Faculty of Physics University of Warsaw > Events > Seminars > J.Pniewski & L.Infeld Colloquium

J.Pniewski & L.Infeld Colloquium

2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024

Information about earlier events available here:

room 0.03, Pasteura 5 at 16:30

prof. Katarzyna Blinowska (University of Warsaw and Institute of Biocybernetics and Biomedical Engineering PAN)

Information transfer between brain structures in norm and pathology

The evaluation of interactions between brain structures plays a central rolein understanding normal and pathological brain function. At present, a largebulk of evidence concerning the localization of active areas in the brain isavailable due to neuroimaging methods. However, much less is known aboutinteractions between them. The connectivity patterns in the brain may bedetermined by means of electroencephalographic (EEG) activity analysis,providing that adequate signal processing methods are applied. The mostappropriate methods involve multivariate autoregressive measures and, amongthem, Directed Transfer Function (DTF). Based on the Granger causalityprinciple, this measure exposes directed relations between brain structuresas a function of frequency, is robust in respect to noise, mitigates volumeconduction, can identify reciprocal interactions, and is free from the commondrive effect. Contrary to popular bivariate methods (e.g., correlation orcoherence), which are biased by spurious connections, it yields sparse,clear-cut functional connectivity patterns. In its time-varying form, DTFreveals dynamical interactions between brain structures. The applicationof DTF to motor and cognitive tasks and to the assessment of pathologicalbrain states will be presented. Moreover, the suitability of DTF for theanalysis of signals of different origins will be shown.

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room 0.03, Pasteura 5 at 16:30

Rafał Grabiański (Urania - Postępy Astronomii)

Science in space; summary of major scientific research activities

Over 100 orbital rocket launches are carried out in the world every year. Most of them send commercial payloads to orbit. Some of these missions, however, have scientific objectives. This presentation will cover the latest science space missions and provide some details on the biggest projects currently being conducted: International Space Station research, preparations for the first in 50 years crewed Moon missions, and Mars exploration. We will also look into the nearest future and see what will be the biggest objectives for space exploration in the coming decades and how the Polish space sector fits into this.

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room 0.03, Pasteura 5 at 16:30

Prof. Michał Matuszewski (Instytut of Physics, Polish Academy of Science, Warsaw)

Efficient optical computing with exciton-polaritons

Recent years have witnessed remarkable developments in big data, artificial intelligence and neural networks. Machine learning has found wide applications in both research and the industry. This comes at the cost of high levels of energy consumption that are necessary to process large amounts of data. It is expected that over 20% of global electricity use by 2030 will be used for information processing. The performance of complementary metal-oxide semiconductors (CMOS) no longer follows Moore's law. In result, much research has been aimed at finding an alternative platform for information processing, characterized by high performance and energy efficiency. In this talk I will review recent progress in machine learning with photons. Photonic information processing benefits from high speed, parallelization, low communication losses, and high bandwidth. Fully functional photonic neurons, including spiking neurons, as well as neural networks, have been already realized in laboratories. Several networks achieved high performance in challenging machine learning tasks, such as image and video recognition.We recently demonstrated hardware neural network systems where strong optical nonlinearity results solely from interactions of exciton-polaritons, quantum superpositions of light and matter. Such superpositions, in the form of mixed quasiparticles of photons and excitons, are characterized by excellent photon-mediated transport properties and strong exciton-mediated interactions. These semiconductor microcavity systems can be used to construct fully all-optical neural networks characterized by extremely high energy efficiency. We show why using polaritonics in place of standard nonlinear optical phenomena, is the key to achieving such a performance.

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join us at 16:30

Chris Westbrook (Laboratoire Charles Fabry de l'Institut d'Optique, Palaiseau, France)

Quantum atom optics using pair correlation measurements

Since the demonstration of Bose-Einstein condensation almost 30 years ago, the study of interacting degenerate quantum gases in various configurations has occupied many researchers. The nature of pair correlations in such systems has played a central role and recent years have seen many experiments on this topic. In this talk, I will discuss the use of spatially and temporally resolved detectors to observe 2 particle and even multi particle correlations. The talk will cover the Hanbury Brown-Twiss effect, the Hong-Ou Mandel effect and the investigation of quantum depletion in a Bose-Einstein condensate.

