Joint Seminar on Quantum Information and Technologies
2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2016/2017 | 2017/2018 | 2018/2019 | 2019/2020 | 2020/2021 | 2021/2022 | 2022/2023 | 2023/2024 | 2024/2025 | YouTube channel
until 2023/2024 Quantum Information Seminar | YouTube channel
2013-06-06 (Thursday)
Dardo Goyeneche (UdeC - Concepción, Chile)
An informationally complete set of measurements for pure states
In this work, we demonstrate that any quantum pure state can bereconstructed from, at most, five probability distributions in everyfinite dimension d. These probability distributions are obtained from 5drank-one projective measurements that can be sorted in 5 orthonormalbases. Our method is adaptative only for a null measure set of purestates. Consequently, our fixed set of five orthonormal bases isinformationaly complete in the sense of Flammia-Silberfarb-Caves (2005).We analyze the quality of the reconstruction when errors in theprobability distributions and noise in the pure state preparation areconsidered. We compare our method with the mutually unbiased basesreconstruction. We show that both methods have the same quality ofreconstruction in dimensions four, five, seven and eight when smallerrors are considered. Finally, we reconstruct a quantum state frommeasurements realized in the laboratory.
2013-05-23 (Thursday)
Jan Kołodyński (IFT UW)
Efficient tools for quantum metrology with decoherence
Quantum metrology under the idealistic assumption of no decoherenceoffers enhancement of measurement precision that grows withoutrestraint with the number of particles involved. Motivated bypractical applications, we propose tools for quantifying theattainable quantum enhancement based on the geometry of quantumchannels and semi-definite programming that account for the inevitableimpact of the noise. As a result we obtain a simple and direct methodyielding bounds that interpolate between the quantum enhanced scalingcharacteristic for small number of particles and the asymptoticregime, where quantum enhancement amounts to a constant factorimprovement.
2013-05-16 (Thursday)
Łukasz Rudnicki (Freiburg Institute for Advanced Studies)
Przyjazne kryteria splątania dla zmiennych ciągłych
Entanglement criteria for continuous variables
2013-05-09 (Thursday)
Mark Tame (Imperial College, London)
Quantum Plasmonics
2013-04-25 (Thursday)
Sammy Ragy (University of Nottingham)
The role of mutual information in quantum illumination
2013-04-18 (Thursday)
Bogna Bylicka (UMK, Toruń)
Procesy nie-markowowskie i kwantowa teoria informacji
Quantum information theory and non-Marcovian processes
2013-04-11 (Thursday)
Daniel McNulty (University of York)
Mutually unbiased bases in composite dimensions
2013-04-04 (Thursday)
Jan Chwedenczuk (IFT UW)
Optimal measurements with a single qubit
2013-03-21 (Thursday)
Radosław Chrapkiewicz (IFD UW)
Korelacje i dekoherencja w wielomodowej pamieci optycznej w parach rubidu
Correlations and decoherence in multimode optical memory in rubidium vapours
2013-03-14 (Thursday)
Vladislav Usenko (Palacky University, Olomouc)