cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Kondo Insulator to Semimetal Transformation Tuned by Spin-Orbit Coupling
Creators: name: Dzsaber, S.
name: Prochaska, L.
name: Sidorenko, A.
name: Eguchi, G.
name: Svagera, R.
name: Waas, M.
name: Prokofiev, A.
name: Si, Q.
name: Paschen, S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Recent theoretical studies of topologically nontrivial electronic states in Kondo insulators have pointed to the importance of spin-orbit coupling (SOC) for stabilizing these states. However, systematic experimental studies that tune the SOC parameter $λ_{\rm{SOC}}$ in Kondo insulators remain elusive. The main reason is that variations of (chemical) pressure or doping strongly influence the Kondo coupling $J_{\text{K}}$ and the chemical potential $μ$ -- both essential parameters determining the ground state of the material -- and thus possible $λ_{\rm{SOC}}$ tuning effects have remained unnoticed. Here we present the successful growth of the substitution series Ce$_3$Bi$_4$(Pt$_{1-x}$Pd$_x$)$_3$ ($0 \le x \le 1$) of the archetypal (noncentrosymmetric) Kondo insulator Ce$_3$Bi$_4$Pt$_3$. The Pt-Pd substitution is isostructural, isoelectronic, and isosize, and therefore likely to leave $J_{\text{K}}$ and $μ$ essentially unchanged. By contrast, the large mass difference between the $5d$ element Pt and the $4d$ element Pd leads to a large difference in $λ_{\rm{SOC}}$, which thus is the dominating tuning parameter in the series. Surprisingly, with increasing $x$ (decreasing $λ_{\rm{SOC}}$), we observe a Kondo insulator to semimetal transition, demonstrating an unprecedented drastic influence of the SOC. The fully substituted end compound Ce$_3$Bi$_4$Pd$_3$ shows thermodynamic signatures of a recently predicted Weyl-Kondo semimetal.
description: 6 pages, 5 figures plus Supplemental Material
Note on Weyl versus Conformal Invariance in Field Theory
Creators: name: Wu, Feng
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It was argued recently that conformal invariance in flat spacetime implies Weyl invariance in a general curved background for unitary theories and possible anomalies in the Weyl variation of scalar operators are identified. We argue that generically unitarity alone is not sufficient for a conformal field theory to be Weyl invariant. Furthermore, we show explicitly that when a unitary conformal field theory couples to gravity in a Weyl invariant way, each primary scalar operator that is either relevant or marginal in the unitary conformal field theory corresponds to a Weyl-covariant operator in the curved background.
description: 10 pages, v3: version to appear in EPJC
title: Measuring fallout plutonium activities in soils to trace the fate of soil organic matter in arable land, Republic of South Africa
Creators: name: Mohren, Joel
name: Wiesel, Hendrik
name: Amelung, Wulf
name: Sandhage-Hofmann, Alexandra
name: Strub, Erik
name: Binnie, Steven A.
name: Heinze, Stefan
name: Dunai, Tibor J.
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
The Free State Province comprises one of the major agricultural regions in the Republic of South Africa. Here, the loss of soil organic matter (SOM) from arable land bears the risk to pose a serious threat to regional crop production yields. For agricultural land located within the Free State Province, previous studies have found a strong relationship between (decreasing) SOM contents and the total time period soils were subject to cropping practices. While wind erosion and mineralisation processes have been identified to be the dominant factors causing this pattern, their individual contribution to SOM loss remained difficult to quantify. Datasets obtained from monitoring stations measuring soil redistribution by wind rarely cover timespans exceeding a few years of observation. To overcome this problem, we measure fallout 239+240Pu inventories in topsoils sampled from agricultural plots with different cropping histories. Plutonium inventories are frequently quantified to infer fluvial soil redistribution patterns and rates during the Anthropocene, but their application to investigate wind erosion is still at an early stage of development. The approach we follow allows us to identify strong correlations between SOM loss and decreasing radionuclide inventories during the second half of the 20th century. Furthermore, cropped soils lost about 50% of their initial 239+240Pu, indicating that the decrease of SOM contents over time is predominantly caused by wind erosion. Our results, which are in good agreement with 137Cs data, underscore the necessity to tackle unsustainable cropping practices in the Republic of South Africa and in comparable settings on Earth.
