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arXiv 2311.02414cond-mat.str-el
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扩展准粒子图像中的电子量子线

Electronic quantum wires in extended quasiparticle picture

Klaus Morawetz, Vinod Ashokan, Kare Narain Pathak, Neil Drummond, Gianaurelio Cuniberti

AI总结:

本文用扩展准粒子图像与 Born 近似研究高密度一维费米量子线,统一计算自能、极化、响应函数及相关能,并揭示离壳能隙、holon–antiholon 分裂和 Peierls 失稳。

摘要:

本文考虑了费米子的一维量子线,并在扩展准粒子图像和 Born 近似下计算了高密度区域的基态性质。通过展开双粒子 Green 函数,在同一基础上确定了自能、极化以及响应函数。尽管由于弹性散射的 Pauli 阻塞,在壳自能严格为零,但离壳行为表现出丰富的结构:激发阻尼中存在一个能隙,当动量趋近 Fermi 动量时该能隙闭合。文中给出了一致的谱函数,使其满足前两个能量加权求和规则。激发谱由于 holon 和 antiholon 而发生分裂,表现为非 Fermi 液体行为。通过减去一个能量常数,提出了一种重整化过程,使 Fock 交换能量有限。由平均场导出的有效质量出现一个凹陷,这是 Peierls 不稳定性的开端。相关能借助考虑离壳效应的扩展准粒子图像进行计算。相应的响应函数给出与自能相同的相关能,这与微扰论一致。约化密度矩阵或动量分布借助 Padé 正则化计算,修复了微扰论的缺陷。Fermi 能量处看似有限、表明 Fermi 液体行为的台阶,也通过这种方式得到修正。

英文摘要:

A one-dimensional quantum wire of Fermions is considered and ground state properties are calculated in the high density regime within the extended quasiparticle picture and Born approximation. Expanding the two-particle Green functions determines the selfenergy and the polarization as well as the response function on the same footing. While the on-shell selfenergies are strictly zero due to Pauli-blocking of elastic scattering, the off-shell behaviour shows a rich structure of a gap in the damping of excitation which is closed when the momentum approaches the Fermi one. The consistent spectral function is presented completing the first two energy-weighted sum rules. The excitation spectrum shows a splitting due to holons and antiholons as non-Fermi liquid behaviour. A renormalization procedure is proposed by subtracting an energy constant to render the Fock exchange energy finite. The effective mass derived from meanfield shows a dip as onset of Peierls instability. The correlation energy is calculated with the help of the extended quasiparticle picture which accounts for off-shell effects. The corresponding response function leads to the same correlation energy as the selfenergy in agreement with perturbation theory. The reduced density matrix or momentum distribution is calculated with the help of a Padé regularization repairing deficiencies of the perturbation theory. A seemingly finite step at the Fermi energy indicating Fermi-liquid behaviour is repaired in this way.

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。

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