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arXiv 2023年

作者： Cao, Huan Morelli, Simon Rozema, Lee A. Zhang, Chao Tavakoli, Armin Walther, Philip Vienna1090 Austria Christian Doppler Laboratory for Photonic Quantum Computer Faculty of Physics University of Vienna Vienna1090 Austria BCAM - Basque Center for Applied Mathematics Mazarredo 14 Basque BilbaoE48009 Spain CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Physics Department Lund University Box 118 Lund22100 Sweden

Standard procedures for entanglement detection assume that experimenters can exactly implement specific quantum measurements. Here, we depart from such idealizations and investigate, in both theory and experiment, the detection of genuine multipartite entanglement when measurements are subject to small imperfections. For arbitrary qubits number n, we construct multipartite entanglement witnesses where the detrimental influence of the imperfection is independent of n. In a tabletop four-partite photonic experiment we demonstrate first how a small amount of alignment error can undermine the conclusions drawn from standard entanglement witnesses, and then perform the correction analysis. Furthermore, since we consider quantum devices that are trusted but not perfectly controlled, we showcase advantages in terms of noise resilience as compared to device-independent models. © 2023, CC BY.

关键词： Quantum entanglement

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Invitation to the Cosmic Ray Extremely Distributed Observatory 37

Invitation to the Cosmic Ray Extremely Distributed Observato...

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37th International Cosmic Ray Conference, ICRC 2021

作者： Homola, Piotr Alvarez Castillo, David E. Cheminant, Kevin Almeida Beznosko, Dmitriy Budnev, Nikolai Góra, Dariusz Gupta, Alok C. Hnatyk, Bohdan Kasztelan, Marcin Kovacs, Peter Lozowski, Bartosz Medvedev, Mikhail V. Miszczyk, Justyna Mozgova, Alona Nazari, Vahab Niedźwiecki, Michal Pawlik, Maciej Rosas, Matías Rzecki, Krzysztof Smelcerz, Katarzyna Smolek, Karel Stasielak, Jaroslaw Stuglik, Slawomir Sushchov, Oleksandr Svanidze, Manana Tursunov, Arman Vaquero, Jose M. Verbetsky, Yuri Wibig, Tadeusz Woźniak, Krzysztof Zamora-Saa, Jilberto Institute of Nuclear Physics Polish Academy of Sciences Radzikowskiego 152 Kraków31-342 Poland Joint Institute for Nuclear Research Dubna141980 Russia Clayton State University MorrowGA United States Irkutsk State University Russia Manora Peak Nainital263001 India Astronomical Observatory of Taras Shevchenko National University of Kyiv Kyiv04053 Ukraine National Centre for Nuclear Research Andrzeja Soltana 7Świerk Otwock05-400 Poland Institute for Particle and Nuclear Physics Wigner Research Centre for Physics 1121 Konkoly-ThegeMiklósút Budapest29-33 Hungary Faculty of Natural Sciences University of Silesia in Katowice Bankowa 9 Katowice40-007 Poland Department of Physics and Astronomy University of Kansas LawrenceKS66045 United States Laboratory for Nuclear Science Massachusetts Institute of Technology CambridgeMA02139 United States Department of Computer Science Faculty of Computer Science and Telecommunications Cracow University of Technology Warszawska 24 Kraków31-155 Poland ACC Cyfronet AGH-UST Kraków30-950 Poland AGH University of Science and Technology Mickiewicz Ave. Kraków30-059 Poland Liceo 6 Francisco Bauzá Montevideo Uruguay Institute of Experimental and Applied Physics Czech Technical University Prague Czech Republic E. Andronikashvili Institute of Physics Tbilisi State University Georgia Research Centre for Theoretical Physics and Astrophysics Institute of Physics Silesian University in Opava Bezručovo nám. 13 OpavaCZ-74601 Czech Republic Department of Physics University of Extremadura Mérida06800 Spain University of Lódź Faculty of Physics and Applied Informatics Pomorska 149/153 Lódź90-236 Poland Universidad Andres Bello Departamento de Ciencias Fisicas Facultad de Ciencias Exactas Avenida Republica 498 Santiago Chile

