cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Dynamics of matter-wave solitons in a ratchet potential
Creators: name: Poletti, Dario
name: Alexander, Tristram J.
name: Ostrovskaya, Elena A.
name: Li, Baowen
name: Kivshar, Yuri S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We study the dynamics of bright solitons formed in a Bose-Einstein condensate with attractive atomic interactions perturbed by a weak bichromatic optical lattice potential. The lattice depth is a biperiodic function of time with a zero mean, which realises a flashing ratchet for matter-wave solitons. The average velocity of a soliton and the directed soliton current induced by the ratchet depend on the number of atoms in the soliton. We employ this feature to study collisions between ratchet-driven solitons and find that soliton transport can be induced through their interactions. In the regime when matter-wave solitons are narrow compared to the lattice period the ratchet dynamics is well described by the effective Hamiltonian theory.
description: 4 pages, 5 figures
Low-energy electromagnetic processes affecting free-falling test-mass charging for LISA and future space interferometers
Creators: name: Grimani, Catia
name: Cesarini, Andrea
name: Fabi, Michele
name: Villani, Mattia
Publisher: name: arXiv
Year: 2020
Subjects: subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Galactic cosmic rays and solar energetic particles charge gold-platinum, free-falling test masses (TMs) on board interferometers for the detection of gravitational waves in space. The charging process induces spurious forces on the test masses that affect the sensitivity of these instruments mainly below $10^{-3}$ Hz. Geant4 and FLUKA Monte Carlo simulations were carried out to study the TM charging process on board the LISA Pathfinder mission that remained into orbit around the Sun-Earth Lagrange point L1 between 2016 and 2017. While a good agreement was observed between simulations and measurements of the TMs net charging, the shot noise associated with charging fluctuations of both positive and negative particles resulted 3-4 times higher that predicted. The origin of this mismatch was attributed to the propagation of electrons and photons only above 100 eV in the simulations. In this paper, low-energy electromagnetic processes to be included in the future Monte Carlo simulations for LISA and LISA-like space interferometers TM charging are considered. {It is found that electrons and photons below 100 eV give a contribution to the effective charging comparable to that of the whole sample of particles above this energy. In particular, for incident protons ionization contributes twice with respect to low energy kinetic emission and electron backscattering. The other processes are found to play a negligible role. For heavy nuclei only sputtering must be considered.
description: Accepted for publication in Classical and Quantum Gravity
Theoretical studies of the atomic transitions in boron-like ions: Mg VIII, Si X and S XII
Creators: name: Nataraj, H. S.
name: Sahoo, B. K.
name: Das, B. P.
name: Chaudhuri, R. K.
name: Mukherjee, D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this paper, we have carried out the calculations of the weighted oscillator strengths and the transition probabilities for a few low-lying transitions of boron-like ions: Mg VIII, Si X and S XII which are astrophysically important, particularly, in the atmospheres of the solar corona. We have employed an all-order relativistic many-body theory called the relativistic coupled-cluster theory to calculate very precisely these atomic quantities of astrophysical interest. We have reported for the first time the transition probabilities for some forbidden transitions which are unavailable in the literature; either theoretically or experimentally. We also discuss the physical effects associated with these transitions. Our data can be used for the identification of spectral lines arising from the coronal atmospheres of Sun and Sun-like stars having an extended corona.
description: 8 pages, 4 tables
Geometric aspects of two- and threepeakons
Creators: name: Cieślak, Tomasz
name: Kryński, Wojciech
Publisher: name: arXiv
Year: 2020
Subjects: subject: Analysis of PDEs (math.AP)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C22, 37J39, 70H06

description: We apply geometric tools to study dynamics of two- and threepeakon solutions of the Camassa--Holm equation. New proofs of asymptotic behavior of the solutions are given. In particular we recover well-known collision conditions. Additionally the Gauss curvature (in the twopeakon case) and the sectional curvature (in the treepeakon case) of corresponding manifolds are computed.
Θερμική μελέτη βιοπολυμερών με βάση τις ρητίνες φαινόλης-φορμαλδεΰδης που χρησιμοποιούνται ως συγκολλητικές ουσίες στην παραγωγή ξυλοσανίδων.
Creators: name: Παπαδοπούλου, Ηλέκτρα Στέφανου
Publisher: name: Aristotle University of Thessaloniki
Year: 2010
Subjects: Ανανεώσιμες πρώτες ύλες
Θερμική μελέτη θερμοσκληραινόμενων ρητινών
Κοντραπλακέ
Renewable raw materials
Thermal study of thermosetting resins
Plywood

description: Σκοπός της διατριβής ήταν η μελέτη θερμοσκληραινόμενων ρητινών φαινόλης-φορμαλδεΰδης, όπου το 20% της απαιτούμενης φαινόλης αντικαταστάθηκε από λιγνίνη, τανίνη, πρωτεΐνη σόγιας, και έλαιο από τον καρπό κάσιους. Οι ρητινές αυτές συγκρίθηκαν με μια πετροχημική ρητίνη φαινόλης-φορμαλδεΰδης ως προς την ικανότητά τους να παράγουν επιτυχώς κοντραπλακέ. Οι ρητίνες αυτές αναλύθηκαν ως προς τις φυσικοχημικές τους ιδιότητες ενώ υποβλήθηκαν σε θερμοσταθμική ανάλυση και μελέτη με διαφορική θερμιδομετρία σάρωσης. Αποδείχθηκε ότι όλες μπορούν να αντικαταστήσουν μια κλασσική ρητίνη φαινόλης-φορμαλδεΰδης στην παραγωγή κοντραπλακέ, ενώ η ρητίνη με έλαιο από τον καρπό κάσιους μπορεί να χρησιμοοποιηθεί χωρίς καμμίά αλλαγή στις βιομηχανικές συνθήκες παραγωγής των ξυλοσανίδων. Επίσης η ρητίνη φαινόλης-φορμαλδεΰδης τροποποιημένη με τανίνη μπορεί να επιφέρει επιβράδυνση στην εξάπλωση της φωτιάς σε μεγαλύτερο βαθμό από τις υπόλοιπες.
