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arXiv 2021年

作者： Wójcik, P. Nowak, M.P. Zegrodnik, M. Agh University of Science and Technology Faculty of Physics and Applied Computer Science Al. Mickiewicza 30 Krakow30-059 Poland Agh University of Science and Technology Academic Centre for Materials and Nanotechnology Al. Mickiewicza 30 Krakow30-059 Poland

The two-dimensional electron gas at the interface between LaAlO3and SrTiO3(LAO/STO) exhibits gate tunable superconductivity with a characteristic dome-like shape of the critical temperature (Tc) in the phase diagram. As shown recently [Phys. Rev. B 102, 085420 (2020)], such an effect can be explained as a consequence of the extended s-wave symmetry of the gap within an intersite real space pairing scenario, leading to a good agreement between the experiment and theory. In this work, we turn to a detailed analysis of the inuence of spin-orbit coupling on the LAO/STO phase diagram by considering the atomic and the Rashba components. In particular, we analyze the optimal carrier concentration for which the maximal Tcis reached relative to the Lifshitz transition point. We find that the a misalignment between the two can be significantly enhanced by the spin-orbit splitting of the bands, combined with the fact that superconductivity sets in when the Fermi level passes the anticrossing induced by the spin-orbital hybridization. In the presence of the external in-plane magnetic field, our calculations show four-fold anisotropy with the paramagnetic limit largely exceeded for B||directed along the high symmetry points [01] and [01]. The obtained electron concentration dependence of Bc||reproduces the characteristic dome-like shape reported in experiments and the estimated value of Bc||corresponds to that measured experimentally. Copyright © 2021, The Authors. All rights reserved.

关键词： Anisotropy

RELATIVE VOLUME OF COMPARABLE PAIRS UNDER SEMIGROUP MAJORIZATION

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arXiv 2024年

作者： Cunden, Fabio Deelan Czartowski, Jakub Gramegna, Giovanni de Oliveira Junior, A. Dipartimento di Matematica Universitá degli Studi di Bari BariI-70125 Italy INFN Sezione di Bari BariI-70126 Italy Doctoral School of Exact and Natural Sciences Jagiellonian University Kraków30-348 Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland Dipartimento di Fisica Università degli Studi di Bari BariI-70126 Italy Center for Macroscopic Quantum States bigQ Department of Physics Technical University of Denmark Fysikvej 307 Kgs. Lyngby2800 Denmark

Any semigroup S of stochastic matrices induces a semigroup majorization relation S on the set Δ−1 of probability -vectors. Pick at random in Δ−1: what is the probability that and are comparable under S? We review recent asymptotic → ∞) results and conjectures in the case of majorization relation (when S is the set of bistochastic matrices), discuss natural generalisations, and prove new exact finite- results in the case of UT-majorization relation, i.e., when S is the set of upper-triangular stochastic matrices. © 2024, CC BY.

关键词： Matrix algebra

Non-maximal entanglement of photons from positron-electron annihilation demonstrated using a plastic PET scanner

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arXiv 2024年

作者： Moskal, Pawel Kumar, Deepak Sharma, Sushil Beyene, Ermias Yitayew Chug, Neha Coussat, Aurélien Curceanu, Catalina Czerwiński, Eryk Das, Manish Dulski, Kamil Gorgol, Marek Jasińska, Bozena Kacprzak, Krzysztof Kaplanoglu, Tevfik Kaplon, Lukasz Kozik, Tomasz Lisowski, Edward Lisowski, Filip Mryka, Wiktor Niedźwiecki, Szymon Parzych, Szymon del Rio, Elena P. Rädler, Martin Skurzok, Magda Stepień, Ewa L. Tanty, Pooja Ardebili, Keyvan Tayefi Eliyan, Kavya Valsan Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University S. Lojasiewicza 11 Kraków30-348 Poland Total-Body Jagiellonian-PET Laboratory Jagiellonian University Poland Center for Theranostics Jagiellonian University Kraków31-034 Poland INFN Laboratori Nazionali di Frascati CP 13 Via E. Fermi 40 Frascati00044 Italy Institute of Physics Maria Curie-Sklodowska University Pl. M. Curie-Sklodowskiej 1 Lublin20-031 Poland Cracow University of Technology Kraków31-864 Poland

In state-of-the-art Positron Emission Tomography (PET), information about annihilation photon polarization is unavailable. Here, we present a PET scanner built from plastic scintillators, where annihilation photons primarily interact via the Compton effect, providing information about both photon polarization and propagation direction. Using this plastic-based PET, we determined the distribution of the relative angle between polarization planes of photons from positron-electron annihilation in a porous polymer. The amplitude of the observed distribution is smaller than predicted for maximally quantum-entangled two-photon states but larger than expected for separable photons. This result can be well explained by assuming that photons from pick-off annihilation are not entangled, while photons from direct and para-positronium annihilations are maximally entangled. Our result indicates that the degree of entanglement depends on the annihilation mechanism in matter, opening new avenues for exploring polarization correlations in PET as a diagnostic indicator. © 2024, CC BY.

