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<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Please join us for the Colloquium with Prof. Radu Coldea, Oxford University<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Tuesday, Nov. 9 at 3:45pm, on Zoom<o:p></o:p></span></b></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Come for snacks in the Atrium at 3:30pm<o:p></o:p></span></b></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Please use the Zoom link below to attend virtually:<o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555"><a href="https://osu.zoom.us/j/94858307115?pwd=K0JDMTROWVhIOUp6bU1sU0prZjNUZz09"><span style="color:#BB0000">https://osu.zoom.us/j/94858307115?pwd=K0JDMTROWVhIOUp6bU1sU0prZjNUZz09</span></a><o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Meeting ID: <strong><span style="font-family:"Helvetica",sans-serif">948 5830 7115</span></strong><o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Password: <strong><span style="font-family:"Helvetica",sans-serif">PRB1080</span></strong><o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Faculty Host: Rolando Valdés Aguilar<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></b></p>
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<b><span style="font-size:18.0pt;font-family:"Helvetica",sans-serif;color:#666666">Experimental exploration of Dirac magnons and excitons in a honeycomb magnet <o:p></o:p></span></b></p>
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<strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Abstract</span></strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">: <o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Complementary to studies of symmetry-protected nodal points for electron bands in single-layer graphene, we explore analogous physics for propagating bosonic magnetic quasiparticles
in a honeycomb magnet. Using inelastic neutron scattering we observe the presence of linear band-touching points in the magnetic dispersions with characteristic periodic intensity modulations in the dynamical structure factor around the nodal points. We also
resolve an unexpected spectral gap at low energies, which cannot be explained semi-classically, and propose possible mechanisms based on quantum fluctuations and spin-orbital exchange. <o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">M. Elliot, P.A. McClarty, D. Prabhakaran, R.D. Johnson, H.C. Walker, P. Manuel and R. Coldea, Nature Communications </span><strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">12</span></strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">,
3936 (2021), <a href="https://www.nature.com/articles/s41467-021-23851-0"><span style="color:#BB0000">https://www.nature.com/articles/s41467-021-23851-0</span></a><o:p></o:p></span></p>
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<em><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Order-by-disorder from bond-dependent exchange and intensity signature of nodal quasiparticles in a honeycomb cobaltate </span></em><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555"><o:p></o:p></span></p>
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<strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">More about Prof. Coldea:</span></strong><span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555"><o:p></o:p></span></p>
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555">Radu Coldea received his doctorate in physics from Oxford University and held postdoctoral positions at Oak Ridge National Laboratory (USA) and Rutherford Appleton Laboratory (UK),
before joining the University of Bristol (UK) as faculty, and then returning to Oxford, where he is currently Professor in the Physics Department, and Walter Stern Fellow at Lincoln College. His current research interests are focused on using neutron and x-ray
scattering to explore “emergent” behavior in quantum materials, where strong electron interactions and quantum correlation effects lead to electrons acting together “in unison” with new properties that are different from the result of adding together the behavior
of individual, un-correlated electrons. His selected awards include the EPSRC Advanced Research Fellowship, the BTM Willis Prize for Neutron Scattering from the Institute of Physics and the Faraday Royal Society of Chemistry (UK), and a European Research Council
Advanced Grant award. For more information on the research in Radu Coldea’s group see <a href="https://www.physics.ox.ac.uk/research/group/quantum-magnetism-and-quantum-phase-transitions"><span style="color:#BB0000">https://www.physics.ox.ac.uk/research/group/quantum-magnetism-and-quantum-phase-transitions</span></a>.
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<span style="font-size:12.0pt;font-family:"Helvetica",sans-serif;color:#555555"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><img border="0" width="224" height="45" style="width:2.3333in;height:.4687in" id="x_Picture_x0020_1" src="cid:image001.png@01D7D488.298B6140" alt="The Ohio State University"><br>
</span><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#BB0000;background:white">Ruth Leonard</span></b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333"><br>
Executive Assistant to the Chair<br>
</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#BB0000;background:white">Department of Physics</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333">
<br>
Physics Research Building, 191 West Woodruff Ave, Columbus, OH 43210<br>
614-292-5018 Office<br>
</span><span style="font-size:12.0pt;font-family:"Times New Roman",serif;color:black"><a href="mailto:leonard.469@osu.edu"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#0563C1;background:white">leonard.469@osu.edu</span></a></span><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:#333333">
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