cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
MRI-active inner regions of protoplanetary discs. II. Dependence on dust, disc and stellar parameters
Creators: name: Jankovic, Marija R.
name: Mohanty, Subhanjoy
name: Owen, James E.
name: Tan, Jonathan C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Close-in super-Earths are the most abundant exoplanets known. It has been hypothesized that they form in the inner regions of protoplanetary discs, out of the dust that may accumulate at the boundary between the inner region susceptible to the magneto-rotational instability (MRI) and an MRI-dead zone further out. In Paper I we presented a model for the viscous inner disc which includes heating due to both irradiation and MRI-driven accretion; thermal and non-thermal ionization; dust opacities; and dust effects on ionization. Here we examine how the inner disc structure varies with stellar, disc and dust parameters. For high accretion rates and small dust grains, we find that: (1) the main sources of ionization are thermal ionization and thermionic and ion emission; (2) the disc features a hot, high-viscosity inner region, and a local gas pressure maximum at the outer edge of this region (in line with previous studies); and (3) an increase in the dust-to-gas ratio pushes the pressure maximum outwards. Consequently, dust can accumulate in such inner discs without suppressing the MRI, with the amount of accumulation depending on the viscosity in the MRI-dead regions. Conversely, for low accretion rates and large dust grains, there appears to be an additional steady-state solution in which: (1) stellar X-rays become the main source of ionization; (2) MRI-viscosity is high throughout the disc; and (3) the pressure maximum ceases to exist. Hence, if planets form in the inner disc, larger accretion rates (and thus younger disks) are favoured.
description: accepted to MNRAS
How does Clifford algebra show the way to the second quantized fermions with unified spins, charges and families, and with vector and scalar gauge fields beyond the {\it standard model}
Creators: name: Borstnik, Norma Susana Mankoc
name: Nielsen, Holger Bech
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: Fifty years ago the standard model offered an elegant new step towards understanding elementary fermion and boson fields, making several assumptions, suggested by experiments. The assumptions are still waiting for an explanation. There are many proposals in the literature for the next step. The spin-charge-family theory of one of us (N.S.M.B.) is offering the explanation for not only all by the standard model assumed properties of quarks and leptons and antiquarks and antileptons, with the families included, of the vectors gauge fields, of the Higgs's scalar and Yukawa couplings, but also for the second quantization postulates of Dirac and for cosmological observations, like there are the appearance of the dark matter, of matter-antimatter asymmetry, making several predictions. This theory proposes a simple starting action in $ d\ge (13+1)$ space with fermions interacting with the gravity only, what manifests in $d=(3+1)$ as the vector and scalar gauge fields, and uses the odd Clifford algebra objects to describe the internal space of fermions, what enables that the creation and annihilation operators for fermions fulfill the anticommutation relations for the second quantized fields without Dirac's postulates: Fermions single particle states already anticommute. We present in this review article a short overview of the spin-charge-family theory, illustrating shortly on the toy model the breaks of the starting symmetries in $d=(13+1)$ space, which are triggered either by scalar fields -- the vielbeins with the space index belonging to $d>(3+1)$ -- or by the condensate of the two right handed neutrinos, with the family quantum number not belonging to the observed families. We compare properties and predictions of this theory with the properties and predictions of $SO(10)$ unifying theories.
description: 130 pages, 2 figures, published by Progress in Particle and Nuclear Physics
Numerical propagation of high energy cosmic rays in the Galaxy I: technical issues
Creators: name: De Marco, Daniel
name: Blasi, Pasquale
name: Stanev, Todor
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the results of a numerical simulation of propagation of cosmic rays with energy above $10^{15}$ eV in a complex magnetic field, made in general of a large scale component and a turbulent component. Several configurations are investigated that may represent specific aspects of a realistic magnetic field of the Galaxy, though the main purpose of this investigation is not to achieve a realistic description of the propagation in the Galaxy, but rather to assess the role of several effects that define the complex problem of propagation. Our simulations of Cosmic Rays in the Galaxy will be presented in Paper II. We identified several effects that are difficult to interpret in a purely diffusive approach and that play a crucial role in the propagation of cosmic rays in the complex magnetic field of the Galaxy. We discuss at length the problem of the extrapolation of our results to much lower energies where data are available on the confinement time of cosmic rays in the Galaxy. The confinement time and its dependence on particles' rigidity are crucial ingredients for 1) relating the source spectrum to the observed cosmic ray spectrum; 2) quantifying the production of light elements by spallation; 3) predicting the anisotropy as a function of energy.
description: 29 pages, 12 figures, submitted to JCAP
Discovery of allenyl acetylene, H2CCCHCCH, in TMC-1. A study of the isomers of C5H4
Creators: name: Cernicharo, J.
name: Cabezas, C.
name: Agundez, M.
name: Tercero, B.
name: Marcelino, N.
name: Pardo, J. R.
name: Tercero, F.
name: Gallego, J. D.
name: Lopez-Perez, J. A.
name: de Vicente, P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the discovery in TMC-1 of allenyl acetylene, H2CCCHCCH, through the observation of nineteen lines with a signal-to-noise ratio ~4-15. For this species, we derived a rotational temperature of 7 +/- 1 K and a column density of (1.2 +/- 0.2)e13 cm-2. The other well known isomer of this molecule, methyl diacetylene (CH3C4H), has also been observed and we derived a similar rotational temperature, Trot = 7.0 +/- 0.3 K, and a column density for its two states (A and E) of (6.5 +/- 0.3)e12 cm-2. Hence, allenyl acetylene and methyl diacetylene have a similar abundance. Remarkably, their abundances are close to that of vinyl acetylene (CH2CHCCH). We also searched for the other isomer of C5H4, HCCCH2CCH (1.4-pentadiyne), but only a 3sigma upper limit of 2.5e12 cm-2 to the column density can be established. These results have been compared to state-of-the-art chemical models for TMC-1, indicating the important role of these hydrocarbons in its chemistry. The rotational parameters of allenyl acetylene have been improved by fitting the existing laboratory data together with the frequencies of the transitions observed in TMC-1.
description: Accepted for publication in A&A Letters. arXiv admin note: text overlap with arXiv:2102.10920
Race for the Kerr field
Creators: name: Dautcourt, G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: History and Philosophy of Physics (physics.hist-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Roy P. Kerr has discovered his celebrated metric 45 years ago, yet the problem to find a generalization of the Schwarzschild metric for a rotating mass was faced much earlier. Lense and Thirring, Bach, Andress, Akeley, Lewis, van Stockum and others have tried to solve it or to find an approximative solution at least. In particular Achilles Papapetrou, from 1952 to 1961 in Berlin, was interested in an exact solution. He directed the author in the late autumn of 1959 to work on the problem. Why did these pre-Kerr attempts fail? Comments based on personal reminiscences and old notes.
description: 16 pages
Schramm-Loewner Equations Driven by Symmetric Stable Processes
Creators: name: Chen, Zhen-Qing
name: Rohde, Steffen
Publisher: name: arXiv
Year: 2007
Subjects: subject: Probability (math.PR)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We consider shape, size and regularity of the hulls of the chordal Schramm-Loewner evolution driven by a symmetric alpha-stable process. We obtain derivative estimates, show that the complements of the hulls are Hoelder domains, prove that the hulls have Hausdorff dimension 1, and show that the trace is right-continuous with left limits almost surely.
description: 22 pages, 4 figures
High p_T Triggered Delta-eta,Delta-phi Correlations over a Broad Range in Delta-eta
Creators: name: Wenger, Edward
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The first measurement of pseudorapidity (Delta-eta) and azimuthal angle (Delta-phi) correlations between high transverse momentum charged hadrons (p_T > 2.5 GeV/c) and all associated particles is presented at both short- (small Delta-eta) and long-range (large Delta-eta) over a continuous pseudorapidity acceptance (-4
description: 5 pages, 2 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 2008. Full author list included and typo corrected in equation 1
Years of RXTE Monitoring of Anomalous X-ray Pulsar 4U 0142+61: Long-Term Variability
Creators: name: Dib, R.
name: Kaspi, V. M.
name: Gavriil, F. P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on 10 years of monitoring of the 8.7-s Anomalous X-ray Pulsar 4U 0142+61 using the Rossi X-Ray Timing Explorer (RXTE). This pulsar exhibited stable rotation from 2000 March until 2006 February: the RMS phase residual for a spin-down model which includes nu, nudot, and nuddot is 2.3%. We report a possible phase-coherent timing solution valid over a 10-yr span extending back to March 1996. A glitch may have occured between 1998 and 2000, but is not required by the existing timing data. The pulse profile has been evolving since 2000. In particular, the dip of emission between its two peaks got shallower between 2002 and 2006, as if the profile were evolving back to its pre-2000 morphology, following an earlier event, which possibly also included the glitch suggested by the timing data. These profile variations are seen in the 2-4 keV band but not in 6-8 keV. We also detect a slow increase in the pulsed flux between 2002 May and 2004 December, such that it has risen by 36+/-3% over 2.6 years in the 2-10 keV band. The pulsed flux variability and the narrow-band pulse profile changes present interesting challenges to aspects of the magnetar model.
description: 28 pages, 8 figures, accepted by ApJ
Precision Test of Mass Ratio Variations with Lattice-Confined Ultracold Molecules
Creators: name: Zelevinsky, T.
name: Kotochigova, S.
name: Ye, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We propose a precision measurement of time variations of the proton-electron mass ratio using ultracold molecules in an optical lattice. Vibrational energy intervals are sensitive to changes of the mass ratio. In contrast to measurements that use hyperfine-interval-based atomic clocks, the scheme discussed here is model-independent and does not require separation of time variations of different physical constants. The possibility of applying the zero-differential-Stark-shift optical lattice technique is explored to measure vibrational transitions at high accuracy.
description: 4 pages, 4 figures
Thiols in the ISM: first detection of HC(O)SH and confirmation of C$_2$H$_5$SH
Creators: name: Rodríguez-Almeida, Lucas F.
name: Jiménez-Serra, Izaskun
name: Rivilla, Víctor M.
name: Martín-Pintado, Jesús
name: Zeng, Shaoshan
name: Tercero, Belén
name: de Vicente, Pablo
name: Colzi, Laura
name: Rico-Villas, Fernando
name: Martín, Sergio
name: Requena-Torres, Miguel A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The chemical compounds carrying the thiol group (-SH) have been considered essential in recent prebiotic studies regarding the polymerization of amino acids. We have searched for this kind of compounds toward the Galactic Centre quiescent cloud G+0.693-0.027. We report the first detection in the interstellar space of the trans-isomer of monothioformic acid (t-HC(O)SH) with an abundance of $\sim\,$1$\,\times\,$10$^{-10}$. Additionally, we provide a solid confirmation of the gauche isomer of ethyl mercaptan (g-C$_2$H$_5$SH) with an abundance of $\sim\,$3$\,\times\,$10$^{-10}$, and we also detect methyl mercaptan (CH$_3$SH) with an abundance of $\sim\,$5$\,\times\,$10$^{-9}$. Abundance ratios were calculated for the three SH-bearing species and their OH-analogues, revealing similar trends between alcohols and thiols with increasing complexity. Possible chemical routes for the interstellar synthesis of t-HC(O)SH, CH$_3$SH and C$_2$H$_5$SH are discussed, as well as the relevance of these compounds in the synthesis of prebiotic proteins in the primitive Earth.
description: 16 pages, 6 figures, article accepted in Astrophysical Journal Letters; typos corrected
Order Parameters and Phase Diagrams of Multiferroics
Creators: name: Harris, A. B.
name: Aharony, Amnon
name: Entin-Wohlman, O.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The symmetry properties, order parameters, and magnetoelectric phase diagrams of multiferroics are discussed. After brief reviews of Ni$_3$V$_2$O$_8$, TbMnO$_3$, and RbFe(MoO$_4$)$_2$, we present a detailed analysis of RMn$_2$O$_5$ (with R=Y, Ho, Dy, Er, Tb, Tm).
description: 23 pages, 7 figures, 3 tables. For FOCUS ON MULTIFERROICS (IOP)
Tomographic techniques and their application to geotechnical and groundwater flow problems
Creators: name: Laidlaw, James Stuart
Publisher: name: University of British Columbia
Year: 2010