description: The aim of the present thesis was the study of phenol-formaldehyde (PF) thermosetting resins where a 20% of phenol was replaced by lignin, tannin, soy protein and cashew nut shell liquid (CNSL). These resins were compared with a petrochemical phenol-formaldehyde resin relatively to their efficiency to produce successfully plywood panels. The resins were analyzed for their specifications and subjected to thermal analysis with TGA & DSC. It was proved that any of them can replace a standard PF resin in plywood production, while the resin with CNSL can be used without any change in the industrial scale production settings. More, the PF resin modified with tannin can yield retardation to the spread of fire at higher degree than the other resins.
description: Σε συνεργασία με το Ινστιτούτο Τεχνολογίας Γκρενόμπλ (Γαλλία), το ΕΚΕΦΕ Δημόκριτος, και το CNRS (Centre National de la Researche Scientifique, Γαλλία)
Spectral signatures of photosynthesis II: coevolution with other stars and the atmosphere on extrasolar worlds
Creators: name: Kiang, Nancy Y.
name: Segura, Antigona
name: Tinetti, Giovanna
name: Govindjee
name: Blankenship, Robert E.
name: Cohen, Martin
name: Siefert, Janet
name: Crisp, David
name: Meadows, Victoria S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take planetary atmospheric compositions simulated by Segura, et al. (2003, 2005) for Earth-like planets around observed F2V and K2V stars, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O2 content in case anoxygenic photosynthesis dominates. We calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the NIR, in bands at 0.93-1.1 microns, 1.1-1.4 microns, 1.5-1.8 microns, and 1.8-2.5 microns. In addition, we calculate wavelength restrictions for underwater organisms and depths of water at which they would be protected from UV flares in the early life of M stars. We estimate the potential productivity for both surface and underwater photosynthesis, for both oxygenic and anoxygenic photosynthesis, and for hypothetical photosynthesis in which longer wavelength, multi-photosystem series are used.
description: 59 pages, 4 figures, 4 tables, forthcoming in Astrobiology ~March 2007
Physical Mechanism behind the Hysteresis-free Negative Capacitance Effect in Metal-Ferroelectric-Insulator-Metal Capacitors with Dielectric Leakage and Interfacial Trapped Charges
Creators: name: Hsu, Chia-Sheng
name: Chang, Sou-Chi
name: Nikonov, Dmitri E.
name: Young, Ian A.
name: Naeemi, Azad
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: The negative capacitance (NC) stabilization of a ferroelectric (FE) material can potentially provide an alternative way to further reduce the power consumption in ultra-scaled devices and thus has been of great interest in technology and science in the past decade. In this article, we present a physical picture for a better understanding of the hysteresis-free charge boost effect observed experimentally in metal-ferroelectric-insulator-metal (MFIM) capacitors. By introducing the dielectric (DE) leakage and interfacial trapped charges, our simulations of the hysteresis loops are in a strong agreement with the experimental measurements, suggesting the existence of an interfacial oxide layer at the FE-metal interface in metal-ferroelectric-metal (MFM) capacitors. Based on the pulse switching measurements, we find that the charge enhancement and hysteresis are dominated by the FE domain viscosity and DE leakage, respectively. Our simulation results show that the underlying mechanisms for the observed hysteresis-free charge enhancement in MFIM may be physically different from the alleged NC stabilization and capacitance matching. Moreover, the link between Merz's law and the phenomenological kinetic coefficient is discussed, and the possible cause of the residual charges observed after pulse switching is explained by the trapped charge dynamics at the FE-DE interface. The physical interpretation presented in this work can provide important insights into the NC effect in MFIM capacitors and future studies of low-power logic devices.
description: 9 pages, 7 captioned figures, 1 table
Pion physics in two flavor strong coupling lattice QED
Creators: name: Cecile, D. J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We consider the lattice field theory involving two flavors of staggered quarks which interact with $U_A(1)$ gauge fields in the strong coupling limit. For massless quarks, this theory has an $SU_L(2)\times SU_R(2) \times U_A(1)$ symmetry. We show explicitly how pions emerge through the phenomena of confinement in this theory. We also show how one can incorporate the physics of the anomaly in this theory. Thus, our approach is a good pedagogical tool to explain how pions arise in real QCD. Another advantage of our approach is that we can easily design efficient cluster algorithms to compute a variety of quantities close to the chiral limit, thus allowing us to understand the low energy physics in a QCD-like setting from first principles.
