cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
BPS spectrum on AdS$_3\times $S$^3 \times $S$^3 \times $S$^1$
Creators: name: Eberhardt, Lorenz
name: Gaberdiel, Matthias R.
name: Gopakumar, Rajesh
name: Li, Wei
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The BPS spectrum of string theory on AdS$_3\times {\rm S}^3 \times {\rm S}^3 \times {\rm S}^1$ is determined using a world-sheet description in terms of WZW models. It is found that the theory only has BPS states with $j^+ = j^-$ where $j^{\pm}$ refer to the spins of the $\mathfrak{su}(2)$ algebras of the large ${\cal N}=4$ superconformal algebra. We then re-examine the BPS spectrum of the corresponding supergravity and find that, in contradistinction to previous claims in the literature, also in supergravity only the states with $j^+=j^-$ are BPS. This resolves a number of long-standing puzzles regarding the BPS spectrum of string theory and supergravity in this background.
description: 36 pages; ancillary file included, v2: changed statement about spectrally flowed sectors, minor typos corrected
Holographic encoding of universality in corner spectra
Creators: name: Huang, Ching-Yu
name: Wei, Tzu-Chieh
name: Orus, Roman
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In numerical simulations of classical and quantum lattice systems, 2d corner transfer matrices (CTMs) and 3d corner tensors (CTs) are a useful tool to compute approximate contractions of infinite-size tensor networks. In this paper we show how the numerical CTMs and CTs can be used, {\it additionally\/}, to extract universal information from their spectra. We provide examples of this for classical and quantum systems, in 1d, 2d and 3d. Our results provide, in particular, practical evidence for a wide variety of models of the correspondence between $d$-dimensional quantum and $(d+1)$-dimensional classical spin systems. We show also how corner properties can be used to pinpoint quantum phase transitions, topological or not, without the need for observables. Moreover, for a chiral topological PEPS we show by examples that corner tensors can be used to extract the entanglement spectrum of half a system, with the expected symmetries of the $SU(2)_k$ Wess-Zumino-Witten model describing its gapless edge for $k=1,2$. We also review the theory behind the quantum-classical correspondence for spin systems, and provide a new numerical scheme for quantum state renormalization in 2d using CTs. Our results show that bulk information of a lattice system is encoded holographically in efficiently-computable properties of its corners.
Frustration-free Hamiltonians supporting Majorana zero edge modes
Creators: name: Jevtic, Sania
name: Barnett, Ryan
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A one-dimensional fermionic system, such as a superconducting wire, may host Majorana zero-energy edge modes (MZMs) at its edges when it is in the topological phase. MZMs provide a path to realising fault-tolerant quantum computation, and so are the focus of intense experimental and theoretical studies. However, given a Hamiltonian, determining whether MZMs exist is a daunting task as it relies on knowing the spectral properties of the Hamiltonian in the thermodynamic limit. The Kitaev chain is a paradigmatic non-interacting model that supports MZMs and the Hamiltonian can be fully diagonalised. However, for interacting models, the situation is far more complex. Here we consider a different classification of models, namely, ones with frustration-free Hamiltonians. Within this class of models, interacting and non-interacting systems are treated on an equal footing, and we identify exactly which Hamiltonians can realise MZMs.
description: 19 pages, 1 figure, improved version v2
Mechanistic models of $α$-synuclein homeostasis for Parkinson's disease: A blueprint for therapeutic intervention
Creators: name: Righetti, Elena
name: Antonello, Alice
name: Marchetti, Luca
name: Domenici, Enrico
name: Reali, Federico
Publisher: name: arXiv
Year: 2022
Subjects: subject: Dynamical Systems (math.DS)
subject: Molecular Networks (q-bio.MN)
subject: FOS: Mathematics
subject: FOS: Biological sciences

description: Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide, yet there is no disease-modifying therapy up to this date. The biological complexity underlying PD hampers the investigation of the principal contributors to its pathogenesis. In this context, mechanistic models grounded in molecular-level knowledge provide virtual labs to uncover the primary events triggering PD onset and progression and suggest promising therapeutic targets. Multiple modeling efforts in PD research have focused on the pathological role of $α$-synuclein ($α$syn), a presynaptic protein that emerges from the intricate molecular network as a crucial driver of neurodegeneration. Here, we collect the advances in mathematical modeling of $α$syn homeostasis, focusing on aggregation and degradation pathways, and discussing potential modeling improvements and possible implications in PD therapeutic strategy design.
