cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Step transform pulse compression and its application to synthetic aperture radar systems
Creators: name: Sack, Mark William
Publisher: name: University of British Columbia
Year: 2010

description: Step transform pulse compression is a matched filtering technique applicable to linear FM signals. A mathematical analysis of the method is developed and its application to the azimuth processing of synthetic aperture radar (SAR) target returns is explored. In particular, several satellite-borne SAR systems are used as examples to compare the performance of this technique to other approaches. Problems peculiar to SAR azimuth processing including FM rate error, range cell migration, and multilook processing are considered. The computation rates, memory requirements, and complexity of the processing algorithms are also evaluated. The step transform is studied analytically to determine how appropriate choices of processing parameters can be made to achieve acceptable image quality, while minimizing the hardware requirements. A method of range cell migration correction, which can be integrated into the step transform process, is proposed and the corresponding parameter restrictions are derived. The hardware requirements of the step transform for SAR applications, relative to some other pulse compression techniques, are shown to be less dependent on SAR system parameters and more dependent on the step transform processing parameters chosen. A computer simulation program was written to confirm the analytical results.
Simultaneously constraining cosmology and baryonic physics via deep learning from weak lensing
Creators: name: Lu, Tianhuan
name: Haiman, Zoltán
name: Matilla, José Manuel Zorrilla
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Ongoing and planned weak lensing (WL) surveys are becoming deep enough to contain information on angular scales down to a few arcmin. To fully extract information from these small scales, we must capture non-Gaussian features in the cosmological WL signal while accurately accounting for baryonic effects. In this work, we account for baryonic physics via a baryonic correction model that modifies the matter distribution in dark matter-only $N$-body simulations, mimicking the effects of galaxy formation and feedback. We implement this model in a large suite of ray-tracing simulations, spanning a grid of cosmological models in $Ω_\mathrm{m}-σ_8$ space. We then develop a convolutional neural network (CNN) architecture to learn and constrain cosmological and baryonic parameters simultaneously from the simulated WL convergence maps. We find that in a Hyper-Suprime Cam (HSC)-like survey, our CNN achieves a 1.7$\times$ tighter constraint in $Ω_\mathrm{m}-σ_8$ space ($1σ$ area) than the power spectrum and 2.1$\times$ tighter than the peak counts, showing that the CNN can efficiently extract non-Gaussian cosmological information even while marginalizing over baryonic effects. When we combine our CNN with the power spectrum, the baryonic effects degrade the constraint in $Ω_\mathrm{m}-σ_8$ space by a factor of 2.4, compared to the much worse degradation by a factor of 4.7 or 3.7 from either method alone.
description: 12 pages, 6 figures
Spin-waves in a complex magnetic system: nonextensive approach
Creators: name: Soares-Pinto, D. O.
name: Reis, M. S.
name: Sarthour, R. S.
name: Oliveira, I. S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: In this paper we analyze the spin-wave excitations (magnons) of an inhomogeneous spin system within the Boltzmann-Gibbs framework and then connect the results with the nonextensive approach (in the sense of Tsallis statistics). Considering an equivalence between those two frameworks, we could connect the entropic parameter q with moments of the distribution of exchange integrals of the inhomogenous system. It ratifies the idea that the entropic parameter is connected to the microscopic properties of the system.
description: 9 pages, 1 figure
Two-phase flow model for energetic proton beam induced pressure waves in mercury target systems in the planned European Spallation Source
Creators: name: Barna, Imre Ferenc
name: Imre, Attila Richard
name: Rosta, Laszlo
name: Mezei, Ferenc
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Two-phase flow calculations are presented to investigate the thermo-hydraulical effects of the interaction between 300 kJ proton pulses (2 ms long, 1.3 GeV) with a closed mercury loop which can be considered as a model system of the target of the planned European Spallation Source(ESS) facility. The two-fluid model consists of six first-order partial differential equations that present one dimensional mass momentum and energy balances for mercury vapour and liquid phases are capable to describe quick transients like cavitation effects or shock waves. The absorption of the proton beam is represented as instantaneous heat source in the energy balance equations. Densities and internal energies of the mercury liquid-vapour system are calculated from van der Waals equation, and the general method how to obtain such properties is also presented. A second order accurate high-resolution shock-capturing numerical scheme is applied with different kinds of limiters in the numerical calculations. %Our two-fluid model is very similar to the RELAP5 thermo-hydraulical code %which is used in the nuclear industry to simulate nuclear power plant accidents. Our analysis show that even 75 degree temperature heat shocks cannot cause considerable cavitation effects in mercury in 2ms long pulses
description: 7 pages, 3 figures, 1 table submitted to the European Physical Journal B
I carbonari della montagna
Creators: name: De Roberto, Federico
Publisher: name: INFN Open Access Repository
Year: 2021
Subjects: de roberto
unict
manoscritto
verismo

description: Sceneggiatura manoscritta della riduzione cinematografica; conservata presso la biblioteca di storia patria per la sicilia orientale; pubblicata in casa verga e altri saggi verghiani, curato da c. musumarra, firenze, le monnier, 1964
description: la.mu.s.a. - ex facoltà di lettere e filosofia - università degli studi di catania - società di storia patria per la sicilia orientale; busta 03
Quantification de la concentration en éosine Y dans l'éosine commerciale.
