cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Search for lepton flavor violation at future lepton colliders
Creators: name: Cho, Gi-Chol
name: Shimo, Hanako
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Lepton flavor violating (LFV) processes via four-Fermi contact interactions at future International Linear Collider (ILC) are studied. The effective Lagrangian is composed of six-operators, and the LFV effects on both $e^+ e^- \to e^+ \ell^-$ and $e^- e^- \to e^- \ell^-$ ($\ell=μ$ or $τ$) processes can be parametrized by three parameters. Taking account of previous experimental results of LFV processes $μ\to 3e$ and $τ\to 3e$, we find that the upper limits on the LFV parameters for $\ell=τ$ could be improved at the ILC experiment using the polarized electron beam. The improvement of the upper limits is more than an order of magnitude smaller than previous ones.
description: 11 pages, 3 figures
title: The effect of water on trace element diffusivities in silicic melts: A case study on Li, Rb, and Cs
Creators: name: Troch, Juliana
name: Huber, Chris
name: Kueter, Nico
name: Guillong, Marcel
name: Ulmer, Peter
name: Ackerson, Michael R
name: Bachmann, Olivier
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
Trace element diffusion is a powerful tracer for the kinetics of magmatic processes such as recharge and fluid exsolution. However, the dependence of diffusivities on melt water contents is poorly understood, and most trace element diffusivities have been determined in water-free melts unrealistic for most natural magmatic systems. Here, we investigate diffusion of the alkali trace elements Li, Rb, and Cs as a function of water content in metaluminous rhyodacite, high-silica rhyolite, and peralkaline rhyolite.

Homogenous hydrous glass cylinders were produced from trace element-doped and undoped powdered glass with 1-8 wt% H2O. For the diffusion experiments, glass cylinders with the same water content but different trace element concentrations are paired along polished contact surfaces. Diffusion experiments were conducted between 720-1100 °C for 5-25 min using gas pressure vessels and a piston cylinder. Diffusion profiles were analyzed by LA-ICPMS and evaluated by a Monte Carlo iterative fitting procedure for full error propagation.

Measured logD values correlate linearly with melt water content, with one order of magnitude increase for DLi, two orders for DRb and three orders for DCs from driest (1 wt%) to wettest (8 wt%) experiment. Variations in major element composition only have a minor effect. Comparing the dependence of Arrhenius parameters D0 and Ea on melt water content, activation energies correlate linearly, while pre-exponential factors suggest negligible correlation. Quantifying these effects facilitates using the diffusion of alkali trace elements for tracking magmatic processes, such as the exsolution of fluids from long-lived shallow mushy magma reservoirs in the Earth’s crust.
Linkage disequilibrium and within-breed genetic diversity in Iranian Zandi sheep
Creators: name: GHOREISHIFAR, Seyed Mohammad
name: Moradi-Shahrbabak, H
name: Parna, N
name: Davoudi, P
name: Khansefid, Majid
Publisher: name: La Trobe
Year: 2023
Subjects: classificationCode: 3003
subject: Animal production

description: This research aimed to measure the extent of linkage disequilibrium (LD), effective population size (Ne), and runs of homozygosity (ROHs) in one of the major Iranian sheep breeds (Zandi) using 96 samples genotyped with Illumina Ovine SNP50 BeadChip. The amount of LD (r2) for single-nucleotide polymorphism (SNP) pairs in short distances (10-20 kb) was 0:21±0:25 but rapidly decreased to 0:10±0:16 by increasing the distance between SNP pairs (40-60 kb). The Ne of Zandi sheep in past (approximately 3500 generations ago) and recent (five generations ago) populations was estimated to be 6475 and 122, respectively. The ROH-based inbreeding was 0.023. We found 558 ROH regions, of which 37% were relatively long (<10 Mb). Compared with the rate of LD reduction in other species (e.g., cattle and pigs), in Zandi, it was reduced more rapidly by increasing the distance between SNP pairs. According to the LD pattern and high genetic diversity of Zandi sheep, we need to use an SNP panel with a higher density than Illumina Ovine SNP50 BeadChip for genomic selection and genome-wide association studies in this breed.
title: New insights on the role of reverse weathering in determining seawater geochemistry: a lithium isotope study
Creators: name: Läuchli, Charlotte
name: Gaviria-Lugo, Nestor
name: Bernhardt, Anne
name: Wittmann, Hella
name: Sachse, Dirk
name: Frings, Patrick
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
The lithium isotope composition (δ7Li) of ancient seawater is a fundamental proxy for the reconstruction of past conditions on Earth. At any given time, seawater δ7Li depends on the magnitude and isotope composition of the major input and output fluxes, which themselves result from interactions between climate, Earth surface processes and tectonics. Characterizing lithium fluxes during modern times and past eras can thus help determining Earth surface response to environmental changes.

