Artigo
Effective theory for trapped few-fermion systems
Fecha
2007-12-01Registro en:
Physical Review A. College Pk: Amer Physical Soc, v. 76, n. 6, 7 p., 2007.
1050-2947
10.1103/PhysRevA.76.063613
WOS:000251985900092
WOS000251985900092.pdf
Autor
Los Alamos Natl Lab
University of Arizona
Univ Groningen
Universidade Estadual Paulista (Unesp)
Iowa State Univ
Resumen
We apply the general principles of effective field theories to the construction of effective interactions suitable for few- and many-body calculations in a no-core shell model framework. We calculate the spectrum of systems with three and four two-component fermions in a harmonic trap. In the unitary limit, we find that three-particle results are within 10% of known semianalytical values even in small model spaces. The method is very general, and can be readily extended to other regimes, more particles, different species (e.g., protons and neutrons in nuclear physics), or more-component fermions (as well as bosons). As an illustration, we present calculations of the lowest-energy three-fermion states away from the unitary limit and find a possible inversion of parity in the ground state in the limit of trap size large compared to the scattering length. Furthermore, we investigate the lowest positive-parity states for four fermions, although we are limited by the dimensions we can currently handle in this case.