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PRODID:-//Nonequilibrium Quantum Workshop NQW - ECPv6.14.2//NONSGML v1.0//EN
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METHOD:PUBLISH
X-WR-CALNAME:Nonequilibrium Quantum Workshop NQW
X-ORIGINAL-URL:https://nqw.ijs.si
X-WR-CALDESC:Events for Nonequilibrium Quantum Workshop NQW
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Europe/Ljubljana
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:20230326T010000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:20231029T010000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T085900
DTEND;TZID=Europe/Ljubljana:20231213T101500
DTSTAMP:20260504T235030
CREATED:20231207T151509Z
LAST-MODIFIED:20231207T151557Z
UID:3138-1702457940-1702462500@nqw.ijs.si
SUMMARY:Chair: Denis Golez
DESCRIPTION:
URL:https://nqw.ijs.si/event/chair-denis-golez-2/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T090000
DTEND;TZID=Europe/Ljubljana:20231213T093000
DTSTAMP:20260504T235030
CREATED:20231201T080000Z
LAST-MODIFIED:20231212T141008Z
UID:2568-1702458000-1702459800@nqw.ijs.si
SUMMARY:Fabian Heidrich-Meisner: Nonequilibrium dynamics and transport in Holstein models
DESCRIPTION:F. Heidrich-Meisner1 \n1Institut für Theoretische Physik\, Georg-August-Universität Göttingen\, Germnay \nUnderstanding the properties of real materials requires the incorporation of multiple degrees of freedom into the theoretical modeling. In this research\, we focus on the coupling of electrons to phonons. We developed a comprehensive matrix-product-states based schemes that allows to compute spectral functions [1]\, optical conductivity [2] and thermal conductivity [3] of one-dimensional Holstein chains\, both for the polaron case and half filling\, and at finite temperatures. These techniques work well in the small-polaron regime and in intermediate regimes where phonon frequency\, electron-phonon coupling and elecronic hopping matrix elements are of the same scale. \nIn order to access the adiabatic regime of phonon frequencies much smaller than the electronic bandwidth\, we combine matrix-product-state and Krylov-space methods with the multritrajectory Ehrenfest technique\, called MPS-MTE and Lanczos-MTE [4]. The latter treats phonons classically and samples over initiial conditions set by the phonons‘ initial quantum state. The resulting hybrid techniqes rely on a propagation of electronic many-body states that depend on the time-dependent classical coordinates and momenta. We verify the correct implemenation by studying the decay of charge-density wave order analyzed in [5] and then apply the MPS-MTE method to the problem of a many-body localized system coupled to classical phonons. We observe a delocalization induced by this coupling. \nThis research was suported by the DFG (Deutsche Forschungsgemeinschaft) via CRC 1073. \n\nD. Jansen\, J. Bonča\, and F. Heidrich-Meisner Phys. Rev. B 102\, 165155 (2020)\nD. Jansen\, J. Bonča\, and F. Heidrich-Meisner\, Phys. Rev. B 106\, 155129 (2022)\nD. Jansen and F. Heidrich-Meisner\, Phys. Rev. B 108\, L081114 (2023)\nH. Menzler\, S. Mondal\, and F. Heidrich-Meisner\, in preparation.\nM. Ten Brink et al. J. Chem. Phys. 156\, 234109 (2022)
URL:https://nqw.ijs.si/event/fabian-heidrich-meisner-nonequilibrium-dynamics-and-transport-in-holstein-models/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T093000
DTEND;TZID=Europe/Ljubljana:20231213T100000
DTSTAMP:20260504T235030
CREATED:20231201T190335Z
LAST-MODIFIED:20231207T151509Z
UID:2597-1702459800-1702461600@nqw.ijs.si
SUMMARY:Jacek Herbrych: Breakdown of Hilbert space fragmentation
DESCRIPTION:J. Herbrych\,1 M. Mierzejewski\,1 J. Bonča2\,3 \n1Wrocław University of Science and Technology\, Wrocław\, Poland \n2J. Stefan Institute\, SI-1000 Ljubljana\, Slovenia \n3Faculty of Mathematics and Physics\, University of Ljubljana\, 1000 Ljubljana\, Slovenia \nDescription of the relaxation or thermalization of the strongly correlated system close to the integrable point remains a challenge. Although the fate of such systems is ultimately an ergodic dynamic\, the road to it could take an extremely long time and can display some exotic (type of integrability breaking-dependent) behavior. On the one hand\, many extremely long-time scales – reminiscent of integrals of motions – prevent numerical simulations from reaching an unbiased conclusion on such systems. On the other hand\, the nonintegrability hinders the analytical approaches. Recently\, a new family of ergodicity-breaking systems was found where the Hilbert space is fragmented into exponentially many parts due to constraints on the possible dynamics. Taking the t-Jz model as an example\, we will show how one can control the degree of Hilbert space fragmentation\, i.e.\, the number of disconnected subspaces. We will discuss how various time scales emerge from the breakdown of fragmentation and how they affect the relaxation of such systems.