Despite a general consensus on the characterization of the major fluxes of lithium to seawater, questions remain regarding the fate of lithium during early-diagenetic reactions taking place at the ocean floor. In particular, the amount of lithium incorporated into new secondary aluminosilicates formed at the seafloor (i.e., reverse weathering), and the Li isotope fractionation associated with this, are poorly constrained.

Here, we tackle these questions with new lithium isotope data and lithium concentrations measured on the clay-sized fraction of terrestrial and marine sediments from the Chilean active margin. The dataset is composed of riverbed sediments from major rivers along the Chilean climatic gradient (26°S to 41°S), hemipelagic sediments from marine core-tops, and three gravity cores located at 36°S, 33°S and 30°S offshore. It allows us to a) detect a systematic overprint of terrestrial signals in the marine realm, explainable only by the formation of authigenic aluminosilicate phases at the ocean floor, b) determine the Li isotopic signature of reverse weathering products, and c) discuss the global modern fluxes of lithium into and out of seawater.
title: CaSO4 crust as potential habitat for microbial life in the extreme hyperarid Atacama Desert and their reciprocal effects
Creators: name: Raffelsiefen, Lina
name: Zinelabedin, Aline
name: Ritter, Benedikt
name: Mißbach-Karmrodt, Helge
name: Heim, Christine
name: Dunai, Tibor J.
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
The Atacama Desert is one of the most extreme landscapes and environments on Earth. Due to its predominant hyperarid climate and high UV radiation, life is mostly absent. Prolonged aridity causes the formation of CaSO4-rich soils and crusts from mostly atmospheric deposition and aeolian input, creating a blanket covering vast landscapes. Water as the defining pre-requisite for life is scarce, however, infrequent precipitation events, fog and dew are potential moisture sources. CaSO4-rich soils in the Atacama Desert are cemented due to secondary modification (dissolution, transport and re-precipitation) of CaSO4 minerals (Gypsum-Basanite-Anhydrite) and other soluble salts, which form an indurated surface cover with several dm to meters thickness. Within these CaSO4-rich soils, cavities and cracks are partly covered with recrystallized evaporitic minerals indicating the temporal presence of water activity (of unknown state and volume). Harsh environmental conditions on the surface contrast life in the subsurface. Microbial communities from different groups of bacteria, archaea and eukaryotes inhabit such endolithic environments, living from captured moisture within the soil, or potential from hydrated CaSO4. Their presence and interaction, however, can also influence pedogenic processes, contributing to CaSO4 dynamics as landscape forming agent and as preconditions for higher developed life. We present some initial results from a CaSO4-rich soil crust study from the Atacama Desert, using XRD, ICP-OES, and SEM imaging along with the lipid-biomarker analysis to explore and characterize the CaSO4-rich soil as habitat for microbial life, and to unravel the potential impact of microbial life on landscape forming processes, i.e. CaSO4 soil dynamics.
Magnetic Evolution and the Disappearance of Sun-like Activity Cycles
Creators: name: Metcalfe, Travis S.
name: van Saders, Jennifer
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: After decades of effort, the solar activity cycle is exceptionally well characterized but it remains poorly understood. Pioneering work at the Mount Wilson Observatory demonstrated that other sun-like stars also show regular activity cycles, and suggested two possible relationships between the rotation rate and the length of the cycle. Neither of these relationships correctly describe the properties of the Sun, a peculiarity that demands explanation. Recent discoveries have started to shed light on this issue, suggesting that the Sun's rotation rate and magnetic field are currently in a transitional phase that occurs in all middle-aged stars. Motivated by these developments, we identify the manifestation of this magnetic transition in the best available data on stellar cycles. We propose a reinterpretation of previously published observations to suggest that the solar cycle may be growing longer on stellar evolutionary timescales, and that the cycle might disappear sometime in the next 0.8-2.4 Gyr. Future tests of this hypothesis will come from ground-based activity monitoring of Kepler targets that span the magnetic transition, and from asteroseismology with the TESS mission to determine precise masses and ages for bright stars with known cycles.
description: 10 text pages with 3 figures (includes review of arXiv:1601.02631 and arXiv:1606.01926). Solar Physics (accepted)
title: Improving the Interoperability of Established Geochemical Databases
Creators: name: Klöcking, Marthe
name: Sarbas, Bärbel
name: Sturm, Adrian
name: Kallas, Leander
name: Brase, Jan
name: Horstmann, Wolfram
name: Kurzawe, Daniel
name: Möller-McNett, Stefan
name: Nieschulze, Jens
name: Willbold, Matthias
name: Wörner, Gerhard
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
Global geochemical datasets are increasingly used to solve ever more complex research questions exploiting sophisticated computational methods. However, standards to guide geochemical data publication and facilitate uniform access to such large datasets are largely lacking. In their absence, the GEOROC database provides access to a curated compilation of igneous and metamorphic rock and mineral compositions from >20,000 publications. GEOROC is also a major contributor to the EarthChem Portal, a single point of access to six independently curated databases with a common data schema.

