Qubits, completeness, and contextuality: A new approach to foundations of quantum information

Speaker: Jan-Åke Larsson (Linköping University) Abstract The usual explanation of the quantum computing speedup is parallel calculation, inserting a superposition of all possible input values into the computation. The picture painted is that the machine performs a calculation for every input, perhaps in multiple parallel worlds, and then combines the outcomes of each individual calculation […]

Speaker: Armin Tavakoli (Lund University) Abstract What is the dimension of a quantum ensemble? The standard answer is to count how many classical states are superposed, but that depends entirely on the reference frame of the observer. I discuss a different approach to the dimensionality of quantum systems which is independent of the frame in […]

Speaker: Thiago H. Moreira Abstract The intersection between quantum mechanics and gravitational physics has been providing challenging puzzles for quite some time. In this presentation I discuss the dynamics of an open quantum system coupled with a bath of gravitons, the quanta of the gravitational field in the linear limit of general relativity. The focus […]

Speaker: Prof. Jungjin Ju Abstract Photonics is a key enabler for quantum systems, providing both core quantum functionality and the means by which quantum effects can be achieved, expressed, combined and utilized. In this talk, long distance quantum communications and silicon based photonic quantum process research activities of ETRI will be presented with short video introduction […]

Speaker: Sergi Nadal-Gisbert Abstract Quantifying entanglement between two regions is particularly elusive in the context of quantum field theory (QFT), mainly because the Hilbert space of a QFT does not factor as a tensor product of Hilbert spaces associated with different regions of spacetime. In this talk, I will adapt tools from Gaussian quantum information […]

Speaker: Grzegorz Rajchel Abstract The ability to characterise and discern quantum channels is a crucial aspect of noisy quantum technologies. In this work, we explore the problem of distinguishing quantum channels when limited to sub-exponential resources, framed as von Neumann (projective) measurements. We completely characterise equivalence classes of quantum channels with different Kraus ranks that […]

Speaker: Dr. Damián Pitalúa-García Abstract Quantum money is the first invention in quantum information science, promising advantages over classical money by simultaneously achieving unforgeability, user privacy, and instant validation. However, standard quantum money relies on quantum memories and long-distance quantum communication, which are technologically extremely challenging. Quantum "S-money" tokens eliminate these technological requirements while preserving […]

Speaker: Michał Oszmaniec (University of Warsaw) Abstract In quantum theory general measurements are described by so-called Positive Operator-Valued Measures (POVMs). In this work we show that in d-dimensional quantum systems an application of depolarizing noise with constant (independent of d) visibility parameter makes any POVM simulable by a randomized implementation of projective measurements that do […]

Speaker: Julian Siegl Abstract The combined action of a DC bias and a microwave drive on the transport characteristic of a superconductor-quantum dot-superconductor junction is investigated. To cope with time dependent non-equilibrium effects and interactions in the quantum dot, we develop a general formalism for the dynamics of the density operator based on a particle […]

Speaker: Tony Apollaro (University of Malta) Abstract The transfer of quantum information between different locations is key to many quantum information processing tasks. Whereas, the transfer of a single qubit state has been extensively investigated, the transfer of a many-body system configuration has insofar remained elusive. We address the problem of transferring the state of […]