CMSP

Europe/Rome 2022-10-05 11:00:00 2022-10-05 12:00:00 CMSP Seminar (Atomistic Simulation Webinar Series): Single-molecule spectroscopy of photosynthetic light-harvesting complexes Tjaart Krüger (University of Pretoria, South Africa)     Abstract:   Photosynthetic light-harvesting complexes have to balance two vital functions: efficient light harvesting and efficient energy dissipation. The former occurs under low levels of solar radiation, during which the absorbed photoenergy is converted into chemical energy with near-unity quantum efficiency. The latter, finely tuned photoprotective function serves to safely remove excess absorbed energy to limit photodamage. The nature of both functions is a subject of intense research. The light-harvesting proteins commonly coordinate numerous chromophores in a dense arrangement, resulting in complex, coupled energy-transfer mechanisms. Consequently, transitions between the light-harvesting and photoprotective functions often involve only subtle protein conformational changes, i.e., the population equilibrium between different conformational states of light-harvesting proteins is often very sensitive to the protein’s local environment. Single-molecule spectroscopy uniquely allows one to monitor protein functional switches in real time, to explore the protein conformational landscapes, and to unravel the underlying photophysical processes. In this webinar I will show how the intrinsic disorder of photosynthetic proteins is regulated by their local environments, allowing them to switch between different light-harvesting and photoprotective states. The unstable equilibrium between different functional states can be finely tuned by the incident photon flux1, pH2, chromophore arrangement3, and interaction with accessory proteins4. Examples of environmentally controlled conformational switching, as assessed by single-molecule spectroscopy, will be given for light-harvesting complexes of plants, cyanobacteria, and diatoms.   References Gwizdala et al. J Am Chem Soc 138 (36): 11616-11622 (2016). Krüger et al. Biophys J 102: 2669–2676 (2012). Krüger et al. Proc Natl Acad Sci USA, 108:13516-13521 (2011); Krüger et al. Proc Natl Acad Sci USA 114: E11063-E11071 (2017). Gwizdala et al. J Phys Chem Lett 9:2426-2432 (2018).   Zoom registration link: https://zoom.us/meeting/register/tJcvdOCtrz8uGNOOWXka0xuyKqDd9L6X2UfZ   Virtual Seminar ICTP pio@ictp.it 5 Oct 2022

Europe/Rome 2022-10-13 16:00:00 2022-10-13 17:00:00 CMSP Seminar (News&Views series): Electrons in moiré materials: from atomistic calculations to effective models Johannes Lischner (Imperial College London)   Abstract:   Beautiful moiré patterns can be created by stacking and twisting two-dimensional crystals, such as graphene or transition metal dichalcogenides. One of the most fascinating discoveries in recent years is that electrons are strongly affected by these moiré patterns and often exhibit completely unexpected behaviour. For example, twisted bilayer graphene – composed of two (semi-)metallic graphene layers – was observed to exhibit correlated insulator states as well as superconductivity at a magic twist angle of 1.1 degrees. In my talk, I will describe my group’s efforts to understand the electronic properties of moiré materials from an atomistic perspective which is challenging because of the large unit cells in these systems (often containing thousands of atoms). To overcome this difficulty, we developed accurate tight-binding models and then incorporate the effects of electron-electron interactions. Based on the atomistic simulations, we also construct effective moiré-scale Hubbard-like models to describe the behaviour at large length scales.   Light Refreshments will be served at the end of the Seminar at 17:00 on the terrace of the Leonardo Building Zoom registration link will follow in due time.   Hybrid Seminar ICTP pio@ictp.it 13 Oct 2022

Europe/Rome 2022-10-20 09:00:00 2022-10-20 10:00:00 CMSP Seminar: How to measure entropy in mesoscopic systems? Eran SELA (Tel Aviv University)       Abstract:   Recently, entropy measurements of quantum dots were demonstrated based on charge sensitivity. These experiments require temperature variations, and extract entropy changes due to gate voltage variations using Maxwell relations. In addition to describing ongoing experimental puzzles, I will discuss new directions that these methods open, such as measurements of fractional entropy in frustrated Kondo systems, in fractional quantum Hall states, and the possibility to detect a decoherence induced phase transition in quantum dots.   Zoom registration link will follow in due time.   Hybrid Seminar ICTP pio@ictp.it 20 Oct 2022

