BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Microscopic Dynamics of Structural Glasses Investigated by Quasiel astic Neutron Scattering DTSTART;VALUE=DATE-TIME:20220902T070000Z DTEND;VALUE=DATE-TIME:20220902T074000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3701@indico.stfc.ac.uk DESCRIPTION:Speakers: Reiner Zorn (Forschungszentrum Juelich)\nIn this pre sentation I will give a short introduction into quasielastic neutron scatt ering (QENS) and its application to glass-forming systems. QENS operates o n time scales from picoseconds to a microsecond and at the same time has a spatial resolution in the Ångström range. Therefore\, it is well suited for the study of molecular and polymeric glass-formers.\n\nThe dynamics o f glass-formers is still poorly understood\, but certain universal feature s can be found which a theory has to explain. Foremost\, there is the α r elaxation\, which governs what is usually called ‘glass transition’. I ts temperature-dependence is highly non-Arrhenius and the shape of correla tion functions non-exponential. In addition\, faster relaxations may be pr esent\, among which the universal ‘fast β relaxation’ in the picoseco nd range is strongly related to the α relaxation in mode-coupling theory. As the fastest universal process\, glasses show an excess of the vibratio nal density of states above the Debye model in the low frequency range\, t he so-called ‘boson peak’.\n\nAll these phenomena can be observed by Q ENS with the additional information of a length scale. In addition\, it is possible to study them in confined glass-formers in order to access their system-size-dependence. Selected QENS experiments will be presented and d iscussed.\n\nhttps://indico.stfc.ac.uk/event/53/contributions/3701/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3701/ END:VEVENT BEGIN:VEVENT SUMMARY:Muons and Quantum Computing Hardware: Challenges and Opportunities DTSTART;VALUE=DATE-TIME:20220901T084000Z DTEND;VALUE=DATE-TIME:20220901T092000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3698@indico.stfc.ac.uk DESCRIPTION:Speakers: Ioan Pop (Karlsruhe Institute of Technology)\nOne mi ght wonder: what do muons have to do with quantum computing? I will argue that environmental muons and ionizing radiation in general represent a sou rce of noise and dissipation which until recently has been underestimated in the quantum devices community. I will present measurements performed in the deep-underground laboratory of Gran Sasso [1] which show a significan t improvement in the performance of superconducting quantum hardware thank s to the shielding provided by 1.6 Km of granite. On the other hand\, low energy muon beams engineered at dedicated large-scale facilities represent a powerful materials characterization tool\, and as such might play a rol e in the understanding and mitigation of material defects in superconducti ng and semiconducting quantum hardware.\n\n[1] Cardani\, Valenti et al.\, Nature Comm. 12\, 2733 (2021)\n\nhttps://indico.stfc.ac.uk/event/53/contri butions/3698/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3698/ END:VEVENT BEGIN:VEVENT SUMMARY:Low-energy Excitations in Quantum Spin Liquid Derived from Molecul ar Mott Insulator DTSTART;VALUE=DATE-TIME:20220901T070000Z DTEND;VALUE=DATE-TIME:20220901T074000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3697@indico.stfc.ac.uk DESCRIPTION:Speakers: Reizo Kato ()\nA molecular Mott insulator ß'-EtMe$_ 3$Sb[Pd(dmit)$_2$]$_2$ (dmit = 1\,3-Dithiol-2-thione-4\,5-dithiolate) is a quantum spin liquid (QSL) candidate. In the crystal with the space group $C2/c$\, Pd(dmit)$_2$ anion radicals are strongly dimerized to form a dime r with spin 1/2. The dimers are arranged in an approximately isosceles-tri angular lattice\, which leads to a frustrated S = 1/2 Heisenberg spin syst em.\nThe system shows no magnetic order down to a very low temperature (~1 9 mK) that corresponds to $J$/12\,000\, where $J$ (~250 K) is the nearest- neighbor spin interaction energy. The HOMO-LUMO mixing in the dimer unit i nduces fragmentation of S=1/2 electron spin with strong quantum fluctuatio n.