東京大学 竹内研究室主催で、下記のオンラインセミナーを開催いたします。奮ってご参加ください。なお、本セミナーは、新学術領域「情報物理学でひもとく生命の秩序と設計原理」が主催するIPBセミナーシリーズの一環として、共同開催となります。セミナーは英語で行われます。

参加される方には事前登録をお願いしておりますので、ご希望の方は本フォームにて登録をお願いいたします。Zoom リンク付の自動返信が送られますので、セミナー開始後でもご登録いただけます。なお、講演者の講演準備の参考・効率化のために、参加登録情報を講演者に提供する可能性がありますので、ご了承ください。

※本セミナーは、対面・Zoomのハイブリッド開催の予定ですが、対面は関係者等に限定させていただきますのでご了承ください。

The following online seminar will be held, organized by Takeuchi Lab (Univ. Tokyo) and jointly by Grant-in-Aid for Innovative Areas "Information physics of living matters" as part of the IPB seminar series. The seminar will be given in English.

We ask participants to register beforehand on this page. A reply including a Zoom link will be given automatically, so you can register even after the seminar has started. Please note that the registration information may be provided to the speaker for reference and efficiency in preparing the presentation.

*This seminar will be given in the hybrid format (in person and Zoom), but please understand that it is only the authorized people that can participate in person.

Speaker:
Prof. Ivan I. Smalyukh (University of Colorado)

Title:
Knotted Matter

Abstract:
Topological order and phases represent an exciting frontier of modern research [1]. Starting with Gauss and Kelvin, knots in fields, like the magnetic field, were postulated to behave like particles. However, experimentally they were found only as transient features and could not self-assemble into three-dimensional crystals. I will describe energetically stable solitonic knots that emerge in the physical fields of chiral liquid crystals and magnets [2,3]. While spatially localized and freely diffusing in all directions, they behave like colloidal particles and atoms, self-assembling into crystalline lattices with open and closed structures, as well as forming low-symmetry mesophases and gas- or liquid-like states [2]. A combination of energy-minimizing numerical modeling and nonlinear optical imaging uncovers the internal structure and topology of individual solitonic knots and the various hierarchical crystalline and other organizations that they form. Being classified as the elements of the third homotopy group of two-spheres, these solitonic knots are robust and topologically distinct from the host medium, though they can be morphed and reconfigured by weak stimuli like electric or magnetic fields. I will show how low-voltage electric fields can switch between the heliknoton [2,3] and hopfion [4] embodiments of such knot solitons while preserving their topology. Finally, I will discuss how this emergent paradigm of knotted solitonic matter could allow for imparting new designable material properties and for realizing phases of matter that so far could not be found in naturally occurring materials [5-7].
1. I. I. Smalyukh. Rep. Prog. Phys. 83, 106601 (2020).
2. J.-S. B. Tai and I. I. Smalyukh. Science 365, 1449 (2019).
3. R. Voinescu, J.-S. B. Tai and I. I. Smalyukh. Phys Rev Lett 125, 057201 (2020)
4. P. J. Ackerman and I. I. Smalyukh. Nature Materials 16, 426 (2017)
5. H. Mundoor, S. Park, B. Senyuk, H. Wensink and I. I. Smalyukh. Science 360, 768 (2018).
6. Y. Yuan, Q. Liu, B. Senyuk and I.I. Smalyukh. Nature 570, 214 (2019).
7. H. Mundoor, J.-S. Wu, H. Wensink and I.I. Smalyukh. Nature 590, 268 (2021).