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arXiv 2021年

作者： Bok, Jan Fiala, Jiří Hliněný, Petr Jedličková, Nikola Kratochvíl, Jan Computer Science Institute Faculty of Mathematics and Physics Charles University Prague Czech Republic Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Prague Czech Republic Faculty of Informatics Masaryk University Brno Czech Republic

We initiate the study of computational complexity of graph coverings, aka locally bijective graph homomorphisms, for graphs with semi-edges. The notion of graph covering is a discretization of coverings between surfaces or topological spaces, a notion well known and deeply studied in classical topology. Graph covers have found applications in discrete mathematics for constructing highly symmetric graphs, and in computer science in the theory of local computations. In 1991, Abello et al. asked for a classification of the computational complexity of deciding if an input graph covers a fixed target graph, in the ordinary setting (of graphs with only edges). Although many general results are known, the full classification is still open. In spite of that, we propose to study the more general case of covering graphs composed of normal edges (including multiedges and loops) and so-called semi-edges. Semi-edges are becoming increasingly popular in modern topological graph theory, as well as in mathematical physics. They also naturally occur in the local computation setting, since they are lifted to matchings in the covering graph. We show that the presence of semi-edges makes the covering problem considerably harder;e.g., it is no longer sufficient to specify the vertex mapping induced by the covering, but one necessarily has to deal with the edge mapping as well. We show some solvable cases, and completely characterize the complexity of the already very nontrivial problem of covering one- and two-vertex (multi)graphs with semi-edges. Our NP-hardness results are proven for simple input graphs, and in the case of regular two-vertex target graphs, even for bipartite ones. This provides a strengthening of previously known results for covering graphs without semi-edges, and may contribute to better understanding of this notion and its complexity. Copyright © 2021, The Authors. All rights reserved.

关键词： Computational complexity

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Quantum Optics Applications of Hexagonal Boron Nitride Defects

arXiv

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arXiv 2024年

作者： Çakan, Aslı Cholsuk, Chanaprom Gale, Angus Kianinia, Mehran Paçal, Serkan Ateş, Serkan Aharonovich, Igor Toth, Milos Vogl, Tobias Department of Computer Engineering TUM School of Computation Information and Technology Technical University of Munich Munich80333 Germany Munich80799 Germany Abbe Center of Photonics Institute of Applied Physics Friedrich Schiller University Jena Jena07745 Germany School of Mathematical and Physical Sciences Faculty of Science University of Technology Sydney UltimoNSW2007 Australia University of Technology Sydney UltimoNSW2007 Australia Department of Physics Izmir Institute of Technology Izmir35430 Turkey

Hexagonal boron nitride (hBN) has emerged as a compelling platform for both classical and quantum technologies. In particular, the past decade has witnessed a surge of novel ideas and developments, which may be overwhelming for newcomers to the field. This review provides an overview of the fundamental concepts and key applications of hBN, including quantum sensing, quantum key distribution, quantum computing, and quantum memory. Additionally, we highlight critical experimental and theoretical advances that have expanded the capabilities of hBN, in a cohesive and accessible manner. The objective is to equip readers with a comprehensive understanding of the diverse applications of hBN, and provide insights into ongoing research efforts. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum computers

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Efficient transmutation of long-lived fission products in a Gamma Factory beam driven advanced nuclear energy system

arXiv

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arXiv 2024年

作者： Hu, Baolong Krasny, Mieczyslaw Witold Placzek, Wieslaw Yuan, Yun Shi, Xiaoming Luo, Kaijun Luo, Wen School of Nuclear Science and Technology University of South China Hengyang421001 China Key Laboratory of Advanced Nuclear Energy Design and Safety Ministry of Education Hengyang421001 China LPNHE University Paris Sorbonne Paris75005 France CERN Geneva1211 Switzerland Faculty of Physics Astronomy and Applied Computer Science Mark Kac Center for Complex Systems Research Jagiellonian University ul. Lojasiewicza 11 Krakow30–348 Poland

