Department of Mathematics and Computer Science

Speaker: Yuanhong Guo(Chinese Academy of Sciences)Abstract: ​In recent years, the bootstrap method has made significant progress in calculating physical quantities in quantum field theories. The main idea of the bootstrap method is to obtain the final result directly by appropriately assuming a general ansatz of the result and utilizing some known physical constraints. The bootstrap method also provides a way to comprehend the maximal transcendentality principle, which claims that the maximally transcendental parts of a class of physical quantities (such as the cusp anomalous dimensions and the loop corrections of the form factors, etc.) are the same in N=4 SYM and QCD. The uniqueness of the results can be understood by the universal physical constraints in different field theories. In this seminar talk, I will present the related progress of bootstrapping the two-loop four-point form factors in the gauge field theories based on the master integrals and demonstrate the maximal transcendentality principle for a series of form factors through the bootstrap strategy.

Bacterial viruses (bacteriophages) have a significant impact on marine prokaryotic mortality, diversity, and biogeochemical cycling. They do this by infecting and lysing cells, which release labile dissolved organic matter and stimulate the mineralization of inorganic nutrients. The sheer abundance of oceanic viruses results in ~1029 viral infections per day, causing the release of 108–109 tonnes of carbon per day from the biological pool, which are potentially available for recycling by prokaryotes. Through their actions of cell lysis, bacteriophages therefore play major roles on marine carbon and nutrient cycling. The efficient bacterial mortality caused by marine bacteriophages can also be exploited in disease control. In aquaculture, antibiotics are currently used to treat bacterial infections, despite serious concerns about the development of bacterial antibiotic resistance. Application of bacteriophages has been suggested as a strategy to control disease outbreaks in aquaculture, we aim at developing novel phage-based strategies for disease prophylaxis and treatment of outbreaks with fish pathogens in aquaculture.In this presentation, I will present our work on the role of bacteriophages in driving marine biogeochemical cycling and discuss the potential and challenges of using bacteriophages for disease control in aquaculture.  About Mathias MiddelboeMathias Middelboe is a professor in marine viral ecology at the Department of Biology, University of Copenhagen and University of Southern Denmark. He earned his PhD in aquatic microbial ecology from the University of Copenhagen in 1994 and established in 1997 a research group with a focus on the role of bacterial viruses (bacteriophages) in marine environments (water column and sediments). He is especially interested in exploring how interactions between bacteriophages and bacteria drive phage and host diversity and evolution, and in resolving the role of bacteriophages in marine biogeochemical cycling. His research also includes more applied aspects of phage–bacteria interactions, exploring the potential and challenges of using phages to control pathogenic bacteria in aquaculture.VenueThe DIAS Auditorium, SDU Campus OdenseThis event is open for all. No registration needed.

Speaker: Hjalte Axel Frellesvig(Zhejiang University)  Abstract: The mathematical field of intersection theory has provided an important new perspective on Feynman integrals and the relations between them. With this approach it is possible to derive such relations with a direct projection, providing a promising alternative to the slow standard approach based on IBPs.I will discuss various aspects of this mathematical framework, including newer developments based on relative cohomology which turns out to be a perfect fit for the mathematical structure of Feynman integrals. I will also discuss some brand new developments, that helps bring the day when the intersection-based approach can outcompete IBPs within sight.

Read more about the Department Council: https://sdunet.dk/en/enheder/institutter/imada/udvalg-og-moeder/institutraad

We live in anthropocene. Human activities dominate all aspects of biogeochemistry on the planet. Particular for nitrogen this is visible in our coastal waters, where we witness a collapse of the ecosystem. The reason for this is decades with elevated nutrient loadings in combination with overfishing and climate change. Today, the only significant human source of nutrients is our industrial production of animals. Every second, 1.3 pigs are born in Denmark, and we are among the most intensively farmed nations in the world with about 63 percent farmland. Currently, a ‘Green deal’ is under implementation, that will change our landscape significantly over the coming years. The aim is to reduce farmland by 15 percent, and most likely 20 to 25 percent. Nitrogen loadings will be reduced by 1/3 and over the next 100 years we can hope that our coastal ecosystems are restored.In the lecture, I will present the mechanisms for eutrophication and other press factors on the sea, the development since year 1900, and a forecast for the ‘Green deal’ and our landscape and coastal ecosystems. About Stiig Markager Stiig Markager is professor in marine ecology and biogeochemistry at Aarhus University, Institute for Ecoscience. He received his master degree from University of Copenhagen in 1987 and a Ph.D. from Aarhus University in 1992. His research topics are aquatic ecology in both freshwater and marine systems, and he has studied aquatic ecology from high Arctic lakes to the blue oceans, e.g. on the third Danish Galathea expedition in 2006/7. Focus has been on growth and ecophysiology of aquatic plants, bio-optics, dissolved organic matter and eutrophication. Stiig Markager pioneered the efforts of establishing relationships between nutrient loadings and the state of coastal marine ecosystems, which today is constitute the scientific basis for the Danish water actions plans. Over the years, public dissemination has become an important part of his job, and in 2024 Stiig Markager was the 7. most used expert in Danish medias. In 2021 he was victim of the first SLAPP case aimed at a scientist in Denmark when the farmers organization sued him with allegations of harming the reputation of Danish farmers, when claiming that they were the source of nitrogen pollution. Stiig Markager also has a voice in the debate for academic freedom and has received several prices for his struggle for a healthy marine environment.VenueThe DIAS Auditorium, SDU Campus OdenseThis event is open for all. No registration needed

All staff at IMADA are invited to the Departmental Fora.Meeting notice and agenda will be sent by email.

We end the academic year at IMADA with strawberry cake, wine, water, beer, snacks and lots of summer mood 😃!

Meeting notice with time and agenda will be sent by email.

Read more about the Teaching Committee: https://www.sdu.dk/da/om_sdu/institutter_centre/imada_matematik_og_datalogi/ledelse_administration/raad_naevn_udvalg/undervisningsudvalg

We are excited to hold the workshop on Quantum Phase of Strong Dynamics from August 26th to 28th, 2025, in Odense, Denmark.The meeting is organized by the Quantum Field Theory Center (QTC) at the Danish Institute for Advanced Studies, the University of Southern Denmark (SDU), Helsinki University and the Department of Physics “Ettore Pancini” of Federico II University.  The event will take place on QTC premises at the Danish Institute for Advanced Study, in Odense, Denmark.