description: Most downhole tools in use today measure properties immediately adjacent to the borehole, and as such, only a small portion of the subsurface volume is known with any degree of certainty. When dealing with geologic situations which are characteristically heterogeneous, the engineer often requires more information than what present tests can provide. Tomography is an in-situ testing method that allows the generation of a two dimensional subsurface image by reconstructing material property variations between boreholes. It is essentially a solution to the inverse problem where signals are measured and, through computer manipulation, are used to infer material contrasts in the subsurface. For the purposes of this thesis, a two dimensional configuration is used to demonstrate and evaluate the tomographic technique with source and receiver locations positioned at intervals down adjacent and nearly vertical boreholes. Both iterative and direct matrix solution methods are used to evaluate the use of seismic and groundwater flow data for subsurface tomography. The iterative methods include a variation of the classical algebraic reconstruction technique (CART), a modified version of the ART algorithm (MART), and a modified version of the ART algorithm using the Chebyshev norm criterion (LART). The purpose of the iterative tests is to determine the best algorithm for signal reconstruction when data noise and different damping parameters are applied. The matrix methodologies include a constrained L¹ linear approximation algorithm and singular value decomposition routines (SVD). These methods solve the set of linear equations (Ax = b) which the tomographic techniques produce. The purpose of this stage of testing is to optimize a direct method of solution to the sets of linear equations such that different forms of anomaly can be discerned. Numerous synthetic seismic and groundwater data sets are used by both iterative and matrix algorithms. Seismic test data sets are generated by calculation of transit times through materials of known seismic velocity. Groundwater test data sets are generated by drawdown analyses and finite element procedures. All algorithms demonstrate a reasonable ability at reconstructing sections which closely re-sembled the known profiles. Vertical anomalies, however, are not as well defined as horizontal anomalies. This is primarily a result of incomplete cross-hole scanning geometry which also affects the rank and condition of the matrices used by the direct forms of solution. The addition of Gaussian noise to the data produces poor reconstructions regardless of the type of algorithm used. This emphasizes the fact that tomographic techniques require clear and relatively error-free signals.
Optimal efficiency of high frequency chest wall oscillations and links with resistance and compliance in a model of the lung
Creators: name: Brunengo, Michaël
name: Mitchell, Barrett R.
name: Nicolini, Antonello
name: Rousselet, Bernard
name: Mauroy, Benjamin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Medical Physics (physics.med-ph)
subject: Computational Physics (physics.comp-ph)
subject: Tissues and Organs (q-bio.TO)
subject: FOS: Physical sciences
subject: FOS: Biological sciences

