TY - JOUR T1 - Long-term monitoring of the ANTARES optical module efficiencies using \(^{40}\)K decays in sea water JF - European Physical Journal C N2 - Cherenkov light induced by radioactive decay products is one of the major sources of background light for deep-sea neutrino telescopes such as ANTARES. These decays are at the same time a powerful calibration source. Using data collected by the ANTARES neutrino telescope from mid 2008 to 2017, the time evolution of the photon detection efficiency of optical modules is studied. A modest loss of only 20% in 9 years is observed. The relative time calibration between adjacent modules is derived as well. KW - Neutrino Telescope KW - Dark-Matter KW - Calibration KW - System KW - Light Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227815 VL - 78 ER - TY - JOUR A1 - Albert, A. A1 - André, M. A1 - Anghinolfi, M. A1 - Anton, G. A1 - Ardid, M. A1 - Aubert, J.-J. A1 - Aublin, J. A1 - Avgitas, T. A1 - Baret, B. A1 - Barrios-Martít, J. A1 - Basa, S. A1 - Belhorma, B. A1 - Bertin, V. A1 - Biagi, S. A1 - Bormuth, R. A1 - Boumaaza, J A1 - Bourret, S. A1 - Bouwhuis, M. C. A1 - Brânzas, H. A1 - Bruijn, R. A1 - Brunner, J. A1 - Busto, J. A1 - Capone, A. A1 - Caramete, L. A1 - Carr, J. A1 - Celli, S. A1 - Chabab, M. A1 - Cherkaoui El Moursli, R. A1 - Chiarusi, T. A1 - Circella, M. A1 - Coelho, J. A. B. A1 - Coleiro, A. A1 - Colomer, M A1 - Coniglione, R. A1 - Costantini, H. A1 - Coyle, P. A1 - Creusot, A. A1 - Díaz, A. F. A1 - Deschamps, A. A1 - Distefano, C. A1 - Di Palma, I. A1 - Domi, A. A1 - Donzaud, C. A1 - Dornic, D. A1 - Drouhin, D. A1 - Eberl, T. A1 - El Bojaddaini, I. A1 - El Khayati, N. A1 - Elsässer, D. A1 - Enzenhöfer, A. A1 - Ettahiri, A. A1 - Fassi, F. A1 - Felis, I. A1 - Fermani, P. A1 - Ferrara, G. A1 - Fusco, L. A. A1 - Gay, P. A1 - Glotin, H. A1 - Grégoire, T. A1 - Gracia Ruiz, R. A1 - Graf, K. A1 - Hallmann, S. A1 - van Haren, H. A1 - Heijboer, A. J. A1 - Hello, Y. A1 - Hernández-Rey, J. J. A1 - Hößl, J. A1 - Hofestädt, J. A1 - Illuminati, G. A1 - de Jong, M. A1 - Jongen, M. A1 - Kadler, M. A1 - Kalekin, O. A1 - Katz, U. A1 - Khan-Chowdhury, N. R. A1 - Kouchner, A. A1 - Kreter, M. A1 - Kreykenbohm, I. A1 - Kulikovskiy, V. A1 - Lachaud, C. A1 - Lahmann, R. A1 - Lefèvre, D. A1 - Leonora, E. A1 - Levi, G. A1 - Lotze, M. A1 - Loucatos, S. A1 - Marcelin, M. A1 - Margiotta, A. A1 - Marinelli, A. A1 - Martínez-Mora, J. A. A1 - Mele, R. A1 - Melis, K. A1 - Migliozzi, P. A1 - Moussa, A. A1 - Navas, S. A1 - Nezri, E. A1 - Nuñez, A. A1 - Organokov, M. A1 - Pavalas, G. E. A1 - Pellegrino, C. A1 - Piattelli, P. A1 - Popa, V. A1 - Pradier, T. A1 - Quinn, L. A1 - Racca, C. A1 - Randazzo, N. A1 - Riccobene, G. A1 - Sánchez-Losa, A. A1 - Saldaña, M. A1 - Salvadori, I. A1 - Samtleben, D. F. E. A1 - Sanguineti, M. A1 - Sapienza, P. A1 - Schüssler, F. A1 - Spurio, M. A1 - Stolarczyk, Th. A1 - Taiuti, M. A1 - Tayalati, Y. A1 - Trovato, A. A1 - Vallage, B. A1 - Van Elewyck, V. A1 - Versari, F. A1 - Vivolo, D. A1 - Wilms, J. A1 - Zaborov, D. A1 - Zornoza, J. D. A1 - Zúñiga, J. T1 - The cosmic ray shadow of the Moon observed with the ANTARES neutrino telescope JF - European Physical Journal C N2 - One of the main objectives of the ANTARES telescope is the search for point- like neutrino sources. Both the pointing accuracy and the angular resolution of the detector are important in this context and a reliableway to evaluate this performance is needed. In order to measure the pointing accuracy of the detector, one possibility is to study the shadow of the Moon, i. e. the deficit of the atmospheric muon flux from the direction of the Moon induced by the absorption of cosmic rays. Analysing the data taken between 2007 and 2016, theMoon shadow is observed with 3.5s statistical significance. The detector angular resolution for downwardgoing muons is 0.73. +/- 0.14.. The resulting pointing performance is consistent with the expectations. An independent check of the telescope