description: 7 pages, 1 figure, Poster presented at XXIV International Symposium on Lattice Field Theory (Lattice 2006, Tucson, Arizona)
Guaranteed Verification of Dynamic Systems
Creators: name: Schwab, Stefan
Publisher: name: Karlsruhe
Year: 2019

description: Diese Arbeit beschreibt einen neuen Spezifikations- und Verifikationsansatz für dynamische Systeme. Der neue Ansatz ermöglicht dabei Ergebnisse, die per Definition frei von Fehlern 2. Art sind. Dies bedeutet, dass das Ergebnis der Verifikation keine versteckten Fehler enthalten kann. Somit können zuverlässige Ergebnisse für die Analyse von sicherheitskritischen Systemen generiert werden. Dazu wird ein neues Verständnis von mengenbasierter Konsistenz dynamischer Systeme mit einer gegebenen Spezifikation eingeführt. Dieses basiert auf der Verwendung von Kaucher Intervall Arithmetik zur Einschließung von Messdaten. Konsistenz wird anhand der vereinigten Lösungsmenge der Kaucher Arithmetik definiert. Dies führt zu mathematisch garantierten Ergebnissen. Die resultierende Methode kann das spezifizierte Verhalten eines dynamischen System auch im Falle von Rauschen und Sensorungenauigkeiten anhand von Messdaten verifizieren. Die mathematische Beweisbarkeit der Konsistenz wird für eine große Klasse von Systemen gezeigt. Diese beinhalten zeitinvariante, intervallartige und hybride Systeme, wobei letztere auch zur Beschreibung von Nichtlinearitäten verwendet werden können. Darüber hinaus werden zahlreiche Erweiterungen dargestellt. Diese führen bis hin zu einem neuartigen iterativen Identifikations- und Segmentierungsverfahren für hybride Systeme. Dieses ermöglicht die Verfikation hybrider Systeme auch ohne Wissen über Schaltzeitpunkte. Die entwickelten Verfahren können darüber hinaus zur Diagnose von dynamischen Systemen verwendet werden, falls eine ausreichend schnelle Berechnung der Ergebnisse möglich ist. Die Verfahren werden erfolgreich auf eine beispielhafte Variation verschiedener Tanksysteme angewendet. Die neuen Theorien, Methoden und Algortihmen dieser Arbeit bilden die Grundlage für eine zuverlässige Analyse von hochautomatisierten sicherheitskritischen Systemen.
Solving the octant degeneracy with the Silver channel
Creators: name: Meloni, D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the potential of the combination of the golden ($ν_e \to ν_μ$) and silver ($ν_e \to ν_τ$) channels to solve the octant degeneracy affecting the measurement of $θ_{13}$ and $δ$ at future neutrino factories. To search for $τ$ leptons produced in $ν_τ$ charged-current interactions, we consider two different detectors: the Emulsion Cloud Chamber detector (ECC) and the Liquid Argon Time Projection Chamber (LAr TPC). We show that, when using similar detector masses, the upgraded version of the ECC detector (sensitive also to hadronic $τ$ decay modes) and the LAr TPC detector have comparable sensitivities to the octant of $θ_{23}$, being able to discriminate the two solutions for $\sin^2 (2θ_{13}) \gtrsim 10^{-3}$ at 3$σ$ level if $θ_{23}=40^\circ$. We also show that the same setups are able to see deviation from maximal mixing as small as $\sim$ (4-6)% (at 3$σ$) if $θ_{13}$ is close to its upper bound.
description: 9 pages and 8 figures
Assessing Automated Machine Learning service to detect COVID-19 from X-Ray and CT images: A Real-time Smartphone Application case study
Creators: name: Mustafiz, Razib
name: Mohsin, Khaled
Publisher: name: arXiv
Year: 2020
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: F.2.2
subject: 03

description: The recent outbreak of SARS COV-2 gave us a unique opportunity to study for a non interventional and sustainable AI solution. Lung disease remains a major healthcare challenge with high morbidity and mortality worldwide. The predominant lung disease was lung cancer. Until recently, the world has witnessed the global pandemic of COVID19, the Novel coronavirus outbreak. We have experienced how viral infection of lung and heart claimed thousands of lives worldwide. With the unprecedented advancement of Artificial Intelligence in recent years, Machine learning can be used to easily detect and classify medical imagery. It is much faster and most of the time more accurate than human radiologists. Once implemented, it is more cost-effective and time-saving. In our study, we evaluated the efficacy of Microsoft Cognitive Service to detect and classify COVID19 induced pneumonia from other Viral/Bacterial pneumonia based on X-Ray and CT images. We wanted to assess the implication and accuracy of the Automated ML-based Rapid Application Development (RAD) environment in the field of Medical Image diagnosis. This study will better equip us to respond with an ML-based diagnostic Decision Support System(DSS) for a Pandemic situation like COVID19. After optimization, the trained network achieved 96.8% Average Precision which was implemented as a Web Application for consumption. However, the same trained network did not perform the same like Web Application when ported to Smartphone for Real-time inference. Which was our main interest of study. The authors believe, there is scope for further study on this issue. One of the main goal of this study was to develop and evaluate the performance of AI-powered Smartphone-based Real-time Application. Facilitating primary diagnostic services in less equipped and understaffed rural healthcare centers of the world with unreliable internet service.
description: 21 Pages, 6 Tables
Input-output relations for multiport ring cavities
Creators: name: Paris, Matteo G. A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum input-output relations for a generic $n$-port ring cavity are obtained by modeling the ring as a cascade of $n$ interlinked beam splitters. Cavity response to a beam impinging on one port is studied as a function of the beam-splitter reflectivities and the internal phase-shifts. Interferometric sensitivity and stability are analyzed as a function of the number of ports.