\n Low-energy excitations in the QSL state are open to debate even now. Heat capacity and magnetization indicate gapless fermion-like excitations\ , while $^{13}$C-NMR indicates an existence of a nodal gap. ESR and µSR p robed the spinons\, revealing their gapless character and an unexpectedly large degree of in-plane anisotropy in the spin dynamics. This anisotropic spin dynamics indicates quasi-one-dimensional diffusive motion in the dir ection of the weakest magnetic coupling in the triangular lattice.\n In 20 10\, it was reported that thermal conductivity is characterized by its lar ge value and gapless behavior (a finite temperature-linear term). In 2019\ , however\, two other research groups reported opposite data (much smaller value and a vanishingly small temperature-linear term) and the discrepanc y in the thermal conductivity measurement data emerges as a serious proble m concerning the ground state of QSL. An origin of the discrepancy will be discussed. \n\nI deeply thank all my collaborators\, especially\, H. Cui\ , M. Uebe\, S. Fujiyama\, Y. Oshima\, I. Watanabe (RIKEN)\, Y. Nakazawa (O saka Univ.)\, Y. Ishii (Shibaura Institute of Technology) and F. L. Pratt (STFC).\n\nhttps://indico.stfc.ac.uk/event/53/contributions/3697/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3697/ END:VEVENT BEGIN:VEVENT SUMMARY:Dipolar-Octupolar Quantum Spin Liquids in Ce-based Pyrochlores DTSTART;VALUE=DATE-TIME:20220831T094000Z DTEND;VALUE=DATE-TIME:20220831T102000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3695@indico.stfc.ac.uk DESCRIPTION:Speakers: Bruce Gaulin (McMaster University)\nIn geometrically -frustrated Ce-based pyrochlores\, such as Ce$_2$Zr$_2$O$_7$\, the effecti ve S=1/2 of the Ce3+ crystal field ground state doublet is known to act bo th as a conventional dipole magnetic moment\, and as an octupole. This co nstrains the form of its near-neighbour Hamiltonian\, and allows for diffe rent ordered or quantum disordered ground states in this family of materi als\, where either the dipolar or octupolar nature of the S=1/2 degree of freedom dominates. I will describe recent experiments [1\,2]\, mostly neu tron scattering and heat capacity\, which show how the nature of the Ce3+ ground state doublet can be revealed\, and how a particular form of quantu m spin liquid can be identified as the likely ground state in Ce$_2$Zr$_2$ O$_7$.\n\nhttps://indico.stfc.ac.uk/event/53/contributions/3695/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3695/ END:VEVENT BEGIN:VEVENT SUMMARY:Challenges in next generation batteries for accelerating decarboni zation DTSTART;VALUE=DATE-TIME:20220830T084000Z DTEND;VALUE=DATE-TIME:20220830T092000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3694@indico.stfc.ac.uk DESCRIPTION:Speakers: Catia Arbizzani (Alma Mater Studiorum - Università di Bologna)\nBatteries are a key-technology for accelerating decarbonizati on. The benefits of the development of advanced batteries are enormous: br oader energy access\, specifically for off-grid communities\, the transpor t electrification that reduce the dependency from fossil fuels and the har mful local emission of nanoparticulates\, better utilization of intermitte nt energy sources [1]. Europe has decided to invest significantly in numer ous projects and initiatives: the European Commission (EC) launched the Eu ropean Battery Alliance in October 2017 to build a competitive manufacturi ng value chain in Europe for the creation of sustainable and fully recycla ble cells and batteries [2\, 3]. The EC funded the long-term research init iative Battery2030+ [4]\, thus guaranteeing accelerated support for resear ch and innovation of advanced lithium-ion batteries and disruptive technol ogies such as Li metal solid state batteries\, and the technologic platfor m Batteries Europe\, which will coordinate the efforts and the resources o f private and public partners to implement the research activities. \nWhil e Li-ion batteries will continue to play a major role in the energy storag e\, new and disruptive ideas are needed for the creation of sustainable ba tteries which pave the way to European competitiveness during the transiti on to a climate-neutral society.