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篇目详细内容 |
【篇名】 |
Polaron, molecule and pairing in one-dimensional spin-1/2 Fermi gas with an attractive Delta-function interaction |
【刊名】 |
Frontiers of Physics |
【刊名缩写】 |
Front. Phys |
【ISSN】 |
2095-0462 |
【EISSN】 |
2095-0470 |
【DOI】 |
10.1007/s11467-011-0213-0 |
【出版社】 |
Higher Education Press and Springer-Verlag Berlin
Heidelberg |
【出版年】 |
2012 |
【卷期】 |
7
卷1期 |
【页码】 |
8-15
页,共
8
页 |
【作者】 |
Xi-Wen Guan;
|
【关键词】 |
spin-1/2 Fermi gas; polaron; molecule; Fredholm equations |
【摘要】 |
Using solutions of the discrete Bethe ansatz equations, we study in detail the quantum impurity problem of a spin-down fermion immersed into a fully ploarized spin-up Fermi sea with weak attraction. We prove that this impurity fermion in the one-dimensional (1D) fermionic medium behaves like a polaron for weak attraction. However, as the attraction grows, the spin-down fermion binds with one spin-up fermion from the fully-polarized medium to form a tightly bound molecule. Thus it is seen that the system undergos a crossover from a mean field polaron-like nature into a mixture of excess fermions and a bosonic molecule as the attraction changes from weak attraction into strong attraction. This polaron–molecule crossover is universal in 1D many-body systems of interacting fermions. In a thermodynamic limit, we further study the relationship between the Fredholm equations for the 1D spin-1/2 Fermi gas with weakly repulsive and attractive delta-function interactions. |
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