description: 6 pages, 5 figures (low-res)
Δικαιοσύνη και Παιδεία στην Πολιτεία του Πλάτωνος:
Creators: name: Καρολίδου, Αθηνά Μιχαήλ
Publisher: name: Aristotle University of Thessaloniki
Year: 2010
Subjects: Δικαιοσύνη
Παιδεία
Πολιτεία
Justice
Education
Republic

description: Στην Πολιτεία ο Πλάτων επιχειρεί αρχικά να επεξηγήσει την πρωταρχική έννοια της κοινωνικής δικαιοσύνης και έπειτα να καθορίσει μια ανάλογη έννοια της ατομικής δικαιοσύνης, προκειμένου να αποδείξει ότι η δικαιοσύνη είναι χρήσιμη αυτή καθεαυτή. Προσδιορίζει την πολιτική αρετή ως την αρμονία σε ένα συγκροτημένο κοινωνικό σώμα. Μια ιδανική πολιτεία στηρίζεται σε τρεις τάξεις ανθρώπων, των παραγωγών, των επικούρων και των φυλάκων. Μια κοινωνία είναι δίκαιη όταν οι σχέσεις μεταξύ αυτών των τριών τάξεων είναι ορθές. Ισχυρίζεται ότι η ατομική δικαιοσύνη αντανακλά την πολιτική δικαιοσύνη. Η ψυχή κάθε ατόμου έχει μια τρίπτυχη δομή ανάλογη προς τις τρεις τάξεις της κοινωνίας. Στην πραγματικότητα, κάθε κοινωνική τάξη κυριαρχείται από ένα από τα τρία μέρη της ψυχής. Οι παραγωγοί κυριαρχούνται από τις επιθυμίες τους, οι φύλακες κυριαρχούνται από το θυμό τους, οι νομοθέτες κυριαρχούνται από το λογικό τους. Ο Πλάτων εστιάζει σε μια ανώτερη Πολιτεία στην οποία κανείς δεν αποκαλεί τίποτα «δικό του» και στην οποία οι βασιλιάδες είναι φιλόσοφοι οι οποίοι ασχολούνται κυρίως με τη δομή μιας ανώτερης Πολιτείας ως επακόλουθο μιας ανώτερης παιδείας. Το πρώτο μέλημα των βασιλιάδων φιλοσόφων είναι η παιδεία η οποία στοχεύει σε μια προσεγμένη θρησκεία και ηθική, σε περισσότερη απλότητα στη μουσική και τη γυμναστική, σε μια πιο ρωμαλέα ποίηση και σε μια υψηλότερη αρμονία ανάμεσα στο ατομικό και το κοινωνικό.
description: In The Republic Plato tries first to explicate the primary notion of societal justice, and then to derive an analogous concept of individual justice, in order to show that justice is worthwhile in and of itself. He identifies political justice as harmony in a structured societal body. An ideal society consists of three main classes of people—producers, auxiliaries and guardians. A society is just when relations between these three classes are right. He claims that individual justice mirrors political justice. The soul of every individual has a three part structure analagous to the three classes of a society. Each of the three classes of society, in fact, is dominated by one of the three parts of the soul. Producers are dominated by their appetites, guardians are dominated by their spirits, rulers are dominated by their rational faculties. Plato focus on a higher State, in which no one calls anything “his own”, and in which kings are philosophers which are mainly occupied with the construction of a higher State according to a higher education.
description: The first care of kings philosophers is to be education, providing only for an improved religion and morality, and more simplicity in music and gymnastic, a manlier strain of poetry, and greater harmony of the individual and the State.
Cardiovascular response to agreement and disagreement: towards explaining the beneficial effect of social support
Creators: name: Lenz, Joseph William
Publisher: name: University of British Columbia
Year: 2009

description: Social support has been associated with reduced mortality and morbidity from a number of causes. To assess possible mechanisms of action relating to cardiovascular (CV) responsiveness, 90 male and female university students delivered a five-minute speech on a controversial topic to a same-sex laboratory confederate. Subjects were randomly assigned to one of three conditions in which the confederate either (a) agreed with the subject, (b) remained impassive (neutral), or (c) disagreed with the subject. Blood pressure (SBP and DBP) and heart rate (HR.) were monitored throughout the experiment. Self-report measures of state self-esteem and affective state were taken pre- and post-task, and reactions to the task were assessed with post-task self-report measures. Subjects reported strong differences in supportiveness of the confederate in the three conditions. Self-report data indicated increase in arousal during the speech (a finding synchronous with CV data), and they reported the Disagree condition to be less pleasant than the Agree condition. CV data were analyzed as a 2 x 3 (sex by experimental condition) repeated measures ANOVA assessing changes from baseline to speech task. Sex differences on CV measures matched patterns generally reported: Men had higher SBP and lower HR than women. All CV measures increased significantly and substantially during the speech task. HR was higher in the Disagree and Neutral conditions than in the Agree condition. SBP and DBP did not differ by condition. There were no sex by condition interactions; however, there was a trend towards men’s HR increasing more in the neutral condition and women’ more in the disagree condition. These data partially support earlier findings in similar experiments while suggesting that subtleties of context, task selection, and content of supportive interaction may have significant impact on the degree to which social support attenuates CV response to social stressors. Unanswered questions for future research are delineated, and implications for designing and implementing interventions that enhance social support are discussed.
