@article{CiuchiDiSanteDobrosavljevićetal.2018,
  author    = {Ciuchi, Sergio and Di Sante, Domenico and Dobrosavljević, Vladimir and Fratini, Simone},
  title     = {The origin of Mooij correlations in disordered metals},
  series = {npj Quantum Materials},
  volume    = {3},
  journal   = {npj Quantum Materials},
  doi       = {10.1038/s41535-018-0119-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-223148},
  year      = {2018},
  abstract  = {Sufficiently disordered metals display systematic deviations from the behavior predicted by semi-classical Boltzmann transport theory. Here the scattering events from impurities or thermal excitations can no longer be considered as additive-independent processes, as asserted by Matthiessen's rule following from this picture. In the intermediate region between the regime of good conduction and that of insulation, one typically finds a change of sign of the temperature coefficient of resistivity, even at elevated temperature spanning ambient conditions, a phenomenology that was first identified by Mooij in 1973. Traditional weak coupling approaches to identify relevant corrections to the Boltzmann picture focused on long-distance interference effects such as "weak localization", which are especially important in low dimensions (1D and 2D) and close to the zero-temperature limit. Here we formulate a strong-coupling approach to tackle the interplay of strong disorder and lattice deformations (phonons) in bulk three-dimensional metals at high temperatures. We identify a polaronic mechanism of strong disorder renormalization, which describes how a lattice locally responds to the relevant impurity potential. This mechanism, which quantitatively captures the Mooij regime, is physically distinct and unrelated to Anderson localization, but realizes early seminal ideas of Anderson himself, concerning the interplay of disorder and lattice deformations.},
  language  = {en}
}
@article{OPUS4-22781,
  title     = {Long-term monitoring of the ANTARES optical module efficiencies using \(^{40}\)K decays in sea water},
  series = {European Physical Journal C},
  volume    = {78},
  journal   = {European Physical Journal C},
  organization    = {The ANTARES Collaboration},
  doi       = {10.1140/epjc/s10052-018-6132-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227815},
  pages     = {1-8},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{AbtErdmenger2018,
  author    = {Abt, Raimond and Erdmenger, Johanna},
  title     = {Properties of modular Hamiltonians on entanglement plateaux},
  series = {Journal of High Energy Physics},
  volume    = {11},
  journal   = {Journal of High Energy Physics},
  number    = {2},
  doi       = {10.1007/JHEP11(2018)002},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227693},
  pages     = {1-22},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{RinaldiVarottoAsaetal.2018,
  author    = {Rinaldi, Christian and Varotto, Sara and Asa, Marco and Slawinska, Jagoda and Fujii, Jun and Vinai, Giovanni and Cecchi, Stefano and Di Sante, Domenico and Calarco, Raffaella and Vobornik, Ivana and Panaccione, Giancarlo and Picozzi, Silvia and Bertacco, Riccardo},
  title     = {Ferroelectric Control of the Spin Texture in GeTe},
  series = {Nano Letters},
  volume    = {18},
  journal   = {Nano Letters},
  number    = {5},
  doi       = {10.1021/acs.nanolett.7b04829},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-226294},
  pages     = {2751-2758},
  year      = {2018},
  abstract  = {The electric and nonvolatile control of the spin texture in semiconductors would represent a fundamental step toward novel electronic devices combining memory and computing functionalities. Recently, GeTe has been theoretically proposed as the father compound of a new class of materials, namely ferroelectric Rashba semiconductors. They display bulk bands with giant Rashba-like splitting due to the inversion symmetry breaking arising from the ferroelectric polarization, thus allowing for the ferroelectric control of the spin. Here, we provide the experimental demonstration of the correlation between ferroelectricity and spin texture. A surface-engineering strategy is used to set two opposite predefined uniform ferroelectric polarizations, inward and outward, as monitored by piezoresponse force microscopy. Spin and angular resolved photoemission experiments show that these GeTe(111) surfaces display opposite sense of circulation of spin in bulk Rashba bands. Furthermore, we demonstrate the crafting of nonvolatile ferroelectric patterns in GeTe films at the nanoscale by using the conductive tip of an atomic force microscope. Based on the intimate link between ferroelectric polarization and spin in GeTe, ferroelectric patterning paves the way to the investigation of devices with engineered spin configurations.},
  language  = {en}
}
@article{RomoliChakrabortyDorneretal.2018,
  author    = {Romoli, Carlo and Chakraborty, Nachiketa and Dorner, Daniela and Taylor, Andrew and Blank, Michael},
  title     = {Flux Distribution of Gamma-Ray Emission in Blazars: The Example of Mrk 501},
  series = {Galaxies},
  volume    = {6},
  journal   = {Galaxies},
  number    = {4},
  organization    = {FACT and H.E.S.S. Collaborations},
  issn      = {2075-4434},
  doi       = {10.3390/galaxies6040135},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-197580},
  year      = {2018},
  abstract  = {Flux distribution is an important tool to understand the variability processes in activegalactic nuclei. We now have available a great deal of observational evidences pointing towards thepresence of log-normal components in the high energy light curves, and different models have beenproposed to explain these data. Here, we collect some of the recent developments on this topic usingthe well-known blazar Mrk 501 as example of complex and interesting aspects coming from its fluxdistribution in different energy ranges and at different timescales. The observational data we refer toare those collected in a complementary manner by Fermi-LAT over multiple years, and by the FirstG-APD Cherenkov Telescope (FACT) telescope and the H.E.S.S. array in correspondence of the brightflare of June 2014},
  language  = {en}
}
@phdthesis{Hetterich2018,
  author    = {Hetterich, Daniel Marcus},
  title     = {Localization within disordered systems of star-like topology},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169318},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {This Thesis investigates the interplay of a central degree of freedom with an environment. Thereby, the environment is prepared in a localized phase of matter. The long-term aim of this setup is to store quantum information on the central degree of freedom while exploiting the advantages of localized systems. These many-body localized systems fail to equilibrate under the description of thermodynamics, mostly due to disorder. Doing so, they form the most prominent phase of matter that violates the eigenstate thermalization hypothesis. Thus, many-body localized systems preserve information about an initial state until infinite times without the necessity to isolate the system. This unique feature clearly suggests to store quantum information within localized environments, whenever isolation is impracticable. After an introduction to the relevant concepts, this Thesis examines to which extent a localized phase of matter may exist at all if a central degree of freedom dismantles the notion of locality in the first place. To this end, a central spin is coupled to the disordered Heisenberg spin chain, which shows many-body localization. Furthermore, a noninteracting analog describing free fermions is discussed. Therein, an impurity is coupled to an Anderson localized environment. It is found that in both cases, the presence of the central degree of freedom manifests in many properties of the localized environment. However, for a sufficiently weak coupling, quantum chaos, and thus, thermalization is absent. In fact, it is shown that the critical disorder, at which the metal-insulator transition of its environment occurs in the absence of the central degree of freedom, is modified by the coupling strength of the central degree of freedom. To demonstrate this, a phase diagram is derived. Within the localized phase, logarithmic growth of entanglement entropy, a typical signature of many-body localized systems, is increased by the coupling to the central spin. This property is traced back to resonantly coupling spins within the localized Heisenberg chain and analytically derived in the absence of interactions. Thus, the studied model of free fermions is the first model without interactions that mimics the logarithmic spreading of entanglement entropy known from many-body localized systems. Eventually, it is demonstrated that observables regarding the central spin significantly break the eigenstate thermalization hypothesis within the localized phase. Therefore, it is demonstrated how a central spin can be employed as a detector of many-body localization.},
  subject      = {Quanteninformatik},
  language  = {en}
}