\n\n![Expected growth in global battery de mand by application (left) and region (right) [4]][1]\n\nReferences:\n[1] https://www.weforum.org/reports/a-vision-for-a-sustainable-battery-value-c hain-in-2030\n[2] https://ec.europa.eu/growth/industry/strategy/industrial -alliances/european-battery-alliance_en\n[3] https://www.eba250.com/\n[4] https://battery2030.eu/battery2030/about-us/challenges/\n\n\n [1]: https: //indico.stfc.ac.uk/event/53/images/140-Catia-Figure.jpg\n\nhttps://indico .stfc.ac.uk/event/53/contributions/3694/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3694/ END:VEVENT BEGIN:VEVENT SUMMARY:Opportunities and challenges of molecular spins in quantum nanosci ence DTSTART;VALUE=DATE-TIME:20220830T070000Z DTEND;VALUE=DATE-TIME:20220830T074000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3700@indico.stfc.ac.uk DESCRIPTION:Speakers: Roberta Sessoli ()\nImplementation of advanced Quant um Technologies might benefit from the remarkable quantum properties shown by molecular spin systems based on the coordination bond. The versatility of the molecular approach combined with rational design has recently boos ted the operativity temperature of molecules acting as bits of memory\, ot herwise known as Single-Molecule Magnets\, or the coherence time of molecu lar spin qubits. The richness and tunability of the spectrum of spin level s make them particularly suitable for quantum error correction\, while spi n-spin interaction can be tuned to realize quantum gates and quantum simul ators. Molecules can also be processed to be deposited on surfaces\, allow ing the realization of hybrid nanostructures. However\, achieving the cont rol of single molecules is also challenging\, requiring to couple the elec tric field\, which can be confined at the molecular scale\, with the spin degrees of freedom of the molecule. Investigation of the spin dynamics at the level of the monolayer requires developing innovative tools and muon s pin resonance might be an important resource. \n\n![][1]\n\n\n [1]: https ://indico.stfc.ac.uk/event/53/images/128-Abstract-Sessoli-Pic1.jpg\n\nhttp s://indico.stfc.ac.uk/event/53/contributions/3700/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3700/ END:VEVENT BEGIN:VEVENT SUMMARY:Unsupervised machine learning of muons experiments – why? DTSTART;VALUE=DATE-TIME:20220829T120000Z DTEND;VALUE=DATE-TIME:20220829T124000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3699@indico.stfc.ac.uk DESCRIPTION:Speakers: Jorge Quintanilla (University of Kent)\nZero-field m uon spin relaxation experiments probe directly the intrinsic magnetic fiel ds that arise spontaneously in a given material. The full understanding of such experiments requires a microscopic description of the material under investigation\, including its electronic state and the complex interactio ns between the muon and the material’s electronic and structural degrees of freedom. However\, paradoxically\, such experiments can also yield cru cial information about poorly-understood systems\, well before we know eno ugh about them for such detailed modelling. In this talk I will ask two qu estions: “How is this possible?” and “Can we do it better?” To add ress the first question I will review the particular cases of LaNiC$_2$ an d LaNiGa$_2$\, two closely related superconductors where the case for an e xotic\, time-reversal symmetry breaking pairing state is now well establis hed\, with muons experiments having played the key role. I will describe h ow we got to this point\, emphasising the prudent use of phenomenological fitting functions and group-theoretical analyses. I will argue that while such approach cannot substitute detailed microscopic modelling (which has to have the final word) it can be crucial to get us to the point where the latter becomes feasible. I will then address the second question\, specif ically asking whether there is room for improvement in the way we tackle m uons data phenomenologically. I will introduce the concept of unsupervised machine learning\, using Principal Component Analysis and Auto-encoders a s paradigmatic examples. I will propose that unsupervised machine learning can be used to find compact descriptions of muons data\, helping with det ection of phase transitions and material classification\, without requirin g either a microscopic theory or phenomenological fitting functions. I wil l illustrate this with muons data on real magnetic and superconducting mat erials and introduce simple software tools that can be used to carry out s imilar analyses.