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  • 1.
    Alberti, Tommaso
    et al.
    INAF Ist Astrofis & Planetol Spaziali, Rome, Italy.
    Consolini, Giuseppe
    INAF Ist Astrofis & Planetol Spaziali, , Rome, Italy.
    Carbone, Vincenzo
    Univ Calabria, Dipartimento Fis, Arcavacata Di Rende, Italy.
    Yordanova, Emiliya
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Marcucci, Maria Federica
    INAF Ist Astrofis & Planetol Spaziali, Rome, Italy.
    De Michelis, Paola
    Ist Nazl Geofis & Vulcanol, Rome, Italy.
    Multifractal and Chaotic Properties of Solar Wind at MHD and Kinetic Domains: An Empirical Mode Decomposition Approach2019In: Entropy, E-ISSN 1099-4300, Vol. 21, no 3, article id 320Article in journal (Refereed)
    Abstract [en]

    Turbulence, intermittency, and self-organized structures in space plasmas can be investigated by using a multifractal formalism mostly based on the canonical structure function analysis with fixed constraints about stationarity, linearity, and scales. Here, the Empirical Mode Decomposition (EMD) method is firstly used to investigate timescale fluctuations of the solar wind magnetic field components; then, by exploiting the local properties of fluctuations, the structure function analysis is used to gain insights into the scaling properties of both inertial and kinetic/dissipative ranges. Results show that while the inertial range dynamics can be described in a multifractal framework, characterizing an unstable fixed point of the system, the kinetic/dissipative range dynamics is well described by using a monofractal approach, because it is a stable fixed point of the system, unless it has a higher degree of complexity and chaos.

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  • 2.
    Alfonso, Leonardo
    et al.
    IHE-Delft.
    Ridolfi, Elena
    Sapienza University of Rome, Rome, Italy.
    Gaytan-Aguilar, Sandra
    Deltares, Rotterdamseweg 185, Delft 2629 HD, Netherlands.
    Napolitano, Francesco
    Sapienza University of Rome.
    Russo, Fabio
    Sapienza University of Rome.
    Ensemble entropy for monitoring network design2014In: Entropy, E-ISSN 1099-4300, Vol. 16, no 3, p. 1365-1375Article in journal (Refereed)
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  • 3.
    Aydin, Alhun
    et al.
    Fritz Haber Research Center, Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel; Nano Energy Research Group, Energy Institute, Istanbul Technical University, 34469 Istanbul, Turkey.
    Sisman, Altug
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Kosloff, Ronnie
    Fritz Haber Research Center, Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
    Landauer’s Principle in a Quantum Szilard Engine without Maxwell’s Demon2020In: Entropy, E-ISSN 1099-4300, Vol. 22, no 3, article id 294Article in journal (Refereed)
    Abstract [en]

    Quantum Szilard engine constitutes an adequate interplay of thermodynamics, information theory and quantum mechanics. Szilard engines are in general operated by a Maxwell’s Demon where Landauer’s principle resolves the apparent paradoxes. Here we propose a Szilard engine setup without featuring an explicit Maxwell’s demon. In a demonless Szilard engine, the acquisition of which-side information is not required, but the erasure and related heat dissipation still take place implicitly. We explore a quantum Szilard engine considering quantum size effects. We see that insertion of the partition does not localize the particle to one side, instead creating a superposition state of the particle being in both sides. To be able to extract work from the system, particle has to be localized at one side. The localization occurs as a result of quantum measurement on the particle, which shows the importance of the measurement process regardless of whether one uses the acquired information or not. In accordance with Landauer’s principle, localization by quantum measurement corresponds to a logically irreversible operation and for this reason it must be accompanied by the corresponding heat dissipation. This shows the validity of Landauer’s principle even in quantum Szilard engines without Maxwell’s demon.

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  • 4.
    Iubini, Stefano
    et al.
    CNR, Ist Sistemi Complessi, Via Madonna Piano 10, I-50019 Sesto Fiorentino, Italy;Univ Padua, Dipartimento Fis & Astron, Via F Marzolo 8, I-35131 Padua, Italy.
    Borlenghi, Simone
    KTH Royal Inst Technol, Sch Engn Sci, Dept Appl Phys, Elect 229, SE-16440 Kista, Sweden.
    Delin, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory. KTH Royal Inst Technol, Sch Engn Sci, Dept Appl Phys, Elect 229, SE-16440 Kista, Sweden.
    Lepri, Stefano
    CNR, Ist Sistemi Complessi, Via Madonna Piano 10, I-50019 Sesto Fiorentino, Italy;Ist Nazl Fis Nucl, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy.
    Piazza, Francesco
    CNRS, UPR 4301, CBM, Rue C Sadron, F-45071 Orleans, France;Univ Orleans, F-45071 Orleans, France.
    Dephasing-Assisted Macrospin Transport2020In: Entropy, E-ISSN 1099-4300, Vol. 22, no 2, article id 210Article in journal (Refereed)
    Abstract [en]

