cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The Ionization and Dynamics of the Makani Galactic Wind
Creators: name: Rupke, David S. N.
name: Coil, Alison L.
name: Perrotta, Serena
name: Davis, Julie D.
name: Diamond-Stanic, Aleksandar M.
name: Geach, James E.
name: Hickox, Ryan C.
name: Moustakas, John
name: Petter, Grayson C.
name: Rudnick, Gregory H.
name: Sell, Paul H.
name: Tremonti, Christy A.
name: Whalen, Kelly E.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Makani galaxy hosts the poster child of a galactic wind on scales of the circumgalactic medium. It consists of a two-episode wind in which the slow, outer wind originated 400 Myr ago (Episode I; R_I = 20-50 kpc) and the fast, inner wind is 7 Myr old (Episode II; R_II = 0-20 kpc). While this wind contains ionized, neutral, and molecular gas, the physical state and mass of the most extended phase--the warm, ionized gas--is unknown. Here we present Keck optical spectra of the Makani outflow. These allow us to detect hydrogen lines out to r = 30-40 kpc and thus constrain the mass, momentum, and energy in the wind. Many collisionally-excited lines are detected throughout the wind, and their line ratios are consistent with 200-400 km/s shocks that power the ionized gas, with v_shock = $σ$_wind. Combining shock models, density-sensitive line ratios, and mass and velocity measurements, we estimate that the ionized mass and outflow rate in the Episode II wind could be as high as that of the molecular gas: M_II(HII) ~ M_II(H_2) = (1-2)x10^9 Msun and dM/dt_II(HII) ~ dM/dt_II(H_2) = 170-250 Msun/yr. The outer wind has slowed, so that dM/dt_I(HII) ~ 10 Msun/yr, but it contains more ionized gas: M_I(HII) = 5x10^9 Msun. The momentum and energy in the recent Episode II wind imply a momentum-driven flow (p ``boost" ~ 7) driven by the hot ejecta and radiation pressure from the Eddington-limited, compact starburst. Much of the energy and momentum in the older Episode I wind may reside in a hotter phase, or lie further into the CGM.
description: ApJ, in press
EUV jets, type III radio bursts and sunspot waves investigated using SDO/AIA observations
Creators: name: Innes, D. E.
name: Cameron, R. H.
name: Solanki, S. K.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Images from the Solar Dynamics Observatory (SDO) at 211A are used to identify the solar source of the type III radio bursts seen in WIND/WAVES dynamic spectra. We analyse a 2.5 hour period during which six strong bursts are seen. The radio bursts correlate very well with the EUV jets coming from the western side of a sunspot in AR11092. The EUV jet emission also correlates well with brightening at what looks like their footpoint at the edge of the umbra. For 10-15 min after strong EUV jets are ejected, the footpoint brightens at roughly 3 min intervals. In both the EUV images and the extracted light curves, it looks as though the brightening is related to the 3-min sunspot oscillations, although the correlation coefficient is rather low. The only open field near the jets is rooted in the sunspot. We conclude that active region EUV/X-ray jets and interplanetary electron streams originate on the edge of the sunspot umbra. They form along a current sheet between the sunspot open field and closed field connecting to underlying satellite flux. Sunspot running penumbral waves cause roughly 3-min jet footpoint brightening. The relationship between the waves and jets is less clear.
