题目：高维孤子（Multidimensional solitons）

　　报告人：以色列特拉维夫大学Boris A. Malomed教授

　　时间：2019年9月6日上午10:00（星期五）

　　地点：瞬态室大会议室（欢迎广大职工和研究生前往聆听）

　　报告摘要：

　　It is commonly known that the interplay of linear and nonlinear effects gives rise to solitons, i.e., self-trapped localized structures, in a wide range of physical settings, including optics, Bose-Einstein condensates (BECs), hydrodynamics, plasmas, condensed-matter physics, etc. Nowadays, solitons are considered as an interdisciplinary class of modes, which feature diverse internal structures.

　　While most experimental realizations and theoretical models of solitons have been elaborated in one-dimensional (1D) settings, a challenging issue is prediction of stable solitons in 2D and 3D media. In particular, multidimensional solitons may carry an intrinsic topological structure in the form of vorticity. In addition to the "simple" vortex solitons, fascinating objects featuring complex structures, such as hopfions, i.e., vortex rings with internal twist, have been predicted too.

　　A fundamental problem is propensity of multidimensional solitons to being unstable (naturally, solitons with a more sophisticated structure, such as vortex solitons, are more vulnerable to instabilities). Recently, novel perspectives for the creation of stable 2D and 3D solitons were brought to the attention of researchers in optics and BEC. The present talk aims to provide an overview of the main results and ongoing developments in this vast field. An essential conclusion is the benefit offered by the exchange of concepts between different areas, such as optics, BEC, and hydrodynamics.

　　[1] Y. Kartashov, G. Astrakharchik, B. Malomed, and L. Torner, Frontiers in multidimensional self-trapping of nonlinear fields and matter, Nature Reviews Physics, 1, pages185–197 (2019). https://doi.org/10.1038/s42254-019-0025-7.

　　报告人简介：

　　Boris A. Malomed教授是非线性光子学和简并量子气体（冷原子、冷分子）等领域享誉寰宇的理论科学家，也是最为活跃的科学家之一，与全球多个研究组保持长期稳定的合作和开展科研扶贫，堪称非线性理论（尤其是孤子）研究领域的“雷锋”、“白求恩”。 Malomed教授科研成绩硕果累累、辛勤耕耘成就斐然，著书立说《Soliton Management in Periodic Systems》、《Guided-Wave Optics》、《Spontaneous symmetry breaking, self-trapping, and Josephson oscillations》和多篇章节（chapters），已在Reviews of Modern Physics、 Nature Reviews Physics、Nature Physics、Nature Photonics、Physical Review Letters等顶级学术期刊发表多篇学术论文，总计被引用四万余次，H指数为86。