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join us at 16:30

Dr. Chris Quigg (Fermilab, USA)

A Century of Noether's Theorem

In the summer of 1918, Emmy Noether published the theorem that now bears her name, establishing a profound two-way connection between symmetries and conservation laws. The influence of this insight is pervasive in physics; it underlies all of our theories of the fundamental interactions and gives meaning to conservation laws that elevates them beyond useful empirical rules. Noether’s papers, lectures, and personal interactions with students and colleagues drove the development of abstract algebra, establishing her in the pantheon of twentieth-century mathematicians. This essay traces her path from Erlangen through Göttingen to a brief but happy exile at Bryn Mawr College, illustrating the importance of "Noether's Theorem" for the way we think today.

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room 0.03, Pasteura 5 at 16:30

Prof. dr Anna Staśto (Penn State University, USA)

"Forever confined but asymptotically free"

The strong interaction is one of the four known forces in nature. It is responsible for the creation of nuclei and for binding quarks into nucleons. Two intriguing phenomena characterize the strong interaction which is confinement and asymptotic freedom. The complexity of strong interaction leads to the richness of the nucleon structure which can be best explored in the high energy electron - nucleon collisions. In this talk I will discuss what we know about the nucleon structure as well as the prospects of expanding our knowledge about strong interactions through the new accelerator facility, Electron Ion Collider (EIC) in the US.

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room 0.03, Pasteura 5 at 16:30

Marek Hołyński (Polskie Towarzystwo Informatyczne)

How physicists contributed to the development of computer science in Poland

Polish computer science is over 70 years old. Physicists contributed significantly to its creation and development. This lecture presents the history of early computing in Poland since its inception at the Warsaw University's Faculty of Physics, first computers and following the expansion of the Internet with particular emphasis on the role that representatives of physical sciences played in these activities.

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You can also join the colloquium using ZOOM:
https://us02web.zoom.us/j/93881687598?pwd=UmFhVUdVSXhnQ2tIVVozNmowSUNtZz09
Meeting ID: 938 8168 7598
Passcode: prv316
If you do not have ZOOM installed, after clicking the link the browser will show the page "Launch Meeting". Let the page open the zoom.us application, then click "cancel". You will see an option "Join from your browser", then show that "you are not a robot", type your name, and then you are connected!

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room 0.03, Pasteura 5 at 16:30

Prof. Jacek Piskozub z Instytutu Oceanologii PAN oraz Prof. Piotr Szymczak z Wydziału Fizyki UW

The 2021 Nobel Prize in Physics

The Nobel Prize in Physics 2021 was awarded "for groundbreaking contributions to our understanding of complex systems" with one half jointly to Syukuro Manabe and Klaus Hasselmann "for the physical modelling of Earth's climate, quantifying variability and reliably predicting global warming" and the other half to Giorgio Parisi "for the discovery of the interplay of disorder and fluctuations in physical systems from atomic to planetary scales."

The prize for Manabe and Hasselmann is the first ever given to physicists working not only in climate research but even broader in geoscience. Syukuro Manabe, in the 1960s, proposed models of the atmosphere which included all vertical energy fluxes, both convective and radiative. Klaus Haselmann has shown mathematically, in the 1970s, how the presence of slowly changing elements of the climate system (mostly oceans but also cryosphere biosphere) must lead to the observed dominance of low frequencies in the spectra of most climate-related time series (“rednoise”).

Research of Manatabe and Hasselman will be presented by prof. Jacek Piskozub from the Institute of Oceanology, Polish Academy of Sciences in Sopot, Poland.

Georgio Parisi is one of the most creative and influential theoretical physicists in recent decades. His work has a large impact on different areas of physics, spanning the realm of particle physics (Altarelli-Parisi equations), growth processes (Kardar-Parisi-Zhang equation), disordered systems (replica method for spin glasses, stochastic resonance in nonlinear systems), turbulence, immune system analysis or the dynamics of flocking birds. Common to most of these systems is that they are complex, where the whole is more than the sum of its parts. As Parisi himself says: "Most of the research that I have done is to get at this thing: how complex collective behavior may arise from elements that each have a simple behavior."

A short overview of the diverse work of Georgio Parisi will be given by prof. Piotr Szymczak from the Faculty of Physics, University of Warsaw.

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The first part of the colloquium will take place via ZOOM
https://us02web.zoom.us/j/93881687598?pwd=UmFhVUdVSXhnQ2tIVVozNmowSUNtZz09
Meeting ID: 938 8168 7598
Passcode: prv316.

If you do not have ZOOM installed, after clicking the link the browser will show the page "Launch Meeting". Let the page open the zoom.us application, then click "cancel". You will see an option "Join from your browser", then show that "you are not a robot", type your name, and then you are connected!

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Pobierz plakat / Download the poster
Pobierz nagranie / Download the recording