URL:https://nqw.ijs.si/event/jacek-herbrych-breakdown-of-hilbert-space-fragmentation/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T100000
DTEND;TZID=Europe/Ljubljana:20231213T101500
DTSTAMP:20260504T235030
CREATED:20231201T190335Z
LAST-MODIFIED:20231207T151509Z
UID:2598-1702461600-1702462500@nqw.ijs.si
SUMMARY:Žiga Krajnik: Dynamical universality of charged single-file systems and integrable spin chains
DESCRIPTION:Ž. Krajnik\,1 J. Schmidt\,2\,3 V. Pasquier\,4 E. Ilievski\,5 T. Prosen5 \n1Department of Physics\, New York University\, 726 Broadway\, NY 10003\, New York\, USA \n2Technische Universitat Berlin\, Hardenbergstr. 36\, D-10623 Berlin\, Germany \n3Bonacci GmbH\, Robert-Koch-Str. 8\, 50937 Cologne\, Germany \n4Institut de Physique Theorique\, Universite Paris Saclay\, \nCEA\, CNRS UMR 3681\, 91191 Gif-sur-Yvette\, France \n5Faculty for Mathematics and Physics\,  University of Ljubljana\, Jadranska ulica 19\, 1000 Ljubljana\, Slovenia \nWe introduce and discuss dynamical universality of charge fluctuations in charged single-file systems. The full counting statistics of such systems out of equilibrium generically undergoes first and second order dynamical phase transitions\, while equilibrium typical fluctuations are non-Gaussian and given by a universal distribution. Similar phenomenology of dynamical criticality is observed in equilibrium in the easy axis and isotropic regimes of an integrable spin chain. While the easy axis regime does not satisfy a single-file kinetic constraint\, it nevertheless supports the non-Gaussian distribution of the charged single-file universality class. Fluctuations at the isotropic point are also anomalous and distinct from those of the Kardar-Parisi-Zhang universality class. \n\nŽ. Krajnik et al. arXiv:2303.16691 (2023)\nŽ. Krajnik et al. arXiv:2208.01463 (2022)\nŽ. Krajnik et al. Phys. Rev. Lett. 128\, 160601 (2022)\nŽ. Krajnik et al. Phys. Rev. Lett. 128\, 090604 (2022)
URL:https://nqw.ijs.si/event/ziga-krajnik-dynamical-universality-of-charged-single-file-systems-and-integrable-spin-chains/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T101500
DTEND;TZID=Europe/Ljubljana:20231213T104500
DTSTAMP:20260504T235030
CREATED:20231201T195307Z
LAST-MODIFIED:20231207T151520Z
UID:2755-1702462500-1702464300@nqw.ijs.si
SUMMARY:Coffee Break
DESCRIPTION:
URL:https://nqw.ijs.si/event/coffee-break-6/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T104400
DTEND;TZID=Europe/Ljubljana:20231213T120000
DTSTAMP:20260504T235030
CREATED:20231207T151520Z
LAST-MODIFIED:20231207T151602Z
UID:3141-1702464240-1702468800@nqw.ijs.si
SUMMARY:Chair: Daniele Fausti
DESCRIPTION:
URL:https://nqw.ijs.si/event/chair-daniele-fausti-2/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T104500
DTEND;TZID=Europe/Ljubljana:20231213T111500
DTSTAMP:20260504T235030
CREATED:20231201T190335Z
LAST-MODIFIED:20231207T151520Z
UID:2600-1702464300-1702466100@nqw.ijs.si
SUMMARY:Theo Rasing: Optical control of magnetism thru strongly non-equilibrium phases
DESCRIPTION:T. Rasing1* \n1Radboud University\, Institute for Molecules and Materials\, Heijendaalseweg 135\, 6525AJ Nijmegen\, the Netherlands \n*theo.rasing@ru.nl \nThe ability to switch magnets between two stable bit states is the main principle of digital data storage technologies since the early days of the computer. Since our demonstration of magnetization reversal by a single 40 femtosecond laser pulse\, the manipulation of spins by ultra-short laser pulses has developed into an alternative and energy efficient approach to magnetic recording. Though originally thought to be due to an optically induced effective field\, later studies demonstrated that the switching occurred via a strongly non-equilibrium state\, exploiting the exchange interaction between the spins. Recent work also show how magnetic textures like skyrmions are generated via a non-equilibrium phase.  \nWhile for a long time\, all-optical switching (AOS) was exclusively observed in ferrimagnetic alloys\, more recent work demonstrated AOS in a broad range of ferromagnetic multilayer materials\, albeit that in those examples a large number of pulses were required. By studying the dynamics of this switching process\, we have discovered that this switching is a 2-step process\, which led us to the subsequent demonstration that highly efficient AOS can be achieved by using pairs of femto/pico-second laser pulses. By combining optical laser excitation with in situ magnetic force microscopy we recently found that the nucleation and switching process evolves via a stochastic network of domains. \nAs new ICT technologies\, such as Artificial Intelligence\, is leading to a dramatic increase of the energy cost of computing\, the development of radically new physical principles that combine energy-efficiency with high speeds and high densities is crucial for a sustainable future. One of those new principles is neuromorphic computing\, that is inspired by the notion that our brain uses a million times less energy than a supercomputer while\, at least for some tasks\, it even outperforms the latter. \nIn this talk\, I will discuss the state of the art in ultrafast manipulation of magnetic bits and present some first results and new ideas to implement brain-inspired computing concepts in magnetic materials.  \nAcknowledgement(s): Support from the Dutch Research Council (NWO) and the European Research Council ERC grant agreement no.856538 (3D-MAGiC) is acknowledged.
