cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Variation of strong correlation effects in A-site ordered perovskites CaCu3Ti4-xRuxO12: Photoemission and inverse photoemission studies
Creators: name: Im, H. J.
name: Iwataki, M.
name: Tsunekawa, M.
name: Watanabe, T.
name: Sato, H.
name: Nakatake, M.
name: Kimura, S.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We have systematically studied the strong correlation effects in A-site ordered perovskites CaCu3Ti4-xRuxO12 (x = 0, 1, 3.5, and 4) by using photoemission and inverse photoemission spectroscopies. In x = 0, 1, 3.5, the peak positions of the strongly correlated Cu 3d states around -3.8 eV and Ti 3d states around 3.6 eV little change. On the other hand, in x = 4, the Cu 3d states split into two peaks around -2.5 and -4 eV. These indicate that Ti plays an important role to retain the strong correlation effects. In addition, the multiplet structures of Cu 3d final states from -8 to -14 eV become weak as Ru increases, indicating the reduction of the localized characters of Cu 3d states. At the Fermi level, we observe the absence of spectral weight in x = 0, 1 and the development of Ru 4d in-gap states in x = 3.5, 4, which give rise to the metal-insulator transition between x = 1 and x = 3.5.
description: 12 pages, 3 figures
A note on the Kuznetsov component of the Veronese double cone
Creators: name: Petkovic, Marin
name: Rota, Franco
Publisher: name: arXiv
Year: 2020
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14F08, 14J45, 14D20

description: This note describes moduli spaces of complexes in the derived category of a Veronese double cone $Y$. Focusing on objects with the same class $κ_1$ as ideal sheaves of lines, we describe the moduli space of Gieseker stable sheaves and show that it has two components. Then, we study the moduli space of stable complexes in the Kuznetsov component of $Y$ of the same class, which also has two components. One parametrizes ideal sheaves of lines and it appears in both moduli spaces. The other components are not directly related by a wall-crossing: we show this by describing an intermediate moduli space of complexes as a space of stable pairs in the sense of Pandharipande and Thomas.
description: V2: 19 pages. Substantially rewritten. Added results on Hilbert scheme of lines, improved exposition, strengthened arguments. References and acknowledgments updated. V3: Final version, to appear in J. Pure Appl. Algebra. The statement of theorem 5.1 contained an imprecision, now corrected. All comments very welcome!
Anomalous relaxation and hyperuniform fluctuations in center-of-mass conserving systems with broken time-reversal symmetry
Creators: name: Mukherjee, Anirban
name: Tapader, Dhiraj
name: Hazra, Animesh
name: Pradhan, Punyabrata
Publisher: name: arXiv
Year: 2023
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study a paradigmatic model of absorbing-phase transition - the Oslo model - on a one-dimensional ring of $L$ sites with a fixed global density $\barρ$; notably, microscopic dynamics conserve both mass and \textit{center of mass (CoM), but lacks time-reversal symmetry}. Despite having highly constrained dynamics due to CoM conservation, the system exhibits diffusive relaxation away from criticality and superdiffusive relaxation near criticality. Furthermore, the CoM conservation severely restricts particle movement, rendering the mobility to vanish exactly. Indeed the temporal growth of current fluctuation is qualitatively different from that observed in diffusive systems with a single conservation law. Away from criticality, steady-state fluctuation $\langle \mathcal{Q}_i^2(T,Δ) \rangle$ of current $\mathcal{Q}_i$ across $i$th bond up to time $T$ \textit{saturates} as $\langle \mathcal{Q}_i^2 \rangle \simeq Σ_Q^2(Δ) - {\rm const.} T^{-1/2}$; near criticality, it grows subdiffusively as $\langle \mathcal{Q}_i^2 \rangle \sim T^α$, with $0 < α< 1/2$, and eventually \textit{saturates} to $Σ_Q^2(Δ)$. The asymptotic current fluctuation $Σ_Q^2(Δ)$ is a \textit{nonmonotonic} function of $Δ$: It diverges as $Σ_Q^2(Δ) \sim Δ^2$ for $Δ\gg ρ_c$ and $Σ_Q^2(Δ) \sim Δ^{-δ}$, with $δ> 0$, for $Δ\to 0^+$. By using a mass-conservation principle, we exactly determine the exponents $δ= 2(1-1/ν_\perp)/ν_\perp$ and $α= δ/z ν_\perp$ via the correlation-length and dynamic exponents, $ν_\perp$ and $z$, respectively. Finally, we show that, in the steady state, the self-diffusion coefficient $\mathcal{D}_s(\barρ)$ of tagged particles is connected to activity by $\mathcal{D}_s(\barρ) = a(\barρ) / \barρ$.
description: 27 pages, 14 figures, some small changes in the text and figures
Electron transport in quantum wire superlattices
Creators: name: Grange, Thomas
Publisher: name: arXiv
Year: 2013
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Electronic transport is theoretically investigated in laterally confined semiconductor superlattices using the formalism of non-equilibrium Green's functions. The transport properties are calculated for nanowire superlattices of varying diameters, from the quantum dot superlattice regime to the quantum well superlattice regime. Scattering processes due to electron-phonon couplings, phonon anharmonicity, charged impurities, surface and interface roughness and alloy disorder are included on a microscopic basis. Elastic scattering mechanisms are treated in a partial coherent way beyond the self-consistent Born approximation. The nature of transport along the superlattice is shown to depend dramatically on the lateral dimensionality. In the quantum wire regime, the electron velocity-field characteristics are predicted to deviate strongly from the standard Esaki-Tsu form, with pronounced current peaks due to integer and fractional resonances with optical phonons.
