Arithmetic loophole in Bell’s theorem: An overlooked threat for entangled-state quantum cryptography

Speaker: Marek Czachor (Gdańsk University of Technology) Abstract Bell's theorem is supposed to exclude all local hidden-variable models of quantum correlations. However, an explicit counterexample shows that a new class of local realistic models, based on generalized arithmetic and calculus, can exactly reconstruct rotationally symmetric quantum probabilities typical of two-electron singlet states. Observable probabilities are […]

Speaker: Roberto D. Baldijão (State University of Campinas, IQOQI Vienna) Abstract Quantum Darwinism posits that the emergence of a classical reality relies on the spreading of classical information from a quantum system to many parts of its environment. But what are the essential physical principles of quantum theory that make this mechanism possible? We address this […]

Speaker: Marius Krumm (IQOQI Vienna and University of Vienna Abstract Nonlocality, as demonstrated by the violation of Bell inequalities, enables device-independent cryptographic tasks that do not require users to trust their apparatus. In this presentation, we consider devices whose inputs are spatiotemporal degrees of freedom, e.g. orientations or time durations. Without assuming the validity of […]

Speaker: Otavio A. D. Molitor, ICTQT Abstract With the study of ever decreasing systems, it's paramount to understand thermodynamic phenomena in ultra-small scales, where quantum phenomena live. This gave origin to the flourishing research field known as quantum thermodynamics. One of its main branches, which deals with quantum systems undergoing thermodynamic cycles, is called quantum […]

Speaker: Labeled graph framework for unique games Abstract We present a framework in which unique games are represented in the form of edge-labelings of graphs. We define an equivalence relation which preserves both classical and quantum values of games. We also show how the classical value of the game depends on the properties of the […]

Speaker: Marco Erba, Università degli Studi di Pavia, INFN   Abstract A standardly adopted notion of classicality is the following: a system is deemed classical if its set of states is a simplex. Also, it is traditionally excluded that a classical theory may admit of entangled states. This is of course the case for classical theory (CT). […]

Speaker: prof. Marek Żukowski, Director of ICTQT Abstract Because of the approaching deadline of 15/12/2020 for many NCN grant applications, the Director, himself a member of NCN and a co-author in many of its projects, will share his expertise in writing them.

Speaker: prof. Marek Żukowski, Director of ICTQT Abstract Because of the approaching deadline of 15/12/2020 for many NCN grant applications, the Director, himself a member of NCN and a co-author in many of its projects, will share his expertise in writing them.

Speaker: Anubhav Chaturvedi, ICTQT Abstract What makes quantum theory stand out against general stochastic classical theories? Such a question necessitates a precise evaluation of the assumptions that go into the definition of classicality. To be of foundational, as well as technological significance, these assumptions must be operationally falsifiable. In this seminar, we shall derive operational properties, […]

Speaker: Alejandro Jenkins, ICTQT Abstract We describe the dynamics of a quantum field coupled to a moving heat bath, in the formalism of the Markovian master equation for the field considered as an open system. We apply this to the superradiance of a rotating black hole, which provides a useful paradigm for understanding other irreversible active […]