    Transport phenomena are ubiquitous in physics, and it is generally understood that the environmental disorder and noise deteriorates the transfer of excitations. There are, however, cases in which transport can be enhanced by fluctuations. In the present work, we show, by means of micromagnetics simulations, that transport efficiency in a chain of classical macrospins can be greatly increased by an optimal level of dephasing noise. We also demonstrate the same effect in a simplified model, the dissipative Discrete Nonlinear Schrodinger equation, subject to phase noise. Our results point towards the realization of a large class of magnonics and spintronics devices, where disorder and noise can be used to enhance spin-dependent transport efficiency.

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  • 5. Kish, Laszlo B.
    et al.
    Granqvist, Claes-Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Elimination of a Second-Law-Attack, and All Cable-Resistance-Based Attacks, in the Kirchhoff-Law-Johnson-Noise (KLJN) Secure Key Exchange System2014In: Entropy, E-ISSN 1099-4300, Vol. 16, no 10, p. 5223-5231Article in journal (Refereed)
    Abstract [en]

    We introduce the so far most efficient attack against the Kirchhoff-law-Johnson-noise (KLJN) secure key exchange system. This attack utilizes the lack of exact thermal equilibrium in practical applications and is based on cable resistance losses and the fact that the Second Law of Thermodynamics cannot provide full security when such losses are present. The new attack does not challenge the unconditional security of the KLJN scheme, but it puts more stringent demands on the security/privacy enhancing protocol than for any earlier attack. In this paper we present a simple defense protocol to fully eliminate this new attack by increasing the noise-temperature at the side of the smaller resistance value over the noise-temperature at the side with the greater resistance. It is shown that this simple protocol totally removes Eve's information not only for the new attack but also for the old Bergou-Scheuer-Yariv attack. The presently most efficient attacks against the KLJN scheme are thereby completely nullified.

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  • 6.
    Mages, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Anastasiadi, Elli
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Non-Negative Decomposition of Multivariate Information: From Minimum to Blackwell-Specific Information2024In: Entropy, E-ISSN 1099-4300, Vol. 26, no 5, article id 424Article in journal (Refereed)
    Abstract [en]

    Partial information decompositions (PIDs) aim to categorize how a set of source variables provides information about a target variable redundantly, uniquely, or synergetically. The original proposal for such an analysis used a lattice-based approach and gained significant attention. However, finding a suitable underlying decomposition measure is still an open research question at an arbitrary number of discrete random variables. This work proposes a solution with a non-negative PID that satisfies an inclusion-exclusion relation for any f-information measure. The decomposition is constructed from a pointwise perspective of the target variable to take advantage of the equivalence between the Blackwell and zonogon order in this setting. Zonogons are the Neyman-Pearson region for an indicator variable of each target state, and f-information is the expected value of quantifying its boundary. We prove that the proposed decomposition satisfies the desired axioms and guarantees non-negative partial information results. Moreover, we demonstrate how the obtained decomposition can be transformed between different decomposition lattices and that it directly provides a non-negative decomposition of R & eacute;nyi-information at a transformed inclusion-exclusion relation. Finally, we highlight that the decomposition behaves differently depending on the information measure used and how it can be used for tracing partial information flows through Markov chains.

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  • 7.
    Mages, Tobias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems.
    Decomposing and Tracing Mutual Information by Quantifying Reachable Decision Regions2023In: Entropy, E-ISSN 1099-4300, Vol. 25, no 7, article id 1014Article in journal (Refereed)
    Abstract [en]

    The idea of a partial information decomposition (PID) gained significant attention for attributing the components of mutual information from multiple variables about a target to being unique, redundant/shared or synergetic. Since the original measure for this analysis was criticized, several alternatives have been proposed but have failed to satisfy the desired axioms, an inclusion–exclusion principle or have resulted in negative partial information components. For constructing a measure, we interpret the achievable type I/II error pairs for predicting each state of a target variable (reachable decision regions) as notions of pointwise uncertainty. For this representation of uncertainty, we construct a distributive lattice with mutual information as consistent valuation and obtain an algebra for the constructed measure. The resulting definition satisfies the original axioms, an inclusion–exclusion principle and provides a non-negative decomposition for an arbitrary number of variables. We demonstrate practical applications of this approach by tracing the flow of information through Markov chains. This can be used to model and analyze the flow of information in communication networks or data processing systems.