Creators: name: Davilerd, Jade
name: Amaro, Lou
Publisher: name: Zenodo
Year: 2023

description: L'éosine est une solution antiseptique de couleur rouge. L'éosine Y, qui la compose, est indiquée comme étant présente à 2 % en masse. Plusieurs méthodes de dosage ont été utilisées pour déterminer cette valeur.
Measurement of low frequency electric fields using electrodeless breakdown of gases
Creators: name: Friedmann, Daniel E.
Publisher: name: University of British Columbia
Year: 2010

description: There is a need for an electric field meter to measure environmental fields under high voltage transmission lines and their associated switchyards. This thesis describes a new electric field meter based on the electrodeless breakdown of gases in insulating vessels. When a glass bulb filled with a gas (e.g. neon) is placed in an alternating electric field it emits light in the form of pulses. The number of pulses per cycle of the electric field is proportional to the field magnitude. An electric field meter is constructed by conveying the light from the gas filled glass bulb (the sensor) to an electronic counter (the detector) with an optical fiber. The resulting meter has a low weight, non metallic sensor that can be separated from the detector electronics by any desired distance. The sensor shape dictates its directional sensitivity. A spherical bulb has an isotropic response to the field while a cylindrical bulb gives a maximum response when its axis is aligned with the field direction. The size of the bulb is inversely proportional to the threshold below which the field can not be measured. A 25mm bulb has a 10kv m-1 threshold. The transmission of the light signal from the sensor to the detector is immune to electrical noise. The detector electronics is simple because the field magnitude information is contained in the number of pulses not in the magnitude of the pulses. This thesis presents the theoretical, experimental and field test results which explain the operation of the meter and substantiates its advantages. The basic physical model for the sensor is established by describing the relation between optical pulses and field magnitude, the effect of sensor shape on this relation, the operation of the sensor in elliptically polarized (including harmonic) fields and the effect of bulb size and gas composition on the phenomena. The basic practical considerations are investigated by studying the environmental effects on the performance of the meter, the lifetime and stability of the meter, the effect of the sensor on the field being measured and the general engineering of meter. This work has resulted in a fully tested prototype meter whose basic operation is well understood.
An Algorithm for Checking Injectivity of Specialization Maps from Elliptic Surfaces
Creators: name: Billingsley, Tyler Raven
Publisher: name: arXiv
Year: 2021
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11G05

description: Let $E/\mathbb Q(t)$ be an elliptic curve and let $t_0 \in \mathbb Q$ be a rational number for which the specialization $E_{t_0}$ is an elliptic curve. Given a subgroup $M$ of $E(\mathbb Q(t))$ with mild conditions and $t_0 \in \mathbb Q$ coming from a relatively large subset $S_M \subset \mathbb Q$, we provide an algorithm that can show that the specialization map $σ_{t_0} : E(\mathbb Q(t)) \to E_{t_0}(\mathbb Q)$ is injective when restricted to $M$. The set $S_M$ is effectively computable in certain cases, and we carry out this computation for some explicit examples where $E$ is given by a Weierstrass equation.
description: Peer-reviewed version to appear in Journal of Number Theory
Brane Inflation and Fine Tuning
Creators: name: Pajer, Enrico
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We argue about the importance of embedding the successful mechanism of Inflation in the context of a fundamental theory. We review some of the attempts in this direction made in the framework of String Theory. In particular we report on recent developments in Brane Inflation with emphasis on the fine tuning issue.
description: To appear in the proceedings of Cargese Summer School 2007 on "Cosmology and Particle Physics Beyond the Standard Models"
3D Modeling of the Structure and Dynamics of a Main-Sequence F-type Star
Creators: name: Kitiashvili, Irina N.
name: Wray, Alan A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Current state-of-the-art computational modeling makes it possible to build realistic models of stellar convection zones and atmospheres that take into account chemical composition, radiative effects, ionization, and turbulence. The standard 1D mixing-length-based evolutionary models are not able to capture many physical processes of the stellar interior dynamics. Mixing-length models provide an initial approximation of stellar structure that can be used to initialize 3D radiative hydrodynamics simulations which include realistic modeling of turbulence, radiation, and other phenomena. In this paper, we present 3D radiative hydrodynamic simulations of an F-type main-sequence star with 1.47 solar mass. The computational domain includes the upper layers of the radiation zone, the entire convection zone, and the photosphere. The effects of stellar rotation is modeled in the f-plane approximation. These simulations provide new insight into the properties of the convective overshoot region, the dynamics of the near-surface, highly turbulent layer, and the structure and dynamics of granulation. They reveal anti-solar-type differential rotation and latitudinal dependence of the tachocline location.