URL:https://nqw.ijs.si/event/theo-rasing-optical-control-of-magnetism-thru-strongly-non-equilibrium-phases/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T111500
DTEND;TZID=Europe/Ljubljana:20231213T114500
DTSTAMP:20260504T235030
CREATED:20231201T190335Z
LAST-MODIFIED:20231207T151520Z
UID:2601-1702466100-1702467900@nqw.ijs.si
SUMMARY:Andrea Caviglia: TBD
DESCRIPTION:A. Caviglia1 \n1University of Geneva\, Switzerland
URL:https://nqw.ijs.si/event/andrea-caviglia-tbd/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T114500
DTEND;TZID=Europe/Ljubljana:20231213T120000
DTSTAMP:20260504T235030
CREATED:20231201T190350Z
LAST-MODIFIED:20231207T151520Z
UID:2602-1702467900-1702468800@nqw.ijs.si
SUMMARY:Viktor Kabanov: The correlated random anisotropy model of the Co-organic composite films
DESCRIPTION:V.V. Kabanov\,1* A.V. Shumilin\,1 M. Benini\,2 T. Mertelj\,1 V.A. Dediu2 \n1Jozef Stefan Institute\, Jamova cesta 39\, SI-1000 Ljubljana\, Slovenia \n2CNR-ISMN\, Via Piero Gobetti 101\, 40129\, Bologna\, Italy \n*viktor.kabanov@ijs.si \nWe propose the correlated random anisotropy model that describes thin ferromagnetic films hybridized with organic molecular layers. The asymmetry of the molecules leads to the random in-plane anisotropy induced at the surface of the magnetic film. We show that this strongly modifies the magnetic anisotropy of the whole cobalt layer which magnitude critically depends on the correlation radius of random anisotropy (fig. a). When this radius is small even strong induced anisotropy can be neglected. However\, with the increase of correlation radius\, the effect of molecules starts to dominate the magnetic properties. It results in the colossal increase of the coercive field\, modification of the hysteresis loop shape (fig. b)\, and breaking of the Raleigh law at low fields. \nPhysically\, the effect results from the modification of pseudoground states in the magnetic film. At a low correlation radius the state can be described by standard domain wall picture\, while at larger correlation radiuses a correlated spin glass state emerges. \nAcknowledgements  \nWe acknowledge the support of the EC projects INTERFAST (H2020-FET-OPEN-965046). \n \nFig. 1. a) The correlation radius rc of molecule-induced anisotropy. b) Hysteresis loops for different values of rc.
URL:https://nqw.ijs.si/event/viktor-kabanov-the-correlated-random-anisotropy-model-of-the-co-organic-composite-films/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T120000
DTEND;TZID=Europe/Ljubljana:20231213T131500
DTSTAMP:20260504T235030
CREATED:20231201T195322Z
LAST-MODIFIED:20231207T151535Z
UID:2756-1702468800-1702473300@nqw.ijs.si
SUMMARY:Lunch
