QWIN SASPRO 0055/01/01 (Marie Curie individual fellowship)

Title: Quantum walks and incompatibility
Duration: 07/04/2015 - 31/12/2018
Principal Investigator: Daniel Reitzner

Project Description: The project focuses on two seemingly different topics. First addressed topic are the scattering properties of quantum walks on different graph structures. Using such scatterings we aim to efficiently detect specific characteristics of graphs as well to be able to design such graphs where the detection of the characteristics is possible and leads to advantageous behavior compared to classical approaches. Second part of the topic is to address the decoherence in the quantum-walks algorithms and assess their efficiency under such conditions. Second addressed topic is incompatibility of quantum measurements as a characteristic effect not only in the quantum theory but also in the whole hierarchy of statistical theories. The aim is to use this knowledge to design testable boundaries based on incompatibility that would distinguish quantum theory from the other theories (not only from the classical). The fusion of the two topics in the future shall be the description of incompatibility of quantum measurements in scatterings of quantum walkers on graph structures with possible use for the distinguishing the quantum theory from other theories.

Researchers: Daniel Reitzner

Publications:

1. Teiko Heinosaari, Jukka Kiukas, Daniel Reitzner: Noise Robustness of the Incompatibility of Quantum Measurements, Phys. Rev. A 92, 022115 (2015) [arXiv:1501.04554]
2. T. Heinosaari, J. Kiukas, D. Reitzner, J. Schultz: Incompatibility breaking quantum channels, J. Phys. A 48, 435301 (2015) [arXiv:1504.05768 ]; JPhysA Highlights of 2015, IOP Insights
3. M. Sedlák, D. Reitzner, G. Chiribella, M. Ziman: Incompatible measurements on quantum causal networks, Phys. Rev. A 93, 052323 (2016) [arXiv:1511.00976]
4. C. Carmeli, T. Heinosaari, D. Reitzner, J. Schultz, A. Toigo: Quantum Incompatibility in Collective Measurements, Mathematics 4, 54 (2016) [arXiv:1605.07551]
5. D. Reitzner, M. Hillery, D. Koch: Finding paths with quantum walks or quantum walking through a maze, Phys. Rev. A 96, 032323 (2017) [arXiv:1707.01581]
6. T. Heinosaari, D. Reitzner, T. Rybár, M. Ziman: Incompatibility of unbiased qubit observables and Pauli channels, Phys. Rev. A 97, 022112 (2018) [arXiv:1710.00878]
7. D. Reitzner, M. Hillery: Grover search under localized dephasing, Phys. Rev. A 99, 012339 (2019) [arXiv:1712.06558]