Kumpula Physics Colloquium

Our next colloquium in the spring series is by Tuomas Lappi from the University of Jyväskylä on April 14th.

Tuomas Lappi obtained his PhD from the University of Helsinki in 2005. After postdocs at Brookhaven National Laboratory and CEA/Saclay he moved to the University of Jyväskylä in 2009. He obtained an ERC Consolidator grant in 2015. Since 2022 he is the director of the Academy of Finland Centre of Excellence in Quark Matter. His research revolves around the interactions of quarks and gluons in high energy collisions, such as relativistic heavy ion collisions aiming to produce deconfined quark matter in the laboratory.

 

The event was held on Friday 14.4.23 at 14:15, in Chemicum A129.
Link to video: https://unitube.it.helsinki.fi/unitube/embed.html?id=3352d6c6-f559-4413-97af-04b610c04939

The title of his talk is: The Electron-Ion Collider EIC – the most powerful microscope on Earth

His abstract reads:

This talk will discuss the physics program of the Electron-Ion Collider EIC. The EIC will be built at Brookhaven, combining the existing proton and ion beams of RHIC with a new electron accelerator, and should start taking data in the early 2030’s. The EIC will be the first collider energy deep inelastic scattering experiment with polarized protons, and the first to collide heavy ions. It will also have a luminosity that is orders of magnitude higher than previous comparable experiments at DESY. These features allow the EIC to access new aspects of gluonic degrees of freedom in ordinary matter, in particular gluons carrying a small fraction of the nucleus momentum. These gluons are also the relevant degrees of freedom for understanding the creation of the matter that subsequently turns into deconfined quark matter in a relativistic heavy ion collision. Thus the EIC physics program has many connections to the research on properties of the quark gluon plasma.

Our first Kumpula Physics Colloquium for the year 2023 will take place on Friday, March 24. We will have a presentation on the regulation of cell fate and integrity to be given by Sara Wickström who is the director of the Max Planck Institute for Molecular Biomedicine in Münster.

Sara’s lab aims to understand how mammalian epithelial tissues are generated and maintained, and in particular how mechanical forces and cellular interactions integrate single cell behaviors to pattern these structurally  extremely robust yet dynamic tissues. Sara Wickström received her MD in 2001 and PhD in 2004 from the University of Helsinki, Finland. After postdoctoral training at the Max Planck Institute (MPI) for Biochemistry she became Group Leader at the MPI for Biology of Ageing in 2010. In 2018 her laboratory moved to the University of Helsinki where she was professor of Cell and Developmental Biology. In 2022, Wickström was appointed as Director of the MPI for Molecular Biomedicine in Münster.

In her colloquium, titled Regulation of cell fate and integrity by nuclear mechanotransduction, Sara will discuss her recent research on how dynamic changes in chromatin organization in response to force change the mechanical properties of the nucleus and chromatin to prevent cell damage.

The event was held on Friday 24.03.23 at 14:15, in Physicum E204.
Link to video: https://unitube.it.helsinki.fi/unitube/embed.html?id=a8a84735-372e-496d-8f28-24e590f5d0f3

Here is her abstract:

The structure of tissues is tightly linked to their function. During formation of functional organs, large-scale changes in tissue elongation, stretching,  compression, folding/buckling, and budding impact the shape, position, packing, and contractility state of cells. Conversely, changes in single cell contractility, shape and position locally alter tissue organization and mechanics. Thus forces function as important ques that are transmitted to the nucleus to coordinate gene expression programs. On the other hand, excessive mechanical stresses have the potential to damage cells and tissues. In my presentation I will discuss our recent research on how dynamic changes in chromatin organization in response to force change the mechanical properties of the nucleus and chromatin to prevent damage, as well how cells integrate mechanical signals with biochemical inputs to alter their state.

Our next Physics Colloquium will take place on Friday, November 11th. We will have a presentation given by Visa Heinonen and Mika Pantzar, professors from the Faculty of Social Sciences (UH).