description: 8 pages, 6 figures; Proceeding of IAU Symposium #354: "Solar and Stellar Magnetic Fields: Origins and Manifestations", 30 June - 6 July 2019, Copiapo, Chile
Universal Extra Dimensions, Radiative Returns and the Inverse Problem at a Linear e+e- Collider
Creators: name: Bhattacherjee, B.
name: Kundu, A.
name: Rai, S. K.
name: Raychaudhuri, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In a five-dimensional model with one Universal Extra Dimension (UED), signals for a pair of n = 1 Kaluza-Klein excitations could be easily observed at a future e+ e- collider if the process in question is kinematically allowed. However, these signals would prove difficult to distinguish from those predicted in other models, such as those with an extended gauge symmetry or supersymmetry. A much better power of discrimination is provided by the fact that the same machine could also produce the n=2 gauge bosons γ_2 and Z_2 as resonances in fermion pair-production without any upgrade in the collision energy \sqrt{s}. Assuming a fixed \sqrt{s}, as is expected at upcoming e+e- machines, we investigate the role of beam radiation in helping to excite such resonances through radiative returns. We then show how these resonances can yield unambiguous signals for UED, if taken in conjunction with the production of Z_1 pairs, identified by their decays to leptons and missing transverse energy.
description: Fig 6 extended, some comments and references added
Deducing the nature of dark matter from direct and indirect detection experiments in the absence of collider signatures of new physics
Creators: name: Beltran, Maria
name: Hooper, Dan
name: Kolb, Edward W.
name: Krusberg, Zosia C.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Despite compelling arguments that significant discoveries of physics beyond the standard model are likely to be made at the Large Hadron Collider, it remains possible that this machine will make no such discoveries, or will make no discoveries directly relevant to the dark matter problem. In this article, we study the ability of astrophysical experiments to deduce the nature of dark matter in such a scenario. In most dark matter studies, the relic abundance and detection prospects are evaluated within the context of some specific particle physics model or models (e.g. supersymmetry). Here, we attempt to develop a model-independent approach toward the phenomenology of weakly interacting massive particles in the absence of any discoveries at the Large Hadron Collider. In particular, we consider generic fermionic or scalar dark matter particles with a variety of interaction forms, and calculate the corresponding constraints from and sensitivity of direct and indirect detection experiments. The results may provide some guidance in disentangling information from future direct and indirect detection experiments.
description: 19 pages, 7 figures
A Binational Project for the Preservation and Control of Censored Magazines from the Allied Occupation of Japan at the University of Maryland
Creators: name: Shulman, Frank Joseph
name: Okuizumi, Eizaburo
Publisher: name: Digital Repository at the University of Maryland
Year: 1983
Subjects: East Asia--Languages
Library of Congress
Gordon W. Prange Collection (University of Maryland at College Park. Libraries)

description: This work is licensed by a Creative Commons Attribution 3.0 license (https://ojs.lib.byu.edu/spc/index.php/JEAL/index)
New metamaterials with macroscopic behavior outside that of continuum elastodynamics
Creators: name: Milton, Graeme W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 35Q72

description: Metamaterials are constructed such that, for a narrow range of frequencies, the momentum density depends on the local displacement gradient, and the stress depends on the local velocity. In these models the momentum density generally depends not only on the strain, but also on the local rotation, and the stress is generally not symmetric. A variant is constructed for which, at a fixed frequency, the momentum density is independent of the local rotation (but still depends on the strain) and the stress is symmetric (but still depends on the velocity). Generalizations of these metamaterials may be useful in the design of elastic cloaking devices.
description: 14 pages, 4 figures
Non-equilibrium evolution of the optical conductivity of the weakly interacting Hubbard model: Drude response and $π$-ton type vertex corrections
Creators: name: Simard, Olivier
name: Eckstein, Martin
name: Werner, Philipp
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The optical conductivity contains information about energy absorption and the underlying physical processes. In finite-dimensional systems, vertex corrections to the bare bubble need to be considered, which is a computationally challenging task. Recent numerical studies showed that in the weak coupling limit, near an ordering instability with wave vector $π$, $π$-tons (or Maki-Thompson diagrams) yield the most relevant vertex corrections. This provides a route for including vertex corrections into, for example, dynamical mean field theory estimates of the optical conductivity. By implementing calculations on the Kadanoff-Baym contour, we reveal the characteristic spectral signatures of the $π$-tons and their evolution under non-equilibrium conditions. We consider interaction quenches of the weakly-correlated Hubbard model near the antiferromagnetic phase boundary, and analyze the evolution of the Drude and $π$-ton features. While the bubble contribution to the optical conductivity is found to thermalize rapidly, after some oscillations with frequencies related to the local spectral function, the $π$-ton contribution exhibits a slower evolution. We link this observation to the prethermalization phenomenon which has been previously studied in weakly interacting, quenched Hubbard models.