关键词： Quantum entanglement

Realistic Total-Body J-PET Geometry Optimization - Monte Carlo Study

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arXiv 2022年

作者： Baran, Jakub Krzemien, Wojciech Parzych, Szymon Raczyński, Lech Bala, Mateusz Coussat, Aurélien Chug, Neha Czerwiński, Eryk Curceanu, Catalina Oana Dadgar, Meysam Dulski, Kamil Eliyan, Kavya Gajewski, Jan Gajos, Aleksander Hiesmayr, Beatrix C. Kacprzak, Krzysztof Kaplon, Lukasz Klimaszewski, Konrad Korcyl, Grzegorz Kozik, Tomasz Kumar, Deepak Niedźwiecki, Szymon Panek, Dominik del Rio, Elena Perez Ruciński, Antoni Sharma, Sushil Shivani Shopa, Roman Y. Skurzok, Magdalena Stępień, Ewa Tayefiardebili, Faranak Tayefiardebili, Keyvan Wiślicki, Wojciech Moskal, Pawel Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Total-Body Jagiellonian-PET Laboratory Jagiellonian University Kraków Poland Center for Theranostics Jagiellonian University Kraków Poland High Energy Physics Division National Centre for Nuclear Research Świerk Otwock Poland Department of Complex Systems National Centre for Nuclear Research Świerk Otwock Poland INFN Laboratori Nazionali di Frascati Frascati Italy Institute of Nuclear Physics Polish Academy of Sciences Kraków Poland Faculty of Physics University of Vienna Vienna Austria

Background: Total-Body PET is one of the most promising medical diagnostics modalities, opening new perspectives for personalized medicine, low-dose imaging, multi-organ dynamic imaging or kinetic modelling. The high sensitivity provided by Total-Body technology can be advantageous for novel tomography methods like positronium imaging, demanding the registration of triple coincidences. Currently, state-of-the-art PET scanners use inorganic scintillators. However, the high acquisition cost reduces the accessibility of Total-Body PET technology. Several efforts are ongoing to mitigate this problem. Among the alternatives, the Jagiellonian PET (J-PET) technology, based on axially arranged plastic scintillator strips, offers a low-cost alternative solution for Total-Body PET. Purpose: The work aimed to compare five Total-Body J-PET geometries with plastic scintillators suitable for multi-organ and positronium tomography as a possible next-generation J-PET scanner design. Methods: We present comparative studies of performance characteristics of the cost-effective Total-Body PET scanners using J-PET technology. We investigated in silico five Total-Body scanner geometries, varying the number of rings, scanner radii, and other parameters. Monte Carlo simulations of the anthropomorphic XCAT phantom, the extended 2-meter sensitivity line source and positronium sensitivity phantoms were used to assess the performance of the geometries. Two hot spheres were placed in the lungs and in the liver of the XCAT phantom to mimic the pathological changes. We compared the sensitivity profiles and performed quantitative analysis of the reconstructed images by using the quality metrics such as contrast recovery coefficient, background variability and root mean squared error. The studies are complemented by the determination of sensitivity for the positronium lifetime tomography and the relative cost analysis of the studied setups. Results: The analysis of the reconstructed XCAT images rev

关键词： Monte Carlo methods

Optical protection of alkali-metal atoms from spin relaxation

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arXiv 2022年

作者： Berrebi, Avraham Dikopoltsev, Mark Katz, Ori Katz, Or Department of Applied Physics The Faculty of Science The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem9190401 Israel Rafael Ltd Haifa31021 Israel Duke Quantum Center Duke University DurhamNC27701 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States

We describe a new mechanism to continuously protect alkali-metal atoms from spin relaxation using a single off-resonant optical beam. We experimentally demonstrate that state-selective light-shifts can synchronize the Larmor frequencies of the two hyperfine manifolds, and by that form a unique decoherence-free subspace. We report an order of magnitude suppression of the spin decoherence for cesium atoms, simultaneously protecting from random spin-exchange collisions and partially also from spin-relaxation by the interaction with weakly-depolarizing walls. We further report an order of magnitude improvement of the quality factor of the magnetic states. Our results demonstrate the ability to use the multi-level structure of atoms or molecules with accessible optical tools to engineer useful decoherence-free subspaces. Copyright © 2022, The Authors. All rights reserved.