Nano-mechanics driven by Andreev tunneling
Creators: name: Parafilo, A. V.
name: Gorelik, L. Y.
name: Fistul, M.
name: Park, H. C.
name: Shekhter, R. I.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We predict and analyze mechanical instability and corresponding self-sustained mechanical oscillations occurring in a nanoelectromechanical system composed of a metallic carbon nanotube (CNT) suspended between two superconducting leads and coupled to a scanning tunneling microscope (STM) tip. We show that such phenomena are realized in the presence of both the coherent Andreev tunneling between the CNT and superconducting leads, and an incoherent single electron tunneling between the voltage biased STM tip and CNT. Treating the CNT as a single-level quantum dot, we demonstrate that the mechanical instability is controlled by the Josephson phase difference, relative position of the electron energy level, and the direction of the charge flow. It is found numerically that the emergence of the self-sustained oscillations leads to a substantial suppression of DC electric current.
A new scale in the sky
Creators: name: Gasperini, M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The existence of a new ultraviolet scale $Λ=g M_P$ for effective theories with gravity and U(1) gauge fields has recently been conjectured as a possible criterion for distinguishing parts of the swampland from the string landscape. Here we discuss a possible phenomenological signature of this scale, for electromagnetic fields, in astrophysical observations.
description: 6 pages, 2 figures included with epsfig. Essay written for the 2006 Awards for Essays on Gravitation (Gravity Research Foundation), and awarded with "Honorable Mention". To appear in Int. J Mod. Phys. D (December 2006, Special Issue)
The coherent measurement cost of coherence distillation
Creators: name: Narasimhachar, Varun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum coherence -- an indispensable resource for quantum technologies -- is known to be distillable from a noisy form using operations that cannot create it. However, distillation exacts a hidden coherent measurement cost, which has not previously been examined. We devise the target effect construction to characterize this cost through detailed conditions on the coherence-measuring structure necessary in any process realizing exact (maximal or non-maximal) or approximate distillation. As a corollary, we lower-bound the requisite measurement coherence, as quantified by operationally-relevant measures. We then consider the asymptotic limit of distilling from many copies of a given noisy coherent state, where we offer rigorous arguments to support the conjecture that the (necessary and sufficient) coherent measurement cost scales extensively in the number of copies. We also show that this cost is no smaller than the coherence of measurements saturating the scaling law in the generalized quantum Stein's lemma. Our results and conjectures apply to any task whereof coherence distillation is an incidental outcome (e.g., incoherent randomness extraction). But if pure coherence is the only desired outcome, our conjectures would have the cautionary implication that the measurement cost is often higher than the distilled yield, in which case coherence should rather be prepared afresh than distilled from a noisy input.
description: Quantum-journal version. 30+11 pages, 1 figure
Moduli of Legendrian foliations and quadratic differentials in the Heisenberg group
Creators: name: Timsit, Robin
Publisher: name: arXiv
Year: 2020
Subjects: subject: Differential Geometry (math.DG)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 32V05, 32G07

description: The aim of the paper is to prove the following result concerning moduli of curve families in the Heisenberg group. Let $Ω$ be a domain in the Heisenberg group foliated by a family $Γ$ of legendrian curves. Assume that there is a quadratic differential $q$ on $Ω$ in the kernel of an operator defined in \cite{Tim2} and every curve in $Γ$ is a horizontal trajectory for $q$. Let $l_Γ: Ω\rightarrow ]0,+\infty[$ be the function that associates to a point $p\in Ω$, the $q$-length of the leaf containing $p$. Then, the modulus of $Γ$ is \[ M_4 (Γ) = \int_Ω\frac{|q|^2}{(l_Γ) ^4} \mathrm{d} L^3.\]
Suboptimal quantum-error-correcting procedure based on semidefinite programming
Creators: name: Yamamoto, Naoki
name: Hara, Shinji
name: Tsumura, Koji
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper, we consider a simplified error-correcting problem: for a fixed encoding process, to find a cascade connected quantum channel such that the worst fidelity between the input and the output becomes maximum. With the use of the one-to-one parametrization of quantum channels, a procedure finding a suboptimal error-correcting channel based on a semidefinite programming is proposed. The effectiveness of our method is verified by an example of the bit-flip channel decoding.
description: 6 pages, no figure, Some notations differ from those in the PRA version
Gas-phase formation of acetaldehyde: review and new theoretical computations
Creators: name: Vazart, Fanny
name: Ceccarelli, Cecilia
name: Balucani, Nadia
name: Bianchi, Eleonora
name: Skouteris, Dimitrios
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Among all the interstellar complex organic molecules (iCOMs), acetaldehyde is one of the most widely detected species. The question of its formation route(s) is, therefore, of a major interest regarding astrochemical models. In this paper, we provide an extensive review of the gas-phase formation paths that were, or are, reported in the literature and the major astrochemical databases. Four different gas-phase formation routes stand out : (1) CH$_3$OCH$_3$ + H$^+$ / CH$_3$CHOH$^+$ + e$^-$, (2) C$_2$H$_5$ + O($^3$P), (3) CH$_3$OH + CH and (4) CH$_3$CH$_2$OH + OH / CH$_3$CHOH + O($^3$P). Paths (2) and (3) were not studied neither via laboratory or theoretical works in the low temperature and density regime valid for the ISM. Thus, we carried out new accurate quantum chemistry computations. A theoretical kinetics study at low temperatures (7-300 K), adopting the RRKM scheme, was also performed. We confirm that reaction (2) is efficient in forming acetaldehyde in the 7-300 temperature range (alpha = 1.21 x 10$^{-10}$ cm$^3$ s$^{-1}$ and beta = 0.16). On the contrary, our new computations disprove the formation of acetaldehyde through reaction (3) (alpha = 1.84, 0.67 x 10$^{-13}$ cm$^3$ s$^{-1}$ and beta = -0.07, -0.95). Path (1) was showed to be inefficient too by recent computations, while path (4) was formerly considered for glycolaldehyde formation, having acetaldehyde as a by-product. In conclusions, of the four above paths only two, the (2) and (4), are potentially efficient gas-phase reaction routes for the formation of acetaldehyde and we encourage astrochemical modellers to only consider them. Comparison with astronomical observations suggest that path (4) may actually play the major role.