ACHIEVING EFFICIENCY BY REDUCING NATURAL DECLINE IN APPLE STORAGE
Creators: name: Tashmanov, R.K.
name: Umidov, Sh.E.
Publisher: name: Zenodo
Year: 2023

description: In this article, the apples grown and stored in Marokand Meva-Sabzavot limited liability company in Jomboy district of Samarkand region were treated with methylcyclopropene drug, Red delicacies, Granny Smith, Scarlet, Pinklady, Golden delicacies, Jiromin, Fuji, Gala and Modi apples. aimed at reducing the natural decline by applying the drug 1-methylcyclopropene to reduce apple fruit decline by applying the drug at acceptable rates to apples after storage.
Precise Fourier parameters of Cepheid Radial Velocity Curves
Creators: name: Hocdé, V.
name: Moskalik, P.
name: Gorynya, N. A.
name: Smolec, R.
name: Rathour, R. Singh
name: Ziółkowska, O.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The primary goal of this paper is to derive precise Fourier parameters of the radial velocity (RV) curves for fundamental and first-overtone Galactic Cepheids. For each star, we carefully selected RV measurements available in the literature which yield the highest precision of Fourier parameters. We performed a Fourier decomposition of the RV curves. We subtracted RV modulations caused by binary motion and have removed other residual trends. Finally, we have displayed and analyzed qualitatively the progressions found for Fourier parameters. We applied a standard identification of their pulsation mode based on their Fourier phase $ϕ_{21}$. Our final sample includes 178 fundamental-mode and 33 first overtone pulsators, as well as 7 additional Cepheids whose pulsation mode is uncertain or undetermined according to our criteria. For the fundamental-mode Cepheids, we improved the precision of Fourier parameters in comparison of previous results from the literature. We are able to firmly identify V495 Cyg as a new first-overtone Cepheid. We confirm first-overtone nature of several other stars. We also show that $α$ UMi should be definitely classified as a first-overtone pulsator. In 3 objects (VY Per, AQ Pup and QZ Nor) we found significant $γ$-velocity variations that we attribute to spectroscopic binarity. Finally, the analysis of the F-mode Fourier parameters up to 7th order reveals tight progression of Fourier phases. For $P<10\,$day we find a well defined upper limit for the Fourier amplitude $A_1$. The pulsation period coverage and the precision obtained, in particular for Fourier phase $ϕ_{21}$, will be useful for studying the dynamics of Cepheid pulsations with the help of hydrodynamical models. Further radial velocity measurements from modern high-resolution spectroscopic instruments will be important to improve these results.
description: 37 pages, 7 figures. Revised version. Originally submitted to A&A on 25/08/2023
GP-SLAM+: real-time 3D lidar SLAM based on improved regionalized Gaussian process map reconstruction
Creators: name: Ruan, Jianyuan
name: Li, Bo
name: Wang, Yinqiang
name: Fang, Zhou
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: This paper presents a 3D lidar SLAM system based on improved regionalized Gaussian process (GP) map reconstruction to provide both low-drift state estimation and mapping in real-time for robotics applications. We utilize spatial GP regression to model the environment. This tool enables us to recover surfaces including those in sparsely scanned areas and obtain uniform samples with uncertainty. Those properties facilitate robust data association and map updating in our scan-to-map registration scheme, especially when working with sparse range data. Compared with previous GP-SLAM, this work overcomes the prohibitive computational complexity of GP and redesigns the registration strategy to meet the accuracy requirements in 3D scenarios. For large-scale tasks, a two-thread framework is employed to suppress the drift further. Aerial and ground-based experiments demonstrate that our method allows robust odometry and precise mapping in real-time. It also outperforms the state-of-the-art lidar SLAM systems in our tests with light-weight sensors.
description: Accepted by IROS 2020
The effect of the WGC condition on the maximal energy extracted from black holes
Creators: name: Mezerji, E. Naghd
name: Sadeghi, J.
name: Pourhassan, B.