On higher-spin supertranslations and superrotations
Creators: name: Campoleoni, Andrea
name: Francia, Dario
name: Heissenberg, Carlo
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the large gauge transformations of massless higher-spin fields in four-dimensional Minkowski space. Upon imposing suitable fall-off conditions, providing higher-spin counterparts of the Bondi gauge, we observe the existence of an infinite-dimensional asymptotic symmetry algebra. The corresponding Ward identities can be held responsible for Weinberg's factorization theorem for amplitudes involving soft particles of spin greater than two.
description: Motivations and clarifications added. Matches published version
Extending Ultra-Diffuse Galaxy Abundances to Milky Way Analogs
Creators: name: Karunakaran, Ananthan
name: Zaritsky, Dennis
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We extend the Ultra-Diffuse Galaxy (UDG) abundance relation, $N_{UDG}-M_{200}$, to lower halo mass hosts $(M_{200}\sim10^{11.6-12.2}M_{\odot})$. We select UDG satellites from published catalogs of dwarf satellite galaxies around Milky Way analogs, namely the Exploration of Local Volume Satellites (ELVES) survey, Satellite Around Galactic Analogs (SAGA) survey, and a survey of Milky Way-like systems conducted using the Hyper-Suprime Cam. Of the 516 satellites around a total of 75 Milky Way-like hosts, we find 41 satellites around 33 hosts satisfy the UDG criteria. The distributions of host halo masses peak around $M_{200}\sim10^{12}M_{\odot}$ independent of whether the host has a UDG satellite or not. We use literature UDG abundances and those derived here to trace the $N_{UDG}-M_{200}$ relation over three orders of magnitude down to $M_{200}=10^{11.6}M_{\odot}$ and find a best-fit linear relation of $N_{UDG} = (38\pm5)\cdot(\frac{M_{200}}{10^{14}})^{0.89\pm0.04}$. This sub-linear slope is consistent with earlier studies of UDG abundances as well as abundance relations for brighter dwarf galaxies, excluding UDG formation mechanisms that require high-density environments. However, we highlight the need for further homogeneous characterization of UDGs across a wide range of environments to properly understand the $N_{UDG}-M_{200}$ relation.
description: 7 pages, 4 figures, 1 table. Accepted for publication in MNRAS. This version has minor updates to text and an expanded Table 1 following referee comments with no changes to conclusions
Hybrid quantum device with a carbon nanotube and a flux qubit for dissipative quantum engineering
Creators: name: Wang, Xin
name: Miranowicz, Adam
name: Li, Hong-Rong
name: Nori, Franco
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We describe a hybrid quantum system composed of a micrometer-size carbon nanotube (CNT) longitudinally coupled to a flux qubit. We demonstrate the usefulness of this device for generating high-fidelity nonclassical states of the CNT via dissipative quantum engineering. Sideband cooling of the CNT to its ground state and generating a squeezed ground state, as a mechanical analogue of the optical squeezed vacuum, are two additional examples of the dissipative quantum engineering studied here. Moreover, we show how to generate a long-lived macroscopically-distinct superposition (i.e., a Schrödinger cat-like) state. This cat state can be trapped, under some conditions, in a dark state, as can be verified by detecting the optical response of control fields.
description: 10 pages, 5 figures
Integrating ecosystem services into land-use modeling to assess the effects of future land-use strategies in Northern Ghana
Creators: name: Koo, Hongmi
name: Kleemann, Janina
name: Fürst, Christine
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2020
Subjects: subject: 550

description: In West Africa, where the majority of the population relies on natural resources and rain-fed agriculture, regionally adapted agricultural land-use planning is increasingly important to cope with growing demand for land-use products and intensifying climate variability. As an approach to identify effective future land-use strategies, this study applied spatially explicit modeling that addresses the spatial connectivity between the provision of ecosystem services and agricultural land-use systems. Considering that the status of ecosystem services varies with the perception of stakeholders, local knowledge, and characteristics of a case study area, two adjoining districts in northern Ghana were integrated into an assessment process of land-use strategies. Based on agricultural land-management options that were identified together with the local stakeholders, 75 future land-use strategies as combinations of multiple agricultural practices were elaborated. Potential impacts of the developed land-use strategies on ecosystem services and land-use patterns were assessed in a modeling platform that combines Geographic Information System (GIS) and Cellular Automaton (CA) modules. Modeled results were used to identify best land-use strategies that could deliver multiple ecosystem services most effectively. Then, local perception was applied to determine the feasibility of the best land-use strategies in practice. The results presented the different extent of trade-offs and synergies between ecosystem services delivered by future land-use strategies and their different feasibility depending on the district. Apart from the fact that findings were context-specific and scale-dependent, this study revealed that the integration of different local characteristics and local perceptions to spatially explicit ecosystem service assessment is beneficial for determining locally tailored recommendations for future agricultural land-use planning.