An Implementation of a Positive Operator Valued Measure
Creators: name: Yan, Feng-Li
name: Gao, Ting
name: Li, You-Cheng
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: An implementation of the positive operator valued measure (POVM) is given. By using this POVM one can realize the probabilistic teleportation of an unknown two-particle state.
description: 4 pages, no figure
Παρασκευή και ιδιότητες μικροσφαιρών που περιέχουν αυτοσχηματιζόμενα μικρογαλακτώματα:
Creators: name: Ματσαρίδου, Ειρήνη Χαραλάμπους
Publisher: name: Aristotle University of Thessaloniki
Year: 2010
Subjects: Μικρογαλακτώματα
Μικροσφαίρες
Αυτογαλακτωματοποιούμενα συστήματα
Microemulsions
Pellets
Self-emulsifying systems

description: Στην παρούσα εργασία παρασκευάστηκαν μικροσφαίρες κυτταρίνης με ενσωματωμένο αυτοσχηματιζόμενο μικρογαλάκτωμα (Self-emulsifying System, SES) μίγματος ελαίου τασενεργής. Για την παρασκευή των μικρογαλακτωμάτων χρησιμοποιήθηκε ως έλαιο τριγλυκερίδια μεσαίας αλύσου (C8-C10), ως εξωτερική φάση απιονισμένο νερό και ως τασενεργές τρία αιθοξυλιωμένα γλυκερίδια παράγωγα του καστορέλαιου, Cremophor τύποι RH 40, EL και ELP, ένας εστέρας υδροξυστεατικού οξέος, Solutol HS-15, και δύο συμπολυμερή πολυαιθυλενογλυκόλης-πολυπροπανόλης, Lutrol 188 και 407. Τα μικρογαλακτώματα που παρασκευάστηκαν χαρακτηρίστηκαν ως προς τη σταθερότητα, το μέγεθος σταγονιδίων και την επίδραση της αραίωσης. Οι μικροσφαίρες κυτταρίνης που παρασκευάστηκαν, χαρακτηρίστηκαν ως προς τις μικροσωματιδικές τους ιδιότητες (μέγεθος, σχήμα και πυκνότητα) και το χρόνο καταθρυμματισμού τους . Τέλος μελετήθηκε η ικανότητα επανασχηματισμού των μικρογαλακτωμάτων μετά από εμβάπτιση των μικροσφαιρών σε νερό. Η ικανότητα επανασχηματισμού εκτιμήθηκε, μελετώντας το ρυθμό και το βαθμό επανασχηματισμού των μικρογαλακτωμάτων, το μέγεθος των σταγονιδίων που λαμβάνονταν συγκριτικά με τα αρχικά μικρογαλακτώματα, την επίδραση του είδους και της περιεκτικότητας της τασενεργής, καθώς και την επίδραση της μεθόδου ξήρανσης (ή πορώδους.
description: In the present work, pellets of microcrystalline cellulose (MCC) with incorporated SES (Self-Emulsifying System) microemulsions were prepared. For the preparation of microemulsion was used medium chain triglyceride C8-C10 (MCT) as the oil phase, and deionised water as the external phase. Surfactants that were used were three ethoxylateded glycerides C-RH, C-EL, C-ELP (castor oil derivatives), a polyethylene glycol ester with hydrostearic acid , Solutol HS-15, and two co-polymers (polyethylene glycol-plpropylene glycol). The microemulsions were characterized for their stability, droplet size and their robustness in dilutions. The formulated pellets were characterized regarding their size, shape and density as well as their disintegration time. Finally, the ability or re-emuslification of microemulsions was examined after immersion of pellets in water. The assesstment of re-emulsification ability was estimated according to the rate and degree of reformation, the droplet size comparing with the initial measurements, the influence of the type and concentration of the surfactant as well as the drying method (porosity) that was followed.