pointing accuracy is realised with the data collected by a shower array detector onboard of a ship temporarily moving around the ANTARES location. KW - Atmospheric muons Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227802 VL - 78 ER - TY - THES A1 - Eck, Philipp T1 - Symmetry Breaking and Spin-Orbit Interaction on the Triangular Lattice T1 - Symmetriebruch und Spin-Bahn-Kopplung im Dreiecksgitter N2 - Since the prediction of the quantum spin Hall effect in graphene by Kane and Mele, \(Z_2\) topology in hexagonal monolayers is indissociably linked to high-symmetric honeycomb lattices. This thesis breaks with this paradigm by focusing on topological phases in the fundamental two-dimensional hexagonal crystal, the triangular lattice. In contrast to Kane-Mele-type systems, electrons on the triangular lattice profit from a sizable, since local, spin-orbit coupling (SOC) and feature a non-trivial ground state only in the presence of inversion symmetry breaking. This tends to displace the valence charge form the atomic position. Therefore, all non-trivial phases are real-space obstructed. Inspired by the contemporary conception of topological classification of electronic systems, a comprehensive lattice and band symmetry analysis of insulating phases of a \(p\)-shell on the triangular lattice is presented. This reveals not only the mechanism at the origin of band topology, the competition of SOC and symmetry breaking, but sheds also light on the electric polarization arising from a displacement of the valence charge centers from the nuclei, i. e., real-space obstruction. In particular, the competition of SOC versus horizontal and vertical reflection symmetry breaking gives rise to four topologically distinct insulating phases: two kinds of quantum spin Hall insulators (QSHI), an atomic insulator and a real-space obstructed higher-order topological insulator. The theoretical analysis is complemented with state-of-the-art first principles calculations and experiments on trigonal monolayer adsorbate systems. This comprises the recently discovered triangular QSHI indenene, formed by In atoms, and focuses on its topological classification and real-space obstruction. The analysis reveals Kane-Mele-type valence bands which profit from the atomic SOC of the triangular lattice. The realization of a HOTI is proposed by reducing SOC by considering lighter adsorbates. Further the orbital Rashba effect is analyzed in AgTe, a consequence of mirror symmetry breaking, the formation of local angular momentum polarization and SOC. As an outlook beyond topology, the Fermi surface and electronic susceptibility of Group V adsorbates on silicon carbide are investigated. In summary, this thesis elucidates the interplay of symmetry breaking and SOC on the triangular lattice, which can promote non-trivial insulating phase. N2 - Seit der Vorhersage des Quanten-Spin-Hall-Effekts in Graphen durch Kane und Mele wird die \(Z_2\) Topologie in hexagonalen Monolagen unausweichlich mit hochsymmetrischen Honigwabengittern assoziiert. Diese Dissertation bricht mit diesem Paradigma, indem sie sich auf topologische Phasen im fundamentalen zweidimensionalen hexagonalem Kristall, dem Dreiecksgitter, konzentriert. Im Gegensatz zu Kane-Mele-artigen Systemen profitieren Elektronen im Dreiecksgitter von einer beträchtlichen, weil lokalen, Spin-Bahn-Kopplung (SBK). Ein nicht-trivialer Grundzustand erfordert das Brechen der Inversionssymmetrie. Gleichzeitig führt dies zu einer Dislokation der Valenzelektronen weg von der atomaren Position. Daher sind alle nicht-trivialen Phasen real-space obstructed. Inspiriert durch die gegenwärtige Auffassung der topologischen Klassifikation von elektronischen Systemen wird eine umfassende Analyse der Gitter- und Bandsymmetrie der isolierenden Phasen einer \(p\)-Schale auf dem Dreiecksgitter präsentiert. Dies offenbart nicht nur den bestimmenden Mechanismus der Bandtopologie, den Wettbewerb von SBK und Symmetriebruch. Letzterer