报告一
【报告题目】：Hybrid metal-carbon nanomaterials for optoelectronic applications
【报告人】：Stella Kavokina 教授，西湖大学、俄罗斯量子中心&莫斯科物理技术学院
【报告时间】：10月13日9:30-10:30
【报告地点】：29-414
【报告摘要】：The hybridization of s – and p-orbitals of carbon atoms gives rise to the formation of a rich variety of allotropic forms of carbon. The great interest of scientific community has been especially attracted to the linear carbon forms for their unique electronic and optical properties as well as for the hard complexity of their synthesis. The recent observation of excitons and trions in sp-carbon nanowires has a fundamental importance as it presents the first experimental evidence of bright exciton states in monoatomic chains. It crowns an effort of many groups who provided the excitonic gaps calculation in one-dimensional carbon chains [1, 2] and predicted the excitonic features in carbon chains. We observe a triplet fine structure in low-temperature photoluminescence spectra that is associated with the spatially direct neutral exciton, positive and negative trion resonances [2]. The time-resolved optical response of excitons in carbon chains is found to be dependent on the bandgap of the chain and the lengths of straight parts of the chains that provides a control tool for fine tuning of the radiative properties of carbon chains for applications in carbon lasers and light-emitting diodes.
[1] Mostaani E., et al., Lambert. Phys. Chem. Chem. Phys. 18, (2016).
[2] S. Kutrovskaya, et al, Nanoletters 20, 9 (2020).
【报告人简介】：Dr. Stella Kavokina got the Master degree in Physics with Honour from the Vladimir State university (Russia) in 2007 and her PhD in Physics from the Moscow State university (Russia). Then for several years she was lecturing at the Vladimir State university, and doing research at the International Center for Quantum Optics & Quantum Technologies in Moscow and MISiS University. Dr. Stella Kavokina combined the research work with teaching until September 2018 when she moved to China as an Associate Research Professor at the Westlake university (Hangzhou). In March 2019 Dr. Kavokina have been promoted to the Research Professor position. Now her group in Hangzhou is working on fabrication of nanoelectronic networks based on carbon 1D and 2D-materials under study of high precision electronic microscopy, quantum transport measurements, cryogenic time-resolved optical spectroscopy and photon correlation measurements etc. It should be also mentioned that Stella has got married in April 2023 and changed her surname from Kutrovskaya to Kavokina, which is why the most part of her publications are signed by Stella Kutrovskaya, while on the recent publications her name appears as Stella Kavokina.
报告二
【报告题目】：Pathways of quantum polaritonics
【报告人】：Alexey Kavokin教授，西湖大学、俄罗斯量子中心&莫斯科物理技术学院
【报告时间】：10月13日10:40-11:40
【报告地点】：29-414
【报告摘要】：Polariton lasers [1] are semiconductor light-emitting devices based on the bosonic condensation of half-light-half-matter quasiparticles: exciton-polaritons. Due to the strong coupling of cavity photons with excitons, exciton-polaritons in microcavities have a peculiar non-parabolic dispersion. Due to the stimulated scattering to one or several quantum states, exciton-polaritons form bosonic condensates characterized by high spatial coherence and superfluid properties. Spatial-light modulators help generating traps for polariton superfluids in plane of GaAs-based microcavities, where size-quantization of many-body wavefunctions of polariton superfluids is observed. Exciting coherent superpositions of pairs of eigen states of polariton superfluids in elliptical traps we create qubits [2] characterized by very slow decoherence dynamics. The characteristic timescales are as follows: approximately every femtosecond a polaritn comes in or goes out from a polariton condensate, the life-time of each individual polariton in a condensate is of the order of 10 picoseconds, the coherence time of a polariton condensate as a whole is of the order of 100 ps, the characteristic relaxation time of the spatial coherence in a trapped polariton condensates is of the order of microseconds or longer. This makes the figure of merit of qubits based on trapped polariton condensates very high, probably over 1000 or more. Quantum logic operations can be performed on these superfluid polariton qubits with use of control laser pulses. We demonstrate the Hadamard and Pauli operations on a single qubit and discuss possible designs of double-qubit gates. The new platform for quantum computing provided by polariton lasers is highly promising due to the remarkable scalability of polariton quantum networks and their potential for room temperature operation.
