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Charge density wave, enhanced mobility, and large nonsaturating magnetoresistance across the magnetic states of HoNiC2 and ErNiC2

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Physical Review B 2024年第7期109卷 075154-075154页

作者： Kamil K. Kolincio Marta Roman Fabian Garmroudi Michael Parzer Ernst Bauer Herwig Michor Faculty of Applied Physics and Mathematics Gdansk University of Technology Narutowicza 11/12 80-233 Gdansk Poland Institute of Solid State Physics TU Wien Wiedner Hauptstrasse 8–10 A-1040 Wien Austria Institute of Physics and Applied Computer Science Faculty of Applied Physics and Mathematics and Advanced Materials Center Gdansk University of Technology Narutowicza 11/12 80-233 Gdansk Poland

We report on magnetotransport and thermoelectric properties of two ternary carbides HoNiC2 and ErNiC2 hosting both charge density wave and long-range magnetic order. In the charge density wave state, both compounds show relatively large magnetoresistance MR ≈ 150% in HoNiC2 and ≈70% in ErNiC2 at a magnetic field of 9 T and temperature as low as 2 K. This positive field-linear magnetoresistance shows no signatures of saturation. Our combined analysis of diagonal and off-diagonal transport responses reveals electronic mobility values on the order of 103cm2V−1s−1 at 2 K. Both the elevated mobility and related enhanced magnetoresistance persist in the zero-field antiferromagnetic ground state and survive the field-induced crossovers through metamagnetic to field-aligned ferromagnetic states. The robustness of the high-mobility Fermi surface pockets across the magnetically ordered states suggests that the charge density wave is not suppressed but coexists with long-range magnetism in the entire dome of the magnetically ordered states.

关键词： Antiferromagnetism Charge density waves Ferromagnetism Hall effect Magnetism Magnetoresistance Magnetotransport Metamagnetism Nesting Peierls transition Thermopower Antiferromagnets Ferromagnets Metals Polycrystalline materials Strongly correlated systems Hall bar Resistivity measurements Transport techniques

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A new class of distances on complex projective spaces

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Linear Algebra and Its Applications 2025年 721卷 577-611页

作者： Bistroń, Rafal Eckstein, Michal Friedland, Shmuel Miller, Tomasz Życzkowski, Karol Institute of Theoretical Physics Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University ul. prof. Stanislawa Lojasiewicza 11 Krakow30-348 Poland Doctoral School of Exact and Natural Sciences Jagiellonian University ul. prof. Stanislawa Lojasiewicza 11 Krakow30-348 Poland Department of Mathematics Statistics and Computer Science University of Illinois at Chicago 851 S. Morgan Street ChicagoIL60607-7045 United States Copernicus Center for Interdisciplinary Studies Jagiellonian University ul. Mikolaja Kopernika 27 Krakow31-501 Poland Center for Theoretical Physics Polish Academy of Science aleja Lotników 32/46 Warsaw02-668 Poland

The complex projective space P(Cn) can be interpreted as the space of all quantum pure states of size n. A distance on this space, interesting from the perspective of quantum physics, can be induced from a classical distance defined on the n-point probability simplex by the ‘earth mover problem’. We show that this construction leads to a quantity satisfying the triangle inequality, which yields a true distance on complex projective space belonging to the family of quantum 2-Wasserstein distances. © 2024 Elsevier Inc.

关键词： State space methods

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Splitting of proton-antiproton directed flow in relativistic heavy-ion collisions

arXiv

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arXiv 2022年

作者： Bozek, Piotr AGH University of Science and Technology Faculty of Physics and Applied Computer Science aleja Mickiewicza 30 Krakow30-059 Poland

The rapidity dependent directed flow of particles produced in a relativistic heavy ion collision can be generated in the hydrodynamic expansion of a tilted source. The asymmetry of the pressure leads to a build up of a directed flow of matter with respect to the collision axis. The experimentally observed ordering of the directed flow of baryons, pions and antibaryons can be described as resulting from the expansion of a baryon inhomogeneous fireball. An uneven distribution of baryons in the transverse plane leads to an asymmetry in the collective push for protons and antiprotons. Precise measurements of the collective flow as a function of rapidity could serve as a strong constraint on mechanism of baryon stopping in the early phase of the collision. © 2022, CC BY.