Umweltbezogene Gerechtigkeit in Halle (Saale) – eine Analyse des Ist-Zustands am Beispiel von Silberhöhe und Neustadt
Creators: name: Geldbach, Luisa
Publisher: name: MLU Human Geography Working Paper Series
Year: 2022
Subjects: subject: 000

description: Social inequality as well as climate change and the associated environmental pollution are two of the central issues that concern politics and society. The discourse on environmental justice connects these two subject areas and examines to which extent socio-economically disadvantaged groups are also particularly exposed to environmental pollution. More recent research approaches refer not only to questions of distribution, but also to other dimensions of justice, such as participation and equal opportunities. The paper examines how and where environmental injustices are present in Halle (Saale). After a general overview about the distribution in the whole city, it focuses on the environmental equity in two GDR housing complexes: Halle-Silberhöhe and Halle-Neustadt. In addition to statistical data, information from interviews is used to analyze the remaining dimensions of environmental justice. It turns out that inequalities in environmental equity exist only to a little extent in Halle (Saale), but that the other dimensions of environmental justice could be improved. The chance for participation heavily depends for example on general living conditions. Even if the municipality shows a lot of commitment in social and environmental issues, a closer link between the two areas would be desirable.
Spin-orbit coupling and Kondo resonance in Co adatom on Cu(100) surface: DFT+ED study
Creators: name: Shick, A. B.
name: Tchaplianka, M.
name: Lichtenstein, A. I.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report density functional theory plus exact diagonalization of the multi-orbital Anderson impurity model calculations for the Co adatom on the top of Cu(001) surface. For the Co atom $d$-shell occupation $n_d \approx$ 8, a singlet many-body ground state and Kondo resonance are found, when the spin-orbit coupling is included in the calculations. The differential conductance is evaluated in a good agreement with the scanning tuneling microscopy measurements. The results illustrate the essential role which the spin-orbit coupling is playing in a formation of Kondo singlet for the multi-orbital impurity in low dimensions.
Spin-Diffusions and Diffusive Molecular Dynamics
Creators: name: Farmer, Brittan A
name: Luskin, Mitchell
name: Plecháč, Petr
name: Simpson, Gideon
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computational Physics (physics.comp-ph)
subject: Numerical Analysis (math.NA)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 60G20 82C80 37N15 74H15

description: Metastable condensed matter typically fluctuates about local energy minima at the femtosecond time scale before transitioning between local minima after nanoseconds or microseconds. This vast scale separation limits the applicability of classical molecular dynamics methods and has spurned the development of a host of approximate algorithms. One recently proposed method is diffusive molecular dynamics which aims to integrate a system of ordinary differential equations describing the likelihood of occupancy by one of two species, in the case of a binary alloy, while quasistatically evolving the locations of the atoms. While diffusive molecular dynamics has shown to be efficient and provide agreement with observations, it is fundamentally a model, with unclear connections to classical molecular dynamics. In this work, we formulate a spin-diffusion stochastic process and show how it can be connected to diffusive molecular dynamics. The spin-diffusion model couples a classical overdamped Langevin equation to a kinetic Monte Carlo model for exchange amongst the species of a binary alloy. Under suitable assumptions and approximations, spin-diffusion can be shown to lead to diffusive molecular molecular dynamics type models. The key assumptions and approximations include a well defined time scale separation, a choice of spin exchange rates, a low temperature approximation, and a mean field type approximation. We derive several models from different assumptions and show their relationship to diffusive molecular dynamics. Differences and similarities amongst the models are explored in a simple test problem.
description: 26 Pages, corrected a typo from the previous version
Three major reasons why transgenerational effects of radiation are difficult to detect in humans
Creators: name: Nakamura, Nori
name: Yoshida, Noriaki
name: Suwa, Tatsuya
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Medicine
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: Evolutionary Biology
subject: Developmental Biology
subject: Cancer
subject: Virology

description: Ionizing radiation can induce mutations in germ cells in various organisms, including fruit flies and mice. However, currently, there is no clear evidence for transgenerational effects of radiation in humans. This review is an effort to identify possible reasons for the lack of such observations. Literature search and narrative review. 1) In both mice and humans, resting oocytes locate primarily in the cortical region of the ovary where the number of blood vessels is very low especially when young and extra-cellular material is rich, and this region is consequently hypoxic, which probably leads to immature oocytes being resistant to the cell killing and mutagenic effects of radiation. 2) In studies of spermatogonia, the mouse genes used for specific locus test (SLT) studies, which include coat color genes, were hypermutable when compared to many other genes. Recent studies which examined over 1,000 segments of genomic DNA indicate that the induction rate of deletion mutation per segment was on the order of 10−6 per Gy, which is one order of magnitude lower than that obtained from the SLT data. Therefore, it appears possible that detecting any transgenerational effects of radiation following human male exposures will be difficult due to a lack of mutable marker genes. 3) Fetal malformations were examined in studies in humans, but the genetic component in such malformations is low, and abnormal fetuses are prone to undergo miscarriage which does not occur in mice, and which leads to difficulties in detecting transgenerational effects. The lack of clear evidence for radiation effects in humans probably does not result from any problem in the methodologies used but may be due largely to biological properties. Currently, whole genome sequencing studies of exposed parents and offspring are planned, but ethical guidelines need to be followed to avoid discrimination, which had once happened to the atomic bomb survivors.