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper, we study the Penrose process and the maximum energy extracted from the collision of two particles near the Kerr-Newman black hole with WGC condition. We consider the collision process when two particles collide in the ergosphere region of a black hole, scattering two new particles; one of them falls into the black hole and the other escapes to infinity. Our calculations also show an increasing in the energy. We also checked how much energy could be received from a black hole for particles with different spins. Results of this paper will help us to identify and study the black holes of astrophysics and the particles with different spins. Also, it states how black holes work in WGC conditions.
description: 18 pages, 33 figures
GCD sums and complete sets of square-free numbers
Creators: name: Bondarenko, Andriy
name: Seip, Kristian
Publisher: name: arXiv
Year: 2014
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11C20

description: It is proved that \[ \sum_{k,{\ell}=1}^N\frac{\gcd(n_k,n_{\ell})}{\sqrt{n_k n_{\ell}}} \ll N\exp\left(C\sqrt{\frac{\log N \log\log\log N}{\log\log N}}\right) \] holds for arbitrary integers $1\le n_1
description: Final version, to appear in Bulletin of the London Mathematical Society
Towards an $\mathfrak{sl}_2$ action on the annular Khovanov spectrum
Creators: name: Akhmechet, Rostislav
name: Krushkal, Vyacheslav
name: Willis, Michael
Publisher: name: arXiv
Year: 2020
Subjects: subject: Geometric Topology (math.GT)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 57K18 (Primary), 55P42 (Secondary)

description: Given a link in the thickened annulus, its annular Khovanov homology carries an action of the Lie algebra $\mathfrak{sl}_2$, which is natural with respect to annular link cobordisms. We consider the problem of lifting this action to the stable homotopy refinement of the annular homology. As part of this program, the actions of the standard generators of $\mathfrak{sl}_2$ are lifted to maps of spectra. In particular, it follows that the $\mathfrak{sl}_2$ action on homology commutes with the action of the Steenrod algebra. The main new technical ingredients developed in this paper, which may be of independent interest, concern certain types of cancellations in the cube of resolutions and the resulting more intricate structure of the moduli spaces in the framed flow category.
description: 55 pages, many figures, comments welcome! This new version contains an additional corollary in the introduction and a new section on link cobordism maps, together with a handful of minor changes
First constraint on the dissipative tidal deformability of neutron stars
Creators: name: Ripley, Justin L.
name: R., Abhishek Hegade K.
name: Chandramouli, Rohit S.
name: Yunes, and Nicolas
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The gravitational waves (GWs) emitted by neutron star binaries probe the physics of matter at supra nuclear densities. During the late inspiral, tidal deformations raised on each star by the gravitational field of its companion depend crucially on the star's internal properties. The misalignment of a star's tidal bulge with its companion's gravitational field encodes the strength of internal dissipative processes, which imprint onto the phase of the gravitational waves emitted. We here analyze GW data from the GW170817 (binary neutron star) event detected by LIGO and Virgo and find the first constraint on the dissipative tidal deformability of a neutron star. From this constraint, \emph{assuming} a temperature profile for each star in the binary, we obtain an order of magnitude bound on the averaged bulk ($ζ$) and shear ($η$) viscosity of each star during the inspiral.: $ζ\lesssim 10^{31} \mathrm{g}\;\mathrm{cm}^{-1}\mathrm{s}^{-1}$ and $η\lesssim 10^{28} \mathrm{g}\;\mathrm{cm}^{-1}\mathrm{s}^{-1} $. We forecast that these bounds could be improved by two orders of magnitude with third-generation detectors, like Cosmic Explorer, using inspiral data. These constraints already inform nuclear physics models and motivate further theoretical work to better understand the interplay between viscosity and temperature in the late inspiral of neutron stars.
description: 7 pages, 4 figures; edits in response to referee comments; minor typos corrected
Supersymmetry Method for Chiral Random Matrix Theory with Arbitrary Rotation Invariant Weights
Creators: name: Kaymak, Vural
name: Kieburg, Mario
name: Guhr, Thomas
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In the last few years, the supersymmetry method was generalized to real-symmetric, Hermitean, and Hermitean self-dual random matrices drawn from ensembles invariant under the orthogonal, unitary, and unitary symplectic group, respectively. We extend this supersymmetry approach to chiral random matrix theory invariant under the three chiral unitary groups in a unifying way. Thereby we generalize a projection formula providing a direct link and, hence, a `short cut' between the probability density in ordinary space and the one in superspace. We emphasize that this point was one of the main problems and critiques of the supersymmetry method since only implicit dualities between ordinary and superspace were known before. As examples we apply this approach to the calculation of the supersymmetric analogue of a Lorentzian (Cauchy) ensemble and an ensemble with a quartic potential. Moreover we consider the partially quenched partition function of the three chiral Gaussian ensembles corresponding to four-dimensional continuum QCD. We identify a natural splitting of the chiral Lagrangian in its lowest order into a part of the physical mesons and a part associated to source terms generating the observables, e.g. the level density of the Dirac operator.