关键词： Atoms

Magnon-magnon entanglement and its quantification via a microwave cavity

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Physical Review B 2021年第22期104卷 224302-224302页

作者： Vahid Azimi Mousolou Yuefei Liu Anders Bergman Anna Delin Olle Eriksson Manuel Pereiro Danny Thonig Erik Sjöqvist Department of Applied Mathematics and Computer Science Faculty of Mathematics and Statistics University of Isfahan Isfahan 81746-73441 Iran Department of Physics and Astronomy Uppsala University Box 516 SE-751 20 Uppsala Sweden Department of Applied Physics School of Engineering Sciences KTH Royal Institute of Technology AlbaNova University Center SE-10691 Stockholm Sweden Swedish e-Science Research Center KTH Royal Institute of Technology SE-10044 Stockholm Sweden School of Science and Technology Örebro University SE-701 82 Örebro Sweden

Quantum magnonics is an emerging research field, with great potential for applications in magnon based hybrid systems and quantum information processing. Quantum correlation, such as entanglement, is a central resource in many quantum information protocols that naturally comes about in any study toward quantum technologies. This applies also to quantum magnonics. Here, we investigate antiferromagnetic coupling of two ferromagnetic sublattices that can have two different magnon modes. We show how this may lead to experimentally measurable bipartite continuous-variable magnon-magnon entanglement. The entanglement can be fully characterized via a single squeezing parameter or, equivalently, entanglement parameter. The clear relation between the entanglement parameter and the Einstein, Podolsky, and Rosen (EPR) function of the ground state opens up for experimental quantification magnon-magnon continuous-variable entanglement and EPR nonlocality. We propose a practical experimental realization to measure the EPR function of the ground state, in a setting that relies on magnon-photon interaction in a microwave cavity.

关键词： Magnetic coupling Nonlocality Quantum correlations in quantum information Quantum entanglement Spin waves Spintronics

Mixing of Endogenous Co2 and Meteoric H2o Causes Superefficient Carbonate Dissolution

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SSRN

SSRN 2024年

作者： Wróblewski, Wojciech Bella, Pavel Drewnik, Marek Duliński, Marek Gradziński, Michal Motyka, Jacek Nęcki, Jaroslaw Przemyslaw, Sala Institute of Geological Sciences Jagiellonian University in Kraków Gronostajowa 3A Kraków30-387 Poland Slovak Caves Administration Hodžova 11 Liptovský Mikuláš03-101 Slovakia Department of Geography Faculty of Education Catholic University Ružomberok Slovakia Institute of Geography and Spatial Management Jagiellonian University in Kraków Gronostajowa 7 Kraków30-387 Poland Faculty of Physics and Applied Computer Science AGH University of Kraków Reymonta 19 Kraków30-059 Poland Faculty of Geology Geophysics and Environmental Protection AGH University of Kraków Mickiewicza 30 Kraków30-059 Poland

Karst corrosion of carbonate rocks by water with dissolved gases is effective in two major scenarios: (i) meteoric water absorbs CO2 from soil and atmosphere, or (ii) ascending water of deep circulation carries with it dissolved endogenous gases, mainly CO2 and H2S. However, we have observed another variant where meteoric water absorbs ascending endogenous gases at a natural gas vent on a travertine mound in Slovakia. We propose the term exhalokarst for this unusually effective form of carbonate corrosion. Carbonate dissolution's extreme effectiveness is demonstrated through the rapid mineralization of rainwater ponded at a gas vent, rising to 3.2 g/L of dissolved solids shortly after the rainfall. One liter of water ponded at the vent and mixing with the venting gas, dissolved up to 800 mg of calcium at a rate exceeding 5.8 mg/L·min. Limestone tablets placed at the vent show a sign of significant corrosion, a rate of which is up to 126 µm/yr. The rate is comparable to the rates in coastal karst, where mixing freshwater with seawater results in the highest rate of karst corrosion hitherto known. © 2024, The Authors. All rights reserved.

