Dilute Fermi gas at fourth order in effective field theory

C. Wellenhofer, C. Drischler, A. Schwenk
2020 Physics Letters B  
Using effective field theory methods, we calculate for the first time the complete fourth-order term in the Fermi-momentum or k F a s expansion for the ground-state energy of a dilute Fermi gas. The convergence behavior of the expansion is examined for the case of spin one-half fermions and compared against quantum Monte-Carlo results, showing that the Fermi-momentum expansion is well-converged at this order for |k F a s | 0.5.
doi:10.15120/gsi-2021-00625 fatcat:tqkps7zzgjhulbioivtao3w6sa