BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Samo Kralj (University of Maribor) DTSTART:20221014T150000Z DTEND:20221014T170000Z DTSTAMP:20260423T021341Z UID:QMFNoT/38 DESCRIPTION:Title: Liquid crystals as a playground of topological defects\nby Samo Kralj (University of Maribor) as part of QM Foundations & Nature of Time seminar \n\n\nAbstract\nPhysical fields might be fundamental constituents of natur e. Furthermore\, topological defects in relevant physical fields might pla y the role of fundamental particles as first demonstrated by Skyrmy [1]. He introduced topologically protected solitons (referred to as skyrmions) as candidates for mesons and baryons. Therefore\, one could explain all na tural complexity from the viewpoint of TDs and their assemblies. \nLiquid crystals (LCs) are particularly adequate to study TDs and related topologi cal phenomena. They exhibit diverse qualitatively different TDs in form of point\, line\, wall\, and texture configurations. In LCs different assemb lies of TDs could be relatively easily created\, stabilized\, manipulated\ , and observed (e.g.\, using polarizing microscopy). \nIn the lecture\, w e will present our studies of different TDs in orientationally ordered LCs that might be analogs of fundamental excitations in nature the behavior of which is still not understood. We demonstrate that geometrical curvatur e [2] is the mean generic formation and TD stabilization mechanism. We sh ow that the topology of torus stabilizes “chargeless” TDs [3] which mi ght play the role of neutrinos. In LCs they form an elastic ribbon-like st ructure that embeds the toroidally shaped LC-immersed colloidal particle. Furthermore\, we present the formation and stabilization mechanism of mero ns (skyrmion family members) and their condensation in crystal-like config urations. In pour experiments\, we made their structural details and dynam ics experimentally accessible by forcing the LC structure close to a criti cal point\, in which the relevant order parameter field correlation length and relaxation time diverge. These quantities dominate the characteristic linear size of the defect core structure and its dynamic features. In par ticular\, we show how TDs mediate temperature-driven order-disorder phase transition in chiral LCs.\n \n\n[1] T. H. R. Skyrme\, A unified fi eld theory of mesons and baryons\, Nucl. Phys. 31\, 556 (1962).\n[2] L. Me sarec\, W. Góźdź\, A. Iglič\, S. Kralj\, Effective topological charge cancelation mechanism\, Sci. Rep. 6\, 27117 (2016).\n[3] S. Harkai\, B.S. Murray\, C. Rosenblatt\, S. Kralj\, Electric field driven reconfigurable m ultistable topological defect patterns\, Phys. Rev. Res. 2\, 013176 (2020) .\n LOCATION:https://researchseminars.org/talk/QMFNoT/38/ END:VEVENT END:VCALENDAR