The Gamma Factory (GF) project aims to generate high-intensity γ-ray beams of tunable energy and relatively small energy spread. Such beams can be optimized to generate an intense photo-neutron source, capable of driving an advanced nuclear energy system (ANES) for nuclear waste transmutation and supplying electrical power that is necessary for the GF operation mode of the Large Hadron Collider storage ring. In this study, we investigate the feasibility of driving ANES with the GF beam which is optimized to maximize the neutron production rate. The dependence of the ANES thermal power on the distance between the positions of the ANES and the GF γ-ray source is evaluated. For the γ-ray beam reaching the intensity of ∼1019 photons per second, the ANES thermal power could exceed 500 MWt. Under the assumption that ANES operates over 20 years, the transmutation rate could reach 30% for five typical long-lived fission products (LLFPs): 79Se, 99Tc, 107Pd, 129I, 137Cs. Our comparative studies show that although the neutron production efficiency of the GF γray beam (per MW of the beam power) is approximately 14 times lower than that of the 500 MeV proton beam, the overall net ANES power production efficiency for the GF beam driver scheme could be comparable to that of the proton beam driver scheme, while providing additional transmutation capacity, not available for the proton beam driven scheme. It is suggested that the GF-based ANES could provide a viable solution for the efficient transmutation of LLFPs without isotopic separation. Copyright © 2024, The Authors. All rights reserved.

关键词： Storage rings

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Towards the first kaonic deuterium measurement with the SIDDHARTA-2 experiment 22

Towards the first kaonic deuterium measurement with the SIDD...

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Corfu Summer Institute "22nd Hellenic School and Workshops on Elementary Particle physics and Gravity", CORFU 2022

作者： Curceanu, C. De Paolis, L. Bazzi, M. Bosnar, D. Bragadireanu, M. Cargnelli, M. Carminati, M. Clozza, A. Deda, G. Grande, R. Del Dulski, K. Fiorini, C. Friščić, I. Guaraldo, C. Iliescu, M. Iwasaki, M. Khreptak, A. Sandri, P. Levi Manti, S. Marton, J. Miliucci, M. Moskal, P. Napolitano, F. Niedźwiecki, S. Onishi, H. Piscicchia, K. Sada, Y. Scordo, A. Sgaramella, F. Silarski, M. Sirghi, D.L. Sirghi, F. Skurzok, M. Spallone, A. Toho, K. Tüchler, M. Yoshida, C. Zmeskal, J. FrascatiI-00044 Italy Department of Physics Faculty of Science University of Zagreb Zagreb10000 Croatia Horia Hulubei National Institute of Physics and Nuclear Engineering Str. Atomistilor No. 407 P.O. Box MG-6-Măgurele Bucharest Romania Stefan Meyer Institute for Subatomic Physics Kegelgasse 27 Wien1030 Austria Politecnico di Milano Dipartimento di Elettronica Informazione e Bioingegneria INFN Sezione di Milano MilanoI-20133 Italy Department E62 Technische Universiät München James-Franck-straße 1 Garching85748 Germany Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Krakow30-348 Poland Center for Theranostics Jagiellonian University Kopernika 40 Krakow31-501 Poland RIKEN Institute of Physical and Chemical Research Tokyo Wako351-0198 Japan Tohoku University Sendai Japan Centro Ricerche Enrico Fermi—Museo Storico della Fisica e Centro Studi e Ricerche "Enrico Fermi" Via Panisperna 89a RomaI-00184 Italy University of Vienna Vienna Doctoral School in Physics Vienna Austria

The SIDDHARTA-2 experiment is presently installed at the interaction point of the DAΦNE electron-positron collider of the National Laboratories of Frascati (LNF-INFN), in Italy, ready to perform the first measurement of the 2p → 1s x-ray transition in kaonic deuterium. This measurement, together with that of the kaonic hydrogen 2p → 1s x-ray transition, performed by the SIDDHARTA experiment in 2009, will allow the determination of antikaon-nucleon isospin-dependent scattering lengths. This paper presents a description of the SIDDHARTA-2 setup, which is getting ready for the kaonic deuterium measurement. © 2023 Sissa Medialab Srl. All rights reserved.