description: Chest physiotherapy is a set of techniques used to help the draining of the mucus from the lung in pathological situations. The choice of the techniques, and their adjustment to the patients or to the pathologies, remains as of today largely empirical. High Frequency Chest Wall Oscillation (HFCWO) is one of these techniques, performed with a device that applies oscillating pressures on the chest. However, there is no clear understanding of how HFCWO devices interact with the lung biomechanics. Hence, we study idealised HFCWO manipulations applied to a mathematical and numerical model of the biomechanics of the lung. The lung is represented by a fluid--structure interaction model based on an airway tree that is coupled to an homogeneous elastic medium. We show that our model is driven by two dimensionless numbers that drive the effect of the idealised HFCWO manipulation on the model of the lung. Our model allow to analyze the stress applied to an idealised mucus by the air--mucus interaction and by the airway walls deformation. This stress behaves as a buffer and has the effect of reducing the stress needed to overcome the idealised mucus yield stress. Moreover, our model predicts the existence of an optimal range of the working frequencies of HFCWO. This range is in agreement with the frequencies actually used by practitioners during HFCWO maneuvers. Finally, our model suggests that analyzing the mouth airflow during HFCWO maneuvers could allow to estimate the compliance and the hydrodynamic resistance of the lung of a patient.
TRIPLE Deliverable: D8.1 Public Website and Social Media Channels Registered
Creators: name: Pohle, Stefanie
Publisher: name: Zenodo
Year: 2019
Subjects: social sciences and humanities
SSH
research infrastructure
OPERAS
TRIPLE
communication