Simultaneous Multi-Slice MRI using Cartesian and Radial FLASH and Regularized Nonlinear Inversion: SMS-NLINV
Creators: name: Rosenzweig, Sebastian
name: Holme, H. Christian M.
name: Wilke, Robin N.
name: Voit, Dirk
name: Frahm, Jens
name: Uecker, Martin
Publisher: name: arXiv
Year: 2017
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Purpose: The development of a calibrationless parallel imaging method for accelerated simultaneous multi-slice (SMS) MRI based on Regularized Nonlinear Inversion (NLINV), evaluated using Cartesian and radial FLASH. Theory and Methods: NLINV is a parallel imaging method that jointly estimates image content and coil sensitivities using a Newton-type method with regularization. Here, NLINV is extended to SMS-NLINV for reconstruction and separation of all simultaneously acquired slices. The performance of the extended method is evaluated for different sampling schemes using phantom and in-vivo experiments based on Cartesian and radial SMS-FLASH sequences. Results: The basic algorithm was validated in Cartesian experiments by comparison with ESPIRiT. For Cartesian and radial sampling, improved results are demonstrated compared to single-slice experiments, and it is further shown that sampling schemes using complementary samples outperform schemes with the same samples in each partition. Conclusion: The extension of the NLINV algorithm for SMS data was implemented and successfully demonstrated in combination with a Cartesian and radial SMS-FLASH sequence.
description: Part of this work has been presented at the ISMRM Annual Conference 2016 (Singapore) and 2017 (Honolulu). 25 pages, 8+4 figures
Many-body mobility edges in a one-dimensional model of interacting fermions
Creators: name: Nag, Sabyasachi
name: Garg, Arti
Publisher: name: arXiv
Year: 2017
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We analyze many body localization (MBL) in an interacting one-dimensional system with a deterministic aperiodic potential. Below the threshold value of the potential $h < h_c$, the non-interacting system has single particle mobility edges at $\pm E_c$ while for $ h > h_c$ all the single particle states are localized. We demonstrate that even in the presence of single particle mobility edges, the interacting system can have MBL. Our numerical calculation of participation ratio in the Fock space and Shannon entropy shows that both for $h < h_c$ (quarter filled) and $h>h_c$ ($h\sim h_c$ and half filled), many body states in the middle of the spectrum are delocalized while the low energy states with $E < E_1$ and the high energy states with $E> E_2$ are localized. Variance of entanglement entropy (EE) also shows divergence at $E_{1,2}$ indicating a transition from MBL to delocalized regime. We also studied eigenstate thermalisation hypothesis (ETH) and found that the low energy many body states, which show area law scaling for EE do not obey ETH. The crossings from volume to area law scaling for EE and from thermal to non-thermal behaviour occurs deep inside the localised regime. For $h \gg h_c$, all the many body states remain localized for weak to intermediate strength of interaction and the system shows infinite temperature MBL phase.
description: 5 pages 8 figures
Flexible Level-1 Consensus Ensuring Stable Social Choice: Analysis and Algorithms
Creators: name: Nitzan, Mor
name: Nitzan, Shmuel
name: Segal-Halevi, Erel
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: FOS: Computer and information sciences

description: Level-1 Consensus is a property of a preference-profile. Intuitively, it means that there exists a preference relation which induces an ordering of all other preferences such that frequent preferences are those that are more similar to it. This is a desirable property, since it enhances the stability of social choice by guaranteeing that there exists a Condorcet winner and it is elected by all scoring rules. In this paper, we present an algorithm for checking whether a given preference profile exhibits level-1 consensus. We apply this algorithm to a large number of preference profiles, both real and randomly-generated, and find that level-1 consensus is very improbable. We support these empirical findings theoretically, by showing that, under the impartial culture assumption, the probability of level-1 consensus approaches zero when the number of individuals approaches infinity. Motivated by these observations, we show that the level-1 consensus property can be weakened while retaining its stability implications. We call this weaker property Flexible Consensus. We show, both empirically and theoretically, that it is considerably more probable than the original level-1 consensus. In particular, under the impartial culture assumption, the probability for Flexible Consensus converges to a positive number when the number of individuals approaches infinity.
Renewable Energy Development in Nepal.pdf
Creators: name: Ghimire, Aatiz
Publisher: name: figshare
Year: 2023
Subjects: Electrical energy generation (incl. renewables, excl. photovoltaics)

description: This research article provides a comprehensive analysis of the renewable energy sector in Nepal, focusing on its potential, policies, and challenges. The study explores the current energy landscape in Nepal, highlighting the dominance of hydropower and the untapped potential of solar, wind, biomass, micro-hydro, and geothermal energy sources. It examines various strategic plans and policies that aim to promote renewable energy in the country and achieve sustainable development goals. Additionally, the article identifies the challenges hindering the growth of renewable energy, including outdated technologies, limited access to finance, ambiguous policies, and inadequate infrastructure. Finally, the article proposes strategic recommendations for advancing renewable energy development in Nepal, including leveraging climate and energy funds, strengthening donor relationships, fostering publicprivate partnerships, collaborating with local governments, and promoting e-cooking initiatives.
A Hubble Space Telescope survey for novae in M87. III. Are novae good standard candles 15 days after maximum brightness?