Whilst providing findable, accessible and reusable data has been GEOROC’s mission for 23 years, interoperability between geochemical data systems, let alone with other disciplines, remains difficult. To improve the FAIRness of global geochemical data and ensure it can be harvested by other disciplines (e.g. through the NFDI4Earth programme), the field of digital geochemistry first needs to be further developed and strengthened. In collaboration with EarthChem, our DIGIS project is revising the IT infrastructure of the GEOROC database (data model, vocabularies, etc) to enable greater interoperability between the two data systems. For the long-term success of this effort, international stakeholder engagement as well as support by publishers, funders and the international geochemical societies is crucial. Together with EarthChem and other participants of the OneGeochemistry initiative, we are therefore actively engaging with the global geochemistry community to improve data services and to develop community-endorsed best practices for geochemical data publication.
Generalized relativistic harmonic oscillator in minimal length quantum mechanics
Creators: name: Castro, Luis B.
name: Obispo, Angel E.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We solve the generalized relativistic harmonic oscillator in 1+1 dimensions in the presence of a minimal length. Using the momentum space representation, we explore all the possible signs of the potentials and discuss their bound-state solutions for fermion and antifermions. Furthermore, we also find an isolated solution from the Sturm-Liouville scheme. All cases already analyzed in the literature, are obtained as particular cases.
description: 12 pages
Spectral energy cascade in thermoacoustic shock waves
Creators: name: Gupta, Prateek
name: Lodato, Guido
name: Scalo, Carlo
Publisher: name: arXiv
Year: 2017
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We have performed a theoretical and numerical investigation of thermoacoustically amplified quasi-planar nonlinear waves driven to the limit of shock-wave formation in a variable-area 2.58 m long looped resonator designed via eigenvalue analysis to maximize the growth rate of the second harmonic (265 Hz). High-order unstructured fully compressible Navier-Stokes simulations reveal the presence of three regimes: (i) Monochromatic harmonic growth, governed by linear thermoacoustics; (ii) Hierarchical spectral broadening, characterized by nonlinear energy cascade; (iii) Shock-wave dominated limit cycle, where energy production is balanced by dissipation occurring at the captured shock-thickness scale. We have modeled these regimes of thermoacoustic wave amplification based on first-principle governing equations and elucidated the physics of energy density production and saturation to a limit cycle.
Diattenuation of Brain Tissue and its Impact on 3D Polarized Light Imaging
Creators: name: Menzel, Miriam
name: Reckfort, Julia
name: Weigand, Daniel
name: Köse, Hasan
name: Amunts, Katrin
name: Axer, Markus
Publisher: name: arXiv
Year: 2017
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: 3D-Polarized Light Imaging (3D-PLI) reconstructs nerve fibers in histological brain sections by measuring their birefringence. This study investigates another effect caused by the optical anisotropy of brain tissue - diattenuation. Based on numerical and experimental studies and a complete analytical description of the optical system, the diattenuation was determined to be below 4 % in rat brain tissue. It was demonstrated that the diattenuation effect has negligible impact on the fiber orientations derived by 3D-PLI. The diattenuation signal, however, was found to highlight different anatomical structures that cannot be distinguished with current imaging techniques, which makes Diattenuation Imaging a promising extension to 3D-PLI.
description: 32 pages, 15 figures
7-dimensional ${\cal N}=2$ Consistent Truncations using $\mathrm{SL}(5)$ Exceptional Field Theory
Creators: name: Malek, Emanuel
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We show how to construct seven-dimensional half-maximally supersymmetric consistent truncations of 11-/10-dimensional SUGRA using $\mathrm{SL}(5)$ exceptional field theory. Such truncations are defined on generalised $\mathrm{SU}(2)$-structure manifolds and give rise to seven-dimensional half-maximal gauged supergravities coupled to $n$ vector multiplets and thus with scalar coset space $\mathbb{R}^+ \times \mathrm{O}(3,n)/\mathrm{O}(3)\times\mathrm{O}(n)$. The consistency conditions for the truncation can be written in terms of the generalised Lie derivative and take a simple geometric form. We show that after imposing certain "doublet" and "closure" conditions, the embedding tensor of the gauged supergravity is given by the intrinsic torsion of generalised $\mathrm{SU}(2)$-connections and automatically satisfies the linear constraint of seven-dimensional half-maximal gauged supergravities, as well as the quadratic constraint when the section condition is satisfied.
description: 46 pages; v2: minor changes, published version
Extended gauge theory and gauged Free Differential Algebras
Creators: name: Salgado, P.
name: Salgado, S.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Recently, Antoniadis, Konitopoulos and Savvidy introduced, in the context of the so-called extended gauge theory, a procedure to construct background-free gauge invariants, using non-abelian gauge potentials described by higher degree forms. In this article it is shown that the extended invariants found by Antoniadis, Konitopoulos and Savvidy can be constructed from an algebraic structure known as Free Differential Algebra. In other words, we show that the above mentioned non abelian gauge theory, where the gauge fields are described by p-forms with p>1, can be obtained by gauging Free Differential Algebras.