description: 4 pages, 7 figures, Accepted by A&A Letters. For associated gif movie, see http://www.mps.mpg.de/data/outgoing/innes/jets/losb_304_211_rd.gif
Xʷay'Xʷəy' and Stanley Park : performing history and land
Creators: name: Couture, Selena Marie
Publisher: name: University of British Columbia
Year: 2015

description: This dissertation demonstrates performance as a mode of knowledge transfer, cultural continuity and intercultural influence that connects people – Indigenous as well as settlers and newcomers – to land. In it I engage with performance studies theory in light of Indigenous conceptions of land, performance and place naming held within the hən'q'əmin'əm' language, while using case studies to explicate histories based on archives and repertoires. Two of my dissertation case studies critically engage with the City of Vancouver Archives. The first deconstructs the use of reenactment to create an origin narrative of benevolent “whiteness” in settler society and the second examines possible Indigenous interventions in the archive through cultural restriction. A third study demonstrates how Aboriginal Tourism of BC’s Klahowya Village, located in Stanley Park 2010-14, presents an enterprise which asserts a connection to land while enabling some intra-nation Indigenous transfer of knowledge. In aiming to rectify the absence of Indigenous women in the archival work that I have undertaken, this dissertation also features performance responses to contemporary theatrical works written and/or performed by Indigenous women in Vancouver between 2012 and 2014. Research methodologies include semiotic and phenomenological analyses enabled by an engagement with Indigenous research methodologies supported by language learning, interviews, as well as archival and field work. This research puts forth a careful examination of the influence of Vancouver’s first archivist, James Skitt Matthews, making note of limitations of the city’s archival collection with regard to Indigenous knowledge and activities. Through analyses of the performative knowledge contained within hən'q'əmin'əm' and colonial place names this research proposes further critical consideration of existing Vancouver place names. I also develop two terms, grounded practices and eddies of influence, which are employed to create a fuller understanding of the significance of land, language and reciprocity, as well as the strategic and tactical methods through which the Indigenous peoples of this area have used performance to contribute to cultural continuation and the maintenance of Indigenous places.
Accelerating In-transit Isosurface Generation With Topology Preserving Compression
Creators: name: Li, Yanliang
name: Chen, Jieyang
Publisher: name: arXiv
Year: 2024
Subjects: subject: Graphics (cs.GR)
subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences
subject: C.4; I.3.7; E.4
subject: 65D18 (Primary) 68P30, 68U10 (Secondary)

description: Data visualization through isosurface generation is critical in various scientific fields, including computational fluid dynamics, medical imaging, and geophysics. However, the high cost of data sharing between simulation sources and visualization resources poses a significant challenge. This paper introduces a novel framework that leverages lossy compression to accelerate in-transit isosurface generation. Our approach involves a Compressed Hierarchical Representation (CHR) and topology-preserving compression to ensure the fidelity of the isosurface generation. Experimental evaluations demonstrate that our framework can achieve up to 4x speedup in visualization workflows, making it a promising solution for real-time scientific data analysis.
description: 3 pages, 4 figures
Expected polarization properties of nonmagnetized CCOs
Creators: name: Suleimanov, Valery F.
name: Poutanen, Juri
name: Doroshenko, Victor
name: Werner, Klaus
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Central compact objects (CCOs) are neutron stars found close to the center of some supernova remnants. A certain number of them are presumably covered by carbon envelopes. Their unpulsed thermal X-ray emission can originate either from the entire surface covered by a carbon atmosphere or alternatively from a nonuniformly emitting hydrogen atmosphere. However, the latter scenario appears unlikely given the available upper limits on the amplitude of pulsations. Here we explore a possibility to further discriminate between the two scenarios using X-ray polarimetric observations. We compute the polarization degree (PD) for nonmagnetized pure-carbon and pure-hydrogen atmospheres with effective temperatures of between 1 and 6 MK and find that it can reach up to 25% and 40% for hydrogen and carbon atmospheres, respectively, in the photon energy band 1-10 keV. However, given the available constraints on possible inhomogeneities of the temperature distribution deduced from models of the X-ray spectrum of the CCO in HESS J1731-347, the integrated PD appears to be very low for both carbon (<0.25%) and hydrogen (a few percent) compositions in the energy band of 2-8 keV covered by the recently launched Imaging X-ray Polarimetry Explorer. We therefore conclude that polarization from CCOs is not expected to be detectable by current facilities, but future detection would strongly support nonuniform hydrogen composition models.
description: 10 pages, 16 figures. accepted to be published by A&A, corrected after the language Editor remarks, misprints in some numbers were corrected, a new version of Fig.15
When taking a step back is a veritable leap forward. Reversing decades of arthroscopy for managing joint pain: Five reasons that could explain declining rates of common arthroscopic surgeries
Creators: name: CL Ardern
name: T Paatela
name: V Mattila
name: S Taimela
name: TLN Järvinen
Publisher: name: La Trobe
Year: 2020
Subjects: Uncategorized

description: No description supplied
title: Researching Writing Technologies through the Speculative Prototype Design of Trina
Creators: name: Burdick, Anne
Publisher: name: Electronic Book Review
Year: 2021

description: Burdick situates the speculative software prototypes of Trina: A Design Fiction as design-theory hybrids that can expand our understanding of critical making and critical design. The essay offers four readings of the Trina prototypes, designed as research into speculative writing technologies that are situated and embodied. The essay concludes with the introduction of an “Indexical Reader,” a design concept for close and distant reading in the Humanities.