Creators: name: Shara, Michael M.
name: Doyle, Trisha F.
name: Pagnotta, Ashley
name: Garland, James T.
name: Lauer, Tod R.
name: Zurek, David
name: Baltz, Edward A.
name: Goerl, Ariel
name: Kovetz, Attay
name: Machac, Tamara
name: Madrid, Juan
name: Mikolajewska, Joanna
name: Neill, J. D.
name: Prialnik, Dina
name: Welch, Doug L.
name: Yaron, Ofer
Publisher: name: arXiv
Year: 2017
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Ten weeks of daily imaging of the giant elliptical galaxy M87 with the Hubble Space Telescope (HST) has yielded 41 nova light curves of unprecedented quality for extragalactic cataclysmic variables. We have recently used these light curves to demonstrate that the observational scatter in the so-called Maximum-Magnitude Rate of Decline (MMRD) relation for classical novae is so large as to render the nova-MMRD useless as a standard candle. Here we demonstrate that a modified Buscombe - de Vaucouleurs hypothesis, namely that novae with decline times t2 > 10 days converge to nearly the same absolute magnitude about two weeks after maximum light in a giant elliptical galaxy, is supported by our M87 nova data. For 13 novae with daily-sampled light curves, well determined times of maximum light in both the F606W and F814W filters, and decline times $t2 > 10 days we find that M87 novae display M(606W,15) = -6.37 +/- 0.46 and M(814W,15) = -6.11 +/- 0.43. If very fast novae with decline times t2 < 10 days are excluded, the distances to novae in elliptical galaxies with stellar binary populations similar to those of M87 should be determinable with 1 sigma accuracies of +/-20% with the above calibrations.
description: 8 pages, 4 figures, accepted in Monthly Notices of the Royal Astronomical Society
Exotic Lifshitz transitions in topological materials
Creators: name: Volovik, G. E.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Topological Lifshitz transitions involve many types of topological structures in momentum and frequency-momentum spaces: Fermi surfaces, Dirac lines, Dirac and Weyl points, etc. Each of these structures has their own topological invariant ($N_1$, $N_2$, $N_3$, $\tilde N_3$, etc.), which supports the stability of a given topological structure. The topology of the shape of Fermi surfaces and Dirac lines, as well as the interconnection of the objects of different dimensions, lead to numerous classes of Lifshitz transitions. The consequences of Lifshitz transitions are important in different areas of physics. The singularities emerging at the transition may enhance the transition temperature to superconductivity; the Lifshitz transition can be in the origin of the small masses of elementary particles in our Universe; the black hole horizon serves as the surface of Lifshitz transition between the vacua with type-I and type-II Weyl points; etc.
description: 11 pages, 18 figures, draft of paper for the issue of Physics-Uspekhi devoted to centenary of I.M. Lifshitz, reference added
Reality from maximizing overlap in the future-included real action theory
Creators: name: Nagao, Keiichi
name: Nielsen, Holger Bech
Publisher: name: arXiv
Year: 2017
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In the future-included real action theory whose path runs over not only past but also future, we demonstrate a theorem, which states that the normalized matrix element of a Hermitian operator $\hat{\cal O}$ defined in terms of the future state at the final time $T_B$ and the fixed past state at the initial time $T_A$ becomes real for the future state selected such that the absolute value of the transition amplitude from the past state to the future state is maximized. This is a special version of our previously proposed theorem for the future-included complex action theory. We find that though the maximization principle leads to the reality of the normalized matrix element in the future-included real action theory, it does not specify the future and past states so much as in the case of the future-included complex action theory. In addition, we argue that the normalized matrix element seems to be more natural than the usual expectation value. Thus we speculate that the functional integral formalism of quantum theory could be most elegant in the future-included complex action theory.
description: Latex 11 pages, typos corrected, presentation improved, the final version to appear in Prog.Theor.Exp.Phys. . arXiv admin note: text overlap with arXiv:1502.00385
Friction of polymers: from PDMS melts to PDMS elastomers
Creators: name: Hénot, Marceau
name: Drockenmuller, Eric
name: Léger, Liliane
name: Restagno, Frédéric
Publisher: name: arXiv
Year: 2017
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The slip behavior of polydimethylsiloxane (PDMS) polymer melts flowing on non-adsorbing surfaces made of short non-entangled PDMS chains densely end-grafted to silica has been characterized. For high enough shear rates, constant slip lengths proportional to the bulk fluid viscosity have been observed, in agreement with Navier's interfacial equation, and demonstrating that the interfacial Navier's friction coefficient is a local quantity, independent of the polymer molecular weight. Comparing the interfacial shear stresses deduced from these measured slip lengths to available friction stress measured for crosslinked PDMS elastomers, we directly compared the interfacial melt or elastomer friction coefficient to the monomer-monomer friction.
description: The file has been withdraw for an error in the version put online
British Gallup Poll CQ 996
Creators: name: Social Surveys (Gallup Poll) Limited
Publisher: name: Roper Center for Public Opinion Research
Year: 2022

description: Government approval (1); Harold Wilson performance (1); Margaret Thatcher performance (1); Jeremy Thorpe performance (1); party support (1); last general election (2); urgent problems (2); best party to handle problems (1); next general election (2); party with best policies (1); party with best leaders (1); party unity (2); government's price & income policy (8); Labor politicians (12); conservative politicians (14); Wilson characteristics (7); Thatcher characteristics (7); concerns of parties (4); Greece Common Market membership (1); shower in home (3); bacon by country (3); kitchen furniture (21); bedroom furniture (16); whisky habits (22).