关键词： Expansion

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Probing flow fluctuations through factorization breaking of harmonic flows in heavy-ion collisions

arXiv

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arXiv 2022年

作者： Bożek, Piotr Samanta, Rupam AGH University of Science and Technology Faculty of Physics and Applied Computer Science aleja Mickiewicza 30 Cracow30-059 Poland

We study factorization-breaking coefficients between the momentum dependent and momentum averaged flow vectors to probe flow fluctuations caused by initial-state fluctuations in heavy-ion collision. The coefficients for the flow vector squared and flow magnitude squared could be used for the extraction of flow angle decorrelations. We compare our model results with preliminary experimental data. We also present the predictions for the momentum dependent correlation between mixed flow harmonics. © 2022, CC BY.

关键词： Factorization

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Evolution equation for elastic scattering of hadrons

arXiv

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arXiv 2022年

作者： Kakkad, Hiren Kohara, Anderson Kendi Kotko, Piotr AGH University Of Science and Technology Faculty of Physics and Applied Computer Science Mickiewicza 30 Kraków30-059 Poland

We turn high energy elastic scattering of hadrons into an initial value problem using an evolution equation based on the Regge Field Theory, which has a form of the complex nonlinear reaction-diffusion equation, with time being played by the logarithm of energy. The initial conditions are provided by the data-driven models for the real and imaginary parts of the amplitude. Numerical calculations of pp differential cross sections and forward quantities for LHC energies agree very well with experimental data extending up to, and including the diffractive cone. Furthermore, we show that at current accessible energies the non-linear effects play an important role, as the impact parameter space profiles approach the unitarity bound. The equation also predicts some other effects discussed in the literature, like the hollowness of nuclear matter or existence of stationary points in momentum transfer t. Copyright © 2022, The Authors. All rights reserved.

关键词： Initial value problems

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On the Uncrossed Number of Graphs 32

On the Uncrossed Number of Graphs

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32nd International Symposium on Graph Drawing and Network Visualization, GD 2024

作者： Balko, Martin Hliněný, Petr Masařík, Tomáš Orthaber, Joachim Vogtenhuber, Birgit Wagner, Mirko H. Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Prague Czech Republic Faculty of Informatics Masaryk University Brno Czech Republic Institute of Informatics Faculty of Mathematics Informatics and Mechanics University of Warsaw Poland Institute of Software Technology Graz University of Technology Austria Institute of Computer Science Osnabrück University Germany

ISBN: (纸本)9783959773430

Visualizing a graph G in the plane nicely, for example, without crossings, is unfortunately not always possible. To address this problem, Masařík and Hliněný [GD 2023] recently asked for each edge of G to be drawn without crossings while allowing multiple different drawings of G. More formally, a collection D of drawings of G is uncrossed if, for each edge e of G, there is a drawing in D such that e is uncrossed. The uncrossed number unc(G) of G is then the minimum number of drawings in some uncrossed collection of G. No exact values of the uncrossed numbers have been determined yet, not even for simple graph classes. In this paper, we provide the exact values for uncrossed numbers of complete and complete bipartite graphs, partly confirming and partly refuting a conjecture posed by Hliněný and Masařík [GD 2023]. We also present a strong general lower bound on unc(G) in terms of the number of vertices and edges of G. Moreover, we prove NP-hardness of the related problem of determining the edge crossing number of a graph G, which is the smallest number of edges of G taken over all drawings of G that participate in a crossing. This problem was posed as open by Schaefer in his book [Crossing Numbers of Graphs 2018]. © Martin Balko, Petr Hliněný, Tomáš Masařík, Joachim Orthaber, Birgit Vogtenhuber, and Mirko H. Wagner.

关键词： Graph theory

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Permanent Magnet Cogging Motor, from Concept to Prototype

Permanent Magnet Cogging Motor, from Concept to Prototype

引用

International Conference on Electrical Machines, ICEM

作者： Tomasz Lerch Szczepan Milewski Michał Drewniak Krzysztof Łukawski Tomasz Kołacz Faculty of Electrical Engineering Automatics Computer Science and Biomedical Engineering AGH University of Krakow Krakow Poland Polytechnic Faculty University of Applied Sciences in Tarnow Tarnów Poland

ISBN: (数字)9798350370607

ISBN: (纸本)9798350370614

This article presents a description of research that has led to the development of a new design permanent magnet machine. The machine is based on the operational principle of the transverse-flux machine (TFM). In the proposed solution, a core commonly used in radial flux machines was employed, significantly simplifying the construction of the TFM machine. This simultaneously reduces flux leakage and enhances the value of the developed electromagnetic torque. The article sequentially outlines the stages of research on the new design, ranging from analytical calculations through Finite Element Method (FEM) simulation to the construction of a machine prototype.