DESCRIPTION:
URL:https://nqw.ijs.si/event/lunch-7/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T131500
DTEND;TZID=Europe/Ljubljana:20231213T163000
DTSTAMP:20260504T235030
CREATED:20231201T190350Z
LAST-MODIFIED:20231207T151535Z
UID:2603-1702473300-1702485000@nqw.ijs.si
SUMMARY:Free time / Poster Session
DESCRIPTION:
URL:https://nqw.ijs.si/event/poster-session-3/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T162900
DTEND;TZID=Europe/Ljubljana:20231213T180000
DTSTAMP:20260504T235030
CREATED:20231207T151535Z
LAST-MODIFIED:20231207T151606Z
UID:3144-1702484940-1702490400@nqw.ijs.si
SUMMARY:Chair: James McIver
DESCRIPTION:
URL:https://nqw.ijs.si/event/chair-james-mciver/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T163000
DTEND;TZID=Europe/Ljubljana:20231213T170000
DTSTAMP:20260504T235030
CREATED:20231201T190350Z
LAST-MODIFIED:20231207T151535Z
UID:2605-1702485000-1702486800@nqw.ijs.si
SUMMARY:Gregor Jotzu: Ultrafast Magnetometry of (Light-Induced) Superconductors
DESCRIPTION:G. Jotzu\,1\,2 S. Fava\,2 M. Buzzi\,2 G. De Vecchi\,2 A. Cavalleri2 \n1Dynamic Quantum Materials Laboratory\, Ecole Polytechnique Fédérale de Lausanne\, 1015 Lausanne\, Switzerland \n2Max Planck Institute for the Structure and Dynamics of Matter\, 22761 Hamburg\, Germany \nDriving certain cuprates and organic materials has been shown to induce THz optical properties reminiscent of superconductivity far above the equilibrium transition temperature. However\, the magnetic response of these non-equilibrium states remains unexplored. This study investigates whether these states exhibit a Meissner effect\, expelling external magnetic fields\, and examines their response to changing magnetic fields on sub-picosecond time scales. \nOur methodology involves studying the ultrafast magnetic response of these materials in static and time-dependent magnetic fields using the Faraday effect in a magneto-optical crystal adjacent to the sample. This provides sub-picosecond time resolution for reconstructing the position-dependent magnetic properties. \nBeginning with the investigation of the destruction of superconductivity below Tc\, we explore signs of the light-induced appearance of superconductivity far above Tc. Our study examines the temperature and magnetic field dependence of these phenomena\, offering new insights into the non-equilibrium dynamics of these systems. \nFurthermore\, we discuss how this method could be extended to probe the dynamics of other laser-driven strongly correlated materials. This research sheds light on the unique properties of non-equilibrium states and their potential applications in the field of condensed matter physics.