Construction of the Lindström valuation of an algebraic extension
Creators: name: Cartwright, Dustin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05B35 (Primary), 12F20 (Secondary)

description: Recently, Bollen, Draisma, and Pendavingh have introduced the Lindström valuation on the algebraic matroid of a field extension of characteristic p. Their construction passes through what they call a matroid flock and builds on some of the associated theory of matroid flocks which they develop. In this paper, we give a direct construction of the Lindström valuated matroid using the theory of inseparable field extensions. In particular, we give a description of the valuation, the valuated circuits, and the valuated cocircuits.
description: 12 pages, v2: added Section 3 on valuated cocircuits and minors, v3: minor changes and corrections, final submitted version
From Exceptional Field Theory to Heterotic Double Field Theory via K3
Creators: name: Malek, Emanuel
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper we show how to obtain the heterotic double field theory from exceptional field theory by breaking half of the supersymmetry. We focus on the $\mathrm{SL}(5)$ exceptional field theory and show that when the extended space contains a generalised $\mathrm{SU}(2)$-structure manifold one can define a reduction to obtain the heterotic $\mathrm{SO}(3,n)$ double field theory. In this picture, the reduction on the $\mathrm{SU}(2)$-structure breaks half of the supersymmetry of the exceptional field theory and the gauge group of the heterotic double field theory is given by the embedding tensor of the reduction used. Finally, we study the example of a consistent truncation of M-theory on K3 and recover the duality with the heterotic string on $T^3$. This suggests that the extended space can be made sense of even in the case of non-toroidal compactifications.
description: 23 pages; v2: minor changes, published version
title: TephATA: A Tephrostratigraphic Framework for the Atacama Desert and its Application on Regional Sedimentary Archives
Creators: name: Leicher, Niklas
name: Wennrich, Volker
name: Wagner, Bernd
name: Hoffmeister, Dirk
name: Kramm, Tanja
name: Feldmar, Vincent
name: Bareth, Georg
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
A fundamental aspect to study past Earth surface process variations over time and to set local observations in a regional and global context is their temporal understanding. However, accurate dating of sedimentary archives documenting these variations can be hampered in extremely water-limited environments by applicable dating methods (type of archive/temporal range). Tephrostratigraphy and -chronology can be applied independent of the type of sedimentary archive and thus represent powerful tools for dating and synchronization of archives. In the Atacama Desert, tephra layers occur in various types of archives and on various time‑scales. A tephrostratigraphic framework, which sets the tephra layers in a stratigraphic and chronological order and shows the regional dispersal of individual tephra layers is currently lacking. Within the CRC1211 “Earth-Evolution at the dry limit”, the project TephATA aims at setting up a regional tephra database to develop the first comprehensive tephrostratigraphic framework for the Atacama. The database TephATA is currently integrated as a web-based part of the CRC1211 database and uses an extended IGSN metadata schema. TephATA combines existing and new chronological as well as stratigraphical information of tephra layers with their glass geochemical compositions, which is the backbone for reliable correlations of tephra layers and identification of widespread marker horizons. If the geochemistry-based approach allows a correlation of tephra layers, age information can be transferred to tephra layers that does not contain sufficient minerals for absolute dating. Particularly widespread tephra layers will function as independent tie-points for the synchronization of the various sedimentary records investigated within the CRC1211.
Testing the Affect of Modified Sense of Place, Conservation Ethic, and Good Farmer Identity Measures on Predicting the Adoption of Cover Crops in Working Landscapes in Iowa
Creators: name: Bennett, Elizabeth A.
name: Burnham, Morey
name: Ulrich-Schad, Jessica D.
name: Arbuckle, J. Gordon
name: Eaton, Weston M.
name: Church, Sarah P.
name: Eanes, Francis R.
name: Cross, Jennifer Eileen
name: Williamson, Matthew A.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Medicine
subject: Genetics
subject: FOS: Biological sciences
subject: Neuroscience
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: Science Policy

description: While sense of place (SOP) has been used in amenity landscapes to understand pro-environmental behavior, in working landscapes, SOP has not been a valid or reliable predictor for explaining conservation behavior. In this paper, we advance theory on SOP in working landscapes by assessing the relationship between several new and modified sense of place measures and farmer adoption of cover crops in Iowa. We used data from a 2018 survey of Iowa farmers and a Bayesian logistic regression, finding that physical dependence and economic dependence are distinct dimensions of SOP in working landscapes and the addition of a measure beyond SOP of who farmers feel responsible to when making land management decisions provides insights on how social groups are influential in farmers’ decision-making. Our results suggest the SOP conceptual framework has the potential to help explain conservation behavior in working landscapes, and identifies opportunities for further reconceptualization and testing.