description: 15 pages, 12 figures
A dynamical perspective on additional planets in 55 Cancri
Creators: name: Raymond, Sean N.
name: Barnes, Rory
name: Gorelick, Noel
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Five planets are known to orbit the star 55 Cancri. The recently-discovered planet f at 0.78 AU (Fischer et al. 2008) is located at the inner edge of a previously-identified stable zone that separates the three close-in planets from planet d at 5.9 AU. Here we map the stability of the orbital space between planets f and d using a suite of n-body integrations that include an additional, yet-to-be-discovered planet g with a radial velocity amplitude of 5 m/s (planet mass = 0.5-1.2 Saturn masses). We find a large stable zone extending from 0.9 to 3.8 AU at eccentricities below 0.4. For each system we quantify the probability of detecting planets b-f on their current orbits given perturbations from hypothetical planet g, in order to further constrain the mass and orbit of an additional planet. We find that large perturbations are associated with specific mean motion resonances (MMRs) with planets f and d. We show that two MMRs, 3f:1g (the 1:3 MMR between planets g and f) and 4g:1d cannot contain a planet g. The 2f:1g MMR is unlikely to contain a planet more massive than about 20 Earth masses. The 3g:1d and 5g:2d MMRs could contain a resonant planet but the resonant location is strongly confined. The 3f:2g, 2g:1d and 3g:2d MMRs exert a stabilizing influence and could contain a resonant planet. Furthermore, we show that the stable zone may in fact contain 2-3 additional planets, if they are ~50 Earth masses each. Finally, we show that any planets exterior to planet d must reside beyond 10 AU.
description: ApJ, in press
Untitled ItemTsunami hazard assessment for the Bechevinsky bay (Kamchatka peninsula): methodology and results
Creators: name: Beisel, Sofya
name: Gusev, Oleg
name: Kikhtenko, Vladimir
name: Chubarov, Leonid
Publisher: name: figshare
Year: 2021
Subjects: subject: 49999 Earth Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Geophysics
subject: Oceanography

description: Methods, algorithms, and programs are proposed for the probabilistic assessment of the tsunami hazard of Bechevinskaya Bay with the aim of choosing options for the placement of floating liquefied gas storages and wave protection structures in its water area. The methodology includes the analysis of seismicity of the region, the construction of a catalog of model tsunami-generating earthquakes, the determination of their statistical characteristics, scenario-based numerical modeling of the dynamics of tsunami waves, the determination of the magnitude of the wave-impact that can be exceeded with a given repeatability, for example, «on average once every 100 years».Оригинальная публикация в Сборнике трудов Всероссийской конференции «Прикладные технологии гидроакустики и гидрофизики». — СПб.: ПОЛИТЕХ-ПРЕСС, 2020. — 600 с. Стр. 243 – 246
Self-interacting Dark Matter via Right Handed Neutrino Portal
Creators: name: Borah, Debasish
name: Dutta, Manoranjan
name: Mahapatra, Satyabrata
name: Sahu, Narendra
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We propose a self-interacting dark matter (DM) scenario with right handed neutrino (RHN) portal to the standard model (SM). The dark sector consists of a particle DM, assumed to be a Dirac fermion, and a light mediator in terms of a dark Abelian vector boson to give rise to the required velocity dependent self-interactions in agreement with astrophysical observations. Irrespective of thermal or non-thermal production of such a DM, its final relic remains under-abundant due to efficient annihilation rates of DM into light mediators by virtue of large self-interaction coupling. We then show that a feeble portal of DM-SM interaction via RHN offers a possibility to fill the relic deficit of DM via the late decay of RHN. As RHN also arises naturally in seesaw models explaining the origin of light neutrino masses, we outline two UV complete realizations of the minimal setup in terms of scotogenic and gauged B-L frameworks where connection to neutrino mass and other phenomenology like complementary discovery prospects are discussed.
description: 48 pages, 21 captioned figures, version accepted for publication in PRD
Entropy production in high-energy heavy-ion collisions and the correlation of shear viscosity and thermalization time
Creators: name: Dumitru, A.
name: Molnar, E.