PTAS for Sparse General-Valued CSPs
Creators: name: Mezei, Balázs F.
name: Wrochna, Marcin
name: Živný, Stanislav
Publisher: name: arXiv
Year: 2020
Subjects: subject: Discrete Mathematics (cs.DM)
subject: Data Structures and Algorithms (cs.DS)
subject: FOS: Computer and information sciences
subject: G.2.2; F.2.2
subject: 68R10, 05C75, 68W25

description: We study polynomial-time approximation schemes (PTASes) for constraint satisfaction problems (CSPs) such as Maximum Independent Set or Minimum Vertex Cover on sparse graph classes. Baker's approach gives a PTAS on planar graphs, excluded-minor classes, and beyond. For Max-CSPs, and even more generally, maximisation finite-valued CSPs (where constraints are arbitrary non-negative functions), Romero, Wrochna, and Živný [SODA'21] showed that the Sherali-Adams LP relaxation gives a simple PTAS for all fractionally-treewidth-fragile classes, which is the most general "sparsity" condition for which a PTAS is known. We extend these results to general-valued CSPs, which include "crisp" (or "strict") constraints that have to be satisfied by every feasible assignment. The only condition on the crisp constraints is that their domain contains an element which is at least as feasible as all the others (but possibly less valuable). For minimisation general-valued CSPs with crisp constraints, we present a PTAS for all Baker graph classes -- a definition by Dvořák [SODA'20] which encompasses all classes where Baker's technique is known to work, except possibly for fractionally-treewidth-fragile classes. While this is standard for problems satisfying a certain monotonicity condition on crisp constraints, we show this can be relaxed to diagonalisability -- a property of relational structures connected to logics, statistical physics, and random CSPs.
description: Full version of a LICS 2021 paper
Presentations for Globular Operads
Creators: name: Griffiths, Rhiannon
Publisher: name: arXiv
Year: 2021
Subjects: subject: Category Theory (math.CT)
subject: FOS: Mathematics

description: In this paper we develop the theory of presentations for globular operads and construct presentations for the globular operads corresponding to several key theories of $n$-category for $n \leqslant 4$.
REDUCING THE NATURAL DECLINE OF APPLES DURING LONG STORAGE
Creators: name: Tashmanov, R.K.
Publisher: name: Zenodo
Year: 2023

description: In this article Samarkand region The apples grown and stored in the limited liability company "Marokand fruit and vegetables" in Jomboy district were treated with methylcyclopropene. 1-methylcyclopropene to reduce apple fruit decline by applying the drug at acceptable rates to apples after long-term storage of Red Delicious, Granny Smith, Scarlet, Pinklady, Golden Delicious, Jiromin, Fuji, Gala and Modi apples, treated with apples aimed at reducing the natural decrease by using the drug.
PSR B0943+10: Mode Switch, Polar Cap Geometry, and Orthogonally Polarized Radiation
Creators: name: Cao, Shunshun
name: Jiang, Jinchen
name: Dyks, Jaroslaw
name: Hao, Longfei
name: Lee, Kejia
name: Li, Zhixuan
name: Lu, Jiguang
name: Pan, Zhichen
name: Wang, Weiyang
name: Wang, Zhengli
name: Xu, Jiangwei
name: Xu, Heng
name: Xu, Renxin
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: As one of the paradigm examples to probe into pulsar magnetospheric dynamics, PSR B0943+10 (J0946+0951) manifests representatively, showing mode switch, orthogonal polarization and subpulse drifting, frequently studied below 600 MHz. Here both integrated and single pulses are studied at a high frequency (1.25 GHz) with FAST. The mode switch is studied using a profile decomposition method. A phase space evolution for the pulsar's mode switch shows a strange-attractor-like pattern. The radiative geometry is proposed by fitting polarization position angles with the rotating vector model. The pulsar pulse profile is then mapped to the sparking locations on pulsar surface, and the differences between the main pulse's and the precursor component's radiative processes may explain the X-ray's synchronization with radio mode switch. Detailed single pulse studies on B0943+10's orthogonally polarized radiation are presented, which may support for certain models of radiative transfer of polarized emission. Especially, the difference in OPMs' circular polarization might reflect the cyclotron absorption in pulsar magnetospheres. B0943+10's B and Q modes evolve differently with frequency and have different proportions of orthogonal modes, which indicates possible magnetospheric changes during mode switch. For Q mode pulse profile, the precursor and the main pulse components are orthogonally polarized, and are probably originated from different depths in the magnetosphere. The findings could impact significantly on pulsar electrodynamics and the radiative mechanism related.
description: The paper has been published by ApJ
Publishing with the rights retention strategy : is it for me ?
Creators: name: Pauplin, Pascale
Publisher: name: Zenodo
Year: 2023
Subjects: rights retention strategy
open access
open science
creative commons
cOAlition S

description: The rights retention strategy, initially put in place by research funders, is available to all researchers and allows them to retain sufficient intellectual property rights on their author manuscript to disseminate their research. On the agenda: - What does a classic (and exclusive) publisher / author agreement say ? - How to apply the rights retention strategy ? - Discussion with Johan Rooryck, Executive Director of cOAlition S.
