26^th IASBS Condensed Matter Physics Meeting

Title: Transport and recombination in organic light-emitting diodes
By: Paul Blom
From: MPI for Polymer Research
Abstract: TBA

Title: Many-body Quantum Chaos
By: John T. Chalker
From: University of Oxford
Abstract: I will give an overview of recent work on quantum dynamics in many-body systems far from the ground state. This work addresses the question of whether, and in what sense, such a quantum system can reach thermal equilibrium if it is isolated from its surroundings and not in contact with any heat bath. While this question is almost as old as the formulation of quantum mechanics, important steps towards a precise and detailed answer have come much more recently. These steps include the formulation of the eigenstate thermalisation hypothesis (ETH) in the 1990’s, numerical demonstration of the accuracy of ETH in the first first decade of the 21st century, and calculations in the past five years using random quantum circuits as simple models for dynamics.

Title: Taming active matter: from ordered topological defects to autonomous shells
By: Amin Doostmohammadi
From: University of Copenhagen
Abstract: The spontaneous emergence of collective flows is a generic property of active fluids and often leads to chaotic flow patterns characterized by swirls, jets, and topological disclinations in their orientation field. I will first discuss two examples of these collective features helping us understand biological processes: (i) to explain the tortoise & hare story in bacterial competition: how motility of Pseudomonas aeruginosa bacteria leads to a slower invasion of bacteria colonies, which are individually faster, and (ii) how self-propelled defects lead to finding an unanticipated mechanism for cell death. I will then discuss various strategies to tame, otherwise chaotic, active flows, showing how hydrodynamic screening of active flows can act as a robust way of controlling and guiding active particles into dynamically ordered coherent structures. I will also explain how combining hydrodynamics with topological constraints can lead to further control of exotic morphologies of active shells.

Title: Dynamics and patterns on graphs: Emergence of topological waves
By: Bard Ermentrout
From: University of Pittsburgh
Abstract: TBA

Title: Practical topological signatures for few-boson fractional Chern insulators
By: Nathan Goldman
From: Université Libre de Bruxelles
Abstract: Realizing strongly-correlated topological phases of ultracold gases is a central goal for ongoing experiments. And while fractional quantum Hall states could soon be implemented in small atomic ensembles, detecting their signatures in few-particle settings remains a fundamental challenge. In this talk, we will analyze practical topological signatures of fractional Chern insulators constituted of a few bosons in a few lattice sites, based on center-of-mass Hall drift and density-distribution measurements. Our calculations suggest that fractional Chern insulators can be detected in cold-atom experiments, using available detection methods.

Title: In-vitro and In-silico 3D Tumor Models
By: Mohammad Kohandel
From: University of Waterloo
Abstract: TBA

Title: Shear Zones in Slow Granular Flows
By: Maniya Maleki
From: Institute for Advanced Studies in Basic Sciences (IASBS)
Abstract: We report experimental and numerical studies on slow granular flows in split-bottom Couette cells. The velocity profile is obtained and the location and width of the shear zone are derived. We show that the shear zone characteristics depend on the filling height of the grains and the friction. Then we show how a confining pressure can affect the evolution of the shear zones. Finally, using the principle of minimization of energy dissipation, and combining experiments and variational analysis, we disentangle the contributions of the gravitational acceleration and confining pressure on shear strain localization.

Title: Magnetic recording of information: from ultrafast magnetism to brain-inspired computing
By: Theo Rasing
From: Radboud University Nijmegen
Abstract: The 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. Due to many new ideas, originating from fundamental research during the last 50 years, this technology has developed in a breath-taking fashion. However, the explosive growth of digital data and its related energy consumption1 is pushing the need to develop fundamentally new physical principles and materials for faster, smaller and more energy-efficient processing and storage of data.
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 recording2. Ultimately, future brain-inspired technology should provide room temperature operation down to picosecond timescales, nanoscale dimensions and at an energy dissipation as low as the Landauer limit (~zJ). In this talk, I will discuss the state of the art in ultrafast manipulation of magnetic bits and present some first results3 to implement brain-inspired computing concepts in magnetic materials that operate close to these ultimate limits.


References:
1. Lannoo, B. Energy consumption of ICT Networks. TREND Final Workshop Brussels (2013)
2. A. Kirilyuk, A. V. Kimel and Th. Rasing, Ultrafast optical manipulation of magnetic order, Rev. Mod. Phys. 82, 2731-2784 (2010)
3. A. Chakravarty, J.H. Mentink, C. S. Davies, K. Yamada, A.V. Kimel and Th. Rasing, Supervised learning of an opto-magnetic neural network with ultrashort laser pulses, Appl. Phys. Lett. 114, 192407 (2019)

Title: Synchronization in small-world networks: effects of noise, contrariety, inhibition and time-delay
By: Farhad Shahbazi
From: Isfahan University of Technology
Abstract: TBA

Title: The neurobiology of aesthetic experiences - from visual to mathematical beauty
By: Semir Zeki
From: University College London
Abstract: TBA