bestimmt auch die elektrische Polarisation, die sich aus der Verschiebung der Valenzladungszentren von den Kernen ergibt. Insbesondere führt der Wettbewerb zwischen SBK und horizontalem sowie vertikalem Reflexionssymmetriebruch zu vier topologisch unterschiedlichen isolierenden Phasen: zwei Quanten-Spin-Hall Isolatoren (QSHI), ein atomarer Isolator und ein real-space obstructed Isolator höherer Ordnung. Die theoretische Analyse wird ergänzt durch moderne ab initio Berechnungen und Experimente an trigonalen Monolagen-Adsorbatsystemen. Dies umfasst den erst kürzlich entdeckten QSHI Indenene, basierend auf einer Dreieckslage von In Atomen, und konzentriert sich auf dessen topologische Klassifikation und Ladungsträgerlokalisation. Die Analyse ergibt Kane-Mele-artige Valenzbänder, die von der atomaren SBK des Dreiecksgitters profitieren. Die Realisierung eines HOTI wird vorgeschlagen, indem die SBK durch die Verwendung leichterer Adsorbate reduziert wird. Weiterhin wird der Orbitale Rashba-Effekt in AgTe analysiert, eine Folge der Spiegelsymmetriebruch, der Bildung von lokalem orbitalem Bahndrehimpuls und SBK. Als Ausblick über die Topologie hinaus werden die Fermi-Oberfläche und die elektronische Suszeptibilität von Gruppe-V Adsorbaten auf Siliziumkarbid untersucht. Zusammenfassend erläutert diese Dissertation das Zusammenspiel von Symmetriebruch und SOC auf dem Dreiecksgitter, die Grundlage für nicht-triviale isolierende Phasen. KW - Topologie KW - Spin-Bahn-Wechselwirkung KW - Symmetrie KW - Bandstruktur KW - Dichtefunktionalformalismus KW - Topology KW - Spin-Orbit Coupling KW - Inversion Symmetry Breaking KW - Band Structure KW - Density Functional Theory KW - Real-Space Obstruction KW - Quantum Spin Hall Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-359186 ER - TY - JOUR T1 - Measuring the atmospheric neutrino oscillation parameters and constraining the 3+1 neutrino model with ten years of ANTARES data JF - Journal of High Energy Physics N2 - The ANTARES neutrino telescope has an energy threshold of a few tens of GeV. This allows to study the phenomenon of atmospheric muon neutrino disappearance due to neutrino oscillations. In a similar way, constraints on the 3+1 neutrino model, which foresees the existence of one sterile neutrino, can be inferred. Using data collected by the ANTARES neutrino telescope from 2007 to 2016, a new measurement of m 2 and (23) has been performed which is consistent with world best-fit values and constraints on the 3+1 neutrino model have been derived. KW - Neutrino Detectors and Telescopes (experiments) KW - Oscillation KW - Matter Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227791 VL - 113 IS - 6 ER - TY - JOUR A1 - Alacevich, Massimo A1 - Carloni Calame, Carlo M. A1 - Chiesa, Mauro A1 - Montagna, Guido A1 - Nicrosini, Oreste A1 - Piccinini, Fulvio T1 - Muon-electron scattering at NLO JF - Journal of High Energy Physics N2 - We consider the process of muon-electron elastic scattering, which has been proposed as an ideal framework to measure the running of the electromagnetic coupling constant at space-like momenta and determine the leading-order hadronic contribution to the muon g-2 (MUonE experiment). We compute the next-to-leading (NLO) contributions due to QED and purely weak corrections and implement them into a fully differential Monte Carlo event generator, which is available for first experimental studies. We show representative phenomenological results of interest for the MUonE experiment and examine in detail the impact of the various sources of radiative corrections under different selection criteria, in order to study the dependence of the NLO contributions on the applied cuts. The study represents the first step towards the realisation of a high-precision Monte Carlo code necessary for data analysis. KW - NLO Computations KW - Anomalous magnetic-moment KW - Radiative-corrections KW - Reduction KW - G-2 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227777 