description: TRIPLE Deliverable: D8.1 Public Website and Social Media Channels Registered
description: The deliverable has been officially approved by the Project Officer. --- The TRIPLE project (https://www.gotriple.eu/), which is financed under the Horizon 2020 framework (https://cordis.europa.eu/project/id/863420), under Grant Agreement No. 863420, with approx. 5.6 million Euros for a duration of 42 months (2019-2023). --- At the heart of the project is the development of the TRIPLE platform, an innovative multilingual and multicultural discovery solution.
Thermal coherence of the Heisenberg model with Dzyaloshinsky-Moriya interactions in an inhomogenous external field
Creators: name: Parthasarathy, Manikandan
name: Jambulingam, Segar
name: Byrnes, Tim
name: Radhakrishnan, Chandrashekar
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The quantum coherence of the two-site XYZ model with Dzyaloshinsky-Moriya (DM) interactions in an external inhomogenous magnetic field is studied. The DM interaction, the magnetic field and the measurement basis can be along different directions, and we examine the quantum coherence at finite temperature. With respect to the spin-spin interaction parameter, we find that the quantum coherence decreases when the direction of measurement basis is the same as that of the spin-spin interaction. When the spin-lattice interaction is varied, the coherence always increases irrespective of the relation between its direction and the measurement basis. Similar analysis of quantum coherence based on the variation of the external inhomogenous magnetic field is also carried out, where we find that the coherence decreases when the direction of the measurement basis is the same as that of the external field.
description: 18 pages
Λόγος: Indagine Abissale
Creators: name: PsykoSapiens
Publisher: name: Zenodo
Year: 2025

description: «Il λόγος non è mai neutro: è atto di potere, di creazione o di annientamento. È lama e fumo. Struttura e inganno. E noi, in bilico sul ciglio del caos, ne siamo la carne pensante».

Il taccuino esplora le profondità etimologiche, filosofiche e cosmologiche del termine greco λόγος (lógos), tracciandone l'evoluzione da radice proto-indoeuropea a concetto cardine del pensiero occidentale. Lungi dall’essere solo “parola” o “discorso”, il lógos emerge come atto primordiale di connessione, ordinamento, selezione, ma anche come strumento ambivalente: può essere verità o menzogna, caos o rivelazione.

Perché ogni parola è una scelta. E ogni scelta è un abisso.

Questo non è un saggio. È un coltello infilato nella gola del linguaggio. Il λόγος, che ci hanno venduto come “discorso”, “pensiero”, “ragione”, viene qui fatto a pezzi. Perché non è mai stato innocente.

Questo taccuino non cerca la verità. La dissangua.

