Newsroom
Stay informed with our latest news and announcements on this page. For more in-depth content, we also encourage visitors to explore our bimonthly STRUCTURES Newsletter magazine, which features a variety of articles, interviews with members, and background information on our latest research and activities.
Special Seminar by Pierre Haas on Cutting Through the Mechanics of Cell Sheet Folding, EMBL HD, Jan 20
On Friday, January 20 at 2 pm (CET), Pierre Haas from Dresden will be giving a talk on Cutting Through the Mechanics of Cell Sheet Folding as part of the Next Generation Seminar Series of Theory@EMBL at EMBL in Heidelberg:
Title: Cutting Through the Mechanics of Cell Sheet Folding
Abstract: The folding of cellular monolayers is a crucial step of multicellular development, including gastrulation, neurulation, and organogenesis, and is often driven by localized "large bending deformations" of apical constriction and cell wedging. The simplest process in which to study its mechanics is perhaps the inversion of the green alga Volvox, the spherical embryos of which turn themselves inside out through a programme of cell shape changes. In the first part of my talk, I will show how a theoretical model in which apical constriction and cell wedging appear as variations of the intrinsic curvatures of an elastic shell reproduces Volvox inversion quantitatively. I will highlight the novel mechanics resulting from these large bending deformations. In the second part of my talk, I will present recent laser ablation experiments revealing additional geometric incompatibilities between the local intrinsic curvature of the cell sheet and its global shape. I will discuss the mechanics of the resulting residual torques in the cell sheet and show how even small incompatibilities of this kind affect tissue folding. This suggests a more global picture of the mechanics of tissue folding, which does not therefore rely on localized apical constriction and cell wedging only, but also on other, more subtle cell shape changes in other parts of the tissue.
Time & place: Friday, January 20th 2023, EMBL Large Operon and via Zoom
Host: Virginie Uhlmann
If you would like to meet with the speaker (individually or in small groups), please sign up for a slot here (contact: Lizette Michele De Paula, EMBL.)
The STRUCTURES Project Management Office is happy to answer questions.
HeiUP Releases Four New Books in Lecture Notes Physics by STRUCTURES Member Björn Malte Schäfer
We are pleased to announce the release of four new books in Heidelberg University Publishing's (HeiUP) Lecture Notes Physik series, written by Björn Malte Schäfer, Professor of Fundamental Physics at the Center for Astronomy Heidelberg (ZAH). The four books, titled:
provide comprehensive overviews of key topics in theoretical physics, modern cosmology, relativity and statistics. The books are also available online at the webpage of HeiUP Lecture Notes Physik.
Click the image to open the Newsletter as PDF.We are happy to present the ninth volume of the STRUCTURES Newsletter with the following topics:
- Recap 2022 and Happy Holidays
- Symmetric Spaces for Machine Learning – Representation Matters! (Project Report by Diaaeldin Taha)
- STRUCTURES Asks: Lavinia Heisenberg
- We Are STRUCTURES
The STRUCTURES Project Management Office is happy to answer questions and to receive feedback.
STRUCTURES Scientists Simulate Curved and Expanding Spacetime Using Ultracold Atoms
In a laboratory experiment, a team of STRUCTURES researchers from CP 4 at Kirchhoff-Institute for Physics (KIP) and Institute for Theoretical Physics (ITP) have succeeded in realising an effective spacetime that is experimentally controllable. In their research with ultracold quantum gases of potassium, they were able to simulate an entire family of curved universes to investigate different cosmological scenarios and compare them with the predictions of a quantum field theoretical model. “For the wave-like excitations on the condensate, the propagation speed depends on the density and the interaction of the atoms. This gives us the opportunity to create conditions like those in an expanding, spatially curved universe,” explains Prof. Dr Stefan Flörchinger. The researcher, who previously worked at Heidelberg University and joined the University of Jena at the beginning of this year, elaborated the theoretical mapping of the atomic system to a noninteracting quantum field in a curved and expanding metric, which was used to benchmark the experimental results.
The success of this experiment shows that quantum field simulators offer the possibility to enter unexplored regimes in quantum cosmology. “Studying the interplay of curved spacetime and quantum mechanical states in the lab will keep us busy for some time to come,” says Prof. Dr Markus Oberthaler, head of the experimental group and STRUCTURES speaker.
