Strongly bound fermion pairs on a ring: a composite-boson approach
arXiv:2108.13806 · doi:10.1103/PhysRevA.105.013302
Abstract
Particles made of two fermions can in many cases be treated as elementary bosons, but the conditions for this treatment to be valid are nontrivial. The so-called "coboson formalism" is a powerful tool to tackle compositeness effects relevant for instance for exciton physics and ultracold atomic dimers. A key element of this theory is an ansatz for the ground state of N pairs, built from the single-pair ground state combined with the exclusion principle. We show that this ansatz can fail in one-dimensional systems which fulfill the conditions expected to make the ansatz valid. Nevertheless, we also explain how coboson theory can recover the correct ground state. Thus, our work highlights limitations and strengths of the formalism and leads to a better treatment of composite bosons.
10 pages including appendices
References in corpus (8)
- Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
- Exact solution for infinitely strongly interacting Fermi gases in tight waveguides
- Four-body problem and BEC-BCS crossover in a quasi-one-dimensional cold fermion gas
- Stability of a Bose-Einstein condensate revisited for composite bosons
- Bosonic behavior of entangled fermions
- Composite-boson approach to molecular Bose-Einstein condensates in mixtures of ultracold Fermi gases
- Fermionic versus bosonic behavior of confined Wigner molecules
- On the description of composite bosons in discrete models