Hypercontractivity for Markov Semigroups
Creators: name: Roberto, C.
name: Zegarlinski, B.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Functional Analysis (math.FA)
subject: Probability (math.PR)
subject: FOS: Mathematics

description: We investigate in a systematic way hypercontractivity property in Orlicz spaces for Markov semi-groups related to homogeneous and non homogeneous diffusions in $\mathbb{R}^{n}$. We provide an explicit construction of a family of Orlicz functions for which we prove that the associated hypercontractivity property is equivalent to a suitable functional inequality.
description: closed to published version
Addressing The Intelligence Applications of Bitcoin Payments Related to Ransomware
Creators: name: Turner, Adam Brian
Publisher: name: Macquarie University
Year: 2023
Subjects: classificationCode: 399999
subject: Other education not elsewhere classified

description: This thesis addresses the evolving threat of the use of cryptocurrency in ransomware attacks. These attacks are a form of cyber extortion in which malicious software (malware) is used to infect, encrypt, and render systems unusable unless the victims pay a ransom. Such attacks can cripple the capabilities of business-critical systems as well as critical infrastructure. Increasingly, ransom payments are being demanded in hard-to-trace cryptocurrency formats such as Bitcoin. This thesis by publication, comprising four published research papers, a published conference proceeding paper, and two research papers submitted for journal publication, demonstrates the utility of taking a target centric approach to intelligence collection and analysis of a ransomware-cryptocurrency network. Utilising graph analysis techniques applied to data gathered from the Bitcoin blockchain, this research addresses challenges security researchers face in preventing the propagation of ransomware payments throughout cryptocurrency networks as well as determining the accountability of such payments. The first paper provides a general perspective on analysis techniques relating to illicit Bitcoin transactions and ransomware incidents, and the second paper develops a target-centric intelligence approach to a specific Bitcoin ransomware incident (WannaCry 2.0). The third study explores the possibility of using a common sharing standard such as STIX to share ransomware payment related cyber intelligence, while the fourth paper discerns Bitcoin payment patterns from well-known ransomware attacks (WannaCry, CryptoDefense, and NotPetya). The fifth paper examines graph embeddings in more IV detail to reveal risky nodes in a ransomware-Bitcoin network, and the sixth paper develops a novel methodology to systematically identify ransomware transactions within cryptocurrency payment networks. By undertaking target network modelling and analysis, this research provides a basis for analysing payment patterns generated by ransomware-Bitcoin transactions as a graph. Furthermore, to enhance the understanding of the ransomware-Bitcoin environment and any points of vulnerability, blockchain data collection is used to populate the target network model. This allows for the development of a knowledge graph for understanding the relationship between data assets in the ransomware-Bitcoin payment network and provides context to the machine learning systems used in this research.
Search for Leptonic Decays of Dark Photons at NA62
Creators: name: The NA62 Collaboration
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The NA62 experiment at CERN, configured in beam-dump mode, has searched for dark photon decays in flight to electron-positron pairs using a sample of $1.4\times 10^{17}$ protons on dump collected in 2021. No evidence for a dark photon signal is observed. The combined result for dark photon searches in lepton-antilepton final states is presented and a region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon mass values between 50 and 600 MeV$/c^2$ and coupling values in the range $10^{-6}$ to $4\times10^{-5}$. An interpretation of the $e^+ e^-$ search result in terms of the emission and decay of an axion-like particle is also presented.
Evolution of Raman G and G'(2D) Modes in Folded Graphene Layers
Creators: name: Cong, Chunxiao
name: Yu, Ting
Publisher: name: arXiv
Year: 2013
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Bernal- and non-Bernal-stacked graphene layers have been systematically studied by Raman imaging and spectroscopy. Two dominant Raman modes, G and G' (or 2D) of folded graphene layers exhibit three types of spectral features when interlayer lattice mismatches, defined by a rotational angle varies. Among these folded graphene layers, the most interesting one is the folded graphene layers that present an extremely strong G mode enhanced by a twist-induced Van Hove singularity. The evolution of Raman G and G' modes of such folded graphene layers are probed by changing the excitation photon energies. For the first time, doublet splitting of the G' mode in folded double-layer (1 + 1) and of the G mode in folded tetra-layer (2 + 2) graphene are clearly observed and discussed. The G' mode splitting in folded double-layer graphene is attributed to the coexistence of inner and outer scattering processes and the trigonal warping effect as well as further downwards bending of the inner dispersion branch at visible excitation energy. While the two peaks of the G mode in folded tetra-layer graphene are assigned to Raman-active mode (E2g) and lattice mismatch activated infrared-active mode (E1u), which is further verified by the temperature-dependent Raman measurements. Our study provides a summary and thorough understanding of Raman spectra of Bernal- and non-Bernal-stacked graphene layers and further demonstrates the versatility of Raman spectroscopy for exploiting electronic band structures of graphene layers.
