| 題名: | Phase diagram and BCS-Bose condensation crossover in 1D and 2D Hubbard models |
| 作者: | Kocharian AN
Yang C
Chiang YL |
| 貢獻者: | 物理系 |
| 關鍵詞: | Hubbard model
Bethe-ansatz
quantum Monte-Carlo
BCS-BC crossover |
| 日期: | 2001 |
| 上傳時間: | 2009-12-11 11:11:21 (UTC+8) |
| 摘要: | The ground-state energy, the concentration of double occupied sites and the density of bound electron pairs in low-dimensional attractive Hubbard model are calculated by means of the generalized self-consistent field (GSCF) approach. This approach gives an excellent agreement with the corresponding Bethe-ansatz solution and the quantum Monte-Carlo calculations in a wide range of interaction strength U < 0 and electron concentration n. A simple relationship is found between the order parameter and the density of bound electron pairs, valid for any dimension and in entire parameter space U, n and magnetic field h. The electron pairing and the crossover from the itinerant BCS regime into the Bose condensation regime of local pairs are studied in dependence of both U and n. The GSCF theory correctly displays the separation of the energy gap from the BCS order parameter at n not equal 1 as \U \ increases. (C) 2001 Elsevier Science B.V. All rights reserved. |
| 關聯: | PHYSICA C Volume: 364 Pages: 131-133 |
| 顯示於類別: | [光電物理系] 期刊論文
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