name: Nara, Y.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We study entropy production in the early stage of high-energy heavy-ion collisions due to shear viscosity. We employ the second-order theory of Israel-Stewart with two different stress relaxation times, as appropriate for strong coupling or for a Boltzmann gas, respectively, and compare the hydrodynamic evolution. Based on present knowledge of initial particle production, we argue that entropy production is tightly constrained. We derive new limits on the shear viscosity to entropy density ratio $η/s$, independent from elliptic flow effects, and determine the corresponding Reynolds number. Furthermore, we show that for a given entropy production bound, that the initial time $τ_0$ for hydrodynamics is correlated to the viscosity. The conjectured lower bound for $η/s$ provides a lower limit for $τ_0$.
description: 10 pages, 10 figures, Text updated, references added, two new figures added, normalization in Fig.1 corrected, final version to be published in PRC
XMM-Newton observations of XTE J1817-330 and XTE J1856+053
Creators: name: Sala, Gloria
name: Greiner, Jochen
name: Bottacini, Eugenio
name: Haberl, Frank
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The black hole candidate XTE J1817-330 was discovered in outburst on 26 January 2006 with RXTE/ASM. One year later, on 28 February 2007, another X-ray transient discovered in 1996, XTE J1856+053, was detected by RXTE during a new outburst. We report on the spectra obtained by XMM-Newton of these two black hole candidates.
description: Replaced with corrected version
Unequal-mass mergers of dark matter haloes with rare and frequent self-interactions
Creators: name: Fischer, Moritz S.
name: Brüggen, Marcus
name: Schmidt-Hoberg, Kai
name: Dolag, Klaus
name: Ragagnin, Antonio
name: Robertson, Andrew
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dark matter (DM) self-interactions have been proposed to solve problems on small length scales within the standard cold DM cosmology. Here, we investigate the effects of DM self-interactions in merging systems of galaxies and galaxy clusters with equal and unequal mass ratios. We perform N-body DM-only simulations of idealized setups to study the effects of DM self-interactions that are elastic and velocity-independent. We go beyond the commonly adopted assumption of large-angle (rare) DM scatterings, paying attention to the impact of small-angle (frequent) scatterings on astrophysical observables and related quantities. Specifically, we focus on DM-galaxy offsets, galaxy--galaxy distances, halo shapes, morphology, and the phase--space distribution. Moreover, we compare two methods to identify peaks: one based on the gravitational potential and one based on isodensity contours. We find that the results are sensitive to the peak finding method, which poses a challenge for the analysis of merging systems in simulations and observations, especially for minor mergers. Large DM-galaxy offsets can occur in minor mergers, especially with frequent self-interactions. The subhalo tends to dissolve quickly for these cases. While clusters in late merger phases lead to potentially large differences between rare and frequent scatterings, we believe that these differences are non-trivial to extract from observations. We therefore study the galaxy/star populations which remain distinct even after the DM haloes have coalesced. We find that these collisionless tracers behave differently for rare and frequent scatterings, potentially giving a handle to learn about the micro-physics of DM.
description: 16 pages, 13 figures, 2 tables + appendices, accepted for publication in MNRAS
Quantitative analysis of clumps in the tidal tails of star clusters
Creators: name: Just, A.
name: Berczik, P.
name: Petrov, M. I.
name: Ernst, A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Tidal tails of star clusters are not homogeneous but show well defined clumps in observations as well as in numerical simulations. Recently an epicyclic theory for the formation of these clumps was presented. A quantitative analysis was still missing. We present a quantitative derivation of the angular momentum and energy distribution of escaping stars from a star cluster in the tidal field of the Milky Way and derive the connection to the position and width of the clumps. For the numerical realization we use star-by-star $N$-body simulations. We find a very good agreement of theory and models. We show that the radial offset of the tidal arms scales with the tidal radius, which is a function of cluster mass and the rotation curve at the cluster orbit. The mean radial offset is 2.77 times the tidal radius in the outer disc. Near the Galactic centre the circumstances are more complicated, but to lowest order the theory still applies. We have also measured the Jacobi energy distribution of bound stars and showed that there is a large fraction of stars (about 35%) above the critical Jacobi energy at all times, which can potentially leave the cluster. This is a hint that the mass loss is dominated by a self-regulating process of increasing Jacobi energy due to the weakening of the potential well of the star cluster, which is induced by the mass loss itself.