Physical observables of the Ising spin glass in 6-epsilon dimensions: asymptotical behavior around the critical fixed point
Creators: name: Temesvári, Tamás
Publisher: name: arXiv
Year: 2016
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The asymptotical behavior of physical quantities, like the order parameter, the replicon and longitudinal masses, is studied around the zero-field spin glass transition point when a small external magnetic field is applied. An effective field theory to model this asymptotics contains a small perturbation in its Lagrangian which breaks the zero-field symmetry. A first order renormalization group supplemented by perturbational results provides the scaling functions. The perturbative zero of the scaling function for the replicon mass defines a generic Almeida-Thouless surface stemming from the zero-field fixed point.
description: 12 pages. Minor changes in the text, two added paragraphs in Sec. VI (3. and 4.) and 7 added references (Refs. 19-25). Accepted for publication in Physical Review B
Inclusive Production Through AdS/CFT
Creators: name: Nally, Richard
name: Raben, Timothy G.
name: Tan, Chung-I
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: It has been shown that AdS/CFT calculations can reproduce certain exclusive 2->2 cross sections in QCD at high energy, both for near-forward and for fixed-angle scattering. In this paper, we extend prior treatments by using AdS/CFT to calculate the inclusive single-particle production cross section in QCD at high center-of-mass energy. We find that conformal invariance in the UV restricts the cross section to have a characteristic power-law falloff in the transverse momentum of the produced particle, with the exponent given by twice the conformal dimension of the produced particle, independent of incoming particle types. We conclude by comparing our findings to recent LHC experimental data from ATLAS and ALICE, and find good agreement.
description: JHEP version. Discussion, appendix, figures, and tables added. Conclusions and key results unchanged
Nodal and nodeless gap in proximity induced superconductivity: application to monolayer CuO$_2$ on BSCCO substrate
Creators: name: Wang, Yimeng
name: Wang, Zhen-Hua
name: Chen, Wei-Qiang
Publisher: name: arXiv
Year: 2017
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We present a detailed analysis on the hopping between monolayer CuO$_2$ and bulk CuO$_2$ plane in the Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ substrate. With a two-band model, we demonstrate that the nodeless gap can only exist when the hole concentration in monolayer CuO$_2$ plane is very large or very small. We argued that the possible phase separation may play important role in the recent experimental observation of nodeless gap.
description: 5 pages, 5 figures
Entanglement, space-time and the Mayer-Vietoris theorem
Creators: name: Patrascu, Andrei T.
Publisher: name: arXiv
Year: 2017
Subjects: subject: General Physics (physics.gen-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Entanglement appears to be a fundamental building block of quantum gravity leading to new principles underlying the nature of quantum space-time. One such principle is the ER-EPR duality. While supported by our present intuition, a proof is far from obvious. In this article I present a first step towards such a proof, originating in what is known to algebraic topologists as the Mayer-Vietoris theorem. The main result of this work is the re-interpretation of the various morphisms arising when the Mayer-Vietoris theorem is used to assemble a torus-like topology from more basic subspaces on the torus in terms of quantum information theory resulting in a quantum entangler gate (Hadamard and c-NOT).
Using Voids to Unscreen Modified Gravity
Creators: name: Falck, B.
name: Koyama, Kazuya
name: Zhao, Gong-bo
name: Cautun, M.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The Vainshtein mechanism, present in many models of gravity, is very effective at screening dark matter halos such that the fifth force is negligible and general relativity is recovered within their Vainshtein radii. Vainshtein screening is independent of halo mass and environment, in contrast to e.g. chameleon screening, making it difficult to test. However, our previous studies have found that the dark matter particles in filaments, walls, and voids are not screened by the Vainshtein mechanism. We therefore investigate whether cosmic voids, identified as local density minima using a watershed technique, can be used to test models of gravity that exhibit Vainshtein screening. We measure density, velocity, and screening profiles of stacked voids in cosmological $N$-body simulations using both dark matter particles and dark matter halos as tracers of the density field. We find that the voids are completely unscreened, and the tangential velocity and velocity dispersion profiles of stacked voids show a clear deviation from $Λ$CDM at all radii. Voids have the potential to provide a powerful test of gravity on cosmological scales.
description: 11 pages, 12 figures; matches version accepted to MNRAS
Long time existence from interior gluing
Creators: name: Chrusciel, Piotr T.