URL:https://nqw.ijs.si/event/gregor-jotzu-ultrafast-magnetometry-of-light-induced-superconductors/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T170000
DTEND;TZID=Europe/Ljubljana:20231213T173000
DTSTAMP:20260504T235030
CREATED:20231201T190350Z
LAST-MODIFIED:20231207T151535Z
UID:2606-1702486800-1702488600@nqw.ijs.si
SUMMARY:Andrei Shumilin: Emergent spin phenomena from hyperfine interaction ‌of localized electrons and nuclear spins
DESCRIPTION:A.V. Shumilin\,1 D.S. Smirnov2  \n1Jozef Stefan Institut\, Jamove cesta 39\, SI-1000 Ljubljana\, Slovenia \n2Ioffe Institute\, Politekhnicheskaya 26\, St Petersburg 194021\, Russia \nMany modern devices are based on the operations with spins. They require the preparation of the initial state: with spin polarization or at least with spin correlations. There is a limited number of conventional methods to achieve this: application of ferromagnetic materials\, current to spin conversion due to spin-orbit interaction and static polarization in high magnetic fields. We show the existence of another way to achieve spin polarization in non-magnetic solid-state devices. It requires small magnetic fields\, hyperfine interaction between electron and nuclear spins and small exchange interaction between electron spins. All the interaction energies are considered small compared to temperature\, but the mechanism requires non-equilibrium conditions.  \n \nFig. 1. The dependence of circular polarization of luminescense in (In\,Al)As/AlAs quantum dots as function of the delay after initial unpolarized excitation pulse. \nThe physics of dynamic spin polarization involves the interplay of non-equilibrium spin phenomena and effect of the magnetic field on spin relaxation provided by hyperfine interaction of electron and nuclear spin. Such interplay occurs in many organic semiconductors and leads to quite strong room temperature “organic” magnetoresistance related to the correlated spin state [1]. \nThe spin polarization appears due to the interplay of “organic magnetoresistance” physics with weak exchange interaction of electron and holes localized at different molecules [2]. Very similar phenomena exist also in quantum dots where it manifests itself as strong circular polarization of luminescence observable in 10mT magnetic fields at temperatures below 10K [3\,4]. The circular polarization has a very complex non-monotonous dependence on the time delay after the initial excitation (Fig. 1) and on the applied magnetic field. \n\nA.V. Shumilin\, Phys. Rev. B 101\, 134201 (2020)\nA.V. Shumilin\, Phys. Rev. B 105  104206 (2022)\nD. S. Smirnov\, T. S. Shamirzaev\, D. R. Yakovlev\, M. Bayer\, Phys. Rev. Lett. 125\, 156801 (2020)\nT.S. Shamirzaev\, A.V. Shumilin\, D.S. Smirnov\, et. al.\, Phys. Rev. B 104\, 115405 (2021)
URL:https://nqw.ijs.si/event/andrei-shumilin-emergent-spin-phenomena-from-hyperfine-interaction-of-localized-electrons-and-nuclear-spins/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T173000
DTEND;TZID=Europe/Ljubljana:20231213T174500
DTSTAMP:20260504T235030
CREATED:20231207T151551Z
LAST-MODIFIED:20231207T151551Z
UID:3148-1702488600-1702489500@nqw.ijs.si
SUMMARY:Madhumita Sarkar: Manipulating exciton binding by floquet engineering ‌in Fermi Hubbard ladder