Design and resonator-assisted characterization of high performance lithium niobate waveguide crossings
Creators: name: Chen, Yikun
name: Zhang, Ke
name: Feng, Hanke
name: Sun, Wenzhao
name: Wang, Cheng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: Waveguide crossings are elementary passive components for signal routing in photonic integrated circuits. Here, we design and characterize two multimode interferometer (MMI)-based waveguide crossings to serve the various routing directions in the anisotropic x-cut thin-film lithium niobate (TFLN) platform. To address the large measurement uncertainties in traditional cut-back characterization methods, we propose and demonstrate a resonator-assisted approach that dramatically reduces the uncertainty of insertion loss measurement(< 0.021 dB) and the lower bound of crosstalk measurement (-60 dB) using only two devices. Based on this approach, we demonstrate and verify TFLN waveguide crossings with insertion losses of < 0.070 dB and crosstalk of < -50 dB along all three routing directions at 1550 nm. The low-loss and low-crosstalk waveguide crossings in this work, together with the simple and efficient characterization strategy, could provide important layout design flexibility for future large-scale classical and quantum TFLN photonic circuits.
description: 10 pages, 4 figures
title: In Conversation with the Decameron 2.0
Creators: name: Liu, Lulu
name: Kim, Jin Sol
Publisher: name: Electronic Book Review
Year: 2021

description: Jin Sol Kim and Lulu Liu interview the Decameron 2.0, a Canadian collaborative made up of professors and artists who are inspired by Giovanni Boccaccio’s plague narrative The Decameron (1348-1353) to develop creative works during and in response to the COVID-19 pandemic.
Controllable Weyl Nodes and Fermi Arcs from Floquet Engineering Triple Fermions
Creators: name: Huang, Shengpu
name: Zhan, Fangyang
name: Ding, Xianyong
name: Xu, Dong-Hui
name: Ma, Da-Shuai
name: Wang, Rui
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Floquet engineering with periodic driving as a powerful tool for designing desirable topological states has been the subject of intense recent studies. Here, we present the application of Floquet engineering to investigate evolution of topological triple fermions under irradiation of circularly polarized light (CPL), a phenomenon that currently remains a mystery. By using first-principles calculations and Floquet theorem, we demonstrate that WC-type TiO and its analogues are promising candidates for Floquet engineering of triple fermions. The symmetry analysis reveals that the electric field of CPL can break the specific symmetries, such as the time-reversal symmetry and its combination of spatial symmetries, inducing a transition to a flexibly controllable Weyl semimetallic phase. The survived spatial symmetry, controlled by light, guarantees that the Weyl nodes are located along the high-symmetry line or in high-symmetry planes in momentum space. Our findings focusing on Floquet engineering in realistic materials featured by triple fermions would facilitate both theoretical and experimental interest.
description: 6 pages, 4 figures
The Pulsation of AGB Stars in the Magellanic Cloud Clusters NGC 1978 and NGC 419
Creators: name: Kamath, D.
name: Wood, P. R.
name: Soszynski, I.
name: Lebzelter, T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The intermediate-age Magellanic Cloud clusters NGC 1978 and NGC 419 are each found to contain substantial numbers of pulsating AGB stars, both oxygen-rich and carbon-rich. Each cluster also contains two pulsating asymptotic giant branch (AGB) stars which are infrared sources with a large mass loss rate. Pulsation masses have been derived for the AGB variables, from the lowest luminosity O-rich variables to the most evolved infrared sources. It is found that the stars in NGC 1978 have a mass of 1.55Msun early on the AGB while the NGC 419 stars have a mass of 1.87Msun early on the AGB. These masses are in good agreement with those expected from the cluster ages determined by main-sequence turnoff fitting. Nonlinear pulsation models fitted to the highly evolved AGB stars show that a substantial amount of mass loss has occurred during the AGB evolution of these stars. An examination of the observed mass loss on the AGB, and the AGB tip luminosities, shows that in both clusters the mass loss rates computed from the formula of Vassiliadis & Wood (1993) reproduce the observations reasonably well. The mass loss rates computed from the formula of Blocker (1995) terminate the AGB in both clusters at a luminosity which is much too low.