[1] Polariton laser and polariton superfluidity in microcavities, Kavokin A, Malpuech G, Laussy FP, Phys. Lett. A 306, 4, 187-199 (2003).
[2] Polariton lasers for classical and quantum computing, A.V. Kavokin, T.C.H. Liew, S. Klembt, P.G. Lagoudakis and S. Hoefling, Nature Reviews Physics, 4, 435–451 (2022).
【报告人简介】：Having obtained a PhD in physics at the Ioffe institute of Russian Academy of Science at the age of 23, Alexey Kavokin had several temporary research appointments in 1994-1998 at the university of Montpellier (France), universities of Pavia and Rome (Italy). In 1998 he obtained a professor position at the Blaise Pascal university (Clermont-Ferrand, France). At the time he was the youngest physics professor in France (28). In 2005, he joined the university of Southampton (UK) as a Chair of Nanophysics and Photonics. This appointment he held until 2024, initially full-time, then part-time. In 2006-2009 he served as a chair-holder of the Marie-Curie Chair of Excellence at the university of Rome II. In 2014 he returned to Rome as a Research Director of the National Council for Research (CNR). In 2018, he accepted an offer of the newly created research-oriented university in China: the Westlake university in Hangzhou. Kavokin resigned from the Research Director position at CNR to become a Chair Professor and Director of the 3 International Center for Polaritonics (ICP) at the Westlake university. In this new role, he was given a startup funding of 100 million RMB (about 12 million euro) to build a high-level research centre specialized in Polaritonics. Despite of the complications caused by the COVID-19 pandemics, this task has been successfully accomplished, and in 2024 the ICP has secured long-term funding as a lead institution on the Quantum Polaritonics network within the national program Quantum 2030. In parallel to the work in China, in the recent decade Kavokin participated in several research initiatives in Russia. He created the Spin Optics laboratory at the State university of St-Petersburg (2012), the Quantum Polaritonics group at the Russian Quantum Center (2014), and, most importantly, contributed to the development of a new research centre at the Moscow Institute of Physics and Technology (MIPT) becoming the first Director of the Abrikosov Center for Theoretical Physics (2022).
• For his theoretical prediction of the Bose-Einstein condensation of exciton-polaritons at the room temperature that resulted in the development of polariton lasers, Kavokin has received an international Quantum Device Award and the Gross medal in 2020. Since 2002, the International Quantum Device award is given to one scientist per year. The award is announced at the yearly Compound Semiconductor Week by an Award committee headed by Prof. Y. Arakawa (Tokyo university).
• In 2020, the work of Kavokin on Polariton lasers was shortlisted by the Falling Walls (Berlin) in the category Breakthrough of the year.
• Kavokin was awarded by the Marie-Curie Chair of Excellence in 2006.
• Kavokin was awarded the Leverhulme fellowship of the Royal Society, UK, in 2008.
• Kavokin was also awarded by the EPSRC Established Carrier fellowship in 2012-2017.
Since 2000 Alexey Kavokin headed the multinational research effort for realisation of the room temperature strong coupling and polariton lasing in semiconductor microcavities. He coordinated three subsequent research-training networks funded by the European Commission (CLERMONT, CLERMONT2, CLERMONT4) that succeeded in fabrication of the world-first polariton lasers and observation of the bosonic condensation of exciton-polaritons at room temperature. Besides this, Kavokin coordinated several other European network projects, including the Marie-Curie conference series project MC-CLERMONT, the MarieCurie Chair of Excellence project POLAROMA, the Specific targeted FET projects STIMSCAT and POLAPHEN. In the UK, Kavokin served as a PI on the EPSRC Program grant on “Hybrid Polaritonics” including the universities of Southampton, Sheffield and Saint Andrews and on a standard response EPSRC grant including the universities of Southampton and Cambridge. He was also a PI on multiple Royal Society grants for international collaboration and a holder of the EPSRC Established Career fellowship and the Royal Society Leverhulme fellowship. In China, Kavokin coordinates a network project on “Quantum Polaritonics” within the Quantum 2030 national program and serves as a PI on an NSFC grant.