DESCRIPTION:M. Sarkar\,1 Z. Lenarcic\,1 D. Golez1 \n1Jozef Stefan Institute\, SI-1000\, Ljubljana\, Slovenia \nStrong excitations of correlated quantum materials give rise to various non-thermal phases which are not present in their equilibrium counterpart. Recently\, it was shown that the one-dimensional Fermi Hubbard Model features charge density wave and η-pairing phases upon photo-doping. In this study\, we explore the non-equilibrium behavior of the Fermi Hubbard ladder and employ the Schrieffer-Wolff transformation to map it to a simplified t-J-like model\, providing an effective equilibrium description of the photo-doped states. Our investigation highlights the significance of applying an electric field along the rung to the hopping term. This floquet manipulation allows to increase the spin and η-exchange coupling along the rung independent of the hopping term. Moreover\, the magnitude of hopping decreases as a result of the drive. These combined effect tends to localize the excitons close to each other and thus enhance its binding energy. To characterize the ground state of the system\, we employ relevant correlators and make notable observations. We show that at certain drive frequencies\, the ground state encompasses a strongly bound holon-holon/doublon-holon pair along the rung\, alongside inter-chain singlets. Additionally\, we propose experimental setups to test our theory.
URL:https://nqw.ijs.si/event/madhumita-sarkar-manipulating-exciton-binding-by-floquet-engineering-in-fermi-hubbard-ladder-2/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T174500
DTEND;TZID=Europe/Ljubljana:20231213T180000
DTSTAMP:20260504T235030
CREATED:20231201T190405Z
LAST-MODIFIED:20231207T151551Z
UID:2608-1702489500-1702490400@nqw.ijs.si
SUMMARY:Jaka Strohsack: Influence of Metal/Organic-Molecules Interface on Magnetic Anisotropy ‌in Co Thin Films: A Time-Resolved MOKE Investigation
DESCRIPTION:J. Strohsack\,1 G. Jecl\,1 H. Zhao\,1 A. Shumilin\,1 V.V. Kabanov\,1 T. Mertelj\,1\,2\,* \nM. Benini\,3 R. Rakshit\,3 V.A. Dediu\,3 M. Rogers\,4 S. Ozdemir\,4 O. Cespedes4 \n1Department for complex matter (F7)\, Jožef Stefan Institute\, 1000 Ljubljana\, Slovenia \n2CENN Nanocenter\, Jamova 39\, 1000 Ljubljana\, Slovenia \n3ISMN-CNR\, Via Piero Gobetti 101\, Bologna\, Italy \n4School of Physics and Astronomy\, University of Leeds\, Leeds\, LS2 9JT\, United Kingdom \nWe investigated by means of the ultrafast time-resolved magneto-optical Kerr effect (MOKE) spectroscopy [1] the effect of the interface between organic molecular semiconductors and cobalt on the magnetic anisotropy of polycrystalline Co thin films. Comparison of the effect was measured on interfaces of Co with: nonmagnetic metal (Al)\, metalorganic complexes tris(8-hydroxyquinoline)gallium (Gaq3) and M-phthalocyanines (M=Cu\, Co) as well as Buckminster-fullerene (C60) molecules. \nIn general\, the transient MOKE signals were found to exhibit damped coherent spin wave oscillations (CSWO) with frequencies up to several tens of GHz. Detailed analysis of the spin-wave temperature and magnetic field dependences allowed us to compare the influence of different molecular interfaces. \nWe found that the thin Co films interfaced with molecular layers display strong hardening of the CSWO frequency at low T with a rather sharp transition in the 150 K – 170 K range. Interfaces with different molecules show qualitatively and quantitatively similar behavior despite different molecular shapes. The hardening is attributed to increase of the interface induced anisotropy due to the hybridization between the molecular-orbitals and the Co d-orbital derived interface states [2]. We also found that the CSWO are more damped at low T\, which we attribute to an increase of magnetic anisotropy inhomegeneity. \n\n\n\n\n\n\n\n\n\n\n\n\nFig. 1. Coherent spin-wave oscillations (left) and the temperature dependence of their frequency (right) in a tris(8-hydroxyquinoline)gallium interfaced Co film. \n\nM. van Kampen et al.