Complex Hadamard matrices with noncommutative entries
Creators: name: Banica, Teodor
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Algebra (math.QA)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: We axiomatize and study the matrices of type $H\in M_N(A)$, having unitary entries, $H_{ij}\in U(A)$, and whose rows and columns are subject to orthogonality type conditions. Here $A$ can be any $C^*$-algebra, for instance $A=\mathbb C$, where we obtain the usual complex Hadamard matrices, or $A=C(X)$, where we obtain the continuous families of complex Hadamard matrices. Our formalism allows the construction of a quantum permutation group $G\subset S_N^+$, whose structure and computation is discussed here.
description: 15 pages
„Am Treff“ in Halle-Neustadt: ethnographische Einblicke in die dynamische Entwicklung einer ostdeutschen Großwohnsiedlung
Creators: name: Winkler, Nora
name: Herzog, Chiara
name: Knechtel, Sarah
name: Pillat, Lena
name: Rieck, Tom Felix
name: Schulze, Jannis
name: Wudy, Lisa
name: Everts, Jonathan
Publisher: name: MLU Human Geography Working Paper Series
Year: 2020
Subjects: subject: 000

description: The article presents the findings of ethnographic research at a central place within Halle-Neustadt. Halle-Neustadt consists mainly of large concrete blocks of housing estates built during GDR times. Meanwhile, Neustadt is reunited with the old city of Halle (Saale). Neustadt counts as a marginalized and stigmatized place. This is both true in relation to the most recent segregation trends as well as the mainly negative stereotypes transported by the general media. In this paper, we seek to employ the perspective on lifeworlds, everyday life and encounters in public places to offer a more nuanced understanding in contrast to the stigmatizing public discourse. Participant observation and interviewing of passers-by aswell as shopkeepers at the place “Am Treff” revealed four themes that are relevant when assessing the current dynamics of the social and urban fabric of Halle-Neustadt. (1) The diversity of the place and its people needs to be acknowledged –there are many young families, often migrants, moving into Neustadt. (2) Many encounters take place in public and semi-public spaces. Who talks to whom and for how longdepends on gender as well as age and ethnicity. (3) People are well aware of the social and ethnic differences within Halle-Neustadt and conflicts revolve around the fault line that divides older from younger people or young families (although the ethnicity is often foregrounded as the main difference).(4) Social change is happening fast in Halle-Neustadt. On the whole, the place is transitioning rapidly from overwhelmingly white working class, now retired residents to young families and migrants. This is also reflected by the types of businesses present at the place of our research, e.g. the “Orienta” supermarket and the newly opened “oriental restaurant”. We infer from our findings that the residents of Halle-Neustadt, old and new, need to be empowered and more generally involved in creating the future of their part of the city.
Emergence of quasiparticle Bloch states in artificial crystals crafted atom-by-atom
Creators: name: Girovsky, Jan
name: Lado, Jose L.
name: Kalff, Floris E.
name: Fahrenfort, Eleonora
name: Peters, Lucas J. J. M.
name: Fernández-Rossier, Joaquín
name: Otte, Alexander F.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The interaction of electrons with a periodic potential of atoms in crystalline solids gives rise to band structure. The band structure of existing materials can be measured by photoemission spectroscopy and accurately understood in terms of the tight-binding model, however not many experimental approaches exist that allow to tailor artificial crystal lattices using a bottom-up approach. The ability to engineer and study atomically crafted designer materials by scanning tunnelling microscopy and spectroscopy (STM/STS) helps to understand the emergence of material properties. Here, we use atom manipulation of individual vacancies in a chlorine monolayer on Cu(100) to construct one- and two-dimensional structures of various densities and sizes. Local STS measurements reveal the emergence of quasiparticle bands, evidenced by standing Bloch waves, with tuneable dispersion. The experimental data are understood in terms of a tight-binding model combined with an additional broadening term that allows an estimation of the coupling to the underlying substrate.
description: 7 figures, 12 pages, main text and supplementary material
Constraints on Cosmological Parameters with a Sample of Type Ia Supernovae from JWST
Creators: name: Lu, Jia
name: Wang, Lifan
name: Chen, Xingzhuo
name: Rubin, David
name: Perlmutter, Saul
name: Baade, Dietrich
name: Mould, Jeremy
name: Vinko, Jozsef
name: Regos, Eniko
name: Koekemoer, Anton M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We investigate the potential of using a sample of very high-redshift ($2\lesssim z \lesssim6$) (VHZ) Type Ia supernovae (SNe~Ia) attainable by the James Webb Space Telescope (JWST) on constraining cosmological parameters. At such high redshifts, the age of the universe is young enough that the VHZ SNIa sample comprises the very first SNe~Ia of the universe, with progenitors among the very first generation of low mass stars that the universe has made. We show that the VHZ SNe~Ia can be used to disentangle systematic effects due to the luminosity distance evolution with redshifts intrinsic to SNIa standardization. Assuming that the systematic evolution can be described by a linear or logarithmic formula, we found that the coefficients of this dependence can be determined accurately and decoupled from cosmological models. Systematic evolution as large as 0.15 mag and 0.45 mag out to $z=5$ can be robustly separated from popular cosmological models for the linear and logarithmic evolution, respectively. The VHZ SNe~Ia will lay the foundation for quantifying the systematic redshift evolution of SNIa luminosity distance scales. When combined with SNIa surveys at comparatively lower redshifts, the VHZ SNe~Ia allow for a precise measurement of the history of the expansion of the universe from $z\sim 0$ to the epoch approaching reionization.