Further reading and information:
- Original Publication 1: Viermann, C., Sparn, M., Liebster, N. et al.: “Quantum field simulator for dynamics in curved spacetime”. Nature (2022)
- Original Publication 2: Tolosa-Simeón, M., Parra-López A., Sánchez-Kuntz N., et al.: “Curved and expanding spacetime geometries in Bose-Einstein condensates”, Physical Review A (2022)
- Article in VICE: Scientists Simulate Early Universe With Quantum State of Matter In Mind-Bending Lab Experiment
- Website: Synthetic Quantum Systems collaboration
On Wednesday, November 30, 2 pm (s.t.) there will be a talk by George Bougas (Hamburg University) on:
Title: Dynamical Association of Efimov Trimers and Atom-Dimers in Cold Gases
Abstract: Properties of Efimov states, that is three-body bound states, are typically measured indirectly through recombination mechanisms, which are ubiquitous in cold gases. Here, a dynamical protocol is investigated allowing for a more controlled probing of these states. In particular, pulses of the scattering length are employed to create a superposition of Efimov trimers and atom-dimers in cold gases, similar to Ramsey spectroscopy. This scheme allows the observation of both the energies and lifetimes of Efimov states, by measuring the remaining fraction of atoms during the free evolution time between the pulses. It is predicted that the mixing of states provided by the second pulse will lead to a measurement of twice the intrinsic lifetime of the Efimov states.
Venue: Philosophenweg 12, kHS (small lecture hall) and online via Zoom.
The talk will be hosted by Prof. Richard Schmidt (ITP). The STRUCTURES Project Management Office is happy to answer questions.
Special Seminar by Christina Kurzthaler: Physics of Bacterial Transport in Dilute & Porous Environments
On Tuesday, November 29, 10:00 am there will be a special seminar by Dr. Christina Kurzthaler – group leader at the Max Planck Institute for the Physics of Complex Systems – in person at the European Molecular Biology Laboratory (EMBL) and on Zoom:
Title: The physics of Bacterial Transport in Dilute and Porous Environments
Abstract: Unraveling the motion of microorganisms in dilute and porous media is important for our understanding of both the molecular basis of their swim gait and their survival strategies in microbial habitats. First, I will show that by using renewal processes to analyze experimental measurements of wild-type E. Coli, we can provide a quantitative spatiotemporal characterization of their run-and-tumble dynamics in bulk. We further demonstrate quantitatively how the persistence length of an engineered strain can be controlled by a chemical inducer and characterize a transition from perpetual tumbling to smooth swimming. Second, I will address how this run-and-tumble gait evolves towards a hop-and-trap motility pattern of agents moving in a porous environment [1]. Using computer simulations, we discover a geometric criterion for their optimal spreading, which emerges when their persistence lengths are comparable to the longest straight path available in the porous medium. Our criterion provides a fundamental principle for optimal transport in densely-packed biological and environmental settings, which could be tested experimentally by using engineered cells and may provide insights into microbial adaption mechanisms. [1] C. Kurzthaler et al. Nat. Commun. 12, 7088 (2021)
Venue: Large Operon & online via Zoom
The STRUCTURES Project Management Office is happy to answer questions.
Film Screening of “Arrival” with Scientific Introduction as part of the Ruperto Carola Lecture Series
In the context of this winter semester's Ruperto Carola Lecture Series “Vom Ende als Anfang” (in German), Heidelberg University will be screening the science fiction movie “Arrival” with a scientific introduction by STRUCTURES member Prof. Dr. Matthias Bartelmann, astrophysicist at the Institute of Theoretical Physics (ITP). Against the backdrop of the climate crisis, war, pandemics and a radically changing world order, speakers from different perspectives will address the highly topical question of the tension between end and beginning. To what extent do catastrophes and crises not only pose a threat, but can also be the beginning of radical metamorphoses and new world models? The movie “Arrival” by Canadian director Denis Villeneuve addresses the difficulty of communication in the context of spreading fears and paranoia fuelled by the arrival of an extraterrestrial civilization on Earth. The film screening will take place on November 28, 2022 at Karlstorkino, Marlene-Dietrich-Platz 3, and will start at 7.30 pm.
For more information, see the University press release (German only).