Baryon Resonances Observed at BES
Creators: name: Zou, B. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The $ψ$ decays provide a novel way to explore baryon spectroscopy and baryon structure. The baryon resonances observed from $ψ$ decays at BES are reviewed. The implications and prospects at upgraded BESIII/BEPCII are discussed.
description: Plenary talk at MENU2007, 12 pages
An Approach to State Signal Shaping by Limit Cycle Model Predictive Control
Creators: name: Yáñez, Carlos Cateriano
name: Lichtenberg, Gerwald
name: Pangalos, Georg
name: Sáez, Javier Sanchis
Publisher: name: arXiv
Year: 2020
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: A novel nonlinear model predictive control approach for state signal shaping is proposed. The control strategy introduces a residual shape cost kernel based on the dynamics of circular limit cycles from a supercritical Neimark-Sacker bifurcation normal form. This allows the controller to impose a fundamental harmonic state signal shape with a specific frequency and amplitude. An application example for harmonic compensation in distribution grids integrated with renewable energies is presented. The controller is tasked with the calculation of the reference current for an active power filter used for load compensation. The results achieved are successful, reducing the harmonic distortion to satisfactory levels while ensuring the correct frequency and amplitude.
description: \copyright 2020 Carlos Cateriano Y\'a\~nez, Gerwald Lichtenberg, Georg Pangalos and Javier Sanchis S\'aez. This work has been accepted to IFAC for publication under a Creative Commons Licence CC-BY-NC-ND
Typicality versus thermality: An analytic distinction
Creators: name: Balasubramanian, Vijay
name: Czech, Bartlomiej
name: Hubeny, Veronika
name: Larjo, Klaus
name: Rangamani, Mukund
name: Simon, Joan
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In systems with a large degeneracy of states such as black holes, one expects that the average value of probe correlation functions will be well approximated by the thermal ensemble. To understand how correlation functions in individual microstates differ from the canonical ensemble average and from each other, we study the variances in correlators. Using general statistical considerations, we show that the variance between microstates will be exponentially suppressed in the entropy. However, by exploiting the analytic properties of correlation functions we argue that these variances are amplified in imaginary time, thereby distinguishing pure states from the thermal density matrix. We demonstrate our general results in specific examples and argue that our results apply to the microstates of black holes.
description: 22 pages + appendices, 3 eps figures
Computational approach to quantum encoder design for purity optimization
Creators: name: Yamamoto, Naoki
name: Fazel, Maryam
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper, we address the problem of designing a quantum encoder that maximizes the minimum output purity of a given decohering channel, where the minimum is taken over all possible pure inputs. This problem is cast as a max-min optimization problem with a rank constraint on an appropriately defined matrix variable. The problem is computationally very hard because it is non-convex with respect to both the objective function (output purity) and the rank constraint. Despite this difficulty, we provide a tractable computational algorithm that produces the exact optimal solution for codespace of dimension two. Moreover, this algorithm is easily extended to cover the general class of codespaces, in which case the solution is suboptimal in the sense that the suboptimized output purity serves as a lower bound of the exact optimal purity. The algorithm consists of a sequence of semidefinite programmings and can be performed easily. Two typical quantum error channels are investigated to illustrate the effectiveness of our method.
description: 13 pages, 1 figure
Hamiltonian Learning via Shadow Tomography of Pseudo-Choi States
Creators: name: Castaneda, Juan
name: Wiebe, Nathan
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We introduce a new approach to learn Hamiltonians through a resource that we call the pseudo-Choi state, which encodes the Hamiltonian in a state using a procedure that is analogous to the Choi-Jamiolkowski isomorphism. We provide an efficient method for generating these pseudo-Choi states by querying a time evolution unitary of the form $e^{-iHt}$ and its inverse, and show that for a Hamiltonian with $M$ terms the Hamiltonian coefficients can be estimated via classical shadow tomography within error $ε$ in the $2$-norm using $\widetilde{O}\left(\frac{M}{t^2ε^2}\right)$ queries to the state preparation protocol, where $t \le \frac{1}{2\left\lVert H \right\rVert}$. We further show an alternative approach that eschews classical shadow tomography in favor of quantum mean estimation that reduces this cost (at the price of many more qubits) to $\widetilde{O}\left(\frac{M}{tε}\right)$. Additionally, we show that in the case where one does not have access to the state preparation protocol, the Hamiltonian can be learned using $\widetilde{O}\left(\frac{α^4M}{ε^2}\right)$ copies of the pseudo-Choi state. The constant $α$ depends on the norm of the Hamiltonian, and the scaling in terms of $α$ can be improved quadratically if using pseudo-Choi states of the normalized Hamiltonian. Finally, we show that our learning process is robust to errors in the resource states and to errors in the Hamiltonian class. Specifically, we show that if the true Hamiltonian contains more terms than we believe are present in the reconstruction, then our methods give an indication that there are Hamiltonian terms that have not been identified and will still accurately estimate the known terms in the Hamiltonian.
description: 64 pages, 3 figures. Pages 50-64 contain appendices
Mapping the stellar age of the Milky Way bulge with the VVV. III. High resolution reddening map
Creators: name: Surot, F.
name: Valenti, E.
name: Gonzalez, O. A.
name: Zoccali, M.
name: Sökmen, E.
name: Hidalgo, S. L.