description: Accepted for publication in ApJ. Typos corrected. Fig.14 updated
Evolving understanding of Antarctic ice-sheet physics and ambiguity in probabilistic sea-level projections
Creators: name: Kopp, Robert E.
name: DeConto, Robert M.
name: Bader, Daniel A.
name: Hay, Carling C.
name: Horton, Radley M.
name: Kulp, Scott
name: Oppenheimer, Michael
name: Pollard, David
name: Strauss, Benjamin H.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: Mechanisms such as ice-shelf hydrofracturing and ice-cliff collapse may rapidly increase discharge from marine-based ice sheets. Here, we link a probabilistic framework for sea-level projections to a small ensemble of Antarctic ice-sheet (AIS) simulations incorporating these physical processes to explore their influence on global-mean sea-level (GMSL) and relative sea-level (RSL). We compare the new projections to past results using expert assessment and structured expert elicitation about AIS changes. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), median projected 21st century GMSL rise increases from 79 to 146 cm. Without protective measures, revised median RSL projections would by 2100 submerge land currently home to 153 million people, an increase of 44 million. The use of a physical model, rather than simple parameterizations assuming constant acceleration of ice loss, increases forcing sensitivity: overlap between the central 90% of simulations for 2100 for RCP 8.5 (93-243 cm) and RCP 2.6 (26-98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches >10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by 950 million people (vs. 167 million for RCP 2.6). The minimal correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond implies current sea-level observations cannot exclude future extreme outcomes. The sensitivity of post-2050 projections to deeply uncertain physics highlights the need for robust decision and adaptive management frameworks.
description: 20 pages, 6 figures (main text); 13 pages, 11 figures (supporting information)
Großwohnsiedlungen als Ankunftsquartier? Wanderungsbewegungen und Segregationsprozess in Halle (Saale)
Creators: name: Schneider, Paul R.
name: Ringel, Florian
name: Everts, Jonathan
Publisher: name: MLU Human Geography Working Paper Series
Year: 2020
Subjects: subject: 000

description: In Germany, large residential housing estates built during the 1950s to 1980s have become important areas for migrants and refugees. In Eastern Germany, estates from the socialist era have lost many of their inhabitants following the reunification in 1990. Some, like those in the city of Halle (Saale), have lost more than half of their population. This downward trend has stopped now and in some areas, population size grows. For Halle (Saale), we computed the in and out-migration of large socialist housing estates from 2011 to 2018 and compared it to the late 19th century parts of the inner city which are now well-sought after residential areas. We find that German residents have left in great numbersthe estates. At the same time, migrants have moved in even greater numbers to the estates. Most of them did not come from the parts of the inner city, suggesting that displacement through gentrification has not (yet) been the decisive factor for ethnic segregation. However, some migrant households are now, most recently, moving away from the estates as well and towards the city centre. This suggests that ethnic segregation is now being superseded by social segregation.
Many-Body Localization: Stability and Instability
Creators: name: De Roeck, Wojciech
name: Imbrie, John Z.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 82D30, 60K35, 82B44

description: Rare regions with weak disorder (Griffiths regions) have the potential to spoil localization. We describe a non-perturbative construction of local integrals of motion (LIOMs) for a weakly interacting spin chain in one dimension, under a physically reasonable assumption on the statistics of eigenvalues. We discuss ideas about the situation in higher dimensions, where one can no longer ensure that interactions involving the Griffiths regions are much smaller than the typical energy-level spacing for such regions. We argue that ergodicity is restored in dimension d > 1, although equilibration should be extremely slow, similar to the dynamics of glasses.
