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Quantum effects of interaction in nanosystems

Work number - M 16 AWARDED

Presented by Institute for Condensed Matter Physics of National Academy of Sciences of Ukraine

Author: SkorobagatkoGlebA.

 The aim of this series of research works is the study of the role of electron-electron and electron-vibron interactions in quantum dynamics of low-dimensional nano-systems, especially, single-electron molecular transistors with movable quantum dots. Another goal of presented study is a progress in general theory of quantum detectors, those designed on the platform of quasi one-dimensional quantum-point contacts with electron-electron interaction in their leads and, as well, the investigation of respective low-temperature effects in quantum detection of charge-qubits’ quantum states by means of such quantum detectors.

In presented theoretical study it was established for the first time by the author how exactly electron-electron interaction (meaning the Luttinger correlation parameter) and quantum fluctuations of quantum dot displacement - both affect resonant tunneling of strongly correlated electrons in such systems. Besides that, the role of these factors in the development of a (shuttle-) instability of quantum dot classical motion was discovered. Also, a general bosonized theory of interacting quantum-point contacts as quantum detectors for charge-qubits was built for the first time in this study. As the result, a novel important many-body effect of interaction-driven instability in low-temperature quantum detection by means of tunnel contact with interacting electrons was discovered by the author. Exact mathematical description of the latter effect was also performed by the author for the first time in this series of works.

Overall a sufficient contribution to the theoretical grounds of molecular transistors and quantum detectors design was performed by the author in the presented series of works. As well, a meaning of obtained results for the theory of non-equilibrium transport of strongly interacting electrons in single-electron transistors and for the theory of quantum detection by means of quantum-point contacts is also considerable. Several results on interaction effects in molecular transistors being obtained in this study for the first time have limited number of analogs in the literature, while a developed bosonized theory of quantum detectors with interaction and corresponding exact results have no analogs in the existing literature yet. The theory of low-temperature quantum detection instability depicted in this study for the first time is shown to explain unusually long decoherence timescales for charge-qubits, which had been observed independently by two groups of researchers in two different experiments on charge-qubit manipulations.

Total number of publications:18, including7 research articlesin international journals( 3–publishedin the world-leadingcondensed matter journal Physical Review B (including 2single-author articles in this journal).Total number of citations for this series of papers/h-index of series: according to Scopus:35/4; according to Google Scholar: 38/4.(Overall author’s number of citations/h-index: Scopus: 60/5;Google Scholar: 64/5.)