{"id":1626,"date":"2026-01-13T10:15:31","date_gmt":"2026-01-13T10:15:31","guid":{"rendered":"https:\/\/www.hip.fi\/seminars\/?page_id=1626"},"modified":"2026-03-26T13:57:14","modified_gmt":"2026-03-26T13:57:14","slug":"seminars-2026","status":"publish","type":"page","link":"https:\/\/www.hip.fi\/seminars\/archive\/seminars-2026\/","title":{"rendered":"Seminars 2026"},"content":{"rendered":"<h2>DEPARTMENT OF PHYSICS \/ HIP JOINT COLLOQUIA \/ SEMINARS 2026<\/h2>\n<ul>\n<li><strong>Tuesday 20 January 2026 at 10:15 in A315 and using Zoom: Michal Heller (Ghent)<br \/>\n<\/strong><em><span data-olk-copy-source=\"MessageBody\">New look at self-similar dynamics far from equilibrium<\/span><br \/>\nAbstract: <\/em><span data-olk-copy-source=\"MessageBody\">Equilibrium systems are simple in the sense that they are characterized by only a few macroscopic parameters, such as temperature or chemical potential. Far-from-equilibrium dynamics, by contrast, appears overwhelmingly complex. Any emergent universality in this regime is therefore both rare and valuable, and calls for a deeper theoretical understanding. In this talk I will discuss a paradigmatic instance of such a universality: self-similar dynamics in time, where far-from-equilibrium evolution reduces to simple rescalings governed by a small set of scaling exponents and time-independent correlation profiles. These nonthermal fixed points play an important role across the energy scale: from theory of ultrarelativistic nuclear collisions to tabletop experiments with cold atomic gases. Drawing\u00a0analogies with black-hole physics and holography, I will explain what controls the attractive nature of nonthermal fixed points and why vastly different microscopic systems can flow toward the same universal behavior. Pushing these analogies further, I will show that nonthermal fixed points give rise to a novel form of fluid mechanics that is intrinsically far from equilibrium. This opens the door to systematic comparisons between familiar near-equilibrium liquids and this newly identified far-from-equilibrium fluid, some aspects of which I will address. Based on 2502.01622 with Lescluze, 2504.18754 with Berges, Denicol and Preis and 2510.15016 with Lescuze, Mazeliauskas, Scheihing-Hitschfeld and Werthmann.<br \/>\nLink to video: <a href=\"https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=fd0d9726-ef23-446c-9dc8-c4675df485c2\">https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=fd0d9726-ef23-446c-9dc8-c4675df485c2<\/a><\/span><\/li>\n<li><strong>Thursday 22 January 2026 at 10:15 in A315 and using Zoom : Ren\u00e9 Meyer (W\u00fcrzburg)<br \/>\n<\/strong><em>Aspects of PT symmetric Non-Hermiticity in AdS\/CFT and in SYK models<br \/>\nAbstract:<\/em> Investigations of non-hermitian quantum systems recently has drawn much interest in the field of holography and the AdS\/CFT correspondence. In this talk, I will focus on non-hermiticity of the PT symmetric type and, after a short introduction into the subject, present several results for PT symmetric systems of interest in holography: In the first part of the talk, I will discuss our recent [1] investigation of the phase structure and the interaction induced quantum critical conductivity in a PT symmetric non-hermitian holographic metal. In particular the conductivity shows interesting new features in the different phases, which are qualitatively reproduced in a PT symmetrically deformed version of Landau-Ginzburg theory. In the second part of the talk, I will present analytic and numerical work [2] on the operator size growth in Lindbladian SYK models. I will in particular present a new timescale, the plateau time, after which the operator size growth reaches a plateau. Finally, I will present recent work [3] on the entanglement structure in these Lindbladian SYK models, and a new entanglement measure with better properties for non-hermitian systems.<br \/>\n[1] Z.Y. Xian, D. Rodriguez-Fernandez, Z.H. Chen, Y. Liu, R. Meyer, SciPost Physics 16 (2024)<br \/>\n[2] J.S. Liu, R. Meyer, Z.Y. Xian, JHEP 08 (2024)<br \/>\n[3] Z.H. Chen, R. Meyer, Z.Y. Xian, arXiv:2508.09261<br \/>\nLink to video: <a href=\"https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=009b011c-6668-458b-acf4-2eb25e2f8eea\">https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=009b011c-6668-458b-acf4-2eb25e2f8eea<\/a><\/li>\n<li><strong>Tuesday 24 February 2026 at 10:15 in A315 and using Zoom: Viljami Leino (Odense)<br \/>\n<\/strong><em>Strong coupling constant from the static energy <\/em><em><br \/>\nAbstract: <\/em>The static energy between the static quark and the static antiquark is a well studied observable on the lattice. For short distances, the static energy can be calculated both on the lattice with the use of Wilson line correlators, and with the perturbation theory up to three loop accuracy with leading ultrasoft log resummation. Comparing the perturbative expression and lattice data allows for precise measurement of the strong coupling constant of QCD. I will show static energy measurements from lattice simulations with a different number of dynamical fermion flavors and present the current status of extracting the strong coupling constant from this data.