In-medium bound states of two bosonic impurities in a one-dimensional Fermi gas
| Autor: | Huber, D., Hammer, H. -W., Volosniev, A. G. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. Research 1, 033177 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevResearch.1.033177 |
| Popis: | We investigate the ground-state energy of a one-dimensional Fermi gas with two bosonic impurities. We consider spinless fermions with no fermion-fermion interactions. The fermion-impurity and impurity-impurity interactions are modelled with Dirac delta functions. First, we study the case where impurity and fermions have equal masses, and the impurity-impurity two-body interaction is identical to the fermion-impurity interaction, such that the system is solvable with the Bethe ansatz. For attractive interactions, we find that the energy of the impurity-impurity subsystem is below the energy of the bound state that exists without the Fermi gas. We interpret this as a manifestation of attractive boson-boson interactions induced by the fermionic medium, and refer to the impurity-impurity subsystem as an in-medium bound state. For repulsive interactions, we find no in-medium bound states. Second, we construct an effective model to describe these interactions, and compare its predictions to the exact solution. We use this effective model to study non-integrable systems with unequal masses and/or potentials. We discuss parameter regimes for which impurity-impurity attraction induced by the Fermi gas can lead to the formation of in-medium bound states made of bosons that repel each other in the absence of the Fermi gas. Comment: version accepted for publication in Physical Review Research |
| Databáze: | arXiv |
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