Per chi non cerca risposte, ma la vertigine che precede ogni pensiero.
Risk perception in epidemic modeling
Creators: name: Bagnoli, Franco
name: Lio, Pietro
name: Sguanci, Luca
Publisher: name: arXiv
Year: 2007
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Other Quantitative Biology (q-bio.OT)
subject: FOS: Biological sciences

description: We investigate the effects of risk perception in a simple model of epidemic spreading. We assume that the perception of the risk of being infected depends on the fraction of neighbors that are ill. The effect of this factor is to decrease the infectivity, that therefore becomes a dynamical component of the model. We study the problem in the mean-field approximation and by numerical simulations for regular, random and scale-free networks. We show that for homogeneous and random networks, there is always a value of perception that stops the epidemics. In the ``worst-case'' scenario of a scale-free network with diverging input connectivity, a linear perception cannot stop the epidemics; however we show that a non-linear increase of the perception risk may lead to the extinction of the disease. This transition is discontinuous, and is not predicted by the mean-field analysis.
description: 6 pages, 6 figures, completely new version
Efficient Transfer Learning via Joint Adaptation of Network Architecture and Weight
Creators: name: Sun, Ming
name: Dou, Haoxuan
name: Yan, Junjie
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Transfer learning can boost the performance on the targettask by leveraging the knowledge of the source domain. Recent worksin neural architecture search (NAS), especially one-shot NAS, can aidtransfer learning by establishing sufficient network search space. How-ever, existing NAS methods tend to approximate huge search spaces byexplicitly building giant super-networks with multiple sub-paths, anddiscard super-network weights after a child structure is found. Both thecharacteristics of existing approaches causes repetitive network trainingon source tasks in transfer learning. To remedy the above issues, we re-duce the super-network size by randomly dropping connection betweennetwork blocks while embedding a larger search space. Moreover, wereuse super-network weights to avoid redundant training by proposinga novel framework consisting of two modules, the neural architecturesearch module for architecture transfer and the neural weight searchmodule for weight transfer. These two modules conduct search on thetarget task based on a reduced super-networks, so we only need to trainonce on the source task. We experiment our framework on both MS-COCO and CUB-200 for the object detection and fine-grained imageclassification tasks, and show promising improvements with onlyO(CN)super-network complexity.
description: NAS is one part of transfer learning
Coherent-incoherent transition in a Cooper-pair-box coupled to a quantum oscillator: an equilibrium approach
Creators: name: Huang, Ying-Hua
name: Wong, Hang
name: Chen, Zhi-De
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Temperature effect on quantum tunneling in a Cooper-pair-box coupled to a quantum oscillator is studied by both numerical and analytical calculations. It is found that, in strong coupling regions, coherent tunneling of a Cooper-pair-box can be destroyed by its coupling to a quantum oscillator and the tunneling becomes thermally activated as the temperature rises, leading to failure of the Cooper-pair-box. The transition temperature between the coherent tunneling and thermo-activated hopping is determined and physics analysis based on small polaron theory is also provided.
description: 8 pages, 7 figures
Supersolidity from defect-condensation in the extended boson Hubbard model
Creators: name: Chen, Yu-Chun
name: Melko, Roger G.
name: Wessel, Stefan
name: Kao, Ying-Jer
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We study the ground state phase diagram of the hard-core extended boson Hubbard model on the square lattice with both nearest- (nn) and next-nearest-neighbor (nnn) hopping and repulsion, using Gutzwiller mean field theory and quantum Monte Carlo simulations. We observe the formation of supersolid states with checkerboard, striped, and quarter-filled crystal structures, when the system is doped away from commensurate fillings. In the striped supersolid phase, a strong anisotropy in the superfluid density is obtained from the simulations; however, the transverse component remains finite, indicating a true two-dimensional superflow. We find that upon doping, the striped supersolid transitions directly into the supersolid with quarter-filled crystal structure, via a first-order stripe melting transition.
description: Revtex 4, 6 pages, 9 figures
Effect of anisotropic hopping on the Bose Hubbard model phase diagram: strong-coupling perturbation theory on a square lattice
Creators: name: Freericks, J. K.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: There has been a recent resurgence of experimental efforts to quantitatively determine the phase diagram of the Bose Hubbard model by carefully analyzing experiments with ultracold bosonic atoms on an optical lattice. In many realizations of these experiments, the hopping amplitudes are not homogeneous throughout the lattice, but instead, the lattice has an anisotropy where hopping along one direction is not exactly equal to hopping along a perpendicular direction. In this contribution, we examine how an anisotropy in the hopping matrix elements affects the Mott lobes of the Bose Hubbard model. For weak anisotropy, we find the phase diagram is only slightly modified when expressed in terms of the average hopping, while for strong anisotropy, one expects to ultimately see dimensional crossover effects.
description: (5 pages, 1 figure, RevTeX)
Cost efficiency of institutional incentives in finite populations
Creators: name: Duong, Manh Hong
name: Han, The Anh
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: Dynamical Systems (math.DS)
subject: Probability (math.PR)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Mathematics
subject: FOS: Biological sciences

