhibit a discrete Goldstone mode, associated with the broken symmetry superfluid phase, as well as pair breaking single-particle excitations. Our techniques yield a direct determination of the superfluid pairing gap and speed of sound in close agreement with a strong-coupling theory. Original version, full text published online in Nature Physics |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|