Europe/Rome 2022-10-21 11:00:00 2022-10-21 12:00:00 CMSP Seminar: Emergent Quantum Spin Liquids in Lower Dimensional Ferromagnetic Spin Systems Ganapathy Baskaran (Matscience, IITMadras, India Perimeter Institute, Waterloo, Canada)     Abstract:   Quantum Fluctuations remove long range Ferromagnetic order in 1D spin-1/2 XX Ferromagnetic Chains: a free Fermi sea of neutral Jordan-Wigner Fermions emerge. A small Ising Ferromagnetic anisotropy in XXZ chain favors pairing of JW Fermions. It results in a novel `Spin Superfluid' phase (Baskaran, 1982, ICTP Internal Report; IC/82/126), via Fermion pair condensation (triplet RVB phase, in modern parlance) in weakly coupled system of Ferromagnetic XXZ Chains. We discuss emergent quantum spin liquids in systems with ferromagnetic anisotropy (eg., Konig, Komijani and Coleman, PRB 2022) and contrast it with currently popular quantum spin liquids in frustrated antiferromagnetic systems.   Zoom registration link will follow in due time. Hybrid Seminar ICTP pio@ictp.it 21 Oct 2022

Europe/Rome 2023-01-11 07:00:00 2023-01-13 21:00:00 21th International Workshop on Computational Physics and Materials Science: Total Energy and Force Methods | (smr 3814) An ICTP Meeting in presence This Workshop is held in Trieste every two years, since 1987, and is  devoted to recent advances in condensed matter physics and materials science, based on realistic calculations of the electronic structure of complex systems. The aim is a critical discussion of methods and challenging applications. It has become one of the most popular regular events of the international ab-initio electronic structure community.  This event also has the ambition to reach out to countries where the electronic structure community is not traditionally as strong as in Europe, the USA and Japan, in coherence with the mission of its host institution, the ICTP. The workshop will also include the Award ceremony for the "Walter Kohn prize for quantum mechanical material modeling" (https://www.ictp.it/about-ictp/prizes-awards/walter-kohn-prize.aspx), co-funded by ICTP and the Quantum ESPRESSO Foundation.   Topics will span a broad range, including, among others: Spectroscopy Strong electronic correlations Electron-phonon coupling Superconductivity Novel functionals Transport Advanced Materials Materials Discovery Machine Learning Quantum Computing Confirmed speakers: N. ARTHRITH, Utrecht University, The Netherlands T. AYRAL, Atos Quantum Lab, France F. BRUNEVAL, CEA, France M. CASULA, Sorbonne University, France A. FERRETTI, CNR, Italy M. FILIP, University of Oxford, UK G. GALLI, University of Chicago, USA E. INACK, Perimeter Institute, Canada S. LOUIE, University of California, USA L. RATCLIFF, University of Bristol, UK Y.-W. SON, Korea Institute for Advanced Study, Republic of Korea U. WAGHMARE, JNCASR, India W.-J. YIN, Soochow University, China Grants: A limited number of grants are available to support the attendance of selected participants, with priority given to participants from developing countries. There is no registration fee. In person participation: As regards the COVID-19 policy, we advise to follow the updated rules available on the ICTP page Access Guidelines for Visitors.   ICTP ICTP pio@ictp.it 11 Jan 2023 - 13 Jan 2023

Europe/Rome 2023-01-23 07:00:00 2023-02-03 21:00:00 School on Synchrotron Light Sources and their Applications | (smr 3815) Online - ICTP pio@ictp.it 23 Jan 2023 - 3 Feb 2023

Europe/Rome 2023-03-13 07:00:00 2023-03-24 21:00:00 Conference and Advanced School on Low-Dimensional Quantum Systems | (smr 3820) Santiago - Chile ICTP pio@ictp.it 13 Mar 2023 - 24 Mar 2023