description: 17 pages, 8 figures. Added section 5. To appear, Phil. Trans. A
Detection of minute-timescale gamma-ray variability in BL Lacertae by Fermi-LAT
Creators: name: Pandey, Ashwani
name: Stalin, C. S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: BL Lacertae, the prototype of the BL Lacertae (BL Lac) category of blazars, underwent a giant $γ-$ray flare in April 2021. The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope (hereafter Fermi-LAT) observed a peak $γ-$ray (0.1$-$500 GeV) flux of $\sim$2 $\times$ 10$^{-5}$ photons cm$^{-2}$ s$^{-1}$ within a single orbit on 2021 April 27, which is historically the brightest $γ-$ray flux ever detected from the source. Here, we report, for the first time, the detection of significant minute-timescale GeV $γ-$ray flux variability in the BL Lac subclass of blazars by the Fermi-LAT. We resolved the source variability down to 2-min binned timescales with a flux halving time of $\sim$1 minute, which is the shortest GeV variability timescale ever observed from blazars. The detected variability timescale is much shorter than the light-crossing time ($\sim 14$ minutes) across the central black hole of BL Lac indicating a very compact $γ-$ray emission site within the outflowing jet. Such a compact emitting region requires the bulk Lorentz factor of the jet to be larger than 16 so that the jet power is not super Eddington. We found a minimum Doppler factor $δ_{min}$ of 15 using the $δ$ function approximation for the $γγ$ opacity constraint. For a conical jet geometry, considering $Γ= δ_{min}$, the observed short variability timescale suggests the very compact emission region to lie at a distance of about 8.62 $\times$ 10$^{14}$ cm from the central engine of BL Lac.
description: 6 pages, 5 figures, 2 tables, accepted for publication in the Astronomy & Astrophysics (A&A) main journal
Die mediale Darstellung von Großwohnsiedlungen – Wie Musik und Fernsehen das Image von Halle-Neustadt prägen
Creators: name: Auge, Yelva
name: Ringel, Florian
Publisher: name: MLU Human Geography Working Paper Series
Year: 2021
Subjects: subject: 000

description: Neighborhoods with a predominance of large housing units, especially those built during the GDR, often face stigmatization and negative reporting in media. Coverage of these neighborhoods mainly focuses on such as empty buildings, violence or crime. In this paper, we look at the ways in which the neighborhood of Halle-Neustadt is being shown and reported about in TV documentaries by public and private broadcasters, as well as hip-hop songs and their music videos. For this purpose, the visual representation, the coverage of certain topics and the moderation of six documentaries about Halle-Neustadt and the visuals and lyrics of hip-hop songs about the city of Halle (Saale) were examined. In the analysis we locate different patterns of how Halle (Saale) and Halle-Neustadt are represented: the showing of imagery with negative connotation, the judgmental ways of naming facts, and the references to change in the neighborhood. Combined with material from qualitative interviews with residents and data from a citizen survey in Halle from 1993-2017, we conclude that the portrayal of Halle-Neustadt in TV documentaries, hip-hop songs and videos is often limited to stereotypical images. This produces a negative image of Halle-Neustadt which influences people’s attitudes within and towards the neighborhood.
Properties of shock waves in the quiet Sun chromosphere
Creators: name: Mathur, Harsh
name: Joshi, Jayant
name: Nagaraju, K.
name: van der Voort, Luc Rouppe
name: Bose, Souvik
Publisher: name: arXiv
Year: 2022
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Short-lived (100s or less), sub-arcsec to a couple of arcsec size features of enhanced brightenings in the narrowband images at the $\mathrm{H_{2V}}$ and $\mathrm{K_{2V}}$ positions of the Ca II H and K lines in the quiet Sun are known as bright grains. With simultaneous observations of a quiet Sun internetwork region in the Fe I 6173 Å, Ca II 8542 {AA}, and Ca II K lines acquired by the CRisp Imaging Spectro-Polarimeter and the CHROMospheric Imaging Spectrometer instruments on the Swedish 1-m Solar Telescope, we performed multi-line non-local thermodynamic equilibrium inversions using the STockholm inversion Code to infer the time-varying stratified atmosphere's physical properties such as the temperature, line-of-sight (LOS) velocity, and microturbulence. The Ca II K profiles of bright grains show enhancement in the $\mathrm{K_{2V}}$ peak intensities with absence of the $\mathrm{K_{2R}}$ features. At the time of maximum enhancement in the $\mathrm{K_{2V}}$ peak intensities, we found average enhancements in temperature at lower chromospheric layers (at $\logτ_{500}$ $\simeq$ $-$4.2) of about 1.1 kK with maximum enhancement of about 4.5 kK. These temperature enhancements are colocated with upflows, as strong as $-$6 $\mathrm{km\;s^{-1}}$, in the direction of the LOS. The LOS velocities at upper chromospheric layers at $\logτ_{500}$ < $-$4.2 show consistent downflows greater than $+$8 $\mathrm{km\;s^{-1}}$. The retrieved value of microturbulence in the atmosphere of bright grains is negligible at chromospheric layers. The study provides observational evidence to support the interpretation that the bright grains observed in narrowband images at the $\mathrm{H_{2V}}$ and $\mathrm{K_{2V}}$ positions of the Ca II H and K lines are manifestations of upward propagating acoustic shocks against a background of downflowing atmospheres.
