Details

Autor(en) / Beteiligte

• Reichert, Benjamin
• Petković, Aleksandra
• Ristivojevic, Zoran

Titel

Quasiparticle decay in a one-dimensional Bose-Fermi mixture

Ist Teil von

• Physical review. B, 2017-01, Vol.95 (4), Article 045426

Ort / Verlag

College Park: American Physical Society

Erscheinungsjahr

2017

Quelle

APS_美国物理学会期刊

Beschreibungen/Notizen

• In a one-dimensional weakly interacting Bose-Fermi mixture, one branch of elementary excitations is well described by the Bogoliubov spectrum. Here we use the microscopic theory to study the decay of such quasiparticle excitations. The main scattering process which leads to their decay is the backscattering of a Bogoliubov quasiparticle off the Fermi sea, where a particle-hole pair is excited. For a low-momentum quasiparticle (phonon) of momentum q, we find that the decay rate scales as q3 provided q is smaller than the Fermi momentum kF, while in the opposite case the decay behaves as q2. If the ratio of the masses of fermions and bosons is equal to the ratio of the boson-fermion and the boson-boson interaction strengths, the decay rate changes dramatically. It scales as q7 for q<kF, while we find q6 scaling at q>kF. For a high-momentum Bogoliubov quasiparticle, we find a constant decay rate for q<kF, while it scales as 1/q for q>kF. We also find an analytic expression for the decay rate in the crossover region between low and high momenta. The decay rate is a continuous, but nonanalytic function of the momentum at q=kF. In the special case when the parameters of our system correspond to the integrable model, we observe that the decay rate vanishes.