Polynomial complexity despite the fermionic sign
Creators: name: Rossi, R.
name: Prokof'ev, N.
name: Svistunov, B.
name: Van Houcke, K.
name: Werner, F.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: It is commonly believed that in quantum Monte Carlo approaches to fermionic many- body problems, the infamous sign problem generically implies prohibitively large computational times for obtaining thermodynamic-limit quantities. We point out that for convergent Feynman diagrammatic series evaluated with the Monte Carlo algorithm of [Rossi, arXiv:1612.05184], the computational time increases only polynomially with the inverse error on thermodynamic-limit quantities.
Chaotic properties of a turbulent isotropic fluid
Creators: name: Berera, A.
name: Ho, R. D. J. G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: High Energy Physics - Theory (hep-th)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: By tracking the divergence of two initially close trajectories in phase space in an Eulerian approach to forced turbulence, the relation between the maximal Lyapunov exponent $λ$, and the Reynolds number $Re$ is measured using direct numerical simulations, performed on up to $2048^3$ collocation points. The Lyapunov exponent is found to solely depend on the Reynolds number with $λ\propto Re^{0.53}$ and that after a transient period the divergence of trajectories grows at the same rate at all scales. Finally a linear divergence is seen that is dependent on the energy forcing rate. Links are made with other chaotic systems.
description: 8 pages, 8 figures
Real-time fMRI neurofeedback of the mediodorsal and anterior thalamus enhances correlation between thalamic BOLD activity and alpha EEG rhythm
Creators: name: Zotev, Vadim
name: Misaki, Masaya
name: Phillips, Raquel
name: Wong, Chung Ki
name: Bodurka, Jerzy
Publisher: name: arXiv
Year: 2017
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Medical Physics (physics.med-ph)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: Real-time fMRI neurofeedback (rtfMRI-nf) with simultaneous EEG allows volitional modulation of BOLD activity of target brain regions and investigation of related electrophysiological activity. We applied this approach to study correlations between thalamic BOLD activity and alpha EEG rhythm. Healthy volunteers in the experimental group (EG, n=15) learned to upregulate BOLD activity of the target region consisting of the mediodorsal (MD) and anterior (AN) thalamic nuclei using the rtfMRI-nf during retrieval of happy autobiographical memories. Healthy subjects in the control group (CG, n=14) were provided with a sham feedback. The EG participants were able to significantly increase BOLD activities of the MD and AN. Functional connectivity between the MD and the inferior precuneus was significantly enhanced during the rtfMRI-nf task. Average individual changes in the occipital alpha EEG power significantly correlated with the average MD BOLD activity levels for the EG. Temporal correlations between the occipital alpha EEG power and BOLD activities of the MD and AN were significantly enhanced, during the rtfMRI-nf task, for the EG compared to the CG. Temporal correlations with the alpha power were also significantly enhanced for the posterior nodes of the default mode network, including the precuneus/posterior cingulate, and for the dorsal striatum. Our findings suggest that the temporal correlation between the MD BOLD activity and posterior alpha EEG power is modulated by the interaction between the MD and the inferior precuneus, reflected in their functional connectivity. Our results demonstrate the potential of the rtfMRI-nf with simultaneous EEG for non-invasive neuromodulation studies of human brain function.
description: 26 pages, 14 figures, to appear in Human Brain Mapping
Evidence for structural damping in a high-stress silicon nitride nanobeam and its implications for quantum optomechanics
Creators: name: Fedorov, S. A.
name: Sudhir, V.
name: Schilling, R.
name: Schütz, H.
name: Wilson, D. J.
name: Kippenberg, T. J.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Optics (physics.optics)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We resolve the thermal motion of a high-stress silicon nitride nanobeam at frequencies far below its fundamental flexural resonance (3.4 MHz) using cavity-enhanced optical interferometry. Over two decades, the displacement spectrum is well-modeled by that of a damped harmonic oscillator driven by a $1/f$ thermal force, suggesting that the loss angle of the beam material is frequency-independent. The inferred loss angle at 3.4 MHz, $ϕ= 4.5\cdot 10^{-6}$, agrees well with the quality factor ($Q$) of the fundamental beam mode ($ϕ= Q^{-1}$). In conjunction with $Q$ measurements made on higher order flexural modes, and accounting for the mode dependence of stress-induced loss dilution, we find that the intrinsic (undiluted) loss angle of the beam changes by less than a factor of 2 between 50 kHz and 50 MHz. We discuss the impact of such "structural damping" on experiments in quantum optomechanics, in which the thermal force acting on a mechanical oscillator coupled to an optical cavity is overwhelmed by radiation pressure shot noise. As an illustration, we show that structural damping reduces the bandwidth of ponderomotive squeezing.
description: Submitted to the special issue of Physics Letters A in the memory of V. Braginsky
Superconducting States for Semi-Dirac Fermions at Zero and Finite Magnetic Fields
Creators: name: Uchoa, Bruno
name: Seo, Kangjun
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We address the superconducting singlet state of anisotropic Dirac fermions that disperse linearly in one direction and parabolically in the other. For systems that have uniaxial anisotropy, we show that the electromagnetic response to an external magnetic flux is extremely anisotropic near the quantum critical point of the superconducting order. In the quantum critical regime and above a critical magnetic field, we show that the superconductor may form a novel exotic smectic state, with a stripe pattern of flux domains.