关键词： Permanent magnet machines Forging Stator cores Torque Windings Prototypes Motors Permanent magnets Finite element analysis Resistance heating

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Interplay of longitudinal and transverse expansion in the kinetic dynamics of heavy-ion collisions

arXiv

引用

arXiv 2022年

作者： Bozek, Piotr AGH University of Science and Technology Faculty of Physics and Applied Computer Science Aleja Mickiewicza 30 Krakow30-059 Poland

The early dynamics in heavy-ion collisions involves a rapid, far from equilibrium evolution. This early pre-equilibrium stage of the dynamics can be modeled using kinetic equations. The effect of this pre-equilibrium stage on final observables derived from transverse momenta of emitted particles is small. The kinetic equations in the relaxation time approximation for a non-boost invariant system are solved. The asymmetry of the flow with respect to the reaction plane at different rapidities is found to be very sensitive to the degree of non-equilibrium in the evolution. This suggests that the rapidity odd directed flow could be studied to identify the occurrence of non-equilibrium effects and to estimate the asymmetry of the pressure between the longitudinal and transverse directions in the collision. © 2022, CC BY.

关键词： Kinetics

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Electric dipole spin resonance in a single- and two-electron quantum dot defined in two-dimensional electron gas at the SrTiO3/LaAlO3 interface

引用

Physical Review B 2024年第15期109卷 155306-155306页

作者： B. Szafran M. Zegrodnik M. P. Nowak R. Citro P. Wójcik AGH University of Krakow Faculty of Physics and Applied Computer Science Al. Mickiewicza 30 30-059 Krakow Poland AGH University of Krakow Academic Centre for Materials and Nanotechnology Al. Mickiewicza 30 30-059 Krakow Poland Department of Physics E. R. Caianiello University of Salerno and CNR-SPIN Via Giovanni Paolo II 132 Fisciano (Sa) Italy

We investigate the energy spectrum of a single- and two-electron quantum dot (QD) embedded in two-dimensional electron gas at the interface between SrTiO3 and LaAlO3, in the presence of the external magnetic field. For this purpose, the three-band model of 3d electrons defined on the square lattice of Ti ions was utilized. We demonstrate that, for the weak parabolic confinement potential, the low-energy spectrum is sufficiently well described by the effective Hamiltonian reduced to the one dxy orbital with the spin-orbit interaction originating from the coupling to the dxz and dyz bands. This is not the case for stronger confinement where contribution of the states related to the dxz/yz orbital is relevant. Based on the time-dependent calculations, we discuss in detail the manipulation of the electron spin in a QD by external AC voltages, in the context of the electric dipole spin resonance. The allowed and forbidden transitions are discussed in detail with respect to the parity selection rule. Our calculations show that, for a single-electron QD, the spin flip in the ground state has the character of a Rabi resonance, while for two electrons, the singlet-triplet transition is forbidden by the parity symmetry. For the two-electron QD, we demonstrate that the spin-flip transition can still be accomplished via a second-order, two-photon process that has a two-state Rabi character for low AC field amplitude. The violation of the parity symmetry on the spin-flip transitions is also analyzed.

关键词： Spin dynamics Spin-orbit coupling Quantum dots Transition metal oxides Two-dimensional electron gas

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Finite-size Catalysis in Quantum Resource Theories

arXiv

引用

arXiv 2024年

作者： Lipka-Bartosik, Patryk Korzekwa, Kamil Department of Applied Physics University of Geneva Geneva1211 Switzerland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland

Quantum catalysis, the ability to enable previously impossible transformations by using auxiliary systems without degrading them, has emerged as a powerful tool in various resource theories. Although catalytically enabled state transformations have been formally characterized by the monotonic behaviour of entropic quantifiers (e.g., the von Neumann entropy or non-equilibrium free energy), such characterizations often rely on unphysical assumptions, namely the ability of using catalysts of infinitely large dimension. This approach offers very limited insights into the practical significance of using catalysis for quantum information processing. Here, we address this problem across a broad class of quantum resource theories. Leveraging quantum information tools beyond the asymptotic regime, we establish sufficient conditions for the existence of catalytic transformations with finite-size catalysts. We further unveil connections between finite-size catalysis and multi-copy transformations. Notably, we discover a fascinating phenomenon of catalytic resonance: by carefully tailoring the catalysts’s state, one can drastically reduce the required dimension of the catalyst, thus enabling efficient catalytic transformations with minimal resources. Finally, we illustrate our findings with examples from the resource theories of entanglement and thermodynamics, as well in the context of catalytic unitary transformations. Copyright © 2024, The Authors. All rights reserved.

关键词： Catalysis

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