**报告时间：**2023年9月5日下午2:30

**报告地点**：实验室一楼会议室

**报告人：**Nicolas Treps 法国巴黎第六大学、玛丽居里大学教授

**报告题目：****Generating, witnessing and certifying non-Gaussian states of optical time-frequency modes**

**报告摘要： **

Certifying reliable sources for quantum information processing is still one of the major challenges towards practical applications. Optical approaches to quantum information processing are being one of the most promising platform, thanks in particular to the ability to generate very efficiently large entangled states[2] - cluster states[1] -. However, there is still many fundamental challenges, in particular on how to generate, measure and certify the class of states necessary for quantum advantage.

We have developed a platform based on optical time-frequency modes, that we use to multiplex continuous variable quantum information. We use mode selective single photon operation in order to produce multimode non-gaussian states, the key ingredient of continuous variable approach to quantum processing[4]. However, the complexity of these states does not allow for an efficient full tomography. Hence on the one hand we developed tools to characterized and certify specific quantum properties, such as Quantum Non-Gaussianity and Wigner negativity[4]. On the other hand we propose a witness base on steering and Fisher information, to witness purely quantum non-gaussian correlations[5].

[1] S. Yokoyama, R. Ukai, S. C. Armstrong, C. Sornphiphatphong, T. Kaji, S. Suzuki, J.-i. Yoshikawa, H. Yonezawa, N. C. Menicucci, and A. Furusawa. “Ultra-Large-Scale Continuous-Variable Cluster States Multiplexed in the Time Domain.” Nature Photon 7, 982 (2013).

[2] V. Roman-Rodriguez, D. Fainsin, G. L. Zanin, N. Treps, E. Diamanti, and V. Parigi, Spectrally Multimode Squeezed States Generation at Telecom Wavelengths, arXiv:2306.07267 (2023).

[3] Ra, Y.-S., A. Dufour, M. Walschaers, C. Jacquard, T. Michel, C. Fabre, and N. Treps Non-Gaussian quantum states of a multimode light field. Nat. Phys. 16, 144–147 (2020).

[4] U. Chabaud, G. Roeland, M. Walschaers, F. Grosshans, V. Parigi, D. Markham, and N. Treps, Certification of Non-Gaussian States with Operational Measurements, ArXiv:2011.04320 [Quant-Ph] (2020).

[5] C. E. Lopetegui, M. Gessner, M. Fadel, N. Treps, and M. Walschaers, Homodyne Detection of Non-Gaussian Quantum Steering, PRX Quantum 3, 030347 (2022).

**报告人简介： **

Nicolas Treps is full professor at Sorbonne Université, Laboratoire Kastler Brossel. He developed modal analysis of multimode quantum light, which lead to pioneering experiments on quantum metrology, quantum imaging and multimode quantum information. His research is now centered on quantum metrology and quantum information with optical frequency combs, new activities that were funded by an ERC starting grant. Focusing on the continuous variable regime, he develops novel approaches to measurement based quantum computing and parameter estimation. He also applied these concepts to classical application, such as the study of ultrafast laser dynamics and spatial multiplexing. This lead to the co-foundation of CAILabs Start-up Company (50 employees, settled in Rennes), that develops a complete imaging system (lossless transformation of amplitude and phase) with applications to spatial multiplexing in optical fiber (for increased communication data rate) and high power laser welding. He co-authored 2 books, over 120 refereed publications and 6 patents.

编辑时间：2023-09-01 17:53:39