一维持续电流：Leggett定理的另一面
Persistent currents in one dimension: the other side of Leggett's theorem
摘要：
本文讨论了一维环中N电子持续流的符号。使用拓扑参数，我们建立了自由能的下限在存在任意的电子-电子相互作用和外部电位。这些界限是莱格特推导的上限的对应物。具有奇数（偶数）极化电子的环总是反磁性的（顺磁性的）。我们发现，非极化电子与N是四的倍数表现出顺磁行为或超导体般的电流相位关系。
英文摘要：
We discuss the sign of the persistent current of N electrons in one dimensional rings. Using a topology argument, we establish lower bounds for the free energy in the presence of arbitrary electron-electron interactions and external potentials. Those bounds are the counterparts of upper bounds derived by Leggett. Rings with odd (even) numbers of polarized electrons are always diamagnetic (paramagnetic). We show that unpolarized electrons with N being a multiple of four exhibit either paramagnetic behavior or a superconductor-like current-phase relation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