description: 4.1 pages + supplemental materials. Added references
title: The lithium isotopic composition of Late Cretaceous seawater: Implications for a correlation between weathering, carbon cycle and climate
Creators: name: Huber, Sandra J.
name: Schlidt, Vanessa
name: Kniest, Jorit F.
name: Lenk, Linus
name: Seitz, H.-Michael
name: Raddatz, Jacek
name: Marschall, Horst R.
name: Voigt, Silke
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
The cause and feedback mechanisms of Late Cretaceous climate cooling are not well understood to date. To evaluate the role of silicate weathering as a thermostat and sink for atmospheric CO2, we generated a lithium isotopic record (δ7Li) of Late Cretaceous seawater using chalk as an archive.

The Late Cretaceous δ7Li record (91–66 Ma) shows an overall increase by 3.5‰. Superimposed, five positive δ7Li events occur during this period, which mostly correlate with δ13C anomalies in the late Santonian, latest Campanian to earliest Maastrichtian and mid-Maastrichtian. In contrast, the δ7Li event in the mid-Campanian shows no correlation with a δ13C anomaly. The overall increase in δ7Li correlates positively with the increase in seawater 87Sr/86Sr. The general shape of the δ7Li curve resembles the evolution of deep-sea temperatures based on benthic foraminiferal δ18O suggesting a link among the weathering flux, lowered atmospheric CO2 concentrations and climate cooling. The apparent covariation between δ7Li and δ18O indicates a strong connection between the congruency of silicate weathering and climate change on a multi-million-year time scale. In contrast, the five positive δ7Li excursions correspond to periods of decreased rates of change in seawater 87Sr/86Sr, typical for a decelerated continental weathering flux.

Here, we suggest that enhanced clay mineral formation in lowlands, increasingly exposed during sea level falls, promoted more incongruent weathering and strong lithium isotope fractionation. The relation between the positive δ7Li and δ13C events appears to be more complex and requires further investigation through box models.
Impacts of Antarctic fast dynamics on sea-level projections and coastal flood defense
Creators: name: Wong, Tony E.
name: Bakker, Alexander M. R.
name: Keller, Klaus
Publisher: name: arXiv
Year: 2016
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: FOS: Physical sciences

description: Strategies to manage the risks posed by future sea-level rise hinge on a sound characterization of the inherent uncertainties. One of the major uncertainties is the possible rapid disintegration of large fractions of the Antarctic ice sheet in response to rising global temperatures. This could potentially lead to several meters of sea-level rise during the next few centuries. Previous studies have typically been silent on two coupled questions: (i) What are probabilistic estimates of this "fast dynamics" contribution to sea-level rise? (ii) What are the implications for strategies to manage coastal flooding risks? Here, we present probabilistic hindcasts and projections of sea-level rise to 2100. The fast dynamics mechanism is approximated by a simple parameterization, designed to allow for a careful quantification of the uncertainty in its contribution to sea-level rise. We estimate that global temperature increases ranging from 1.9 to 3.1°C coincide with fast Antarctic disintegration, and these contributions account for sea-level rise of 21-74 centimeters this century (5-95% range, Representative Concentration Pathway 8.5). We use a simple cost-benefit analysis of coastal defense to demonstrate in a didactic exercise how neglecting this mechanism and associated uncertainty can (i) lead to strategies which fall sizably short of protection targets and (ii) increase the expected net costs.
Jamming transitions induced by an attraction in pedestrian flow
Creators: name: Kwak, Jaeyoung
name: Jo, Hang-Hyun
name: Luttinen, Tapio
name: Kosonen, Iisakki
Publisher: name: arXiv
Year: 2017
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: We numerically study jamming transitions in pedestrian flow interacting with an attraction, mostly based on the social force model for pedestrians who can join the attraction. We formulate the joining probability as a function of social influence from others, reflecting that individual choice behavior is likely influenced by others. By controlling pedestrian influx and the social influence parameter, we identify various pedestrian flow patterns. For the bidirectional flow scenario, we observe a transition from the free flow phase to the freezing phase, in which oppositely walking pedestrians reach a complete stop and block each other. On the other hand, a different transition behavior appears in the unidirectional flow scenario, i.e., from the free flow phase to the localized jam phase and then to the extended jam phase. It is also observed that the extended jam phase can end up in freezing phenomena with a certain probability when pedestrian flux is high with strong social influence. This study highlights that attractive interactions between pedestrians and an attraction can trigger jamming transitions by increasing the number of conflicts among pedestrians near the attraction. In order to avoid excessive pedestrian jams, we suggest suppressing the number of conflicts under a certain level by moderating pedestrian influx especially when the social influence is strong.