name: Minniti, D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The detailed study of the Galactic bulge stellar population necessarily requires an accurate representation of the interstellar extinction particularly toward the Galactic plane and center, where the severe and differential reddening is expected to vary on sub-arcmin scales. Although recent infrared surveys have addressed this problem by providing extinction maps across the whole Galactic bulge area, dereddened color-magnitude diagrams near the plane and center appear systematically undercorrected, suggesting the need for higher resolutions. These undercorrections affect any stellar study sensitive to color (e.g. star formation history analysis via color-magnitude diagram fitting), either making them inaccurate or limiting them to small low/stable extinction windows where this value is better constrained. We aim at providing a high-resolution (2 arcmin to $\sim$ 10 arcsec) color excess map for the VVV bulge area, in $\mathrm{J}-\mathrm{K}_s$ color. We use the MW-BULGE-PSFPHOT catalogs sampling $\sim$ 300 deg$^2$ across the Galactic bulge ($|l| < 10^\circ$ and $-10^\circ < b < 5^\circ$) to isolate a sample of red clump and red giant branch stars, for which we calculate average $\mathrm{J}-\mathrm{K}_s$ color in a fine spatial grid in $(l, b)$ space. We obtain a E$(\mathrm{J}-\mathrm{K}_s)$ map spanning the VVV bulge area of roughly 300 deg$^2$, with the equivalent to a resolution between $\sim$ 1 arcmin for bulge outskirts ($l < -6^\circ$) to below 20 arcsec within the central $|l| < 1^\circ$, and below 10 arcsec for the innermost area ($|l| < 1^\circ$ and $|b| < 3^\circ$). The result is publicly available at http://basti-iac.oa-teramo.inaf.it/vvvexmap/
description: 11 pages, 5 figures, Accepted for publication on A&A. Map accessible through http://basti-iac.oa-teramo.inaf.it/vvvexmap/
A natural extension to the convex hull problem and a novel solution
Creators: name: Mao, Xiao
Publisher: name: arXiv
Year: 2020
Subjects: subject: Computational Geometry (cs.CG)
subject: FOS: Computer and information sciences
subject: F.2.2

description: We study a natural extension to the well-known convex hull problem by introducing multiplicity: if we are given a set of convex polygons, and we are allowed to partition the set into multiple components and take the convex hull of each individual component, what is the minimum total sum of the perimeters of the convex hulls? We show why this problem is intriguing, and then introduce a novel algorithm with a run-time cubic in the total number of vertices. In the case that the input polygons are disjoint, we show an optimization that achieves a run-time that, in most cases, is cubic in the total number of polygons, within a logarithmic factor.
description: The result is non-original and inferior compared to https://dl.acm.org/doi/pdf/10.1145/3188745.3188878
Non-Perturbative Formulation of Non-Critical String Models
Creators: name: Alexandre, Jean
name: Ellis, John
name: Mavromatos, Nikolaos E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We apply to non-critical bosonic Liouville string models, characterized by a central-charge deficit Q, a new non-perturbative renormalization-group technique based on a functional method for controlling the quantum fluctuations. We demonstrate the existence of a renormalization-group fixed point of Liouville string theory as Q to 0, in which limit the target space-time is Minkowski and the dynamics of the Liouville field is trivial, as it neither propagates nor interacts. This calculation supports in a non-trival manner the identification of the zero mode of the Liouville field with the target time variable, up to a crucial minus sign.
description: 16 pages latex, 2 eps figures
Redox electrodes for electrochemical energy storage and thermal energy conversion
Creators: name: Palanisamy, Rupa Ranjani
name: Narayanasamy, Padmanathan
name: Biswas, Subhajit
name: Holmes, Justin D.
name: Razeeb, Kafil M.
Publisher: name: Zenodo
Year: 2024
Subjects: energy harvesting
waste heat
waste heat recovery
nanofluidics
electrochemistry
nanochannels
heat to electrical energy
Heat to electricity conversion
Supercapacitors
electrodes
Metal selenide
thermoelectrochemical cell

description: ABSTRACT:

Thermo-electrochemical cells (TECs) are a new kind of energy conversion device that can convert thermal energy into electricity. TECs can be integrated with supercapacitors (SCs) to store the generated electricity. TECs consist of two major components namely electrodes and electrolyte. The selection of appropriate electrode materials with rational nanostructured design should improve the thermoelectrochemical performance of the TECs.  In this study, bilayer of nickel cobalt selenide nanowires was successfully grown on activated carbon cloth (NCS/ACC) via one step hydrothermal method and its electrochemical performance was evaluated and compared with nickel selenide (NS/ACC) and cobalt selenide on activated carbon cloth (CS/ACC). NCS/ACC exhibited the best electrochemical performance compared to other electrodes, leading to its further investigation in an asymmetric supercapacitor (ASC) configuration with activated carbon (AC) as the cathode. The NCS/ACC ASC demonstrated superior rate capability with 85% capacitive retention after 10,000 cycles, along with a high specific energy (28 Wh kg-1) and specific power (646 W kg-1). Subsequently, the NCS/ACC electrode was employed in a thermo-electrochemical cell (TEC) for heat to electricity conversion, revealing a Seebeck coefficient of -2 mV/K with high reversibility. Thereby, NCS/ACC electrode can be a suitable candidate for bi-functional applications, showcasing its efficacy in both supercapacitors and heat to electricity conversion technologies. 

KEYWORDS: Heat to electricity conversion; Supercapacitors; Electrodes; Metal selenide; Thermo-Electrochemical Cell.
description: TRANSLATE is a €3.4 million EU-funded research project that aims to develop a new nanofluidic platform technology to effectively convert waste heat to electricity. This technology has the potential to improve the energy efficiency of many devices and systems, and provide a radically new zero-emission power source. The TRANSLATE project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 964251, for the action of 'The Recycling of waste heat through the Application of Nanofluidic ChannelS: Advances in the Conversion of Thermal to Electrical energy'. More information can be be found on the TRANSLATE project website: https://translate-energy.eu/