2019/08/31 by David Durel, Michael Urban, Michael Urban · 6 citations
Chemistry · Physics and Astronomy · #Advanced Condensed Matter Physics #Chemistry #Cold Atom Physics and Bose-Einstein Condensates #Condensed matter physics #Crossover #Fermi Gamma-ray Space Telescope #Fermi gas #Mathematical physics #Pairing #Physics #Physics of Superconductivity and Magnetism #Polarization (electrochemistry) #Quantum mechanics #Random phase approximation #Renormalization #Superconductivity #Unitarity #cond-mat.quant-gas
paper · pdf · doi:10.1103/physreva.101.013608
published in Physical Review A 101(1) (American Physical Society) · 10 pages, 12 figures; added figure, phase diagram extension, revisit the section on the FFLO phase, added references
openalex created_date 2019/08/13 · arxiv created 2019/11/05 · openalex publication_date 2020/01/09 · arxiv updated 2020/01/10 · openalex updated_date 2026/08/05
We consider a spin-imbalanced Fermi gas at zero temperature in the normal phase on the BCS side of the BCS-BEC crossover and around unitarity. We compute the critical polarization for pairing, the correlated occupation numbers, and the contact in an extension of particle-particle random-phase approximation (RPA) (also called non-self-consistent T-matrix approach or ladder approximation). The so-called renormalized RPA consists in computing the T matrix with self-consistently determined occupation numbers. The occupation numbers are determined either by keeping the self-energy only to first order or by resumming the Dyson equation. In this way, the result for the critical polarization, strongly overestimated in standard RPA, is clearly improved. We also discuss some problems of this approach.