description: 16 pages, 13 figures
Empirical information on nuclear matter fourth-order symmetry energy from an extended nuclear mass formula
Creators: name: Wang, Rui
name: Chen, Lie-Wen
Publisher: name: arXiv
Year: 2017
Subjects: subject: Nuclear Theory (nucl-th)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We establish a relation between the equation of state (EOS) of nuclear matter and the fourth-order symmetry energy $a_{\rm{sym,4}}(A)$ of finite nuclei in a semi-empirical nuclear mass formula by self-consistently considering the bulk, surface and Coulomb contributions to the nuclear mass. Such a relation allows us to extract information on nuclear matter fourth-order symmetry energy $E_{\rm{sym,4}}(ρ_0)$ at normal nuclear density $ρ_0$ from analyzing nuclear mass data. Based on the recent precise extraction of $a_{\rm{sym,4}}(A)$ via the double difference of the "experimental" symmetry energy extracted from nuclear masses, for the first time, we estimate a value of $E_{\rm{sym,4}}(ρ_0) = 20.0\pm4.6$ MeV. Such a value of $E_{\rm{sym,4}}(ρ_0)$ is significantly larger than the predictions from mean-field models and thus suggests the importance of considering the effects of beyond the mean-field approximation in nuclear matter calculations.
description: 7 pages, 1 figure. Presentation improved and discussions added. Accepted version to appear in PLB
Measurement of the excited-state transverse hyperfine coupling in NV centers via dynamic nuclear polarization
Creators: name: Poggiali, F.
name: Cappellaro, P.
name: Fabbri, N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Precise knowledge of a quantum system's Hamiltonian is a critical pre-requisite for its use in many quantum information technologies. Here, we report a method for the precise characterization of the non-secular part of the excited-state Hamiltonian of an electronic-nuclear spin system in diamond. The method relies on the investigation of the dynamic nuclear polarization mediated by the electronic spin, which is currently exploited as a primary tool for initializing nuclear qubits and performing enhanced nuclear magnetic resonance. By measuring the temporal evolution of the population of the ground-state hyperfine levels of a nitrogen-vacancy center, we obtain the first direct estimation of the excited-state transverse hyperfine coupling between its electronic and nitrogen nuclear spin. Our method could also be applied to other electron-nuclear spin systems, such as those related to defects in silicon carbide.
Test of special relativity using a fiber network of optical clocks
Creators: name: Delva, P.
name: Lodewyck, J.
name: Bilicki, S.
name: Bookjans, E.
name: Vallet, G.
name: Targat, R. Le
name: Pottie, P. -E.
name: Guerlin, C.
name: Meynadier, F.
name: Poncin-Lafitte, C. Le
name: Lopez, O.
name: Amy-Klein, A.
name: Lee, W. -K.
name: Quintin, N.
name: Lisdat, C.
name: Al-Masoudi, A.
name: Dörscher, S.
name: Grebing, C.
name: Grosche, G.
name: Kuhl, A.
name: Raupach, S.
name: Sterr, U.
name: Hill, I. R.
name: Hobson, R.
name: Bowden, W.
name: Kronjäger, J.
name: Marra, G.
name: Rolland, A.
name: Baynes, F. N.
name: Margolis, H. S.
name: Gill, P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Phase compensated optical fiber links enable high accuracy atomic clocks separated by thousands of kilometers to be compared with unprecedented statistical resolution. By searching for a daily variation of the frequency difference between four strontium optical lattice clocks in different locations throughout Europe connected by such links, we improve upon previous tests of time dilation predicted by special relativity. We obtain a constraint on the Robertson--Mansouri--Sexl parameter $|α|\lesssim 1.1 \times10^{-8}$ quantifying a violation of time dilation, thus improving by a factor of around two the best known constraint obtained with Ives--Stilwell type experiments, and by two orders of magnitude the best constraint obtained by comparing atomic clocks. This work is the first of a new generation of tests of fundamental physics using optical clocks and fiber links. As clocks improve, and as fiber links are routinely operated, we expect that the tests initiated in this paper will improve by orders of magnitude in the near future.
description: 6 pages, 3 figures, published in Phys. Rev. L
A bound state model for a light scalar
Creators: name: Holdom, Bob
name: Koniuk, Roman
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: Recent lattice studies of near-conformal strong dynamics suggest the existence of a light scalar. This provides motivation to consider a simple Hamiltonian-based bound-state model where the pseudoscalar, scalar, vector and axial-vector states are treated on an equal footing. The model interpolates between the non-relativistic limit and the highly relativistic chiral limit, where the pseudoscalar mass drops to zero. The fermion mass becomes purely dynamical at this point. When the gauge coupling is constant over a moderate range of scales the scalar becomes significantly lighter than the spin 1 states as the chiral limit is approached. We relate this result to the behavior of the form factors of the respective states and their decay constants. In the conformal limit of the model all masses vanish and the theory is characterized by scaling dimensions.