\, Phys. Rev. Lett. 88 (2002) 227201\nT. Moorsom et al.\, Phys. Rev. B. 101 (2020) 060408
URL:https://nqw.ijs.si/event/jaka-strohsack-influence-of-metal-organic-molecules-interface-on-magnetic-anisotropy-in-co-thin-films-a-time-resolved-moke-investigation/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T180000
DTEND;TZID=Europe/Ljubljana:20231213T193000
DTSTAMP:20260504T235030
CREATED:20231201T195352Z
LAST-MODIFIED:20231207T151551Z
UID:2757-1702490400-1702495800@nqw.ijs.si
SUMMARY:Dinner
DESCRIPTION:
URL:https://nqw.ijs.si/event/dinner-8/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T192900
DTEND;TZID=Europe/Ljubljana:20231213T203000
DTSTAMP:20260504T235030
CREATED:20231207T151551Z
LAST-MODIFIED:20231207T151624Z
UID:3149-1702495740-1702499400@nqw.ijs.si
SUMMARY:Chair: Zala Lenarčič
DESCRIPTION:
URL:https://nqw.ijs.si/event/chair-zala-lenarcic-2/
CATEGORIES:NQW 2023
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T193000
DTEND;TZID=Europe/Ljubljana:20231213T200000
DTSTAMP:20260504T235030
CREATED:20231201T190405Z
LAST-MODIFIED:20231207T151551Z
UID:2610-1702495800-1702497600@nqw.ijs.si
SUMMARY:Denis Golez: Chirped amplitude mode in photo-doped superconductors
DESCRIPTION:D. Golež\,1\,2 T. Blommel\,3 J. Kaye\,4 Y. Murakami5 \n1JSI\, Jamova cesta 23\, SI-1000 Ljubljana\, Slovenia \n2University of Ljubljana\, Kongresni trg 12\, 1000 Ljubljana \n3Department of Physics\, University of Michigan\, Ann Arbor\, Michigan 48109\, USA \n4Center for Computational Quantum Physics\, Flatiron Institute\, New York\, New York\, 10010\, USA \n5Center for Emergent Matter Science\, RIKEN\, Wako\, Saitama 351-0198\, Japan \nWhen a continuous symmetry is spontaneously broken\, two types of collective modes emerge: phase and amplitude mode fluctuations of the order parameter. The latter is a massive excitation living at the edge of the gap. Recently\, signatures of the amplitude mode were observed in photo-doped superconductors using third-harmonics generation in the terahertz regime\, which opened the field of nonlinear light-amplitude mode coupling. \nWe will show that a weak photo-excitation in superconductors leads to a long-lived prethermal phase with a reduced order parameter and superimposed amplitude oscillations. As we increase the intensity of the pump pulse\, the amplitude mode oscillations exhibit chirping; namely\, the frequency slows down as a function of time. The chirping gets amplified as we approach the nonthermal critical point – an excitation at which the intensity of the light is large enough to destroy the superconducting order. We identify signatures of the chirped amplitude mode in photo-induced current after a monocycle or Gaussian pulse and propose a transmission line circuit experiment to detect the phenomena. In the last part\, we will present recent theoretical advances based on the compressed representation of quantum propagators\, which allow the analysis of time scales relevant for the collective mode dynamics.