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We prove the "existence of a piece of Scri near $i^0$" (with most likely poor differentiability of the conformally rescaled metric) for general asymptotically flat data with well-defined energy-momentum. The proof uses scaling and a gluing construction to reduce the problem to Bieri's stability theorem.
description: arXiv admin note: text overlap with arXiv:1612.04359 authors note: this paper builds upon arXiv:1612.04359 v2: various small improvements
Polaron-Polaritons in the Integer and Fractional Quantum Hall Regimes
Creators: name: Ravets, Sylvain
name: Knüppel, Patrick
name: Faelt, Stefan
name: Kroner, Martin
name: Wegscheider, Werner
name: Imamoglu, Atac
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Elementary quasi-particles in a two dimensional electron system can be described as exciton-polarons since electron-exciton interactions ensures dressing of excitons by Fermi-sea electron-hole pair excitations. A relevant open question is the modification of this description when the electrons occupy flat-bands and electron-electron interactions become prominent. Here, we perform cavity spectroscopy of a two dimensional electron system in the strong-coupling regime where polariton resonances carry signatures of strongly correlated quantum Hall phases. By measuring the evolution of the polariton splitting under an external magnetic field, we demonstrate the modification of electron-exciton interactions that we associate with phase space filling at integer filling factors and polaron dressing at fractional filling factors. The observed non-linear behavior shows great promise for enhancing polariton-polariton interactions.
description: 6 pages, 3 figures
GoDP: Globally optimized dual pathway system for facial landmark localization in-the-wild
Creators: name: Wu, Yuhang
name: Shah, Shishir K.
name: Kakadiaris, Ioannis A.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Facial landmark localization is a fundamental module for pose-invariant face recognition. The most common approach for facial landmark detection is cascaded regression, which is composed of two steps: feature extraction and facial shape regression. Recent methods employ deep convolutional networks to extract robust features for each step, while the whole system could be regarded as a deep cascaded regression architecture. In this work, instead of employing a deep regression network, a Globally Optimized Dual-Pathway (GoDP) deep architecture is proposed to identify the target pixels through solving a cascaded pixel labeling problem without resorting to high-level inference models or complex stacked architecture. The proposed end-to-end system relies on distance-aware softmax functions and dual-pathway proposal-refinement architecture. Results show that it outperforms the state-of-the-art cascaded regression-based methods on multiple in-the-wild face alignment databases. The model achieves 1.84 normalized mean error (NME) on the AFLW database, which outperforms 3DDFA by 61.8%. Experiments on face identification demonstrate that GoDP, coupled with DPM-headhunter, is able to improve rank-1 identification rate by 44.2% compared to Dlib toolbox on a challenging database.
description: Accepted by Image and Vision Computing in December, 2017
Rapid X-ray variability properties during the unusual very hard state in neutron-star low-mass X-ray binaries
Creators: name: Wijnands, R.
name: Parikh, A. S.
name: Altamirano, D.
name: Homan, J.
name: Degenaar, N.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Here we study the rapid X-ray variability (using XMM-Newton observations) of three neutron-star low-mass X-ray binaries (1RXS J180408.9-342058, EXO 1745-248, and IGR J18245-2452) during their recently proposed very hard spectral state (Parikh et al. 2017). All our systems exhibit a strong to very strong noise component in their power density spectra (rms amplitudes ranging from 34% to 102%) with very low characteristic frequencies (as low as 0.01 Hz). These properties are more extreme than what is commonly observed in the canonical hard state of neutron-star low-mass X-ray binaries observed at X-ray luminosities similar to those we observe from our sources. This suggests that indeed the very hard state is a distinct spectral-timing state from the hard state, although we argue that the variability behaviour of IGR J18245-2452 is very extreme and possibly this source was in a very unusual state. We also compare our results with the rapid X-ray variability of the accreting millisecond X-ray pulsars IGR J00291+5934 and Swift J0911.9-6452 (also using XMM-Newton data) for which previously similar variability phenomena were observed. Although their energy spectra (as observed using the Swift X-ray telescope) were not necessarily as hard (i.e., for Swift J0911.9-6452) as for our other three sources, we conclude that likely both sources were also in very similar state during their XMM-Newton observations. This suggest that different sources that are found in this new state might exhibit different spectral hardness and one has to study both the spectral as well as rapid variability to identify this unusual state.