description: 23 pages, 12 figures, accepted to be published in Astronomy and Astrophysics on 3rd October, 2022
Halle-Neustadt als dynamisches Ankunftsquartier nach dem langen Sommer der Migration – Migrantische Aushandlungs- und Aneignungspraktiken in einer ostdeutschen Großwohnsiedlung
Creators: name: Wudy, Lisa
Publisher: name: MLU Human Geography Working Paper Series
Year: 2021
Subjects: subject: 000

description: Urban spaces are changing through transnational migration processes and the increasing diversification of society. Thereby immigration is concentrated in specific urban areas, regarded as arrival spaces or neighbourhoods. The impact of urban arrival spaces also has also been the focus of media, scientific and (departmental-)policy in Germany, particularly regarding the immigration of refugees since 2015. In geographical and sociological urban research, the structures and networks of these arrival spaces are examined in how they affect arrival processes of such district-newcomers. Consequently, challenges and opportunities can be recognized and deliberately promoted. This paper discusses the meaning of the district Halle-Neustadt as an arrival space for immigrants who moved there from 2015 onwards, focussing on processes of appropriation and negotiation in their day-to-day life. The research builds on discussions about arrival spaces in Germany and attempts to illuminate blind spots and contradictions on previous concepts about arrival areas. The large East German housing estate Halle-Neustadt, which marks the western outskirt of Halle (Saale), has undergone rapid change since the beginning of the 1990s. Through guided interviews, immigrants’ perceptions of the area are recounted, carving out the meaning and the role of Halle-Neustadt as a potential arrival area. Interview partners were newcomers from Syria, Afghanistan, and Iran who migrated since 2015 to Germany. The analysis considers the choice of residential locations, as well as the individual expectation and experience of one as a newcomer. Based on this, the general wellbeing, and the valuation of the district, plus the neighbourhood relationship and social contacts were questioned.
Low Fine Tuning in Yukawa-deflected Gauge Mediation
Creators: name: Ahmed, Waqas
name: Calibbi, Lorenzo
name: Li, Tianjun
name: Mustafayev, Azar
name: Raza, Shabbar
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We discuss a class of models with gauge-mediated supersymmetry breaking characterized by a non-unified messenger sector inducing non-standard gaugino mass ratios, as well as by additional contributions to the soft mass terms from a matter-messenger coupling. The well-known effect of this coupling is to generate A-terms at one-loop level, hence raising the Higgs mass without relying on super-heavy stops. At the same time, a hierarchy between Wino and gluino masses, as induced by the non-unified messenger fields, can greatly lower the radiative corrections to the Higgs soft mass term driven by the high-energy parameters, thus reducing the fine tuning. We search for models with low fine tuning within this scenario, and we discuss the spectrum, collider phenomenology, constraints, and prospects of the found solutions. We find that some setups are accessible or already excluded by searches at the Large Hadron Collider, and all our scenarios with a tuning better than about 2\% can be tested at the International Linear Collider.
description: 19 pages, 6 figures, 1 table. v2: version accepted for publication in PRD
Theory of hydrodynamic transport in fluctuating electronic charge density wave states
Creators: name: Delacrétaz, Luca V.
name: Goutéraux, Blaise
name: Hartnoll, Sean A.
name: Karlsson, Anna
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We describe the collective hydrodynamic motion of an incommensurate charge density wave state in a clean electronic system. Our description simultaneously incorporates the effects of both pinning due to weak disorder and also phase relaxation due to proliferating dislocations. We show that the interplay between these two phenomena has important consequences for charge and momentum transport. For instance, it can lead to metal-insulator transitions. We furthermore identify signatures of fluctuating density waves in frequency and spatially resolved conductivities. Phase disordering is well known to lead to a large viscosity. We derive a precise formula for the phase relaxation rate in terms of the viscosity in the dislocation cores. We thereby determine the viscosity of the superconducting state of BSCCO from the observed melting dynamics of Abrikosov lattices and show that the result is consistent with dissipation into Bogoliubov quasiparticles.
description: 1+24+10 pages + refs, 6 figures; v2, extended discussion of phase relaxation; v3, moved detailed discussion of review material to appendices to shorten main text; v4, presentation improved and shortened
The Belt and Road Initiative: A Driver for Securitization in China’s Xinjiang Uyghur Autonomous Region?
Creators: name: Frenzel, Florian
Publisher: name: MLU Human Geography Working Paper Series
Year: 2021
Subjects: subject: 000

description: In recent years, the province of Xinjiang in northwest China has increasingly developed into a 'security state' in which Muslim minorities, especially the Uyghurs, are objects of State arbitrariness, discrimination and violence. Simultaneously, the region is of crucial importance for China's Belt and Road Initiative, which raises the question whether there is a linkage between the securitization of Xinjiang and the mega-project. This paper provides an analysis of the current securitization in Xinjiang and explores the relationship of the process to the Belt and Road Initiative. The author draws on the concept of the Copenhagen school for analyzing securitization and conducts a rapid literature review to collect, analyze and compare information on Chinese policies in Xinjiang. In conclusion, Xinjiang's securitization is not due to the Belt and Road Initiative, but rather reflects the efforts of the People's Republic to construct a unified (Han-)Chinese State.
