@article{DiSanteErdmengerGreiteretal.2020,
  author    = {Di Sante, Domenico and Erdmenger, Johanna and Greiter, Martin and Matthaiakakis, Ioannis and Meyer, Ren{\´e} and Fernandez, David Rodr{\´i}guez and Thomale, Ronny and van Loon, Erik and Wehling, Tim},
  title     = {Turbulent hydrodynamics in strongly correlated Kagome metals},
  series = {Nature Communications},
  volume    = {11},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-020-17663-x},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230380},
  year      = {2020},
  abstract  = {A current challenge in condensed matter physics is the realization of strongly correlated, viscous electron fluids. These fluids can be described by holography, that is, by mapping them onto a weakly curved gravitational theory via gauge/gravity duality. The canonical system considered for realizations has been graphene. In this work, we show that Kagome systems with electron fillings adjusted to the Dirac nodes provide a much more compelling platform for realizations of viscous electron fluids, including non-linear effects such as turbulence. In particular, we find that in Scandium Herbertsmithite, the fine-structure constant, which measures the effective Coulomb interaction, is enhanced by a factor of about 3.2 as compared to graphene. We employ holography to estimate the ratio of the shear viscosity over the entropy density in Sc-Herbertsmithite, and find it about three times smaller than in graphene. These findings put the turbulent flow regime described by holography within the reach of experiments. Viscous electron fluids are predicted in strongly correlated systems but remain challenging to realize. Here, the authors predict enhanced effective Coulomb interaction and reduced ratio of the shear viscosity over entropy density in a Kagome metal, inferring turbulent flow of viscous electron fluids.},
  language  = {en}
}
@article{VainioValtonenHeberetal.2013,
  author    = {Vainio, Rami and Valtonen, Eino and Heber, Bernd and Malandraki, Olga E. and Papaioannou, Athanasios and Klein, Karl-Ludwig and Afanasiev, Alexander and Agueda, Neus and Aurass, Henry and Battarbee, Markus and Braune, Stephan and Dr{\"o}ge, Wolfgang and Ganse, Urs and Hamadache, Clarisse and Heynderickx, Daniel and Huttunen-Heikinmaa, Kalle and Kiener, J{\"u}rgen and Kilian, Patrick and Kopp, Andreas and Kouloumvakos, Athanasios and Maisala, Sami and Mishev, Alexander and Miteva, Rosita and Nindos, Alexander and Oittinen, Tero and Raukunen, Osku and Riihonen, Esa and Rodriguez-Gasen, Rosa and Saloniemi, Oskari and Sanahuja, Blai and Scherer, Renate and Spanier, Felix and Tatischeff, Vincent and Tziotziou, Kostas and Usoskin, Ilya G. and Vilmer, Nicole},
  title     = {The first SEPServer event catalogue similar to ~68-MeV solar proton events observed at 1 AU in 1996-2010},
  series = {Journal of Space Weather and Space Climate},
  volume    = {3},
  journal   = {Journal of Space Weather and Space Climate},
  number    = {A12},
  issn      = {2115-7251},
  doi       = {10.1051/swsc/2013030},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-122847},
  year      = {2013},
  abstract  = {SEPServer is a three-year collaborative project funded by the seventh framework programme (FP7-SPACE) of the European Union. The objective of the project is to provide access to state-of-the-art observations and analysis tools for the scientific community on solar energetic particle (SEP) events and related electromagnetic (EM) emissions. The project will eventually lead to better understanding of the particle acceleration and transport processes at the Sun and in the inner heliosphere. These processes lead to SEP events that form one of the key elements of space weather. In this paper we present the first results from the systematic analysis work performed on the following datasets: SOHO/ERNE, SOHO/EPHIN, ACE/EPAM, Wind/WAVES and GOES X-rays. A catalogue of SEP events at 1 AU, with complete coverage over solar cycle 23, based on high-energy (similar to 68-MeV) protons from SOHO/ERNE and electron recordings of the events by SOHO/EPHIN and ACE/EPAM are presented. A total of 115 energetic particle events have been identified and analysed using velocity dispersion analysis (VDA) for protons and time-shifting analysis (TSA) for electrons and protons in order to infer the SEP release times at the Sun. EM