关键词： Deuterium

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Bouncing Cosmology in VCDM

arXiv

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arXiv 2022年

作者： Ganz, Alexander Martens, Paul Mukohyama, Shinji Namba, Ryo Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Krakow30-348 Poland Kyoto University Kyoto606-8502 Japan The University of Tokyo Chiba Kashiwa277-8583 Japan Saitama Wako351-0198 Japan

We construct an asymmetric bouncing scenario within the VCDM model —also known as type-II minimally modified gravity—, a modified gravity theory with two local physical degrees of freedom. The scenario is exempt of any ghost or gradient instability, ad-hoc matching conditions or anisotropic stress issue (BKL instability). It moreover succeeds in generating the cosmological perturbations compatible with the observations. The scalar spectral index can be adapted by the choice of the equation of state of the matter sector and the form of the VCDM potential leading to an almost scale-invariant power spectrum. Satisfying the CMB bounds on the tensor-to-scalar ratio leads to a blue tensor spectrum. Copyright © 2022, The Authors. All rights reserved.

关键词： Tensors

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Biased dynamics of the miscible-immiscible quantum phase transition in a binary Bose-Einstein condensate

arXiv

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arXiv 2023年

作者： Bayocboc, Francis A. Dziarmaga, Jacek Zurek, Wojciech H. Jagiellonian University Faculty of Physics Astronomy and Applied Computer Science Institute of Theoretical Physics ul. Lojasiewicza 11 Kraków30-348 Poland Jagiellonian University Mark Kac Center for Complex Systems Research ul. Lojasiewicza 11 Kraków30-348 Poland Theory Division Los Alamos National Laboratory Los AlamosNM87545 United States

A quantum phase transition from the miscible to the immiscible phase of a quasi-one-dimensional binary Bose-Einstein condensate is driven by ramping down the coupling amplitude of its two hyperfine states. It results in a random pattern of spatial domains where the symmetry is broken separated by defects. In distinction to previous studies [J. Sabbatini et al., Phys. Rev. Lett. 107, 230402 (2011), New J. Phys. 14 095030 (2012)], we include nonzero detuning between the light field and the energy difference of the states, which provides a bias towards one of the states. Using the truncated Wigner method, we test the biased version of the quantum Kibble-Zurek mechanism [M. Rams et al., Phys. Rev. Lett. 123, 130603 (2019)] and observe a crossover to the adiabatic regime when the quench is sufficiently fast to dominate the effect of the bias. We verify a universal power law for the population imbalance in the nonadiabatic regime both at the critical point and by the end of the ramp. Shrinking and annihilation of domains of the unfavourable phase after the ramp, that is, already in the broken symmetry phase, enlarges the defect-free sections by the end of the ramp. The consequences of this phase-ordering effect can be captured by a phenomenological power law. © 2023, CC BY.

关键词： Annihilation

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When invariable cross sections change: The Electron-Ion Collider case

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Physical Review D 2021年第5期103卷 L051901-L051901页

作者： Krzysztof Piotrzkowski Mariusz Przybycien Centre for Cosmology Particle Physics and Phenomenology Université catholique de Louvain 1348 Louvain-la-Neuve Belgium AGH University of Science and Technology Faculty of Physics and Applied Computer Science Aleje Mickiewicza 30 30-059 Kraków Poland

In everyday research, it is tacitly assumed that scattering cross sections have fixed values for a given particle species, center-of-mass energy, and particle polarization. However, this assumption has been called into question after several observations of suppression of high-energy bremsstrahlung. This process will play a major role in experiments at the future Electron-Ion Collider, and we show how variations of the bremsstrahlung cross section can be profoundly studied there using the lateral beam displacements. In particular, we predict a very strong increase of the observed cross sections for large beam separations. We also discuss the relation of these elusive effects to other quantum phenomena occurring over macroscopic distances. In this context, spectacular and possibly useful properties of the coherent bremsstrahlung at the Electron-Ion Collider are also evaluated.

关键词： Beam diagnostics Particle interactions Quantum electrodynamics

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Antiferromagnetic domains distribution carried by stoichiometry

Antiferromagnetic domains distribution carried by stoichiome...

