Cooper pairing reexamined
| Autor: | Fortes, M., de Llano, M., Solis, M. A. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | When both two-electron \textit{and} two-hole Cooper-pairing are treated on an equal footing in the ladder approximation to the Bethe-Salpeter (BS) equation, the zero-total-momentum Cooper-pair energy is found to have two \textit{real} solutions $\mathcal{E}_{0}^{BS}=\pm 2\hbar \omega_{{D}%}/\sqrt{{e}^{2/\lambda }+{1}}$ which coincide with the zero-temperature BCS energy gap $\Delta =\hbar \omega_{D}/\sinh (1/\lambda) $ in the weak coupling limit. Here, $\hbar \omega_{D}$ is the Debye energy and $\lambda \geq 0$ the BCS model interaction coupling parameter. The interpretation of the BCS energy gap as the binding energy of a Cooper-pair is often claimed in the literature but, to our knowledge, never substantiated even in weak-coupling as we find here. In addition, we confirm the two purely-\textit{imaginary} solutions assumed since at least the late 1950s as the \textit{only} solutions, namely, $\mathcal{E}_{0}^{BS}=\pm i2\hbar \omega_{{D}}/\sqrt{{e}^{2/\lambda}{-1}}.$ Comment: 5 pages and 2 figures. Submitted for publication |
| Databáze: | arXiv |
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