description: Accepted for publication in MNRAS on 2 August 2017
Constraining Black Holes with Light Boson Hair and Boson Stars using Epicyclic Frequencies and QPOs
Creators: name: Franchini, Nicola
name: Pani, Paolo
name: Maselli, Andrea
name: Gualtieri, Leonardo
name: Herdeiro, Carlos A R
name: Radu, Eugen
name: Ferrari, Valeria
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Light bosonic fields are ubiquitous in extensions of the Standard Model. Even when minimally coupled to gravity, these fields might evade the assumptions of the black-hole no-hair theorems and give rise to spinning black holes which can be drastically different from the Kerr metric. Furthermore, they allow for self-gravitating compact solitons, known as (scalar or Proca) boson stars. The quasi-periodic oscillations (QPOs) observed in the X-ray flux emitted by accreting compact objects carry information about the strong-field region, thus providing a powerful tool to constrain deviations from Kerr's geometry and to search for exotic compact objects. By using the relativistic precession model as a proxy to interpret the QPOs in terms of geodesic frequencies, we investigate how the QPO frequencies could be used to test the no-hair theorem and the existence of light bosonic fields near accreting compact objects. We show that a detection of two QPO triplets with current sensitivity can already constrain these models, and that the future eXTP mission or a LOFT-like mission can set very stringent constraints on black holes with bosonic hair and on (scalar or Proca) boson stars. The peculiar geodesic structure of compact scalar/Proca boson stars implies that these objects can easily be ruled out as alternative models for X-ray source GRO J1655-40.
description: 16 pages, 10 figures; v2: revised version containing an improved discussion and one new plot; v3: minor changes to match published version
Enhancing the reach of LifeCourse Forums to build a thriving community of practice
Creators: name: Duncan, Anna
name: O'Connor, Meredith
Publisher: name: Murdoch Childrens Research Institute
Year: 2023
Subjects: Uncategorised

description: One area of focus for LifeCourse is the promotion of a thriving community of practice around cohort research, creating opportunities for connection and synergy through a range of “meeting places”. These presentations are recorded to allow for broader engagement, however, there have been barriers to accessing the recordings in the past. In an effort to engage more campus researchers, as well as national and international data users, and make LifeCourse cohorts and LifeCourse resources more visible to a wider audience, we now want to share presentation recordings more broadly, when appropriate. This document outlines the process used by LifeCourse to determine how to share session recordings with the most appropriate audience, including gaining consent to share and considerations around licensing.
Mean Field Analysis of Algorithms for Scale-free Networks in Molecular Biology
Creators: name: Konini, S
name: van Rensburg, EJ Janse
Publisher: name: arXiv
Year: 2017
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Molecular Networks (q-bio.MN)
subject: FOS: Physical sciences
subject: FOS: Biological sciences
subject: 92C42, 90B15

description: The sampling of scale-free networks in Molecular Biology is usually achieved by growing networks from a seed using recursive algorithms with elementary moves which include the addition and deletion of nodes and bonds. These algorithms include the Barabasi-Albert algorithm. Later algorithms, such as the Duplication-Divergence algorithm, the Solé algorithm and the iSite algorithm, were inspired by biological processes underlying the evolution of protein networks, and the networks they produce differ essentially from networks grown by the Barabasi-Albert algorithm. In this paper the mean field analysis of these algorithms is reconsidered, and extended to variant and modified implementations of the algorithms. The degree sequences of scale-free networks decay according to a powerlaw distribution, namely $P(k) \sim k^{-γ}$, where $γ$ is a scaling exponent. We derive mean field expressions for $γ$, and test these by numerical simulations. Generally, good agreement is obtained. We also found that some algorithms do not produce scale-free networks (for example some variant Barabasi-Albert and Solé networks).
DeepBach: a Steerable Model for Bach Chorales Generation
Creators: name: Hadjeres, Gaëtan
name: Pachet, François
name: Nielsen, Frank
Publisher: name: arXiv
Year: 2016
Subjects: subject: Artificial Intelligence (cs.AI)
subject: Sound (cs.SD)
subject: FOS: Computer and information sciences

description: This paper introduces DeepBach, a graphical model aimed at modeling polyphonic music and specifically hymn-like pieces. We claim that, after being trained on the chorale harmonizations by Johann Sebastian Bach, our model is capable of generating highly convincing chorales in the style of Bach. DeepBach's strength comes from the use of pseudo-Gibbs sampling coupled with an adapted representation of musical data. This is in contrast with many automatic music composition approaches which tend to compose music sequentially. Our model is also steerable in the sense that a user can constrain the generation by imposing positional constraints such as notes, rhythms or cadences in the generated score. We also provide a plugin on top of the MuseScore music editor making the interaction with DeepBach easy to use.