URL:https://nqw.ijs.si/event/denis-golez-chirped-amplitude-mode-in-photo-doped-superconductors/
CATEGORIES:NQW 2023
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BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T200000
DTEND;TZID=Europe/Ljubljana:20231213T201500
DTSTAMP:20260504T235030
CREATED:20231201T190405Z
LAST-MODIFIED:20231207T151601Z
UID:2611-1702497600-1702498500@nqw.ijs.si
SUMMARY:Carlo Vanoni: A renormalization group analysis of the Anderson model ‌in infinite dimensions
DESCRIPTION:C. Vanoni\,1 B. Altshuler\,2 V. Kravtsov\,3 A. Scardicchio3 \n1SISSA – International School for Advanced Studies\, via Bonomea 265\, 34136\, Trieste\, Italy \n2Physics Department\, Columbia University\, 538 West 120th Street\, New York\, New York 10027\, USA \n3ICTP\, Strada Costiera 11\, 34151\, Trieste\, Italy \nIn this talk\, I will present a renormalization group analysis of the problem of Anderson localization on Regular Random Graphs (RRGs). I will first review and extend the finite-dimensional analysis of Abrahams\, Anderson\, Licciardello\, and Ramakrishnan in terms of spectral observables\, and discuss how to take the large-d limit. I will then motivate that the infinite-dimensional case\, relevant also in the context of Many-Body Localization\, recovers the Anderson model on RRGs. In this case\, the renormalization group β-function necessarily involves two parameters\, but the one-parameter scaling hypothesis is recovered for sufficiently large system sizes. I will also discuss how to understand this change in behavior in terms of the geometrical properties of the graphs. The talk will be based on arXiv:2306.14965 and ongoing work.
URL:https://nqw.ijs.si/event/carlo-vanoni-a-renormalization-group-analysis-of-the-anderson-model-in-infinite-dimensions/
CATEGORIES:NQW 2023
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BEGIN:VEVENT
DTSTART;TZID=Europe/Ljubljana:20231213T201500
DTEND;TZID=Europe/Ljubljana:20231213T203000
DTSTAMP:20260504T235030
CREATED:20231201T190420Z
LAST-MODIFIED:20231207T151601Z
UID:2612-1702498500-1702499400@nqw.ijs.si
SUMMARY:Rafał Świętek: A note on weak eigenstate thermalization and normalization of operators
DESCRIPTION:P. Łydżba\,1 R. Świętek\,2\,3 M. Mierzejewski\,1 M. Rigol\,4 L. Vidmar2\,3 \n1Institute of Theoretical Physics\, Faculty of Fundamental Problems of Technology\, Wrocław \nUniversity of Science and Technology\, 50-370 Wrocław\, Poland \n2Department of Physics\, Faculty of Mathematics and Physics\, University of Ljubljana\, SI- \n1000 Ljubljana\, Slovenia \n3Department of Theoretical Physics\, J. Stefan Institute\, SI-1000 Ljubljana\, Slovenia \n4Department of Physics\, The Pennsylvania State University\, University Park\, Pennsylvania \n16802\, USA \nWhile the eigenstate thermalization hypothesis (ETH) is well established for quantum-chaotic interacting systems\, its validity for other classes of systems remains a matter of intense debate. Focusing on quadratic fermionic Hamiltonians\, we here argue that the weak ETH is satisfied for few-body observables in many-body eigenstates of quantum-chaotic quadratic (QCQ) Hamiltonians. In contrast\, the weak ETH is violated in two cases: (a) for sums of few-body observables in all quadratic Hamiltonians\, and (b) for few-body observables in localized quadratic Hamiltonians. We argue that these properties can be traced back to the validity of single-particle eigenstate thermalization\, and we highlight the subtle role of normalization of operators. Our results suggest that the difference between weak and no ETH in many-body eigenstates allows for a distinction between single-particle quantum chaos and localization. We test to which degree this phenomenology holds true for integrable systems such as the XYZ and XXZ models.
URL:https://nqw.ijs.si/event/rafal-swietek-a-note-on-weak-eigenstate-thermalization-and-normalization-of-operators/
CATEGORIES:NQW 2023
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