Quantum quench of Kondo correlations in optical absorption
| Autor: | Wolf Wuester, P. Fallahi, Florian Haupt, Stefan Faelt, Hakan E. Türeci, J. von Delft, Atac Imamoglu, Andreas Weichselbaum, Martin Claassen, Christian Latta, Leonid I. Glazman, M. Hanl |
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| Rok vydání: | 2011 |
| Předmět: |
Quantum optics
Physics Multidisciplinary Photon Condensed matter physics Degenerate energy levels 02 engineering and technology Electron 021001 nanoscience & nanotechnology 01 natural sciences Quantum dot 0103 physical sciences Kondo effect 010306 general physics 0210 nano-technology Wave function Quantum |
| Zdroj: | Nature |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/nature10204 |
| Popis: | One of the most celebrated phenomena in many-body physics is the Kondo effect, which describes the interaction between a single confined spin and the spins of an electron reservoir. In the past decade, the effect has been extensively studied in quantum dots, where a single electron spin in the quantum dot interacts with the sea of electrons in the contacts. So far, only electronic transport measurements have been done on these systems, but Latta et al. add a new dimension by carrying out optical measurements. They show that, remarkably, absorption of a single photon leads to an abrupt change in the interactions of the single spin with the electron reservoir; a quantum quench of Kondo correlations. The study initiates a new direction where quantum optics techniques are used to study many-body phenomena. 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 effect1,2. Electronic transport measurements on single artificial atoms, or quantum dots, have made it possible to study the effect in great detail3,4,5. 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 catastrophe6,7, 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 field8, 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. |
| Databáze: | OpenAIRE |
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