VL - 155 IS - 2 ER - TY - JOUR T1 - Sensitivity of the KM3NeT/ARCA neutrino telescope to point-like neutrino sources JF - Astroparticle Physics N2 - KM3NeT will be a network of deep-sea neutrino telescopes in the Mediterranean Sea. The KM3NeT/ARCA detector, to be installed at the Capo Passero site (Italy), is optimised for the detection of high-energy neutrinos of cosmic origin. Thanks to its geographical location on the Northern hemisphere, KM3NeT/ARCA can observe upgoing neutrinos from most of the Galactic Plane, including the Galactic Centre. Given its effective area and excellent pointing resolution, KM3NeT/ARCA will measure or significantly constrain the neutrino flux from potential astrophysical neutrino sources. At the same time, it will test flux predictions based on gamma-ray measurements and the assumption that the gamma-ray flux is of hadronic origin. Assuming this scenario, discovery potentials and sensitivities for a selected list of Galactic sources and to generic point sources with an E-2 spectrum are presented. These spectra are assumed to be time independent. The results indicate that an observation with 3 sigma significance is possible in about six years of operation for the most intense sources, such as Supernovae Remnants RX J1713.7-3946 and Vela Jr. If no signal will be found during this time, the fraction of the gamma-ray flux coming from hadronic processes can be constrained to be below 50% for these two objects. (C) 2019 The Authors. Published by Elsevier B.V. KW - Astrophysical neutrino sources KW - Cherenkov underwater neutrino telescope KW - KM3NeT KW - Remnant RX J1713.7-3946 KW - Particle-acceleration KW - Galactic sources KW - Cosmic-rays KW - Supernova KW - Radiation KW - Icecube KW - Shell KW - TEV Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227759 VL - 111 ER - TY - JOUR A1 - Abt, Raimond A1 - Erdmenger, Johanna A1 - Gerbershagen, Marius A1 - Melby-Thompson, Charles M. A1 - Northe, Christian T1 - Holographic subregion complexity from kinematic space JF - Journal of High Energy Physics N2 - We consider the computation of volumes contained in a spatial slice of AdS(3) in terms of observables in a dual CFT. Our main tool is kinematic space, defined either from the bulk perspective as the space of oriented bulk geodesics, or from the CFT perspective as the space of entangling intervals. We give an explicit formula for the volume of a general region in a spatial slice of AdS(3) as an integral over kinematic space. For the region lying below a geodesic, we show how to write this volume purely in terms of entangling entropies in the dual CFT. This expression is perhaps most interesting in light of the complexity = volume proposal, which posits that complexity of holographic quantum states is computed by bulk volumes. An extension of this idea proposes that the holographic subregion complexity of an interval, defined as the volume under its Ryu-Takayanagi surface, is a measure of the complexity of the corresponding reduced density matrix. If this is true, our results give an explicit relationship between entanglement and subregion complexity in CFT, at least in the vacuum. We further extend many of our results to conical defect and BTZ black hole geometries. KW - AdS-CFT Correspondence KW - Gauge-gravity correspondence KW - Black Holes in String Theory KW - Black-hole KW - Entanglement Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227711 VL - 1 IS - 12 ER - TY - JOUR A1 - Abt, Raimond A1 - Erdmenger, Johanna T1 - Properties of modular Hamiltonians on entanglement plateaux JF - Journal of High Energy Physics N2 - The modular Hamiltonian of reduced states, given essentially by the logarithm of the reduced density matrix, plays an important role within the AdS/CFT correspondence in view of its relation to quantum information. In particular, it is an essential ingredient for quantum information measures of distances between states, such as the