description: 10 pages, ICML2017 version
Signal Recovery from Unlabeled Samples
Creators: name: Haghighatshoar, Saeid
name: Caire, Giuseppe
Publisher: name: arXiv
Year: 2017
Subjects: subject: Information Theory (cs.IT)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: In this paper, we study the recovery of a signal from a set of noisy linear projections (measurements), when such projections are unlabeled, that is, the correspondence between the measurements and the set of projection vectors (i.e., the rows of the measurement matrix) is not known a priori. We consider a special case of unlabeled sensing referred to as Unlabeled Ordered Sampling (UOS) where the ordering of the measurements is preserved. We identify a natural duality between this problem and classical Compressed Sensing (CS), where we show that the unknown support (location of nonzero elements) of a sparse signal in CS corresponds to the unknown indices of the measurements in UOS. While in CS it is possible to recover a sparse signal from an under-determined set of linear equations (less equations than the signal dimension), successful recovery in UOS requires taking more samples than the dimension of the signal. Motivated by this duality, we develop a Restricted Isometry Property (RIP) similar to that in CS. We also design a low-complexity Alternating Minimization algorithm that achieves a stable signal recovery under the established RIP. We analyze our proposed algorithm for different signal dimensions and number of measurements theoretically and investigate its performance empirically via simulations. The results are reminiscent of phase-transition similar to that occurring in CS.
description: 18 pages, 11 figures. Submitted to IEEE Trans. on Signal Processing
Heavy quarkonium photoproduction in ultrarelativistic heavy ion collisions
Creators: name: Yu, Gong-Ming
name: Cai, Yan-Bing
name: Li, Yun-De
name: Wang, Jian-Song
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Based on the factorization formalism of nonrelativistic quantum chromodynamics (NRQCD), we calculate the production cross section for the charmonium and the bottomonium produced by the hard photoproduction processes and fragmentation processes in relativistic heavy ion collisions. It is shown that the existing experimental data on heavy quarkonium production at the Large Hadron Collider (LHC) can be described in the framework of the NRQCD formalism, and the phenomenological values of matrix elements for color-singlet and color-octet components give the main contribution. The numerical results of photoproduction processes and fragmentation processes for the heavy quarkonium production become prominent in p-p collisions and Pb-Pb collisions at LHC energies.
description: 13 pages, 8 figures
title: A terrestrial archive of marine environmental conditions in Antarctica - evidence from snow petrel stomach oil deposits
Creators: name: Berg, Sonja
name: Emmerson, Louise
name: Buchta, Eric
name: Fromm, Tanja
name: Heim, Christine
name: Hermichen, Wolf-Dieter
name: Kuhn, Gerhard
name: Rethemeyer, Janet
name: Wand, Ulrich
name: Zech, Michael
name: Melles, Martin
Publisher: name: Deutsche Geologische Gesellschaft - Geologische Vereinigung e.V. (DGGV)
Year: 2022

description:
In the Southern Ocean microfossil records from marine sediments indicate large shifts in species assemblages and nutrient cycling in response to changing climatic conditions and sea-ice extent during the Late Pleistocene and Holocene. While the northern latitudes of the Southern Ocean are relatively well covered by sedimentary records, little is known about past changes in sea-ice coverage and the abundance and activity of polynyas, and associated ecological changes in near coastal areas off East Antarctica. In that regard, deposits of fossil stomach oil of snow petrels (Pagodroma nivea) (also termed Antarctic mumiyo) are unique records that can be found in un-glaciated terrestrial areas of Antarctica. The stomach oil is of dietary origin and contains information on the composition of snow petrel food, which is linked to environmental conditions in the marine foraging range of the birds, such as summer sea-ice variability and productivity in the coastal ocean. Our geochemical data (lipids, stable isotopes, inorganic composition) suggests that this information is preserved to some extent in the fossil stomach oil deposits. Radiocarbon analysis shows that the material comprises records of hundreds to thousands of years, with the oldest deposits being older than 50 thousand years. Stratigraphic analysis combined with geochemical data and correlation with coastal sediment records, makes the deposits a novel archive of past marine environmental conditions, biogeochemical cycling, and food web structure.
Connectedness of two-sided group digraphs and graphs
Creators: name: Chikwanda, Patreck
name: Kriloff, Cathy
name: Lee, Yun Teck
name: Sandow, Taylor
name: Smith, Garrett
name: Yeroshkin, Dmytro
Publisher: name: arXiv
Year: 2017
Subjects: subject: Combinatorics (math.CO)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 05C25, 05C20, 05C40

description: Two-sided group digraphs and graphs, introduced by Iradmusa and Praeger, provide a generalization of Cayley digraphs and graphs in which arcs are determined by left and right multiplying by elements of two subsets of the group. We characterize when two-sided group digraphs and graphs are weakly and strongly connected and count connected components, using both an explicit elementary perspective and group actions. Our results and examples address four open problems posed by Iradmusa and Praeger that concern connectedness and valency. We pose five new open problems.