Cosmic Ray Ensembles (CRE) are very large, yet not observed particle cascades initiated above the Earth atmosphere. Such cascades could be formed both within classical models (e.g. products of photon-photon interactions) and exotic scenarios (e.g. result of decay of Super Heavy Dark Matter particles and subsequent interactions). Some of CRE might have a significant spatial extent which could serve as a unique signature detectable with the existing cosmic ray infrastructure taken as a network of detectors. This signature would be composed of a number of air showers with parallel axes. An obvious, although yet not probed, CRE „detection horizon" can be located somewhere between an air shower induced by an CRE composed of tightly collimated particles (preshower effect), and undetectable CRE composed of particles spread so widely that only one of them have a chance to reach Earth. Probing the CRE horizon with a global approach to the cosmic ray data, as proposed by the newly formed Cosmic Ray Extremely Distributed Observatory (CREDO), defines an extensive scientific program oriented on the search for physics manifestations at largest energies known, with potential impact on ultra-high energy astrophysics, the physics of fundamental particle interactions and cosmology. In this talk the current status and perspectives of CREDO will be summarized, with an open invitation for the colleagues interested in a global approach to cosmic ray studies, and in particular in observing and investigating multi-primary cosmic ray events such as CRE. © 2022 Sissa Medialab Srl. All rights reserved.

关键词： Cosmic rays

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Development of J-PEM for breast cancer detection and diagnosis using positronium imaging

Development of J-PEM for breast cancer detection and diagnos...

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作者： Shivani Luczyńska, Elżbieta Heinze, Sylwia Moskal, Pawel Faculty of Physics and Applied Computer Science Jagiellonian University Kraków Poland Faculty of Medicine University of Rzeszów Rzeszów Poland Department of Radiology Center of Oncology Kraków Branch Kraków Poland

The purpose of the presented investigations is to design, construct and establish the characteristic performance of the Jagiellonian Positron Emission Mammography (J-PEM), being designed for the detection and diagnosis of breast cancer. Its construction is based on a novel idea of PET tomography based on plastic scintillators and wavelength shifter (WLS), and a new concept of positronium imaging. We have prepared a simulation program based on Monte Carlo methods for optimizing the geometry and material of the J-PEM prototype. Here, we present the first results from the simulations and a brief review of the state of art of breast imaging modalities and their characteristics motivating our investigation. © 2020 Jagellonian University. All rights reserved.

关键词： Monte Carlo methods

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Nanoporosity imaging by positronium lifetime tomography

arXiv

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arXiv 2024年

作者： Dulski, K. Beyene, E. Chug, N. Curceanu, C. Czerwinski, E. Das, M. Gorgol, M. Jasinska, B. Kacprzak, K. Kaplon, L. Korcyl, G. Kozik, T. Kubat, K. Kumar, D. Lisowski, E. Lisowski, F. Medrala-Sowa, J. Niedzwiecki, S. Pandey, P. Parzych, S. del Rio, E. Perez Rädler, M. Sharma, S. Skurzok, M. Tayefi, K. Tanty, P. Stepien, E.L. Moskal, P. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University S. Lojasiewicza 11 Krakow30-348 Poland Centre for Theranostics Jagiellonian University Kopernika 40 Krakow31-501 Poland INFN Laboratori Nazionali di Frascati Via E. Fermi 40 Frascati00044 Italy Institute of Physics Maria Curie-Sklodowska University Radziszewskiego 10 Lublin20-031 Poland Cracow University of Technology Warszawska 24 Kraków31-864 Poland

Positron Annihilation Lifetime Spectroscopy (PALS) is a well-established non-destructive technique used for nanostructural characterization of porous materials. It is based on the annihilation of a positron and an electron. Mean positron lifetime in the material depends on the free voids size and molecular environment, allowing the study of porosity and structural transitions in the nanometer scale. We have developed a novel method enabling spatially resolved PALS, thus providing tomography of nanostructural characterization of an extended object. Correlating space (position) and structural (lifetime) information brings new insight in materials studies, especially in the characterization of the purity and pore distribution. For the first time, a porosity image using stationary positron sources for the simultaneous measurement of the porous polymers XAD4, silica aerogel powder IC3100, and polyvinyl toluene scintillator PVT by the J-PET tomograph is demonstrated. © 2024, CC BY.