description: Institutions can provide incentives to increase cooperation behaviour in a population where this behaviour is infrequent. This process is costly, and it is thus important to optimize the overall spending. This problem can be mathematically formulated as a multi-objective optimization problem where one wishes to minimize the cost of providing incentives while ensuring a desired level of cooperation within the population. In this paper, we provide a rigorous analysis for this problem. We study cooperation dilemmas in both the pairwise (the Donation game) and multi-player (the Public Goods game) settings. We prove the regularity of the (total incentive) cost function, characterize its asymptotic limits (infinite population, weak selection and large selection) and show exactly when reward or punishment is more efficient. We prove that the cost function exhibits a phase transition phenomena when the intensity of selection varies. We calculate the critical threshold in regards to the phase transition and study the optimization problem when the intensity of selection is under and above the critical value. It allows us to provide an exact calculation for the optimal cost of incentive, for a given intensity of selection. Finally, we provide numerical simulations to demonstrate the analytical results. Overall, our analysis provides for the first time a selection-dependent calculation of the optimal cost of institutional incentives (for both reward and punishment) that guarantees a minimum amount of cooperation. It is of crucial importance for real-world applications of institutional incentives since intensity of selection is specific to a given population and the underlying game payoff structure.
description: preliminary version
Tracking translation invariance in CNNs
Creators: name: Myburgh, Johannes C.
name: Mouton, Coenraad
name: Davel, Marelie H.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: Although Convolutional Neural Networks (CNNs) are widely used, their translation invariance (ability to deal with translated inputs) is still subject to some controversy. We explore this question using translation-sensitivity maps to quantify how sensitive a standard CNN is to a translated input. We propose the use of Cosine Similarity as sensitivity metric over Euclidean Distance, and discuss the importance of restricting the dimensionality of either of these metrics when comparing architectures. Our main focus is to investigate the effect of different architectural components of a standard CNN on that network's sensitivity to translation. By varying convolutional kernel sizes and amounts of zero padding, we control the size of the feature maps produced, allowing us to quantify the extent to which these elements influence translation invariance. We also measure translation invariance at different locations within the CNN to determine the extent to which convolutional and fully connected layers, respectively, contribute to the translation invariance of a CNN as a whole. Our analysis indicates that both convolutional kernel size and feature map size have a systematic influence on translation invariance. We also see that convolutional layers contribute less than expected to translation invariance, when not specifically forced to do so.
Heavy-quark production in massless quark scattering at two loops in QCD
Creators: name: Czakon, M.
name: Mitov, A.
name: Moch, S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the two-loop virtual QCD corrections to the production of heavy quarks in the quark--anti-quark--annihilation channel in the limit when all kinematical invariants are large compared to the mass of the heavy quark. Our result is exact up to terms suppressed by powers of the heavy-quark mass. The derivation is based on a simple relation between massless and massive scattering amplitudes in gauge theories proposed recently by two of the authors as well as a direct calculation of the massive amplitude at two loops. The results presented here form an important part of the next-to-next-to-leading order QCD contributions to heavy-quark production in hadron-hadron collisions.
description: 17 pages latex, 2 figures
The Ellerman bomb and Ultraviolet burst triggered successively by an emerging magnetic flux rope
Creators: name: Cheng, Guanchong
name: Ni, Lei
name: Chen, Yajie
name: Ziegler, Udo
name: Lin, Jun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Ellerman bombs (EBs) and Ultraviolet (UV) bursts are common brightening phenomena which are usually generated in the low solar atmosphere of emerging flux regions. In this paper, we have investigated the emergence of an initial un-twisted magnetic flux rope based on three-dimensional (3D) magneto-hydrodynamic (MHD) simulations. The EB-like and UV burst-like activities successively appear in the U-shaped part of the undulating magnetic fields triggered by Parker Instability. The EB-like activity starts to appear earlier and lasts for about 80 seconds. Six minutes later, a much hotter UV burst-like event starts to appear and lasts for about 60 seconds. Along the direction vertical to the solar surface, both the EB and UV burst start in the low chromosphere, but the UV burst extends to a higher altitude in the up chromosphere. The regions with apparent temperature increase in the EB and UV burst are both located inside the small twisted flux ropes generated in magnetic reconnection processes, which are consistent with the previous 2D simulations that most hot regions are usually located inside the magnetic islands. However, the twisted flux rope corresponding to the EB is only strongly heated after it floats up to an altitude much higher than the reconnection site during that period. Our analyses show that the EB is heated by the shocks driven by the strong horizontal flows at two sides of the U-shaped magnetic fields. The twisted flux rope corresponding to the UV burst is heated by the driven magnetic reconnection process.
Reconciling Higgs physics and pseudo-Nambu-Goldstone dark matter in the S2HDM using a genetic algorithm
Creators: name: Biekötter, Thomas
name: Olea, María Olalla
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate a possible realization of pseudo-Nambu-Goldstone (pNG) dark matter in the framework of a singlet-extended 2 Higgs doublet model (S2HDM). pNG dark matter gained attraction due to the fact that direct-detection constraints can be avoided naturally because of the momentum-suppressed scattering cross sections, whereas the relic abundance of dark matter can nevertheless be accounted for via the usual thermal freeze-out mechanism. We confront the S2HDM with a multitude of theoretical and experimental constraints, paying special attention to the theoretical limitations on the scalar potential, such as vacuum stability and perturbativity. In addition, we discuss the complementarity between constraints related to the dark matter sector, on the one hand, and to the Higgs sector, on the other hand. In our numerical discussion we explore the Higgs funnel region with dark matter masses around $60$GeV using a genetic algorithm. We demonstrate that the S2HDM can account for the measured relic abundance while being in agreement with all relevant constraints. We also discuss whether the so-called galactic center excess and the antiproton excess can be accommodated, possibly in combination with a Higgs boson at about $96$GeV that can be the origin of the LEP- and the CMS-excess observed at this mass in the $b \bar b$-quark and the diphoton final state, respectively.
description: 30 pages, 8 figures, v2: Minor changes, matches published version
Launch of the Space experiment PAMELA
Creators: name: Casolino, M.
name: Picozza, P.
name: Altamura, F.
name: Basili, A.
name: De Simone, N.
name: Di Felice, V.
name: De Pascale, M. P.
name: Marcelli, L.
name: Minori, M.
name: Nagni, M.
name: Sparvoli, R.
name: Galper, A. M.
name: Mikhailov, V. V.
name: Runtso, M. F.
name: Voronov, S. A.
name: Yurkin, Y. T.
name: Zverev, V. G.
name: Castellini, G.
name: Adriani, O.
name: Bonechi, L.
name: Bongi, M.
name: Taddei, E.
name: Vannuccini, E.
name: Fedele, D.
name: Papini, P.
name: Ricciarini, S. B.
name: Spillantini, P.
name: Ambriola, M.
name: Cafagna, F.
name: De Marzo, C.
name: Barbarino, G. C.
name: Campana, D.
name: De Rosa, G.
name: Osteria, G.
name: Russo, S.
name: Bazilevskaja, G. A.
name: Kvashnin, A. N.
name: Maksumov, O.
name: Misin, S.
name: Stozhkov, Yu. I.
name: Bogomolov, E. A.
name: Krutkov, S. Yu.
name: Nikonov, N. N.
name: Bonvicini, V.
name: Boezio, M.
name: Lundquist, J.
name: Mocchiutti, E.
name: Vacchi, A.
name: Zampa, G.
name: Zampa, N.
name: Bongiorno, L.
name: Ricci, M.
name: Carlson, P.
name: Hofverberg, P.
name: Lund, J.
name: Orsi, S.
name: Pearce, M.
name: Menn, W.
name: Simon, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10^-8). The experiment, housed on board the Russian Resurs-DK1 satellite, was launched on June, 15, 2006 in a 350*600 km orbit with an inclination of 70 degrees. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, Time-of-Flight and rigidity information. Lepton/hadron identification is performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the Calorimeter, the neutron detector and a shower tail catcher are capable of an independent measure of the lepton component up to 2 TeV. In this work we describe the experiment, its scientific objectives and the performance in the first months after launch.
description: Accepted for publication on Advances in Space Research
Hidden quantum spin gap state in the static stripe phase of La$_{2-x}$Sr$_{x}$CuO$_{4}$
Creators: name: Kofu, M.
name: Lee, S. -H.
name: Fujita, M.
name: Kang, H. -J.
name: Eisaki, H.
name: Yamada, K.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Low energy spin excitations were investigated in the static stripe phase of La_{2-x}Sr_xCuO_4 using elastic and inelastic neutron scattering on single crystals. For x = 1/8 in which long-range static stripe order exists, an energy gap of E_g = 4 meV exists in the excitation spectrum in addition to strong quasi-elastic, incommensurate spin fluctuations associated with the static stripes. When x increases, the spectral weight of the spin fluctuations shifts from the quasi-elastic continuum to the excitation spectrum above E_g. The dynamic correlation length as a function of energy and the temperature evolution of the energy spectrum suggest a phase separation of two distinct magnetic phases in real space.
description: 5pages, 4figures
NGTS-19b : A high mass transiting brown dwarf in a 17-day eccentric orbit
Creators: name: Acton, Jack S.
name: Goad, Michael R.
name: Burleigh, Matthew R.
name: Casewell, Sarah L.
name: Breytenbach, Hannes
name: Nielsen, Louise D.
name: Smith, Gareth
name: Anderson, David R.
name: Battley, Matthew P.
name: Bayliss, Daniel
name: Bouchy, François
name: Bryant, Edward M.
name: Csizmadia, Szilárd
name: Eigmüller, Phillip
name: Gill, Samuel
name: Gillen, Edward
name: Grieves, Nolan
name: Günther, Maximilian N.
name: Henderson, Beth A.
name: Hodgkin, Simon T.
name: Jackman, James A. G.
name: Jenkins, James S.
name: Lendl, Monika
name: McCormac, James
name: Moyano, Maximiliano
name: Nelson, Richard P.
name: Sefako, Ramotholo R.
name: Smith, Alexis M. S.
name: Stalport, Manu
name: Thomas, Jessymol K.
name: Tilbrook, Rosanna H.
name: Udry, Stéphane
name: West, Richard G.
name: Wheatley, Peter J.
name: Worters, Hannah L.
name: Vines, Jose I.
name: Alves, Douglas R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the discovery of NGTS-19b, a high mass transiting brown dwarf discovered by the Next Generation Transit Survey (NGTS). We investigate the system using follow up photometry from the South African Astronomical Observatory, as well as sector 11 TESS data, in combination with radial velocity measurements from the CORALIE spectrograph to precisely characterise the system. We find that NGTS-19b is a brown dwarf companion to a K-star, with a mass of $69.5 ^{+5.7}_{-5.4}$ M$_{Jup}$ and radius of $1.034 ^{+0.055}_{-0.053}$ R$_{Jup}$. The system has a reasonably long period of 17.84 days, and a high degree of eccentricity of $0.3767 ^{+0.0061}_{-0.0061}$. The mass and radius of the brown dwarf imply an age of $0.46 ^{+0.26}_{-0.15}$ Gyr, however this is inconsistent with the age determined from the host star SED, suggesting that the brown dwarf may be inflated. This is unusual given that its large mass and relatively low levels of irradiation would make it much harder to inflate. NGTS-19b adds to the small, but growing number of brown dwarfs transiting main sequence stars, and is a valuable addition as we begin to populate the so called brown dwarf desert.
description: Accepted for Publication in MNRAS
MPEC 2023-Y90 : 2023 YJ1
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2023
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2023 YJ1