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  • 8. Murari, Andrea
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, F.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, N.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, C.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, High Energy Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, M.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    On the Use of Transfer Entropy to Investigate the Time Horizon of Causal Influences between Signals2018In: Entropy, E-ISSN 1099-4300, Vol. 20, no 9, article id 627Article in journal (Refereed)
    Abstract [en]

    Understanding the details of the correlation between time series is an essential step on the route to assessing the causal relation between systems. Traditional statistical indicators, such as the Pearson correlation coefficient and the mutual information, have some significant limitations. More recently, transfer entropy has been proposed as a powerful tool to understand the flow of information between signals. In this paper, the comparative advantages of transfer entropy, for determining the time horizon of causal influence, are illustrated with the help of synthetic data. The technique has been specifically revised for the analysis of synchronization experiments. The investigation of experimental data from thermonuclear plasma diagnostics proves the potential and limitations of the developed approach.

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  • 9. Murari, Andrea
    et al.
    Andersson Sundén, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Binda, Federico
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Cecconello, Marco
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Conroy, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Dzysiuk, Nataliia
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Ericsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Eriksson, Jacob
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hellesen, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Hjalmarsson, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Sjöstrand, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Skiba, Mateusz
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Weiszflog, Matthias
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Zychor, I.
    Detection of Causal Relations in Time Series Affected by Noise in Tokamaks Using Geodesic Distance on Gaussian Manifolds2017In: Entropy, E-ISSN 1099-4300, Vol. 19, no 10, article id 569Article in journal (Refereed)
    Abstract [en]

    Modern experiments in Magnetic Confinement Nuclear Fusion can produce Gigabytes of data, mainly in form of time series. The acquired signals, composing massive databases, are typically affected by significant levels of noise. The interpretation of the time series can therefore become quite involved, particularly when tenuous causal relations have to be investigated. In the last years, synchronization experiments, to control potentially dangerous instabilities, have become a subject of intensive research. Their interpretation requires quite delicate causality analysis. In this paper, the approach of Information Geometry is applied to the problem of assessing the effectiveness of synchronization experiments on JET (Joint European Torus). In particular, the use of the Geodesic Distance on Gaussian Manifolds is shown to improve the results of advanced techniques such as Recurrent Plots and Complex Networks, when the noise level is not negligible. In cases affected by particularly high levels of noise, compromising the traditional treatments, the use of the Geodesic Distance on Gaussian Manifolds allows deriving quite encouraging results. In addition to consolidating conclusions previously quite uncertain, it has been demonstrated that the proposed approach permit to successfully analyze signals of discharges which were otherwise unusable, therefore salvaging the interpretation of those experiments.

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  • 10.
    Tamburini, Fabrizio
    et al.
    ZKM, Lorentzstr 19, D-76135 Karlsruhe, Germany.;MSC BW, Nobelstr 19, D-70550 Stuttgart, Germany..
    De laurentis, Mariafelicia
    Goethe Univ, Inst Theoret Phys, Max von Laue Str 1, D-60438 Frankfurt, Germany.;Tomsk State Pedag Univ, Ul Kievskaya 60, Tomsk 634061, Russia.;Tomsk State Univ Control Syst & Radioelectron TUS, Lab Theoret Cosmol, Tomsk 634050, Russia.;INFN, Sez Napoli, Compl Univ Monte S Angelo,Edificio G,Via Cinthia, I-80126 Naples, Italy..
    Licata, Ignazio
    Inst Sci Methodol ISEM, I-90146 Palermo, Italy.;Sch Adv Int Studies Theoret & Nonlinear Methodol, I-70124 Bari, Italy.;BM Birla Sci Ctr, IIAMIS, Hyderabad 500463, Andhra Pradesh, India..
    Thide, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Swedish Institute of Space Physics, Uppsala Division.
    Twisted Soft Photon Hair Implants on Black Holes2017In: Entropy, E-ISSN 1099-4300, Vol. 19, no 9, article id 458Article in journal (Refereed)
    Abstract [en]

    Background: The Hawking-Perry-Strominger (HPS) work states a new controversial idea about the black hole (BH) information paradox, where BHs maximally entropize and encode information in their event horizon area, with no "hair" thought to reveal information outside but angular momentum, mass, and electric charge only in a unique quantum gravity (QG) vacuum state. New conservation laws of gravitation and electromagnetism, appear to generate different QG vacua, preserving more information in soft photon/graviton hair implants. We find that BH photon hair implants can encode orbital angular momentum (OAM) and vorticity of the electromagnetic (EM) field. Methods: Numerical simulations are used to plot an EM field with OAM emitted by a set of dipolar currents together with the soft photon field they induce. The analytical results confirm that the soft photon hair implant carries OAM and vorticity. Results: a set of charges and currents generating real EM fields with precise values of OAM induce a "curly", twisted, soft-hair implant on the BH with vorticity and OAM increased by one unit with respect to the initial real field. Conclusions: Soft photon implants can be spatially shaped ad hoc, encoding structured and densely organized information on the event horizon.

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