Warsaw Colloquium for Theoretical Physics – CFT PAN – Centrum Fizyki Teoretycznej Polskiej Akademii Nauk

Simulating quantum many-body systems with classical and quantum computers

cft — Wed, 06 Aug 2025 20:50:25 +0000

Understanding and applications of quantum Hall effects

cft — Wed, 06 Aug 2025 20:40:30 +0000

In the talk I will present the role played by charges and magnetic impurities in the topological physics of quantum Hall effects. I will also mention the application of quantum macroscopic phenomena in solids to high-precision metrology. Finally, I will address the speculative question of whether the redundancy of quantum effects and host materials can reveal new physics, so far sought in expensive high-energy colliders.

Experimental tests of Bell’s inequalities at Institut d’Optique (1980-82): past achievements and future directions.

dev — Fri, 27 Dec 2024 12:19:37 +0000

We will review the motivations and history of the experiments that lead to the Nobel Prize in Physics 2022, attributed to Alain Aspect, John Clauser and Anton Zeilinger. We will then discuss some future perspectives, both on the side of quantum technologies, and on the side of the more philosophical issues that motivated initially these experiments.

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This is an onsite event:Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

IM/DD OKD: Intensity modulation/direct detection optical key distribution

dev — Fri, 27 Dec 2024 12:19:37 +0000

Intensity modulation/direct detection optical key distribution (IM/DD OKD) is a technique to generate a cryptographic key over an optical communication link that is secure against passive eavesdropping. The key security is guaranteed by the shot noise inherent to the photodetection process and can be ensured even when the fraction of the signal captured by an eavesdropper is larger than that received by the legitimate recipient. This talk will review the physical principle of IM/DD OKD, present a proof-of-principle demonstration, and discuss estimates for attainable key rates in space-to-ground communication scenarios.

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This is a hybrid event:
Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)

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Neutrino oscillations – current experimental results

dev — Fri, 27 Dec 2024 12:19:37 +0000

The existence of neutrino oscillations was confirmed 25 years ago. Since that time, a lot of experiments have been performed with different sources of neutrinos and detection techniques.
Now, we know the values of the neutrino mixing angles with quite good precision, yet there are still questions to be answered, such as the neutrino mass ordering, CP-violation in the neutrino sector, or the existence of sterile neutrinos. The presentation is an extended and updated talk given at the EPS HEP 2023 conference and will summarize the current knowledge of neutrino oscillations and present recent results from selected experiments as well as some perspectives for the future.

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This is a hybrid event:
Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)

Time crystals

dev — Fri, 27 Dec 2024 12:19:37 +0000

Periodically driven systems allow us to create time crystalline structures that exhibit various condensed matter properties. Time crystals can also spontaneously form in periodically driven many-body systems. During the lecture, both of these methods of creating time crystals will be discussed, and the path to time-tronics, which involves building useful systems where crystalline structures in time play a crucial role, will be outlined.

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This is a hybrid event:
Room D, the Institute of Physics PAS, Al. Lotników 32/46

Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)

What is an acoustic decaphonic piano?

dev — Fri, 27 Dec 2024 12:19:37 +0000

The hero of this lecture, the decaphonic piano, is an acoustic concert hall instrument created on the demand of the world-famous jazz pianist Leszek Możdżer. The piano is decaphonic since it needs ten sounds only to play the entire octave, in contrast to the twelve sounds played in an octave by the usual piano. Musical tuning system of this piano is the ten–scale well temperament, as opposed to the 12-scale well temperament used by musicians in most of the Western music since the times of J. S. Bach.

The acoustic decaphonic piano was created by four people: Aleksander Bogucki, a physicist from the Institute of Experimental Physics of the University of Warsaw, Paweł Nurowski, a mathematician from the Center for Theoretical Physics of the Polish Academy of Sciences, Andrzej Włodarczyk, a constructor and a restorer of ancient pianos, and by Leszek Możdżer – the initiator of the project. As far as we know it is the first such musical piano instrument in the world.

In this lecture I, as one of the two scientific designers of the piano, will explain technical difficulties, scientific obstacles and esthetic prejudices, which we had to overcome to create an actual physical implementation of the instrument.

People without a musical education are most welcome to the lecture. All the relevant scientific information to understand the innovative nature of the instrument, and motivations for creating it, will be explained. In particular, I will explain the mathematics principles of various musical tuning systems used in the history of Western music, so that after the lecture everybody will know what is the Pythagorian tuning, just intonation, well temperament and how the tuning system of our instrument is related to these classical notions. I will try to argue that mathematics prefers the tuning system employed in the decaphonic piano. The sounds of these various tuning systems will be presented and compared with each other during the lecture.

A physical implementation of the decaphonic piano, and the actual music played by the instrument, was presented on the concert of Leszek Możdżer during the World Premiere of the Acoustic Decaphonic Piano, which took place at the Concert Hall Nowa Miodowa in Warsaw, Poland, on 13th of July 2023. The concert was an accompanying event of the mathematics conference 'GRIEG meets Chopin’, which gathered together about 100 mathematicians and theoretical physicists from the World.

The entire Decaphonic Piano Project was financed from the grant SCREAM (Symmetry, Curvature Reductions, EquivAlence Methods), sponsored by the Polish National Science Center via the Norwegian Financial Mechanism 2014-2021 of the European Union.

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This is an onsite event:Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

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Photon: A Very Peculiar Elementary Particle

dev — Fri, 27 Dec 2024 12:19:37 +0000

In my talk I will show that photons have properties which set them apart from all other elementary particles. These properties are quite intriguing but they are never mentioned in textbooks on quantum electrodynamics.

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This is a hybrid event:
Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)

Attoscience, Nobel 2023 and Quantum Simulators

dev — Fri, 27 Dec 2024 12:19:37 +0000

I will start my talk with an introduction to „super-intense laser-matter physics”. I will then focus on the phenomenon of High Harmonics Generation (HHG) and its physical nature. I will explain how this phenomenon may lead to generations of attosecond pulse trains or isolated attosecond pulses in XUV range. In the second part, I will focus on recent developments in the field that allow to study QED aspects of attophysics. The third part will be devoted to the discussion of quantum simulators of atto-physics with ultracold atoms. I will end with my personal story of Nobel 2023.

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This is an onsite event:
Auditorium of the Institute of Physics PAS, Al. Lotników 32/46

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Beyond quantum Markovian semigroups

dev — Fri, 27 Dec 2024 12:19:37 +0000

In most realistic situations a quantum system is never perfectly isolated and has to be considered as an open quantum system: it is coupled to an environment that induces decoherence and dissipation. These phenomena can not be described within the standard Schroedinger unitary evolution. In my talk I provide a basic introduction to Markovian semigroups stressing the very concept of complete positivity which plays a key role in modern quantum information theory being a mathematical representation of a quantum channel. However, quantum systems cannot always be described within a Markovian semigroup, which requires a large separation of system and environment time scales. I discuss basic concepts of non-Markovian evolution which are illustrated with simple physical models. Finally, I discuss a natural connection to quantum stochastic processes and the property of Markovianity and classicality.

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This is a hybrid event:

Room D, the Institute of Physics PAS, Al. Lotników 32/46

Online: Zoom Link, (Passcode: 134595, Meeting ID: 823 8038 0442)