description: 29 pages, 10 figures
This photograph has been altered: Testing the effectiveness of image forensic labeling on news image credibility
Creators: name: Shen, Cuihua
name: Kasra, Mona
name: O'Brien, James
Publisher: name: arXiv
Year: 2021
Subjects: subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: Despite the ubiquity and proliferation of images and videos in online news environments, much of the existing research on misinformation and its correction is solely focused on textual misinformation, and little is known about how ordinary users evaluate fake or manipulated images and the most effective ways to label and correct such falsities. We designed a visual forensic label of image authenticity, Picture-O-Meter, and tested the label's efficacy in relation to its source and placement in an experiment with 2440 participants. Our findings demonstrate that, despite human beings' general inability to detect manipulated images on their own, image forensic labels are an effective tool for counteracting visual misinformation.
description: Harvard Kennedy School (HKS) Misinformation Review (2021)
Bogoliubov Excited States and the Lyth Bound
Creators: name: Aravind, Aditya
name: Lorshbough, Dustin
name: Paban, Sonia
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We show that Bogoliubov excited scalar and tensor modes do not alleviate Planckian evolution during inflation if one assumes that $r$ and the Bogoliubov coefficients are approximately scale invariant. We constrain the excitation parameter for the scalar fluctuations, $β$, and tensor perturbations, $\tildeβ$, by requiring that there be at least three decades of scale invariance in the scalar and tensor power spectrum. For the scalar fluctuations this is motivated by the observed nearly scale invariant scalar power spectrum. For the tensor fluctuations this assumption may be shown to be valid or invalid by future experiments.
description: 8 pages, bound strengthened, version accepted for publication
Back to (In-Person) School: Examining Chicago Public Schools Teachers’ Perceptions on Workload
Creators: name: Dodgen, Kaitlyn
Publisher: name: University of Chicago
Year: 2023

description: Scholars have extensively studied teachers’ workloads and the connection between teacher workload and burnout. The changes in workload during virtual learning caused by the COVID-19 pandemic have been documented, but changes upon the return to in-person schooling have yet to be explored. In this paper, I examine Chicago Public Schools teachers’ perceptions of their workload and how they are reacting to this. Using nine qualitative interviews, I found strong evidence of a rise in workload caused by the decline of students’ emotional and academic skills. As teachers take on multiple roles in the classroom, they have been left to support students on all fronts. In response to this workload, most teachers have reported taking a step-back from all these responsibilities and only doing the minimum requirements of their job. The exceptions in this trend may point to inequities in the resources available to each school and teacher. These findings further current research on teacher workload, burnout, and effects of the COVID-19 pandemic. Three policy recommendations to Chicago Public Schools are offered to aid with teachers’ workload based on the findings of this study. The findings presented here may help guide future studies on how teachers at different types of schools adapted to in-person learning after the pandemic.
Deliverable D2.1 Use cases, deployment and techno-economic requirements - high level description
Creators: name: Altevet, Yossi
name: Gonzalez, Jose Enrique
Publisher: name: Zenodo
Year: 2019

description: One of the key features of the 5 th Generation mobile wireless communication system (5G) networks is the ability to efficiently support a multitude of services that have different network requirements. 5G networks allow network operators to simultaneously run services that have different vertical requirements on the same network by allowing flexible allocation of resources and tailoring the network capabilities to the vertical service requirements. As a key feature of the 5G network, validating that the network can indeed provide tailored capabilities to different vertical services simultaneously is imperative. Most of the efforts to evaluate 5G networks conducted so far by public and private sectors were focused on individual vertical use cases, therefore, the need for evaluating the 5G networks performance on multiple vertical use cases became prominent. 5G-TOURS aims to fill this gap by demonstrating the ability of 5G to support multiple vertical use cases concurrently on the same infrastructure. The use cases addressed by 5G-TOURS revolve around the life in a city. The focus of these use cases is on improving the quality of life of the citizens as well as the experience of the tourists visiting the city, ultimately making the city more attractive to visit, more efficient in terms of mobility, and safer for everybody. During the project, 5G-TOURS will deploy thirteen use cases of interest for tourists and citizens around the themes of the touristic city, the safe city and the mobility-efficient city, and trial them in a real environment involving all the relevant players of the ecosystem and providing an operational service to the relevant vertical customer in each use case. This document describes these use cases, their objectives and the benefit they devise to provide to the various stakeholders. The document also provides both technical as well as economic analysis (preliminary) and will be used by the relevant Work Package (WP) teams of the 5G-TOURS project as a baseline for their analysis.