\n\nhttps://indico.stfc.ac.uk/event/53/contributions/3699/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3699/ END:VEVENT BEGIN:VEVENT SUMMARY:What high resolution RIXS can tell us of cuprates (and of other q uantum materials) DTSTART;VALUE=DATE-TIME:20220829T094000Z DTEND;VALUE=DATE-TIME:20220829T102000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3696@indico.stfc.ac.uk DESCRIPTION:Speakers: Giacomo Ghiringhelli (Politecnico di Milano)\nResona nt Inelastic X-rays Scattering (RIXS) is an energy loss spectroscopy made with x rays whose energy is tuned to a suitable absorption edge. When the instrumental resolution is good enough\, RIXS spectra provide information on the energy\, dispersion and symmetry of local and collective excitation s\, such as ligand field excitations\, magnons and paramagnons\, phonons\, particle-hole pairs\, charge density fluctuations and order. RIXS is a po werful complement of more traditional techniques like inelastic neutron sc attering\, Raman scattering\, electron energy loss spectroscopy. \nThe ric h physics of cuprates is very effectively captured by high resolution RIXS experiments made at Cu L3 and O K edges. This fortunate conjuncture has boosted the development of better and better instrumentation at synchrotro ns and has served as one of the scientific cases for RIXS at XFELs. The fi eld is expanding and experiments are leading to more insightful results\, where the different degrees of freedom are organically studied.\nAfter int roducing the technique\, I will provide a survey of results on cuprate par ent compounds [1] and superconductors [2\,3] and on infinite layer nickela tes [4]\, which share several properties with high Tc superconductors. \n\ nReferences\n\n1. Martinelli\, L\, Betto\, D.\, et al. *Fractional spin ex citations in the infinite-layer cuprate CaCuO2*\, Phys. Rev. X **12**\, 02 1041 (2022)\n2. Arpaia\, R.\, Caprara\, S.\, et al\, *Dynamical charge den sity fluctuations pervading the phase diagram of a Cu-based high-Tc superc onductor*\, Science **365**\, 906 (2019)\n3. Peng\, Y.Y\, Martinelli\, L\, et al. *Doping-dependence of the electron-phonon coupling in two families of bilayer superconducting cuprates*. Phys. Rev. B **105**\, 115105 (2022 ).\n4. Krieger\, G.\, Martinelli\, L. et al. *Charge and spin order dichot omy in NdNiO2 driven by SrTiO3 capping layer* arXiv:2112.03341 (2021)\n\nh ttps://indico.stfc.ac.uk/event/53/contributions/3696/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3696/ END:VEVENT BEGIN:VEVENT SUMMARY:Yamazaki Prize Giving DTSTART;VALUE=DATE-TIME:20220829T072000Z DTEND;VALUE=DATE-TIME:20220829T074000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3853@indico.stfc.ac.uk DESCRIPTION:https://indico.stfc.ac.uk/event/53/contributions/3853/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3853/ END:VEVENT BEGIN:VEVENT SUMMARY:Yamazaki Prize Lecture - The quantum muon DTSTART;VALUE=DATE-TIME:20220829T074000Z DTEND;VALUE=DATE-TIME:20220829T082000Z DTSTAMP;VALUE=DATE-TIME:20220826T104629Z UID:indico-contribution-204-3702@indico.stfc.ac.uk DESCRIPTION:Speakers: Stephen Blundell (University of Oxford)\nThe key phy sical process at the heart of the muon-spin rotation ($\\mu$SR) technique is that the spin of the positive muon precesses in a local magnetic field\ , a process that can be modelled either classically (torque on a magnetic dipole) or quantum mechanically (interference between components in a supe rposition). However\, some aspects of the muon's interaction with its env ironment bring out features which are purely quantum mechanical and have n o classical analogue. Understanding this requires an accurate modelling o f the muon site\, only possible with modern electronic structure (DFT+$\\m u$) methods. I will review a variety of examples of muon experiments on o rganic\, molecular and inorganic systems which will highlight some importa nt qualities of this viewpoint and demonstrate the utitlity of "the quantu m muon".\n\n(Yamazaki lecture)\n\nhttps://indico.stfc.ac.uk/event/53/contr ibutions/3702/ LOCATION:Science and Technology Campus\, University of Parma URL:https://indico.stfc.ac.uk/event/53/contributions/3702/ END:VEVENT END:VCALENDAR