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Exact semianalytical calculation of rotation curves with Bekenstein-Milgrom nonrelativistic MOND
Creators: name: Lopez-Corredoira, M.
name: Betancort-Rijo, J. E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Astronomers use to derive MOdified Newtonian Dynamics (MOND) rotation curves using the simple algebraic rule of calculating the acceleration as equal to the Newtonian acceleration ($a$) divided by some factor $μ(a)$. However, there are velocity differences between this simple rule and the calculation derived from more sophisticated MOND versions such as AQUAL or QMOND, created to expand MOND heuristic law and preserve the conservation of momentum, angular momentum, and energy, and follow the weak equivalence principle. Here we provide recipes based on Milgrom's proposal to calculate semianalytically (without numerical simulations) MOND rotation curves for any density distribution based on AQUAL, applying it to different models of thin disks. The application of this formalism is equivalent to the creation of a fictitious phantom mass whose field may be used in a Newtonian way to calculate iteratively the MOND accelerations. In most cases, the differences between the application of the simple algebraic rule and the AQUAL-MOND calculations are small, $\lesssim 5$%. However, the error of the algebraic solution is larger than 5% when more than half of the mass is in the MONDian regime (where Newtonian and MOND rotation speeds differ by more than 10%), reaching in some cases $>70$% discrepance, such as in Maclaurin disks, representative of galaxies for which the rotational velocity rises to the edge of the disk as is seen in irregular galaxies. The slope of the rotation speed in the dependence with the radius or the vertical distance of the plane is also significantly changed.
description: accepted to be published in ApJ
The quantization of gravity: Quantization of the Hamilton equations
Creators: name: Gerhardt, Claus
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences
subject: 83, 83C, 83C45