<br \/>\nLink to video: <a href=\"https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=1beecd5f-6291-4408-8b70-385c0adafc42\">https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=1beecd5f-6291-4408-8b70-385c0adafc42<\/a><\/li>\n<li><strong>Tuesday 24 March 2026 at 10:15 in A315 and using Zoom: Lotta Jokiniemi (Darmstadt)<br \/>\n<\/strong><em><i class=\"moz-txt-slash\">Ab initio studies on muon capture and rare decays<\/i><br \/>\nAbstract: <\/em>Neutrinoless double-beta (0\u03bd\u03b2\u03b2) decay is a hypothetical nuclear decay in which two nucleons inside the nucleus beta-decay simultaneously emitting only two beta-particles without the associated (anti-)neutrinos. The process violates lepton-number conservation and requires that neutrinos are their own antiparticles (or Majorana particles), and observation of the decay would hence have implications in the understanding of the matter-antimatter asymmetry of the Universe. Furthermore, 0\u03bd\u03b2\u03b2 decay is an excellent probe of the absolute neutrino mass scale, as the decay rate can be related to the effective neutrino mass. While experiments hunting for this decay are approaching ton scales, the required nuclear-theory input remains a major obstacle to planning and interpreting the experiments.<br \/>\nI will start by discussing recent advances in the ab initio theory predictions for neutrinoless double-beta decay. These systematically improvable calculations are based on nuclear interactions and currents derived from chiral effective field theory, allowing for uncertainty quantification. I will show how the new theory predictions affect the interpretation of current and future experiments. Then, I will talk about <span class=\"moz-txt-tag\">\/<\/span>ab initio<span class=\"moz-txt-tag\">\/<\/span>\u00a0studies on muon capture in light nuclei. Thanks to the high momentum transfer involved in the process, it can be used to probe the weak currents at the momentum regime relevant for the 0\u03bd\u03b2\u03b2 decay. The computed rates are found to be in good agreement with available experimental counterparts, motivating future experimental and theoretical explorations.<br \/>\nLink to video: <a href=\"https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=67e2f81f-4c8d-4085-8792-56e7164464a8\">https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=67e2f81f-4c8d-4085-8792-56e7164464a8<\/a><\/li>\n<li><strong>Thursday 26 March 2026 at 10:15 in A315 and using Zoom: Greg Jackson (Nantes)<br \/>\n<\/strong><em>Stochastic collisional energy loss of a heavy quark crossing a finite-size QGP<br \/>\nAbstract: <\/em>An energetic parton crossing a hot or dense quark-gluon plasma (QGP) can lose energy through elastic collisions with the medium, a process contributing to jet and hadron suppression observed in heavy-ion, and recently also in light-ion collisions. Going beyond existing approaches, which mostly focus on the average energy loss per unit distance for large systems, we derive the full energy loss probability distribution (or quenching weight) from first principles using Landau&#8217;s kinetic equation to resum the energy losses suffered in multiple successive elastic scatterings. The distribution captures large event-by-event fluctuations, arising from the long tail of the single scattering spectrum, and includes the possibility of energy gain from the medium, both effects being especially relevant for small systems. Our results fill a conceptual gap in the modelling of jet\/hadron and heavy flavour suppression, where usually only those fluctuations of the radiative energy loss are taken into account, and may help interpreting high-multiplicity pp and pA data.<br \/>\nLink to video: <a href=\"https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=7aebe687-f2de-4a55-a70b-66f7391c1c6f\">https:\/\/unitube.it.helsinki.fi\/unitube\/embed.html?id=7aebe687-f2de-4a55-a70b-66f7391c1c6f<\/a><\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>DEPARTMENT OF PHYSICS \/ HIP JOINT COLLOQUIA \/ SEMINARS 2026 Tuesday 20 January 2026 at 10:15 in A315 and using Zoom: Michal Heller (Ghent) New look at self-similar dynamics far from equilibrium Abstract: Equilibrium systems are simple in the sense that they are characterized by only a few macroscopic parameters, such as temperature or chemical [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":16,"menu_order":81,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1626","page","type-page","status-publish","hentry","post"],"_links":{"self":[{"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/pages\/1626","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/comments?post=1626"}],"version-history":[{"count":9,"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/pages\/1626\/revisions"}],"predecessor-version":[{"id":1676,"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/pages\/1626\/revisions\/1676"}],"up":[{"embeddable":true,"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/pages\/16"}],"wp:attachment":[{"href":"https:\/\/www.hip.fi\/seminars\/wp-json\/wp\/v2\/media?parent=1626"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}