description: 14 pages, 17 figures; accepted by MNRAS
Additivity of component regression equations when the underlying model is linear
Creators: name: Chiyenda, Simeon Sandaramu
Publisher: name: University of British Columbia
Year: 2010

description: This thesis is concerned with the theory of fitting models of the form y = Xβ + ε, where some distributional assumptions are made on ε. More specifically, suppose that y[sub=j] = Zβ[sub=j] + ε [sub=j] is a model for a component j (j = 1, 2, ..., k) and that one is interested in estimation and interference theory relating to y[sub=T] = Σ [sup=k; sub=j=1] y[sub=j] = Xβ[sub=T] + ε[sub=T]. The theory of estimation and inference relating to the fitting of y[sub=T] is considered within the general framework of general linear model theory. The consequence of independence and dependence of the y[sub=j] (j = 1, 2, ..., k) for estimation and inference is investigated. It is shown that under the assumption of independence of the y[sub=j], the parameter vector of the total equation can easily be obtained by adding corresponding components of the estimates for the parameters of the component models. Under dependence, however, this additivity property seems to break down. Inference theory under dependence is much less tractable than under independence and depends critically, of course, upon whether y[sub=T] is normal or not. Finally, the theory of additivity is extended to classificatory models encountered in designed experiments. It is shown, however, that additivity does not hold in general in nonlinear models. The problem of additivity does not require new computing subroutines for estimation and inference in general in those cases where it works.
Galaxy Velocity Bias in Cosmological Simulations: Towards Percent-level Calibration
Creators: name: Anbajagane, Dhayaa
name: Aung, Han
name: Evrard, August E.
name: Farahi, Arya
name: Nagai, Daisuke
name: Barnes, David J.
name: Cui, Weiguang
name: Dolag, Klaus
name: McCarthy, Ian G.
name: Rasia, Elena
name: Yepes, Gustavo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Galaxy cluster masses, rich with cosmological information, can be estimated from internal dark matter (DM) velocity dispersions, which in turn can be observationally inferred from satellite galaxy velocities. However, galaxies are biased tracers of the DM, and the bias can vary over host halo and galaxy properties as well as time. We precisely calibrate the velocity bias, b_v -- defined as the ratio of galaxy and DM velocity dispersions -- as a function of redshift, host halo mass, and galaxy stellar mass threshold (Mstarsat), for massive halos (M200c > 1e13.5 msun) from five cosmological simulations: IllustrisTNG, Magneticum, Bahamas + Macsis, The Three Hundred Project, and MultiDark Planck-2. We first compare scaling relations for galaxy and DM velocity dispersion across simulations; the former is estimated using a new ensemble velocity likelihood method that is unbiased for low galaxy counts per halo, while the latter uses a local linear regression. The simulations show consistent trends of b_v increasing with M200c and decreasing with redshift and Mstarsat. The ensemble-estimated theoretical uncertainty in b_v is 2-3% but becomes percent-level when considering only the three highest resolution simulations. We update the mass-richness normalization previously estimated by Farahi et al. (2016) for an SDSS redMaPPer cluster sample. The improved accuracy of our b_v estimates reduces the mass normalization uncertainty from 22% to 8%, demonstrating that dynamical estimation techniques can be competitive with weak lensing in calibrating population mean masses. We discuss necessary steps for further improving this precision. Our estimates for b_v(M200c, Mstarsat, z) are made publicly available.
description: [v1]: 8 figures, 14 pages in main text + 5 figures, 3 pages in Appendix. [v2]: Minor text edits. Accepted in MNRAS
Estimation of the force impact of long surface waves on an anchored hydrotechnical object by numerical modeling methods
Creators: name: Gusev, Oleg
name: Gayaz Khakimzyanov
name: Chubarov, Leonid
Publisher: name: figshare
Year: 2021
Subjects: subject: 49999 Earth Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: 50204 Environmental Impact Assessment
subject: 40604 Natural Hazards

description:
We present the method of computing the force effect of long surface waves on an anchored hydrotechnical structure. This task is associated with the need to make decisions on the design, placement and operation of structures of this kind. The problem is investigated under the assumption of the potentiality of the flow of an ideal fluid using an original algorithm that allows computations on curvilinear grids adapted to the shape of the structure. The results obtained allows the determination of the dependence of the force effect on the characteristics of the waves, the shape, size and depth of the structure, its position relative to the direction of movement of the waves.
Оригинал опубликован в Сборнике трудов Всероссийской конференции «Прикладные технологии гидроакустики и гидрофизики». — СПб.: ПОЛИТЕХ-ПРЕСС, 2020. — 600 с. Стр. 239 – 242
Role of resonances in rho^0 -> pi^+ pi^- gamma
Creators: name: Sanchez, G. Toledo
name: Garcia-Luna, J. L.
name: Gonzalez-Enciso, V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0 -> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are driven by the mass and width parameters of the sigma(600), and the usually neglected contribution of the a_1(1260), although small by itself, may become sizable through its interference with pion bremsstrahlung, and the proper relative sign can favor the central value of the experimental branching ratio. We present a procedure, using the gauge invariant structure of the resonant amplitudes, to kinematically enhance the resonant effects in the angular and energy distribution of the photon. We also elaborate on the coupling constants involved.