description: We quantize the Hamilton equations instead of the Hamilton condition. The resulting equation has the simple form $-\D u=0$ in a fiber bundle, where the Laplacian is the Laplacian of the Wheeler-DeWitt metric provided $n\not=4$. Using then separation of variables the solutions $u$ can be expressed as products of temporal and spatial eigenfunctions, where the spatial eigenfunctions are eigenfunctions of the Laplacian in the symmetric space $SL(n,\R[])/SO(n)$. Since one can define a Schwartz space and tempered distributions in $SL(n,\R[])/SO(n)$ as well as a Fourier transform, Fourier quantization can be applied such that the spatial eigenfunctions are transformed to Dirac measures and the spatial Laplacian to a multiplication operator.
description: 33 pages, v2: Typos corrected and two sections added. This is the published version
Causal simplicity and (maximal) null pseudoconvexity
Creators: name: Hedicke, Jakob
name: Minguzzi, Ettore
name: Schinnerl, Benedict
name: Steinbauer, Roland
name: Suhr, Stefan
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We consider pseudoconvexity properties in Lorentzian and Riemannian manifolds and their relationship in static spacetimes. We provide an example of a causally continuous and maximal null pseudoconvex spacetime that fails to be causally simple. Its Riemannian factor provides an analogous example of a manifold that is minimally pseudoconvex, but fails to be convex.
Initial study with a national online panel: Exploring participant motivations and preferences
Creators: name: Elgersma, Ingeborg Hess
name: Munthe-Kaas, Heather Menzies
name: Holst, Christine
Publisher: name: Zenodo
Year: 2025
Subjects: Communication
Online panel
Survey

description: The objective of this study is to better understand the preferences and needs of Norwegian adults related to health crisis communication. The specific aims are to:

1.       Identify motivations and preferences of Norwegian adults for participating in the online panel

2.       Explore the preferred components of communication by authorities during a health crisis