They will open the academic history of economics through the writings of two classics, John Maynard Keynes and John von Neumann. In the 1930s, Keynes questioned the policy doctrines underlying the equilibrium theory of economics, emphasized the importance of uncertainty and highlighted aggregate demand – consumption and investments – as a determinant of gross domestic product. Von Neumann, on the other hand, was a scientific all-rounder, whose early history focused on the discussion of the development of quantum mechanics and Heisenberg’s uncertainty principle. As a computer developer, von Neumann drew his ideas from brain physiology and especially from the modeling of neural networks. Economists know von Neumann as the father of game theory and mathematical economics, in specific equilibrium theory. However, practical economic policy draws only to a limited extent from economic theoretical thinking and, for example, national accounting systems affect the way we see today the dynamics of the economy. Visa Heinonen and Mika Pantzar have studied the Finnish economic policy debate using computer-assisted rhetorical analysis. According to them, for example, the prevailing understanding of the nature of the national economy’s productivity is based on biblical metaphors and gendered deep structures. 

In this colloquium, titled What you always wanted to know about economics but didn’t dare to ask?, Visa and Mika will introduce us to contemporary economics.

The event will be held on Friday 11.11.22 at 14:15, in Physicum E204.

Our first Physics Colloquium for the new academic year will take place on Friday, October 7th. We will have a presentation to be given by Aleksi Vuorinen, who recently became a Full Professor in our department.

Aleksi obtained his PhD in theoretical physics at the University of Helsinki in 2004. After postdocs at the University of Washington and CERN, he established his own group in Bielefeld, funded by the Sofja Kovalevskaja award. He then returned to Helsinki as an Academy Research Fellow in 2013, where he obtained an ERC Consolidator Grant in 2016. His research interests focus on quantum chromodynamics and other quantum field theories at nonzero temperature and density, with applications to the physics of neutron stars and the early Universe. In 2022, he received the Magnus Ehrnrooth Award for his work on the application of quantum chromodynamics to the properties of high-density quark matter.

In his colloquium, titled Neutron-star cores as a laboratory for particle physics, Aleksi will present recent results on the physics taking place in the heart of neutron stars.

The event was held on Friday 07.10.22 at 14:15, in Physicum E204.
Link to video: https://unitube.it.helsinki.fi/unitube/embed.html?id=b8a5ad64-6366-4ff3-871f-10aeb011e37d

Here is his abstract:

Neutron stars contain the densest matter found in our present-day Universe, with the density of their cores greatly exceeding that of individual nucleons. These conditions may in fact be extreme enough for the appearance of an entirely new phase of matter consisting of quarks and gluons liberated from their color confinement: quark matter. Whether this is indeed the case and massive neutron stars contain quark-matter cores is one of the major unsolved problems of modern nuclear astrophysics.

In my talk, I will describe recent efforts to combine ab-initio nuclear and particle theory calculations with neutron-star observations to constrain the properties of matter inside neutron-star cores. Our earlier results have already indicated that the centers of maximally massive neutron stars behave in a way expected of deconfined quark matter – a conclusion that has recently been strengthened by our new preliminary data. I will argue that with expected improvements from both particle theory calculations and astrophysical measurements, a robust discovery of quark-matter cores is only a matter of time.

Our next Kumpula Physics Colloquium will take place on Thursday (note the change of a day!), April 21st.

We will have a talk about the design of quantum materials given by Peter Liljeroth, who is a professor at the Department of Applied Physics at Aalto University, Finland, since 2011 and heads the Atomic Scale Physics group.

Peter’s group focuses on probing the atomic scale structure and electronic properties of molecular structures and 2D materials using low-temperature scanning probe microscopies. Peter was awarded an ERC Advanced Grant (”Artificial designer materials”) in 2018, and he currently holds a post of an Academy Professor (2019-2023).

Previous work experience
1999 – 2002 doctoral student, Helsinki University of Technology, Finland.
2003 – 2006 Post-doc, Utrecht University, the Netherlands.
2006 – 2007 Post-doc, IBM Zurich Research Laboratory, Switzerland.
2007 – 2010 VIDI-fellow, Utrecht University, the Netherlands.
2011 – Professor, Department of Applied Physics, Aalto University, Finland

Condensed matter physics has seen an explosion of activity in realizing exotic quantum states of matter in layered van der Waals (vdW) materials. The concept of designer quantum materials can be pushed even further by using 2D heterostructures where the desired physics arises through the engineered interactions between the different components.

In his colloquium, entitled Designer quantum materials with van der Waals heterostructures, Peter will illustrate the idea using his recent results on realizing topological superconductivity and artificial heavy fermion systems in vdW heterostructures. These examples highlight the versatility of vdW heterostructures in realizing quantum states that are difficult to find and control in naturally occurring materials.

The event will be held on Thursday 21.04.22 at 14:15 in Physicum E204. It will also be streamed on Zoom (Meeting ID: 63155048211 – Passcode:325079).