observations during the times of the SEP event onset have been gathered and compared to the release time estimates of particles. Data from those events that occurred during the European day-time, i.e., those that also have observations from ground-based observatories included in SEPServer, are listed and a preliminary analysis of their associations is presented. We find that VDA results for protons can be a useful tool for the analysis of proton release times, but if the derived proton path length is out of a range of 1 AU < s less than or similar to 3 AU, the result of the analysis may be compromised, as indicated by the anti-correlation of the derived path length and release time delay from the associated X-ray flare. The average path length derived from VDA is about 1.9 times the nominal length of the spiral magnetic field line. This implies that the path length of first-arriving MeV to deka-MeV protons is affected by interplanetary scattering. TSA of near-relativistic electrons results in a release time that shows significant scatter with respect to the EM emissions but with a trend of being delayed more with increasing distance between the flare and the nominal footpoint of the Earth-connected field line.},
  language  = {en}
}
@article{KimKusudoLoeffleretal.2013,
  author    = {Kim, N. Y. and Kusudo, K. and L{\"o}ffler, A. and H{\"o}fling, S. and Forchel, A. and Yamamoto, Y.},
  title     = {Exciton-polariton condensates near the Dirac point in a triangular lattice},
  series = {New Journal of Physics},
  volume    = {15},
  journal   = {New Journal of Physics},
  number    = {035032},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/15/3/035032},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123103},
  year      = {2013},
  abstract  = {Dirac particles, massless relativistic entities, obey linear energy dispersions and hold important implications in particle physics. The recent discovery of Dirac fermions in condensed matter systems including graphene and topological insulators has generated a great deal of interest in exploring the relativistic properties associated with Dirac physics in solid-state materials. In addition, there are stimulating research activities to engineer Dirac particles, elucidating their exotic physical properties in a controllable setting. One of the successful platforms is the ultracold atom-optical lattice system, whose dynamics can be manipulated and probed in a clean environment. A microcavity exciton-polariton-lattice system offers the advantage of forming high-orbital condensation in non-equilibrium conditions, which enables one to explore novel quantum orbital order in two dimensions. In this paper, we experimentally construct the band structures near Dirac points, the vertices of the first hexagonal Brillouin zone with exciton-polariton condensates trapped in a triangular lattice. Due to the finite spectral linewidth, the direct map of band structures at Dirac points is elusive; however, we identify the linear part above Dirac points and its associated velocity value is similar to ~0.9-2 x \(10^8 cm s^{-1}\), consistent with the theoretical estimate \(1 x 10^8 cm s^{-1}\) with a \(2 \mu m\) lattice constant. We envision that the exciton-polariton condensates in lattices would be a promising solid-state platform, where the system order parameter can be accessed in both real and momentum spaces.},
  language  = {en}
}
@phdthesis{Parragh2013,
  author    = {Parragh, Nicolaus},
  title     = {Strongly Correlated Multi-Orbital Systems : A Continuous-Time Quantum Monte Carlo Analysis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85253},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2013},
  abstract  = {In this thesis I present results concerning realistic calculations of correlated fermionic many-body systems. One of the main objectives of this work was the implementation of a hybridization expansion continuous-time quantum Monte Carlo (CT-HYB) algorithm and of a flexible self-consistency loop based on the dynamical mean-field theory (DMFT). DMFT enables us to treat strongly correlated electron systems numerically. After the implementation and extensive testing of the program we investigated different problems to answer open questions concerning correlated systems and their numerical treatment.},
  subject      = {Monte-Carlo-Simulation},
  language  = {en}
}