"Modeling of Complex Systems" Seminar
2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025
2022-01-27 (Thursday)
room 1.03, Pasteura 5 at 15:15 
Rastko Sknepnek (School od Science and Engineering and School of Life Sciences, University of Dundee, United Kingdom)Active Junction Model for Epithelial Tissues
Convergence-extension in embryos is driven by cellular behaviours controlled by chemical and mechanical signalling. A key cellular process is intercalation - the exchange of neighbours via T1 transitions. We analyse a model with positive feedback between recruitment of myosin motors and mechanical tension in cell junctions. The model characterises active T1 events, which occur against external pulling, as a function of the pulling force, remodelling timescales in cell junctions, and myosin kinetics. Using several active cells in a passive tissue with hexagonal cells, we found an optimal range of pulling forces that induce active T1 events, which initiate deformations that extend the tissue perpendicular to the pulling force. We showed that pulling generate tensions chains in a random patch of active cells, identified the parameter range for convergence-extension to occur, and compared our finding with experiments on chick embryos. The mechanochemical feedback, therefore, provides a mechanism for tissue-scale remodelling.
Seminar will be hold on the Zoom platform:Topic: Seminar Modeling of Complex SystemsTime: Jan 27, 2022 03:10 PM WarsawJoin Zoom Meetinghttps://zoom.us/j/99338090255?pwd=bEFPQVhrRkhzRmhVZnp6NmFxWTVyUT09Meeting ID: 993 3809 0255Passcode: vK4pc7
2022-01-20 (Thursday)
room 1.03, Pasteura 5 at 15:15
dr Oleksandr Gamayun (IFT UW)Static and dynamic properties of an integrable mobile impurit
Abstract: A single impurity particle in an ultracold atomic gas is a prospective model for probing relaxation dynamics of an interacting out-of-equilibrium quantum system. I will focus on McGuire's model that describes an impurity that propagates in a one-dimensional gas of free fermions. It is the simplest and yet fundamental model capturing the peculiar physics and mathematics of the non-equilibrium processes. The integrability of the model allows one to obtain a complete nonperturbative solution and express physical quantities in terms of the Fredholm determinants. After a detailed analysis of these determinants, I will discuss several striking physical phenomena such as incomplete relaxation and momentum-dependent impurity statistics. The universal properties of such one-dimensional systems can be described by the nonlinear Luttinger liquid (nLL). I will explain the microscopic derivation of nLL from the form-factors and discuss the generalization to finite temperatures.
The seminar will start at 3:10pm on the Zoom platform,:Link to the meeting:Jacek Majewski is inviting you to a scheduled Zoom meeting.Topic: Seminar Modeling of Complex SystemsTime: Jan 20, 2022 03:05 PM WarsawJoin Zoom Meetinghttps://zoom.us/j/91235254992?pwd=bHp4bmhTL0hUemJqaGJKRVRIcWRrQT09Meeting ID: 912 3525 4992Passcode: 6XN5xeHowever, it will be also possible to follow the seminar in the usual lectrure room no. 1.03, starting at 3:10pm.
2022-01-13 (Thursday)
room 1.03, Pasteura 5 at 15:15
dr Krzysztof Jachymski (IFT UW)From few-body physics to quantum simulations
seminar also on Zoom platform: Link to the meeting:Jacek Majewski is inviting you to a scheduled Zoom meeting.Topic: Jacek Majewski's Zoom MeetingTime: Jan 13, 2022 03:05 PM WarsawJoin Zoom Meetinghttps://zoom.us/j/93500379099?pwd=SDJDcHJnZHhVQ3VneStlVDRCVTJGQT09Meeting ID: 935 0037 9099Passcode: EkT6aZ------ -- -------------------------Abstract: Atomic gases cooled to quantum degeneracy offer exciting opportunities for quantum simulations and precision measurements. Since the first realization of the Bose-Einstein condensate in a weakly interacting gas, many new systems emerged with different types of interactions. In particular, creation of hybrid ion-atom systems enabled the studies of impurity physics in the strongly interacting regime. In this talk, I will discuss recent breakthrough experiment demonstrating control over the ion-atom interaction in Ba+ - Li system by means of Feshbach resonances and present the prospects for quantum simulation of strongly interacting many-body systems based on this setup.
Abstract: Atomic gases cooled to quantum degeneracy offer exciting opportunities for quantum simulations and precision measurements. Since the first realization of the Bose-Einstein condensate in a weakly interacting gas, many new systems emerged with different types of interactions. In particular, creation of hybrid ion-atom systems enabled the studies of impurity physics in the strongly interacting regime. In this talk, I will discuss recent breakthrough experiment demonstrating control over the ion-atom interaction in Ba+ - Li system by means of Feshbach resonances and present the prospects for quantum simulation of strongly interacting many-body systems based on this setup.
2021-12-16 (Thursday)
room 1.03, Pasteura 5 at 15:15
Jacek Gębala (IFT UW)Universality in two- and three body systems
I will introduce the concept of universality: a tool for efficient description of the scattering properties of ultracold three-body systems. Furthermore, I will discuss the motivations behind implementing universal potential models in order to calculate the recombination losses in ion-atom samples. Then I will discuss how we can model an exemplary three-particle collision in a system interacting via the sum of two-body potentials. Briefly, I will mention the physics of Efimov states in considered systems.
2021-12-02 (Thursday)
room 1.03, Pasteura 5 at 15:15
Rishabh Prakash Sharma (IFT UW)Study of geometrical measures of wormholes using 4D-tomography
In this work, we have used 4D micro-tomography (XCT) to study the dissolution channels aka wormholes. 16-bit grayscale scans of dissolving samples are obtained at constant time-interval during the dissolution experiments. The grayscale scans are segmented to binary images by a novel volume-based segmentation technique to preserve the maximum features of the wormhole. Finally, image-processing techniques such as connected-component labelling, smoothing median filters and skeletonization are used to extract the wormholes and their geometrical properties. Several measures such as tip-propagation, wastefulness and branchedness have been proposed which show a high correlation of wormhole propagation speed with rock internal structure.
2021-11-18 (Thursday)
room 1.03, Pasteura 5 at 15:15
Michał Suchorowski (IFT UW)Rotating Impurity in the 2D Bose-Einstein Condensate
In the talk, I will focus on the theoretical description of the rotating impurity interacting with the two-dimensional bosonic bath employing the angulon quasiparticle formalism. The presented results will show the vortex nucleation hinting at the existence of instabilities that were already observed in the 3D systems caused by the transfer of angular momentum between impurity and bath. We additionally investigate the real-time dynamics of the condensate after the rapid spin of the molecule. We hope that our research will give additional insight into recent experimental work with molecules on the surface of superfluid helium droplets.
2021-11-04 (Thursday)
room 1.03, Pasteura 5 at 15:15
dr Piotr Bentkowski (Institute for Interdysciplinary Studies "Artes Liberales", University of Warsaw)Data-driven modeling of infectious disease; Case study of seasonal influenza in France
2021-10-28 (Thursday)
room 1.03, Pasteura 5 at 15:15
Adam Koza (IFT UW)Towards collisional cooling of polyatomic molecule
2021-10-21 (Thursday)
room 1.03, Pasteura 5 at 15:15
dr Jacek Dobrzyniecki (IFT UW)Unconvemntional pairing in few-fermion systems tuned by external confinement
2021-10-14 (Thursday)
room 1.03, Pasteura 5 at 15:15
dr Daniel Matoz-Fernandez (IFT UW)