description: 5 pages, 5 figures, accepted for publication in PRD
Supplementary document for High-order exciton complexes induced by interlayer carrier transfer in 2D Van der Waals heterostructures - 6722945.pdf
Creators: name: Sui, Yizhen
name: Cheng, Xiang'ai
name: Liu, Qirui
name: Tang, Yuxiang
name: Xu, Zhongjie
name: We, Ke
Publisher: name: Optica Publishing Group
Year: 2023
Subjects: Uncategorized

description: Supplemental information
Magnetic barrier induced conductance fluctuations in quantum wires
Creators: name: Hugger, S.
name: Xu, Hengyi
name: Tarasov, A.
name: Cerchez, M.
name: Heinzel, T.
name: Zozoulenko, I. V.
name: Reuter, D.
name: Wieck, A. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Quasi-ballistic semiconductor quantum wires are exposed to localized perpendicular magnetic fields, also known as magnetic barriers. Pronounced, reproducible conductance fluctuations as a function of the magnetic barrier amplitude are observed. The fluctuations are strongly temperature dependent and remain visible up to temperatures of about 10 K. Simulations based on recursive Green functions suggest that the conductance fluctuations originate from parametric interferences of the electronic wave functions which experience scattering between the magnetic barrier and the electrostatic potential landscape.
description: 4 pages, 4 figures
Rate Determining Factors in Protein Model Structures
Creators: name: Bruscolini, Pierpaolo
name: Pelizzola, Alessandro
name: Zamparo, Marco
Publisher: name: arXiv
Year: 2007
Subjects: subject: Biomolecules (q-bio.BM)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Biological sciences
subject: FOS: Physical sciences

description: Previous research has shown a strong correlation of protein folding rates to the native state geometry, yet a complete explanation for this dependence is still lacking. Here we study the rate-geometry relationship with a simple statistical physics model, and focus on two classes of model geometries, representing ideal parallel and antiparallel structures. We find that the logarithm of the rate shows an almost perfect linear correlation with the "absolute contact order", but the slope depends on the particular class considered. We discuss these findings in the light of experimental results.
description: 4 pages, 2 figures
On the surface of glasses
Creators: name: Stevenson, Jacob D.
name: Wolynes, Peter G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Dynamics near the surface of glasses is generally much faster than in the bulk. Neglecting static perturbations of structure at the surface, we use random first order transition theory to show the free energy barrier for activated motion near a free surface should be half that of the bulk at the same temperature. The increased mobility allows the surface layers to descend much further on the energy landscape than the bulk ordinarily does. The simplified RFOT calculation however predicts a limiting value for the configurational entropy a vapor deposited glass may reach as a function of deposition rate. We sketch how mode coupling effects extend the excess free surface mobility into the bulk so that the glass transition temperature is measurably perturbed at depths greater than the naive length scale of dynamic cooperativity.
description: 5 pages 2 figures
A Case Study of Low-Mass Star Formation
Creators: name: Swift, J.
name: Welch, Wm. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: This article synthesizes observational data from an extensive program aimed toward a comprehensive understanding of star formation in a low-mass star-forming molecular cloud. New observations and published data spanning from the centimeter wave band to the near infrared reveal the high and low density molecular gas, dust, and pre-main sequence stars in L1551.
description: 24 pages, 21 figures, ApJS accepted
A numerical finite size scaling approach to many-body localization
Creators: name: Fleury, Genevieve
name: Waintal, Xavier
Publisher: name: arXiv
Year: 2007
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We develop a numerical technique to study Anderson localization in interacting electronic systems. The ground state of the disordered system is calculated with quantum Monte-Carlo simulations while the localization properties are extracted from the ``Thouless conductance'' $g$, i.e. the curvature of the energy with respect to an Aharonov-Bohm flux. We apply our method to polarized electrons in a two dimensional system of size $L$. We recover the well known universal $β(g)=\rm{d}\log g/\rm{d}\log L$ one parameter scaling function without interaction. Upon switching on the interaction, we find that $β(g)$ is unchanged while the system flows toward the insulating limit. We conclude that polarized electrons in two dimensions stay in an insulating state in the presence of weak to moderate electron-electron correlations.
