Playing Games with Multiple Access Channels

Speaker: Felix Leditzky, IQC, University of Waterloo / Perimeter Institute Abstract Communication networks have multiple users, each sending and receiving messages. A multiple access channel (MAC) models multiple senders transmitting to a single receiver, such as the uplink from many mobile phones to a single base station. The optimal performance of a MAC is quantified by […]

Speaker: Felix Huber, ICFO (Castelldefels) Abstract The study of polynomials that are positive on certain sets has a rich history, going back to Hilbert's seventeenth problem. Here we will look at multivariate polynomials (and more generally, contractions) that have matrices as their variables. These are constructed such that they yield positive semi-definite expressions whenever they […]

Speaker: Katarzyna Roszak, Wroclaw University of Science and Technology Abstract The problem of detecting entanglement between a qubit and its environment is known to be complicated [1]. To simplify the issue, we study the class of Hamiltonians that describe the interacting system in such a way that the resulting evolution of the qubit alone is […]

Speaker: Marcin Karczewski ICTQT Abstract Two identical photons impinging on different arms of a balanced beam splitter always end up grouped together. In other words, the probability that they stay separate vanishes. Finding such forbidden outcomes is, in general, a demanding task when the number of particles and modes increases. The paper [Phys. Rev. Lett. […]

Speaker: Steven Bass, Jagiellonian University (Cracow) Abstract The cosmological constant in Einstein's equations of General Relativity is a prime candidate to describe the dark energy that drives the accelerating expansion of the Universe and which contributes 69% of its energy budget. The cosmological constant measures the energy density of the vacuum perceived by gravitation. Experimentally, it […]

Speaker: Antonio Mandarino ICTQT Abstract The aim of this journal club talk will be the discussion of a topic that is getting more attention in the quantum thermodynamics community. In fact, numerous efforts, both theoretically and experimentally, are devoted to design technologies able to control and to route the heat flow in qubit systems suitable […]

Speaker: Kamil Korzekwa, Jagiellonian University (Kraków) Abstract It is of foremost importance, both from the foundational and technological point of view, to understand what components of the quantum theory are responsible for quantum supremacy, i.e. the potential ability of quantum computers to solve problems that cannot be solved efficiently on classical machines. One of the most […]

Speaker:  Roberto Baldijão, University of Campinas, IQOQI (Vienna) Abstract Contextuality is regarded as a non-classical feature, challenging our everyday intuition; quantum contextuality is currently seen as a resource for many applications in quantum computation, being responsible for quantum advantage over classical analogs. In our work, we adapt the N-cycle scenarios with odd N to multiple independent observers […]

Speaker: Erik Aurell,  KTH Royal Institute of Technology (Stockholm), Jagiellonian University (Kraków)  Abstract Most of the entropy in the current universe is believed to be in the form of Bekenstein-Hawking (BH) entropy of super-massive black holes. This entropy is proportional to the area of the horizon in units of Planck area, or, alternatively, proportional to […]

Speaker: Erik Aurell,  KTH Royal Institute of Technology (Stockholm), Jagiellonian University (Kraków) Abstract I will discuss two extensions of the standard theory of open quantum systems. The first concerns the heat current flowing through a system between two baths, quantified by its generating function. As shown previously the corresponding system functional has the form of […]