Sequential single pion production explaining the dibaryon "$d^*(2380)$" peak
Creators: name: Molina, R.
name: Ikeno, N.
name: Oset, E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the two step sequential one pion production mechanism, $np(I=0)\to π^-pp$, followed by the fusion reaction $pp\to π^+d$, in order to describe the $np\to π^+π^-d$ reaction with $π^+π^-$ in $I=0$, where a narrow peak, so far identified with a "$d(2380)$" dibaryon, has been observed. We find that the second step $pp\to π^+d$ is driven by a triangle singularity that determines the position of the peak of the reaction and the large strength of the cross section. The combined cross section of these two mechanisms produce a narrow peak with the position, width and strength compatible with the experimental observation within the approximations done. This novel interpretation of the peak without invoking a dibaryon explains why the peak is not observed in other reactions where it has been searched for.
description: 6 pages, 2 figures, 1 table
Primordial black hole compaction function from stochastic fluctuations in ultra-slow-roll inflation
Creators: name: Raatikainen, Sami
name: Rasanen, Syksy
name: Tomberg, Eemeli
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the formation of primordial black holes (PBH) with ultra-slow-roll inflation when stochastic effects are important. We use the $ΔN$ formalism and simplify the stochastic equations with an analytical constant-roll approximation. Considering a viable inflation model, we find the spatial profile of the PBH compaction function numerically for each stochastic patch, without assumptions about Gaussianity or the radial profile. The stochastic effects that lead to an exponential tail for the density distribution also make the compaction function very spiky, unlike assumed in the literature. Naively using collapse thresholds found for smooth profiles, the PBH abundance is enhanced by up to a factor of $10^9$, and the PBH mass distribution is spread over three orders of magnitude in mass. The results point to a need to redo numerical simulations of PBH formation with spiky profiles.
description: 5+3 pages, 3 figures. v2: Added an appendix with a plot, fixed a typo. Published version
Deliverable D3.1 Baseline architecture and deployment objectives
Creators: name: Gramaglia, Marco
Publisher: name: Zenodo
Year: 2019

description: The scope of this deliverable is to report on the initial activities for the network planning in 5G-TOURS. The project spans three trial sites (Turin, Rennes, and Athens), which are part of the 5G EVE infrastructure. The main contributions of this document can be summarized in the following three areas: • The initial discussion on the overall 5G-TOURS architecture, which relies on the 5G EVE platform, and the possible needed extensions to support the innovative use cases defined by WP2 “Use Cases design”. In particular, we discuss the extensions of the Management and Orchestration (MANO) framework, which needs to support the following three functional innovations developed in the project: o The introduction of Artificial Intelligence (AI) into a Data Driven management of the network. In particular, the relationship between the 5G-TOURS architecture and the ones defined by the major standard development organizations, such as ETSI or 3GPP, are discussed. o The inclusion of specific Broadcast modules in the architecture. This is of paramount importance for the immersive media use cases which will be developed in the Turin trial site. In particular, we focus the discussion on the relevant standard elements defined by 3GPP. o The integration of an enhanced Service Layer in the management system, to provide the verticals with efficient ways to manage their network slice. This innovation, which is going to be developed throughout the platform, also has to rely on the available software components created for the host platform, 5G EVE. • The detailed development plan for the infrastructure in the three trial sites. We especially discuss the capabilities of the sites along the following three main dimensions: o The extensions planned by each partner involved in the trial sites about the planned extension with respect to the 5G EVE platform. Some of the use cases need additional infrastructure (both hardware and software) to support the needed network requirements. Thus, we also discuss the available capabilities with respect to the ones needed by the different use cases. o The phasing of new functionality along the 5G-TOURS phases and the 5G EVE platform releases. This also includes fundamental aspects, such as spectrum allocation. o The integration of the novel functionality in the available network architecture. • The initial description of the development plans for the three innovations that will characterize the 5GTOURS network deployment. In particular, we detail the baseline software components that will be leveraged for their implementation, and an initial evaluation of different software architecture options. These points will be further detailed in the subsequent releases of the work package deliverables. The work performed by this Work Package “Network architecture and deployment” for the editing of this deliverable has been strictly coordinated with the one of Work Packages 4, 5 and 6, which focus on the vertical development of each test site respectively.
Demographics of Tidal Disruption Events with L-Galaxies: I. Volumetric TDE rates and the abundance of Nuclear Star Clusters
Creators: name: Polkas, M.
name: Bonoli, S.
name: Bortolas, E.
name: Izquierdo-Villalba, D.
name: Sesana, A.
name: Broggi, L.
name: Hoyer, N.
name: Spinoso, D.
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Stars can be ripped apart by tidal forces in the vicinity of a massive black hole (MBH), causing luminous flares known as tidal disruption events (TDEs). These events could be contributing to the mass growth of intermediate-mass MBHs, and new samples from transient surveys can provide useful information on this growth channel. This work aims to study the demographics of TDEs by modeling the co-evolution of MBHs and their galactic environments in a cosmological framework. We use the semi-analytic galaxy formation model \emph{L-Galaxies}BH, which follows the evolution of galaxies as well as of MBHs, including multiple scenarios for MBH seeds and growth, spin evolution, and binary MBH dynamics. Time-dependent TDE rates are associated with each MBH depending on the stellar environment, following the solutions to the 1-D Fokker Planck equation solved with \textsc{PhaseFlow}. Our model produces volumetric rates that are in agreement with the latest optical and previous X-ray samples. This agreement requires a high occupation fraction of nuclear star clusters with MBHs since these star reservoirs host the majority of TDEs at all mass regimes. We predict that TDE rates are an increasing function of MBH mass up to $\sim\, 10^{5.5}$M$_\odot$, beyond which the distribution flattens and eventually drops for $>\,10^{7}$M$_\odot$. In general, volumetric rates are predicted to be redshift-independent at $z\,{<}\,1$. We discuss how the spin distribution of MBHs around the event horizon suppression can be constrained via TDE rates and what is the average contribution of TDEs to the MBH growth. In our work, the majority of low-mass galaxies host nuclear star clusters that have their loss-cone depleted by $z\,=\,0$, explaining why TDEs are rare in these systems. This highlights that time-dependent TDE rates are essential for any model to be in good agreement with observations at all mass regimes.