description: 14 pages, 8 figures, published version
Quantum metrology in local dissipative environments
Creators: name: Wang, Yuan-Sheng
name: Chen, Chong
name: An, Jun-Hong
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum metrology allows us to attain a measurement precision that surpasses the classically achievable limit by using quantum characters. The metrology precision is raised from the standard quantum limit (SQL) to the Heisenberg limit (HL) by using entanglement. However, it was reported that the HL returns to the SQL in the presence of local dephasing environments under the long encoding-time condition. We evaluate here the exact impacts of local dissipative environments on quantum metrology, based on the Ramsey interferometer. It is found that the HL is asymptotically recovered under the long encoding-time condition for a finite number of the probe atoms. Our analysis reveals that this is essentially due to the formation of a bound state between each atom and its environment. This provides an avenue for experimentation to implement quantum metrology under practical conditions via engineering of the formation of the system-environment bound state.
description: 12 pages, 3 figures
AdS Poisson homogeneous spaces and Drinfel'd doubles
Creators: name: Ballesteros, Angel
name: Meusburger, Catherine
name: Naranjo, Pedro
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The correspondence between Poisson homogeneous spaces over a Poisson-Lie group $G$ and Lagrangian Lie subalgebras of the classical double $D({\mathfrak g})$ is revisited and explored in detail for the case in which ${\mathfrak g}=D(\mathfrak a)$ is a classical double itself. We apply these results to give an explicit description of some coisotropic 2d Poisson homogeneous spaces over the group $\mathrm{SL}(2,R)\cong\mathrm{SO}(2,1)$, namely 2d anti de Sitter space, 2d hyperbolic space and the lightcone in 3d Minkowski space. We show how each of these spaces is obtained as a quotient with respect to a Poisson-subgroup for one of the three inequivalent Lie bialgebra structures on ${sl}(2,R)$ and as a coisotropic one for the others. We then construct families of coisotropic Poisson homogeneous structures for 3d anti de Sitter space $\mathrm{AdS}_3$ and show that the ones that are quotients by a Poisson subgroup are determined by a three-parameter family of classical $r$-matrices for ${so}(2,2)$, while the non Poisson-subgroup cases are much more numerous. In particular, we present the two Poisson homogeneous structures on $\mathrm{AdS}_3$ that arise from two Drinfel'd double structures on $\mathrm{SO}(2,2)$. The first one realises $\mathrm{AdS}_3$ as a quotient of $\mathrm{SO}(2,2)$ by the Poisson-subgroup $\mathrm{SL}(2,R)$, while the second one, the non-commutative spacetime of the twisted $κ$-AdS deformation, realises $\mathrm{AdS}_3$ as a coisotropic Poisson homogeneous space.
description: 25 pages, journal version, section 2 fully rewritten, some comments and references added
In-orbit Calibrations of the Ultra-Violet Imaging Telescope
Creators: name: Tandon, S. N.
name: Subramaniam, Annapurni
name: Girish, V.
name: Postma, J.
name: Sankarasubramanian, K.
name: Sriram, S.
name: Stalin, C. S.
name: Mondal, C.
name: Joseph, S. Sahu P.
name: Hutchings, J.
name: Ghosh, S. K.
name: Barve, I. V.
name: George, K.
name: Kamath, P. U.
name: Kathiravan, S.
name: Kumar, A.
name: Lancelot, J. P.
name: Leahy, D.
name: Mahesh, P. K.
name: Mohan, R.
name: Nagabhushana, S.
name: Pati, A. K.
name: Rao, N. Kameswara
name: Sreedhar, Y. H.
name: Sreekumar, P.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375mm telescopes: one for the far-ultraviolet (FUV) channel (1300--1800Å), and the other for the near-ultraviolet (NUV) channel (2000--3000Å) and the visible (VIS) channel (3200--5500Å). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.8 arcsec, along with provision for slit-less spectroscopy in the NUV and FUV channels.The results of in-orbit calibrations of UVIT are presented in this paper.
description: Accepted to appear in AJ
Spontaneous Beliaev-Landau scattering out of equilibrium
Creators: name: Van Regemortel, Mathias
name: Casteels, Wim
name: Carusotto, Iacopo
name: Wouters, Michiel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We investigate Beliaev-Landau scattering in a gas of interacting photons in a coherently driven array of nonlinear dissipative resonators, as described by the 1D driven-dissipative Bose-Hubbard model. Due to the absence of detailed balance in such an out-of-equilibrium setup, steady-state properties can be much more sensitive to the underlying microscopic dynamics. As the popular truncated Wigner approximation dramatically fails in capturing this physics, we present an alternative approach, based on a systematic expansion beyond the Bogoliubov approximation, which includes the third-order correlation functions in the dynamics. As experimentally accessible signatures of Beliaev-Landau processes, we report a small but nonnegligible correction to the Bogoliubov prediction for the steady-state momentum distribution showing a characteristic series of peaks and dips, as well as non-Gaussian features in the statistics of the cavity output field.