关键词： Positron annihilation

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Correlation between magnetism and the Verwey transition in magnetite

arXiv

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arXiv 2025年

作者： Podgórska, Karolina Gala, Mateusz A. Komędera, Kamila Muniraju, N.K. Chogondahalli Nasrallah, Serena Kąkol, Zbigniew Sabol, Joseph Marin, Christophe Wlodek, Adam Kozlowski, Andrzej Lorenzo, J. Emilio Barišić, Neven Rybicki, Damian Tabiś, Wojciech AGH University of Krakow Faculty of Physics and Applied Computer Science Aleja Mickiewicza 30 Kraków30-059 Poland Institute of Solid State Physics TU Wien Vienna1040 Austria Mössbauer Spectroscopy Laboratory Institute of Technology University of the National Education Commission Podchorążych 2 Kraków30-084 Poland The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences ul. Radzikowskiego 152 Krakow31-342 Poland Department of Chemistry Purdue University West LafayetteIN United States Univ. Grenoble Alpes Grenoble INP CEA IRIG PHELIQS Grenoble38000 France AGH University of Krakow Faculty of Geology Geophysics and Environmental Protection Aleja Mickiewicza 30 Kraków30-059 Poland Institut Néel CNRS Univ. Grenoble Alpes Grenoble38042 France Department of Physics Faculty of Science University of Zagreb Bijenicka cesta 32 ZagrebHR-10000 Croatia

Seeking to unravel the enigmatic Verwey transition and its interplay with magnetism, we have conducted comprehensive measurements on the temperature-dependent electrical resistivity and magnetic moment of stoichiometric and doped-magnetite single crystals at temperatures reaching 1000 K. These investigations have allowed us to identify the Curie temperature, TC, and other characteristic temperatures of the electrical resistivity. Remarkably, we have identified correlations between these temperatures and the Verwey temperature, TV, indicating that the electrical transport properties and the mechanism of the Verwey transition are closely related to the magnetic properties. © 2025, CC BY.

关键词： Single crystals

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Ageing of complex networks

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Physical Review E 2020年第4期102卷 042302-042302页

作者： Zdzislaw Burda Michalina Kotwica Krzysztof Malarz AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

Many real-world complex networks arise as a result of a competition between growth and rewiring processes. Usually the initial part of the evolution is dominated by growth while the later one rather by rewiring. The initial growth allows the network to reach a certain size while rewiring to optimize its function and topology. As a model example we consider tree networks which first grow in a stochastic process of node attachment and then age in a stochastic process of local topology changes. The ageing is implemented as a Markov process that preserves the node-degree distribution. We quantify differences between the initial and aged network topologies and study the dynamics of the evolution. We implement two versions of the ageing dynamics. One is based on reshuffling of leaves and the other on reshuffling of branches. The latter one generates much faster ageing due to nonlocal nature of changes.

关键词： Degree distributions Network evolution Network formation & growth

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Electrostatic quantum dot confinement in phosphorene

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Physical Review B 2020年第23期101卷 235313-235313页

作者： Bartłomiej Szafran Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. Mickiewicza 30 30-059 Kraków Poland

We consider states localized by electrostatic potentials in phosphorene using an atomistic tight-binding approach. From the tight-binding spectra of states confined in a parabolic potential we extract effective masses for conduction band electrons moving along the armchair and zigzag crystal directions by a fit to the harmonic oscillator spectrum. The masses derived in this way are used for a simple single-band effective-mass model which, as we find, reproduces very well the tight-binding energy spectra in an external magnetic field, the confined probability densities, and the interaction effects. We study the confined states in the conduction band and find that both methods produce Wigner crystallization with separated single-electron islands already for small quantum dots. The effective-mass model works with slightly worse precision for confined states of the valence band. The continuum approach deviates considerably from the tight-binding model only in the limit of extremely strong lateral confinement.

