BEC–BCS crossover, phase transitions and phase separation in polarized resonantly-paired superfluids

摘要: Abstract We study resonantly-paired s-wave superfluidity in a degenerate gas of two species (hyperfine states labeled by ↑, ↓) fermionic atoms when the numbers N↑ and N↓ are unequal, i.e., system is “polarized.” find that continuous crossover from Bose–Einstein condensate (BEC) limit tightly-bound diatomic molecules to Bardeen–Cooper–Schrieffer (BCS) weakly correlated Cooper pairs, studied extensively at equal populations, interrupted variety distinct phenomena under an imposed population difference ΔN ≡ N↑ − N↓. Our findings summarized “polarization” (ΔN) versus Feshbach-resonance detuning (δ) zero-temperature phase diagram, which exhibits regions separation, periodic FFLO superfluid, polarized normal Fermi molecular superfluid consisting fully gas. describe numerous experimental signatures such phases transitions between them, particular focusing on their spatial structure inhomogeneous environment atomic trap.