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Magnetic Conference - Short Papers (INTERMAG Short Papers), IEEE International

作者： Anna Mandziak Juan De La Figuera Jose Emilio Prieto Adrian Quesada Cecilia Granados Miralles Alba Berja Lucia Aballe Michael Foerster Miguel Angel Nino Pawel Nita Solaris Synchrotron Cracow Poland Instituto de Química Física Rocasolano (CSIC) Madrid Spain Instituto de Cerámica y Vidrio (CSIC) Madrid Spain Alba Synchrotron Light Facility CELLS Barcelona Spain Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Cracow Poland

We present a spatially resolved X-ray magnetic linear dichroism study of high quality micron-sized mixed nickel-cobalt oxide (NCO) crystals. Ni x Co 1−x O were prepared in-situ by high-temperature oxygen-assisted molecular beam epitaxy on Ru(0001) single crystal. To check the effect of incorporating Ni in the cobalt oxide films, three different composition were prepared. The element specific XMLD measurements reveal strong antiferromagnetic contrast at room temperature and magnetic domains up to one micron wide, reflecting the high structural quality of the islands. By means of vectorial magnetometry, the spin axis orientation of the domains was determined with nanometer spatial resolution, and found to depend on the stoichiometry of prepared crystals.

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Wakefields in superconducting rf cavities and the impact on vacuum ultraviolet free-electron laser oscillator performance

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Physical Review Accelerators and Beams 2023年第10期26卷 100701-100701页

作者： Alex H. Lumpkin Henry P. Freund Matthias Reinsch Peter J. M. van der Slot Fermi National Accelerator Laboratory Batavia Illinois 60510 USA Department of Electrical and Computer Engineering University of New Mexico Albuquerque New Mexico 87131 USA Institute for Research in Electronics & Applied Physics University of Maryland College Park Maryland 20742 USA Lawrence Berkeley National Laboratory Berkeley California 94720 USA Faculty of Science and Technology University of Twente Enschede Netherlands

The Fermilab Accelerator science and Technology facility is currently in operation with its linac based on TESLA-type superconducting rf cavities. Using a 3-MHz micropulse repetition rate with a long macropulse composed of up to 3000 micropulses, and with beam energies demonstrated at 300 MeV and projected to reach 800 MeV with two additional cryomodules, the feasibilities for a vacuum ultraviolet (VUV) and an extreme ultraviolet (EUV) free-electron laser oscillator (FELO) with the two energies are evaluated. We have used both the ginger code with an oscillator module and the minerva/opc code to assess FELO saturation prospects at 120 nm with a 5.0-cm-period undulator of 4.5-m length and the minerva/opc code to assess the FELO at 13.4 nm with adjusted parameters. The simulation results support saturation at both of these wavelengths which are much shorter than the demonstrated shortest wavelength record of 168.6 nm from a storage-ring-based FELO. This indicates superconducting rf linac-driven FELOs can be extended into this VUV-EUV wavelength regime previously only reached with single-pass FEL configurations. In addition, emittance-dilution effects due to wakefields in the cavities and the resulting submacropulse centroid slew effects on FELO performance are addressed using minerva/opc simulations for the first time.

关键词： Laser wakefield acceleration

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Electronic Structure Calculations using Quantum Computing

arXiv

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arXiv 2023年

作者： Innan, Nouhaila Khan, Muhammad Al-Zafar Bennai, Mohamed Quantum Physics and Magnetism Team LPMC Faculty of Sciences Ben M'sick Hassan II University of Casablanca Morocco Quantum Formalism Zaiku Group Ltd Liverpool United Kingdom School of Computer Science and Applied Mathematics University of the Witwatersrand 1 Jan Smuts Ave Braamfontein Gauteng Johannesburg2000 South Africa

The computation of electronic structure properties at the quantum level is a crucial aspect of modern physics research. However, conventional methods can be computationally demanding for larger, more complex systems. To address this issue, we present a hybrid Classical-Quantum computational procedure that uses the Variational Quantum Eigensolver (VQE) algorithm. By mapping the quantum system to a set of qubits and utilising a quantum circuit to prepare the ground state wavefunction, our algorithm offers a streamlined process requiring fewer computational resources than classical methods. Our algorithm demonstrated similar accuracy in rigorous comparisons with conventional electronic structure methods, such as Density Functional Theory and Hartree-Fock Theory, on a range of molecules while utilising significantly fewer resources. These results indicate the potential of the algorithm to expedite the development of new materials and technologies. This work paves the way for overcoming the computational challenges of electronic structure calculations. It demonstrates the transformative impact of quantum computing on advancing our understanding of complex quantum systems. © 2023, CC BY.

关键词： Electronic structure

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