description: 26 pages, 11 figures
Linking Multi-Category Purchases to Latent Activities of Shoppers: Analysing Market Baskets by Topic Models
Creators: name: Hruschka, Harald
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: multi-category buying behavior; market basket analysis; topic models
subject: 330 Wirtschaft
subject: M32
subject: L81
subject: C35
subject: C11

description: We investigate the application of two topic models, latent Dirichlet allocation (LDA) and the correlated topic model (CTM), to market basket analysis. Topic models measure the association between observed purchases and underlying latent activities of shoppers by conceiving each basket as random mixture of latent activities. We explain the structure of the two topic models used. We discuss estimation of LDA models by blocked Gibbs sampling. In addition we show how to evaluate the performance of topic models on estimation and holdout data. In the empirical study we analyse a total of 18,000 purchases made at a medium-sized supermarket which refer to 60 product categories. The LDA model performs better than the CTM in terms of log likelihood values. Latent activities inferred by this models are intuitive and interpretable, e.g., related to shopping of beverages or personal care, to baking or to an inclination towards luxury food. To illustrate the managerial relevance of estimated topic models we sketch the core of a recommender system which ranks purchase probabilities of other product categories conditional on the basket of a shopper.
Novel correlated ${{{D}^{0}}{\overline{D}{}^{0}}}$ systems for ${c/b}$ physics and tests of ${T/CPT}$
Creators: name: Naik, Paras
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Decays of charmonia(-like) particles with definite $J^{PC}$ (e.g. ${χ_{c{\rm 1}}(3872)}$) to a ${{D}^{0}}{\overline{D}{}^{0}}$ system and any combination of $C$-definite decay particles, are sources of quantum-correlated ${{D}^{0}}{\overline{D}{}^{0}}$ systems with $C = P = \pm 1$. Several $b$-hadron decays also produce quantum-correlated ${{D}^{0}}{\overline{D}{}^{0}}$ systems. Advantages of isolating these systems in their $C = +1$ components for amplitude analyses and studies of lineshapes are discussed. Methods to separate the $C = \pm 1$ ${{D}^{0}}{\overline{D}{}^{0}}$ components from ${χ_{c{\rm 1}}(3872)}$ decay samples are presented. Studies of $T$ and $CPT$ conservation in $C = +1$ ${{D}^{0}}{\overline{D}{}^{0}}$ systems can be performed with more easily reconstructible final states, when compared to $C = -1$ ${{D}^{0}}{\overline{D}{}^{0}}$ systems. Experimental mechanisms that can produce $C = \pm 1$ ${{D}^{0}}{\overline{D}{}^{0}}$ systems are described in an appendix.
description: 43 pages, 5 figures
Bounds on quantum communication via Newtonian gravity
Creators: name: Kafri, D.
name: Milburn, G. J.
name: Taylor, J. M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Newtonian gravity yields specific observable consequences, the most striking of which is the emergence of a $1/r^2$ force. In so far as communication can arise via such interactions between distant particles, we can ask what would be expected for a theory of gravity that only allows classical communication. Many heuristic suggestions for gravity-induced decoherence have this restriction implicitly or explicitly in their construction. Here we show that communication via a $1/r^2$ force has a minimum noise induced in the system when the communication cannot convey quantum information, in a continuous time analogue to Bell's inequalities. Our derived noise bounds provide tight constraints from current experimental results on any theory of gravity that does not allow quantum communication.
description: 13 pages, 1 figure
A restricted dimer model on a 2-dimensional random causal triangulation
Creators: name: Ambjorn, J.
name: Durhuus, B.
name: Wheater, J. F.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Combinatorics (math.CO)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We introduce a restricted hard dimer model on a random causal triangulation that is exactly solvable and generalizes a model recently proposed by Atkin and Zohren. We show that the latter model exhibits unusual behaviour at its multicritical point; in particular, its Hausdorff dimension equals 3 and not 3/2 as would be expected from general scaling arguments. When viewed as a special case of the generalized model introduced here we show that this behaviour is not generic and therefore is not likely to represent the true behaviour of the full dimer model on a random causal triangulation.
description: 26 pages, typos corrected, slight generalization added