description: Made changes suggested by referee. Added five new open problems. To appear in Involve
Group classification of (1+3)-dimensional Schrödinger equations with position dependent mass
Creators: name: Nikitin, A. G.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 81Qxx, 81Vxx

description: Kinematical invariance groups of the 3d Schrödinger equations with position dependent masses (PDM) and arbitrary potentials are classified. It is shown that there exist 94 classes of such equations defined up to the generic equivalence group, and 70 classes defined up to the equivalence groupoid. The maximally extended kinematical invariance algebras of such equations appears to be eight dimensional. The specific symmetries connected with the presence of the ambiguity parameters are discussed and an extended class of systems which keep their forms for arbitrary or particular changes of these parameters is specified. The exact solution of the selected PDM Schrödinger equation is presented. This equation describes a deformed 3d isotropic harmonic oscillator and possesses extended continuous symmetries and hidden supersymmetries with two different superpotentials as well.
description: Additional equivalence transformations are presented
More on Polyakov Loops in the Deconfined Phase and Gauge/String Duality
Creators: name: Andreev, Oleg
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We consider a multi-string configuration that provides a new way to compute the expectation value of the Polyakov loop in a five-dimensional framework known as AdS/QCD. The obtained results are in reasonably good agreement with those obtained by lattice simulations for pure SU(3) gauge theory and also by the usual single string configuration.
description: 11 pages, 7 figures; v2: comments and references added, published version
No inflation in type IIA strings on rigid CY spaces
Creators: name: Wakimoto, Yuki
name: Ketov, Sergei V.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We investigate whether cosmological inflation is possible in a class of flux compactifications of type IIA strings on rigid Calabi-Yau manifolds, when all perturbative string corrections are taken into account. We confine ourselves to the universal hypermultiplet and an abelian vector multiplet, representing matter in four dimensions. Since all axions can be stabilized by D-instantons, we choose dilaton and a Kähler modulus as the only running scalars. Though positivity of their scalar potential can be achieved, we find that there is no slow roll ($\varepsilon > 2$ and $η>2$), and no Graceful Exit because the scalar potential has the run-away behaviour resulting in decompactification. We conclude that it is impossible to generate phenomenologically viable inflation in the given class of flux compactifications of type IIA strings, without explicit breaking of $N=2$ local supersymmetry of the low-energy effective action.
description: 17 pages, 5 figures, LaTeX2e; minor revision: section 3 expanded and a reference added. arXiv admin note: substantial text overlap with arXiv:1607.05293
Hodge Numbers from Picard-Fuchs Equations
Creators: name: Doran, Charles F.
name: Harder, Andrew
name: Thompson, Alan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14D07, 14D05, 14J32

description: Given a variation of Hodge structure over $\mathbb{P}^1$ with Hodge numbers $(1,1,\dots,1)$, we show how to compute the degrees of the Deligne extension of its Hodge bundles, following Eskin-Kontsevich-Möller-Zorich, by using the local exponents of the corresponding Picard-Fuchs equation. This allows us to compute the Hodge numbers of Zucker's Hodge structure on the corresponding parabolic cohomology groups. We also apply this to families of elliptic curves, K3 surfaces and Calabi-Yau threefolds.
Oscillators that sync and swarm
Creators: name: O'Keeffe, Kevin P.
name: Hong, Hyunsuk
name: Strogatz, Steven H.
Publisher: name: arXiv
Year: 2017
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: Synchronization occurs in many natural and technological systems, from cardiac pacemaker cells to coupled lasers. In the synchronized state, the individual cells or lasers coordinate the timing of their oscillations, but they do not move through space. A complementary form of self-organization occurs among swarming insects, flocking birds, or schooling fish; now the individuals move through space, but without conspicuously altering their internal states. Here we explore systems in which both synchronization and swarming occur together. Specifically, we consider oscillators whose phase dynamics and spatial dynamics are coupled. We call them swarmalators, to highlight their dual character. A case study of a generalized Kuramoto model predicts five collective states as possible long-term modes of organization. These states may be observable in groups of sperm, Japanese tree frogs, colloidal suspensions of magnetic particles, and other biological and physical systems in which self-assembly and synchronization interact.
Lyapunov Exponent and Criticality in the Hamiltonian Mean Field Model
Creators: name: Filho, L. H. Miranda
name: Amato, M. A.
name: Filho, T. M. Rocha
Publisher: name: arXiv
Year: 2017
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We investigate the dependence of the largest Lyapunov exponent of a $N$-particle self-gravitating ring model at equilibrium with respect to the number of particles and its dependence on energy. This model has a continuous phase-transition from a ferromagnetic to homogeneous phase, and we numerically confirm with large scale simulations the existence of a critical exponent associated to the largest Lyapunov exponent, although at variance with the theoretical estimate. The existence of chaos in the magnetized state evidenced by a positive Lyapunov exponent, even in the thermodynamic limit, is explained by the resonant coupling of individual particle oscillations to the diffusive motion of the center of mass of the system due to the thermal excitation of a classical Goldstone mode. The transition from "weak" to "strong" chaos occurs at the onset of the diffusive motion of the center of mass of the non-homogeneous equilibrium state, as expected. We also discuss thoroughly for the model the validity and limits of a geometrical approach for their analytical estimate.
description: 21 pages, 14 figures