关键词： Dissolution

A resetting particle embedded in a viscoelastic bath

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arXiv 2024年

作者： Biswas, Arup Dubbeldam, Johan L.A. Sandev, Trifce Pal, Arnab The Institute of Mathematical Sciences CIT Campus Taramani Chennai600113 India Homi Bhabha National Institute Training School Complex Anushakti Nagar Mumbai400094 India Delft Institute of Applied Mathematics Delft University of Technology Delft2628 CD Netherlands Research Center for Computer Science and Information Technologies Macedonian Academy of Sciences and Arts Bul. Krste Misirkov 2 Skopje1000 Macedonia Institute of Physics Faculty of Natural Sciences and Mathematics Ss. Cyril and Methodius University Arhimedova 3 Skopje1000 Macedonia Department of Physics Korea University Seoul02841 Korea Republic of

We examine the behavior of a colloidal particle immersed in a viscoelastic bath undergoing stochastic resetting at a rate r. Microscopic probes suspended in viscoelastic environment do not follow the classical theory of Brownian motion. This is primarily because the memory from successive collisions between the medium particles and the probes does not necessarily decay instantly as opposed to the classical Langevin equation. To treat such a system one needs to incorporate the memory effects to the Langevin equation. The resulting equation formulated by Kubo, known as the Generalized Langevin equation (GLE), has been instrumental to describe the transport of particles in inhomogeneous or viscoelastic environments. The purpose of this work, henceforth, is to study the behavior of such a colloidal particle governed by the GLE under resetting dynamics. To this end, we extend the renewal formalism to compute the general expression for the position variance and the correlation function of the resetting particle driven by the environmental memory. These generic results are then illustrated for the prototypical example of the Jeffreys viscoelastic fluid model. In particular, we identify various timescales and intermittent plateaus in the transient phase before the system relaxes to the steady state;and further discuss the effect of resetting pertaining to these behaviors. Our results are supported by numerical simulations showing an excellent agreement. © 2024, CC BY.

关键词： Stochastic systems

Cyclic measurements and simplified quantum state tomography

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arXiv 2024年

作者： Avella, Victor González Czartowski, Jakub Goyeneche, Dardo Życzkowski, Karol Departamento de Física Facultad de Ciencias Básicas Universidad de Antofagasta Casilla 170 Antofagasta Chile Doctoral School of Exact and Natural Sciences Jagiellonian University ul. Lojasiewicza 11 Kraków30-348 Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland Instituto de Física Pontificia Universidad Católica de Chile Casilla 306 Santiago Chile Center for Theoretical Physics Polish Academy of Scienes ul Lotników 32/46 Warszawa02-668 Poland

Tomographic reconstruction of quantum states plays a fundamental role in benchmarking quantum systems and retrieving information from quantum computers. Among the informationally complete sets of quantum measurements, the tight ones provide a linear reconstruction formula and minimize the propagation of statistical errors. However, implementing tight measurements in the lab is challenging due to the high number of required measurement projections, involving a series of experimental setup preparations. In this work, we introduce the notion of cyclic tight measurements, which allow us to perform full quantum state tomography while considering only repeated application of a single unitary-based quantum device during the measurement stage process. This type of measurements significantly simplifies the complexity of the experimental setup required to retrieve the quantum state of a physical system. Additionally, we design feasible setup preparation procedure that produce well-approximated cyclic tight measurements, in every finite dimension. © 2024, CC BY.

关键词： Quantum computers

Suppressing the decoherence of alkali-metal spins at low magnetic fields

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arXiv 2022年

作者： Dikopoltsev, Mark Avraham, Berrebi Levy, Uriel Katz, Or Department of Applied Physics The Faculty of Science The Center for Nanoscience and Nanotechnology The Hebrew University of Jerusalem Jerusalem9190401 Israel Rafael Ltd Haifa31021 Israel Duke Quantum Center Duke University DurhamNC27701 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States

Interactions of electron spins with rotational degrees of freedom during collisions or with external fields are fundamental processes that limit the coherence time of spin gases. We experimentally study the decoherence of warm cesium spins dominated by spin rotation-interaction during binary collisions with N2 molecules or by absorption of near-resonant light. We report an order of magnitude suppression of the spin decoherence rate by either of those processes at low magnetic fields. We find that the excess decoherence at higher magnetic fields originates from an asynchronous Larmor precession, which is a mechanism that universally affects all alkali atoms, and can yet be suppressed at low magnetic-fields. This work extends the widely-used regime of Spin-Exchange Relaxation Free (SERF), which provides protection from decoherence by random spin-conservative processes, now for random processes which do not conserve but rather destruct electron spins. Copyright © 2022, The Authors. All rights reserved.

关键词： Electrospinning