Gravitational waves from extreme-mass-ratio systems in astrophysical environments
Creators: name: Cardoso, Vitor
name: Destounis, Kyriakos
name: Duque, Francisco
name: Macedo, Rodrigo Panosso
name: Maselli, Andrea
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We establish a generic, fully-relativistic formalism to study gravitational-wave emission by extreme-mass-ratio systems in spherically-symmetric, non-vacuum black-hole spacetimes. The potential applications to astrophysical setups range from black holes accreting baryonic matter to those within axionic clouds and dark matter environments, allowing to assess the impact of the galactic potential, of accretion, gravitational drag and halo feedback on the generation and propagation of gravitational-waves. We apply our methods to a black hole within a halo of matter. We find fluid modes imparted to the gravitational-wave signal (a clear evidence of the black hole fundamental mode instability) and the tantalizing possibility to infer galactic properties from gravitational-wave measurements by sensitive, low-frequency detectors.
description: v2. Supplemental Material added, minor improvements. Accepted for publication in Physical Review Letters
Influence of external magnetic field, finite-size effects and chemical potential on the phase transition of a complex scalar field
Creators: name: Cavalcanti, Erich
name: Castro, Erick
name: Linhares, Cesar A.
name: Malbouisson, Adolfo P. C.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A scalar model is built, as a quantum field theory defined on toroidal topologies, to describe phase transition in films subjected to periodic boundary conditions and influenced by an external and constant magnetic field. Criticality is studied and the relations between the critical temperature, the film thickness, the magnetic field strength and the chemical potential are investigated. Since the model describes a second-order phase transition a comparison with the Ginzburg-Landau theory is made.
Modeling the Extragalactic Background Light and the Cosmic Star Formation History
Creators: name: Finke, Justin D.
name: Ajello, Marco
name: Dominguez, Alberto
name: Desai, Abhishek
name: Hartmann, Dieter H.
name: Paliya, Vaidehi S.
name: Saldana-Lopez, Alberto
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present an updated model for the extragalactic background light (EBL) from stars and dust, over wavelengths approximately 0.1 to 1000 $μ$m. This model uses accurate theoretical stellar spectra, and tracks the evolution of star formation, stellar mass density, metallicity, and interstellar dust extinction and emission in the universe with redshift. Dust emission components are treated self-consistently, with stellar light absorbed by dust reradiated in the infrared as three blackbody components. We fit our model, with free parameters associated with star formation rate and dust extinction and emission, to a wide variety of data: luminosity density, stellar mass density, and dust extinction data from galaxy surveys; and $γ$-ray absorption optical depth data from $γ$-ray telescopes. Our results strongly constraint the star formation rate density and dust photon escape fraction of the universe out to redshift $z=10$, about 90% of the history of the universe. We find our model result is, in some cases, below lower limits on the $z=0$ EBL intensity, and below some low-$z$ $γ$-ray absorption measurements.
description: 23 pages, 12 figures, 3 tables. Accepted for publication in AAS journals
The spin-flop transition in the quasi two dimensional antiferromagnet MnPS3 detected via thermally generated magnon transport
Creators: name: Feringa, F.
name: Vink, J. M.
name: van Wees, B. J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present the detection of the spin-flop transition in the antiferromagnetic van der Waals material MnPS3 via thermally generated nonlocal magnon transport using permalloy detector strips. The inverse anomalous spin Hall effect has the unique power to detect an out-of-plane spin accumulation which enables us to detect magnons with an out-of-plane spin polarization; in contrast to strips of high spin-orbit material such as Pt which only possess the spin Hall effect and are only sensitive to an in-plane spin polarization of the spin accumulation. We show that nonlocal magnon transport is able to measure the spin-flop transition in the absence of other spurious effects. Our measurements show the detection of magnons generated by the spin Seebeck effect before and after the spin-flop transition where the signal reversal of the magnon spin accumulation agrees with the OOP spin polarization carried by magnon modes before and after the SF transition.
Consequences of nonreciprocity in reflection from a truncated spatial Kramers-Kronig medium
Creators: name: Saha, Sudipta
name: Sai, K. V. Sowmya
name: Ghosh, Nirmalya
name: Gupta, Subhasish Dutta
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We study the truncated Kramers-Kronig (KK) medium to reveal the effects of nonreciprocity in reflection on the scattering and the wave guiding properties. We focus on the simplest possible spatial profile mimicking the dielectric response. We show that a finite slab of KK medium can support only one sided null scattering under bidirectional identical illumination. However, for a phase lag between the two incident beams it is possible to have null scattering on the other side. This is shown to be a consequence of the nonreciprocity in reflection due to the inherent asymmetry of the KK medium. We further look at the possibility of surface modes for unidirectional illumination. For specific range of parameters, we show the existence of TM polarized surface plasmons only for illumination from one side. The origin of such modes is traced to the inhomogeneous metal like layer with negative real part of the permittivity in the KK medium.