description: 5 pages, 4 figures
Stellar Populations in the Andromeda V Dwarf Spheroidal Galaxy
Creators: name: Mancone, Conor
name: Sarajedini, Ata
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Using archival imaging from the Wide Field Planetary Camera 2 aboard the Hubble Space Telescope, we investigate the stellar populations of the Local Group dwarf spheroidal Andromeda V - a companion satellite galaxy of M31. The color-magnitude diagram (CMD) extends from above the first ascent red giant branch (RGB) tip to approximately one magnitude below the horizontal branch (HB). The steep well-defined RGB is indicative of a metal-poor system while the HB is populated predominantly redward of the RR Lyrae instability strip. Utilizing Galactic globular cluster fiducial sequences as a reference, we calculate a mean metallicity of [Fe/H] = -2.20 +/- 0.15 and a distance of (m-M)0 = 24.57 +/- 0.04 after adopting a reddening of E(B-V) = 0.16. This metal abundance places And V squarely in the absolute magnitude - metallicity diagram for dwarf spheroidal galaxies. In addition, if we attribute the entire error-corrected color spread of the RGB stars to an abundance spread, we estimate a range of ~0.5 dex in the metallicities of And V stars. Our analysis of the variable star population of And V reveals the presence of 28 potential variables. Of these, at least 10 are almost certainly RR Lyrae stars based on their time sequence photometry.
description: 4 pages, 6 figures Accepted to the Astronomical Journal
Relationship between Hawking radiation from black holes and spontaneous excitation of atoms
Creators: name: Yu, Hongwei
name: Zhou, Wenting
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Using the formalism that separates the contributions of vacuum fluctuations and radiation reaction to the rate of change of the mean atomic energy, we show that a two-level atom in interaction with a quantum massless scalar field both in the Hartle-Hawking and Unruh vacuum in a 1+1 dimensional black hole background spontaneously excites as if there is thermal radiation at the Hawking temperature emanating from the black hole. Our calculation, therefore, ties the existence of Hawking radiation to the spontaneous excitation of a two-level atom placed in vacuum in the exterior of a black hole and shows pleasing consistence of two different physical phenomena, the Hawking radiation and the spontaneous excitation of atoms, which are quite prominent in their own right.
description: 9 pages, no figures, typos corrected in the references, published version
Review of searches for Higgs bosons and beyond the standard model physics at the Tevatron
Creators: name: Duperrin, Arnaud
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The energy frontier is currently at the Fermilab Tevatron accelerator, which collides protons and antiprotons at a center-of-mass energy of 1.96 TeV. The luminosity delivered to the CDF and D0 experiments has now surpassed the 4 fb-1. This paper reviews the most recent direct searches for Higgs bosons and beyond-the-standard-model (BSM) physics at the Tevatron. The results reported correspond to an integrated luminosity of up to 2.5 fb-1 of Run II data collected by the two Collaborations. Searches covered include: the standard model (SM) Higgs boson (including sensitivity projections), the neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM), charged Higgs bosons and extended Higgs models, supersymmetric decays that conserve or violate R-parity, gauge-mediated supersymmetric breaking models, long-lived particles, leptoquarks, compositeness, extra gauge bosons, extra dimensions, and finally signature-based searches. Given the excellent performance of the collider and the continued productivity of the experiments, the Tevatron physics potential looks promising for discovery with the coming larger data sets. In particular, evidence for the SM Higgs boson could be obtained if its mass is light or near 160 GeV. The observed (expected) upper limits are currently a factor of 3.7 (3.3) higher than the expected SM Higgs boson cross section at m_H=115 GeV and 1.1 (1.6) at m_H=160 GeV at 95% C.L.
description: submitted to European Physical Journal C, Particles and Fields
Laser-induced thermal source for cold atoms
Creators: name: Hsu, Chung Chuan
name: Larue, Rémy
name: Kwong, Chang Chi
name: Wilkowski, David
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We demonstrate a simple and compact approach to laser cool and trap atoms based on laser-induced thermal ablation (LITA) of a pure solid granule. A rapid thermalisation of the granule leads to a fast recovery of the ultra-high vacuum condition required for a long trapping lifetime of the cold gas. We give a proof-of-concept of the technique, performing a magneto-optical trap on the 461 nm $^1S_0\rightarrow^1P_1$ transition of strontium. We get up to 3.5 million of cold strontium-88 atoms with a trapping lifetime of more than 4 s. The lifetime is limited by the pressure of the strontium-free residual background vapour. We also implement an original configuration of permanent magnets to create the quadruple magnetic field of the magneto-optical trap. The LITA technique can be generalized to other atomic elements such as transition metals and lanthanide atoms, and shows a strong potential for applications in quantum technologies ranging from quantum computing to precision measurements such as outdoor inertial sensing.
description: 9 pages, 4 figures
Quantum Well Based on Graphene and Narrow-Gap Semiconductors
Creators: name: Ratnikov, P. V.
name: Silin, A. P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We consider the energy spectrum of the planar quantum well which consisted of two ribbons of narrow-gap semiconductors and a graphene ribbon between ones. It is shown that the gapless mode appears only in case of inverted narrow-gap semiconductors. Spin splitting of the energy spectrum for a nonsymmetric quantum well is calculated taking into account a specificity of graphene. We investigate interface states and optical transitions. It is shown that the optical transitions are possible only with a conservation of a parity.
description: 13 pages, 2 figures, 1 table