Quantum quench of Kondo correlations in optical absorption
Quantum quench of Kondo correlations in optical absorption
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DOI：
10.1038/nature10204
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发表时间：
2011-02
期刊：
影响因子：
64.8
通讯作者：
C. Latta;F. Haupt;M. Hanl;A. Weichselbaum;M. Claassen;W. Wuester;P. Fallahi;S. Faelt;L. Glazman-L.-Gla
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文献类型：
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作者：
C. Latta;F. Haupt;M. Hanl;A. Weichselbaum;M. Claassen;W. Wuester;P. Fallahi;S. Faelt;L. Glazman-L.-Gla
单个受限自旋与电子库自旋之间的相互作用导致了多体物理学中最显著的现象之一——近藤效应。在单个人造原子或量子点上的电子输运测量，使得非常详细地研究这种效应成为可能。在这里，我们报告了一个半导体量子点隧道耦合到简并电子气体的光学测量结果，表明单个光子的吸收导致系统哈密顿量的突变和近道相关的量子猝灭。通过从实验吸收线形状中推断出特征幂律指数，我们发现了由初始和最终多体波函数之间的重叠消失引起的安德森正交突变形式的独特猝灭特征。我们表明，确定正交度的幂律指数可以使用外部磁场进行调谐，这明确表明观察到的吸收线形状源于近藤相关性。我们的实验表明，对单个人造原子的光学测量为以前仅使用输运光谱研究的多体现象提供了新的视角。
The interaction between a single confined spin and the spins of an electron reservoir leads to one of the most remarkable phenomena of many-body physics—the Kondo effect,. Electronic transport measurements on single artificial atoms, or quantum dots, have made it possible to study the effect in great detail,,. Here we report optical measurements on a single semiconductor quantum dot tunnel-coupled to a degenerate electron gas which show that absorption of a single photon leads to an abrupt change in the system Hamiltonian and a quantum quench of Kondo correlations. By inferring the characteristic power-law exponents from the experimental absorption line shapes, we find a unique signature of the quench in the form of an Anderson orthogonality catastrophe,, induced by a vanishing overlap between the initial and final many-body wavefunctions. We show that the power-law exponent that determines the degree of orthogonality can be tuned using an external magnetic field, which unequivocally demonstrates that the observed absorption line shape originates from Kondo correlations. Our experiments demonstrate that optical measurements on single artificial atoms offer new perspectives on many-body phenomena previously studied using transport spectroscopy only.