Exact elementary excitations with a complex wave vector in the one-dimensional Hubbard model
Abstract
Computer calculations of finite Hubbard chains indicate two peaks for the specific heat for a large Coulomb interaction U for band fillings less than 1/2. Even though the origin of this is physically obvious, no elementary excitations with a gap energy U have been explicitly demonstrated from the exact solution of the Hubbard model. We here demonstrate that there exists elementary excitation with a complex wave vector k for the N-1 spin-up case. These excitations with complex wave vectors have never been discussed previously. These results suggest similar excitations for the case with more general spin arrangements and may account for the specific-heat results.
- Publication:
-
Physical Review B
- Pub Date:
- April 1980
- DOI:
- 10.1103/PhysRevB.21.3269
- Bibcode:
- 1980PhRvB..21.3269C