relative entropy and the Fisher information metric. However, the modular Hamiltonian is known explicitly only for a few examples. For a family of states rho(lambda) that is parametrized by a scalar lambda, the first order contribution in (lambda) over tilde = lambda-lambda(0) of the modular Hamiltonian to the relative entropy between rho(lambda) and a reference state rho(lambda 0) is completely determined by the entanglement entropy, via the first law of entanglement. For several examples, e.g. for ball-shaped regions in the ground state of CFTs, higher order contributions are known to vanish. In these cases the modular Hamiltonian contributes to the Fisher information metric in a trivial way. We investigate under which conditions the modular Hamiltonian provides a non-trivial contribution to the Fisher information metric, i.e. when the contribution of the modular Hamiltonian to the relative entropy is of higher order in (lambda) over tilde. We consider one-parameter families of reduced states on two entangling regions that form an entanglement plateau, i.e. the entanglement entropies of the two regions saturate the Araki-Lieb inequality. We show that in general, at least one of the relative entropies of the two entangling regions is expected to involve (lambda) over tilde contributions of higher order from the modular Hamiltonian. Furthermore, we consider the implications of this observation for prominent AdS/CFT examples that form entanglement plateaux in the large N limit. KW - AdS-CFT Correspondence KW - Gauge-gravity correspondence KW - Conformal Field Theory KW - Relative Entropy KW - Complexity Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227693 VL - 11 IS - 2 ER - TY - JOUR A1 - Dürrnagel, Matteo A1 - Beyer, Jacob A1 - Thomale, Ronny A1 - Schwemmer, Tilman T1 - Unconventional superconductivity from weak coupling JF - The European Physical Journal B N2 - We develop a joint formalism and numerical framework for analyzing the superconducting instability of metals from a weak coupling perspective. This encompasses the Kohn–Luttinger formulation of weak coupling renormalization group for superconductivity as well as the random phase approximation imposed on the diagrammatic expansion of the two-particle Green’s function. The central quantity to resolve is the effective interaction in the Cooper channel, for which we develop an optimized numerical framework. Our code is capable of treating generic multi-orbital models in two as well as three spatial dimensions and, in particular, arbitrary avenues of spin-orbit coupling. KW - superconducting instability KW - metals KW - weak coupling KW - unconventional superconductivity Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325153 SN - 1434-6028 VL - 95 IS - 7 ER - TY - JOUR A1 - Beyer, Jacob A1 - Goth, Florian A1 - Müller, Tobias T1 - Better integrators for functional renormalization group calculations JF - The European Physical Journal B N2 - We analyze a variety of integration schemes for the momentum space functional renormalization group calculation with the goal of finding an optimized scheme. Using the square lattice t-t' Hubbard model as a testbed we define and benchmark the quality. Most notably we define an error estimate of the solution for the ordinary differential equation circumventing the issues introduced by the divergences at the end of the FRG flow. Using this measure to control for accuracy we find a threefold reduction in number of required integration steps achievable by choice of integrator. We herewith publish a set of recommended choices for the functional renormalization group, shown to decrease the computational cost for FRG calculations and representing a valuable basis for further investigations. KW - functional renormalization group KW - FRG KW - FRG calculations KW - integrators KW - ordinary differential equations KW - ODE Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-325131 SN - 1434-6028 VL - 95 IS - 7 ER -