关键词： Few-body systems Phosphorene Quantum dots Wigner crystal

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ESTIMATION OF 511 keV GAMMA SCATTER FRACTION IN WLS LAYER IN TOTAL-BODY J-PET;A SIMULATION STUDY

Acta Physica Polonica B, Proceedings Supplement

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Acta Physica Polonica B, Proceedings Supplement 2022年第4期15卷

作者： Ardebili, K. Tayefi Niedzwiecki, S. Moskal, P. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 30-348 Kraków Poland and Center for Theranostics Kopernika 40 31-034 Kraków Poland and Total-Body Jagiellonian-PET Laboratory Jagiellonian University Lojasiewicza 11 30-348 Kraków Poland

Positron emission tomography (PET) is essential in medical diagnostics and monitoring therapy. The J-PET Collaboration at Jagiellonian University is developing a new generation of Total-Body PET scanners based on plastic scintillators. One of the Total-Body J-PET designs comprises seven rings, each consisting of 24 modules. A single module is built of 2 layers, each comprises of 16 axially arranged plastic scintillator strips of 330 mm length, read out by silicon photomultiplier (SiPM) arrays from both ends, and an additional layer of 50 wavelength shifter (WLS) bars, placed perpendicular to plastic layers. This study estimates the scatter fraction of the Total-Body J-PET manufactured from plastic scintillator strips according to the NEMA NU 2-2018 standards by using the GATE software. The scatter phantom was simulated as a solid cylinder with a length of 700 mm and an outside diameter equal to 203 mm. At the same time, at a radial distance of 45 mm, we have a hole with a diameter of 6.4 mm where a linear source with total activity of 1 MBq is placed. For data processing, sinograms were generated, and the Single Slice Rebinning (SSRB) algorithm was used for the scatter fraction calculation. As a result, we estimate that addition of the WLS layer is increasing the scatter fraction by 0.67%. © 2022 Jagellonian University. All rights reserved.

关键词： Cylinders (shapes)

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Aharonov-Bohm oscillations of four-probe resistance in topological quantum rings in silicene and bilayer graphene

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Physical Review B 2020年第11期101卷 115308-115308页

作者： Bartłomiej Rzeszotarski Alina Mreńca-Kolasińska Bartłomiej Szafran AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

We consider observation of Aharonov-Bohm oscillations in clean systems based on the flow of topologically protected currents in silicene and bilayer graphene. The chiral channels in these materials are defined by the flips of the vertical electric field. The line of the flip confines chiral currents flowing along it in the direction determined by the valley. We present an electric field profile that forms a crossed ring to which four terminals can be attached, and find that the conductance matrix elements oscillate in the perpendicular magnetic field in spite of the absence of backscattering. We propose a four-probe resistance measurement setup, and demonstrate that the resistance oscillations have large visibility provided that the system is prepared in such a way that a direct transfer of the chiral carriers between the current probes is forbidden.

关键词： Aharonov-Bohm effect Electrical conductivity Graphene Silicene Landauer formula Tight-binding model

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Persistent currents in topological and trivial confinement in silicene

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Physical Review B 2020年第7期101卷 075408-075408页

作者： Piotr Jurkowski Bartłomiej Szafran AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

We consider states bound at the flip of the electric field in buckled silicene. Along the electric flip lines a topological confinement is formed with the orientation of the charge current and the resulting magnetic dipole moment determined by the valley index. We compare the topological confinement to the trivial one that is due to a local reduction of the vertical electric field but without energy gap inversion. For the latter the valley does not protect the orientation of the magnetic dipole moment from inversion by external magnetic field. We demonstrate that the topologically confined states can couple and form extended bonding or antibonding orbitals with the energy splitting influenced by the geometry and the external magnetic field.

关键词： Topological insulators 2-dimensional systems Quantum rings Silicene Topological materials Tight-binding model

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