Effects of quantum noise on dephasing in mesoscopic systems

量子噪声对介观系统相移的影响

• 批准号: 185960027
• 负责人: Professor Dr. Jan von Delft
• 金额: --
• 依托单位: Lehrstuhl für Theoretische Festkörperphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/185960027?language=en
• 关键词: Effects; quantum; noise; dephasing; mesoscopic

We propose to study the effects of quantum noise on dephasing due to electronelectron interactions in mesoscopic disordered systems, in the context of weak localization (WL) and universal conductance fluctuations (UCFs). In such systems, interactions can be described via a fluctuating effective noise field affecting the quantum mechanical phase of electron wave functions. The phase space for energy transfer between conduction electrons and this noise field, however, is restricted by Pauli blocking and hence depends on the temperature T. This very fundamental effect can be accounted for by using an effective quantum noise field with a nonzero noise correlation time, TT 1/T (whereas the commonly-used classical noise field has TT = 0). We will study two types of systems for which using TT ≠ 0 is essential: (i) Complex geometries such as rings and grids constructed from quasi-1D wires, characterized by a Thouless energy ETh (the inverse time for traversing a ring or a grid plaquette); and (ii) dephasing in external AC fields, characterized by an AC frequency ωac. For these, the temperature-dependence of the dephasing time Tφ(T) changes qualitatively once T drops below ETh or ωac, with experimentally measurable consequences for phenomena involving WL and UCFs.

在弱局域化（WL）和普适电导涨落（UCFs）的背景下，研究了介观无序系统中由于电子-电子相互作用引起的量子噪声对退相的影响.在这样的系统中，相互作用可以通过影响电子波函数的量子力学相位的波动有效噪声场来描述。然而，传导电子和该噪声场之间的能量转移的相空间受到泡利阻塞的限制，因此取决于温度T。这种非常基本的效应可以通过使用具有非零噪声相关时间TT 1/T的有效量子噪声场来解释（而常用的经典噪声场具有TT = 0）。我们将研究两种类型的系统，其中使用TTT 0是必不可少的：（i）复杂的几何形状，如环和网格构造的准一维线，其特征在于一个无量纲的能量ETh（逆时间穿越一个环或网格元格）;和（ii）在外部交流场的移相，其特征在于一个交流频率ωac。对于这些，一旦T下降到ETh或ωac以下，失相时间Tφ（T）的温度依赖性就会发生定性变化，并对涉及WL和UCF的现象产生实验可测量的后果。

项目成果

Quantum corrections to the polarizability and dephasing in isolated disordered metals

对孤立无序金属的极化率和相移的量子校正

• DOI: 10.1103/physrevb.88.024201
• 发表时间: 2013
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Treiber;P. M. Ostrovsky;O. M. Yevtushenko;J. von Delft;I. V. Lerner
• 通讯作者: I. V. Lerner

Transport and dephasing in a quantum dot: Multiply connected graph model

量子点中的传输和移相：多重连通图模型

• DOI: 10.1002/andp.201100258
• 发表时间: 2012
• 期刊: Annalen der Physik
• 影响因子: 2.4
• 作者: M. Treiber;O. M. Yevtushenko;F. Marquardt;J. von Delft;I. V. Lerner
• 通讯作者: I. V. Lerner