2017/08/31 by Hadrien Kurkjian, J. Tempere, Jacques Tempere · 17 citations
Physics and Astronomy · #Amplitude #Cold Atom Physics and Bose-Einstein Condensates #Coupling (piping) #Creation and annihilation operators #Electron #Excitation #Fermi Gamma-ray Space Telescope #Fermi gas #Fermion #Long wavelength limit #Operator (biology) #Physics #Physics of Superconductivity and Magnetism #Quantum #Quantum electrodynamics #Quantum mechanics #Quantum, superfluid, helium dynamics #Quasiparticle #Roton #Superconductivity #Superfluid helium-4 #Superfluidity #cond-mat.quant-gas #physics.atm-clus #physics.atom-ph
paper · pdf · doi:10.1088/1367-2630/aa969b
published in New Journal of Physics 19(11), 113045 (IOP Publishing) · 13 pages, 5 figures
openalex publication_date 2017/10/27 · arxiv created 2020/05/18 · arxiv updated 2020/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the process of absorption or emission of a bosonic collective excitation by a fermionic quasiparticle in a superfluid of paired fermions. From the random phase approximation equation of motion of the bosonic excitation annihilation operator, we obtain an expression of the coupling amplitude of this process, which is limited neither to resonant processes nor to the long wavelength limit. We confirm our result by independently deriving it in the functional integral approach using the gaussian fluctuation approximation, and by comparing it in the long wavelength limit to the quantum hydrodynamic result. Lastly, we give a straightforward application of the coupling amplitude we obtain by calculating the lifetime of the bosonic excitations of an arbitrary wave number. We find a mode quality factor that decreases from its maximum at low wave numbers and vanishes when the bosonic branch hits the continuum of fermionic biexcitations.