description: 13 pages, 11 figures, To be published in MNRAS
A spatially resolved optical method to measure thermal diffusivity
Creators: name: Sun, F.
name: Mishra, S.
name: McGuinness, P. H.
name: Filipiak, Z. H.
name: Markovic, I.
name: Sokolov, D. A.
name: Kikugawa, N.
name: Orenstein, J. W.
name: Hartnoll, S. A.
name: Mackenzie, A. P.
name: Sunko, V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Instrumentation and Detectors (physics.ins-det)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We describe an optical method to directly measure position-dependent thermal diffusivity of reflective single crystal samples across a broad range of temperatures for condensed matter physics research. Two laser beams are used, one as a source to locally modulate the sample temperature, and the other as a probe of sample reflectivity, which is a function of the modulated temperature. Thermal diffusivity is obtained from the phase delay between source and probe signals. We combine this technique with a microscope setup in an optical cryostat, in which the sample is placed on a 3-axis piezo-stage, allowing for spatially resolved measurements. Furthermore, we demonstrate experimentally and mathematically that isotropic in-plane diffusivity can be obtained when overlapping the two laser beams instead of separating them in the traditional way, which further enhances the spatial resolution to a micron scale, especially valuable when studying inhomogeneous or multidomain samples. We discuss in detail the experimental conditions under which this technique is valuable, and demonstrate its performance on two stoichiometric bilayer ruthenates: Sr3Ru2O7 and Ca3Ru2O7. The spatial resolution allowed us to study the diffusivity in single domains of the latter, and we uncovered a temperature-dependent in-plane diffusivity anisotropy. Finally, we used the enhanced spatial resolution enabled by overlapping the two beams to measure temperature-dependent diffusivity of Ti-doped Ca3Ru2O7, which exhibits a metal-insulator transition. We observed large variations of transition temperature over the same sample, originating from doping inhomogeneity, and pointing to the power of spatially resolved techniques in accessing inherent properties.
description: 30 pages, 5 figures in the main text, and 5 figures in Appendix
Re-engaging with reading material after a mind wandering episode
Creators: name: Varao Sousa, Patricia
Publisher: name: University of British Columbia
Year: 2015

description: Despite active growth in the field of mind wandering over the past decade, there is currently a lack of understanding of what happens when mind wandering ends and individuals’ focus returns to their original task. The present thesis proposes and explores the idea that following a mind wandering occurrence during a reading task, individuals will re-engage with the text by re-reading. In Experiment 1 participants were asked to indicate where in the passage they mind wandered and note any re-reading that occurred. Experiment 2 extended this investigation to address whether re-reading as a compensatory behaviour extends to non-plot based texts, if it differs as a function of mind wandering methodology (self-caught versus probe-caught) and explored the subjective decision to complete re-engagement behaviours. Results from both studies revealed that participants re-read following mind wandering occurrences, with rates up to 45%. Furthermore, participants typically re-read 1-2 lines of text, or less, and were equally likely to re-read following probe-caught and self-caught reports of mind wandering. Experiment 2 also established that individuals were most likely to engage in compensatory acts when they felt that further clarification was needed. This thesis provides a framework that could extend to other settings, both those that easily allow for re-engagement via reviewing missed information (e.g., listening to an audiobook) and those that do not (e.g., attending live lectures, driving). Understanding how individuals re-engage in various settings where mind wandering is likely to occur can provide insight into the fluctuation of attentional focus and the immediate impact of a mind wandering episode.
Entanglement spectrum and boundary theories with projected entangled-pair states
Creators: name: Cirac, J. Ignacio
name: Poilblanc, Didier
name: Schuch, Norbert
name: Verstraete, Frank
Publisher: name: arXiv
Year: 2011
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In many physical scenarios, close relations between the bulk properties of quantum systems and theories associated to their boundaries have been observed. In this work, we provide an exact duality mapping between the bulk of a quantum spin system and its boundary using Projected Entangled Pair States (PEPS). This duality associates to every region a Hamiltonian on its boundary, in such a way that the entanglement spectrum of the bulk corresponds to the excitation spectrum of the boundary Hamiltonian. We study various specific models, like a deformed AKLT [1], an Ising-type [2], and Kitaev's toric code [3], both in finite ladders and infinite square lattices. In the latter case, some of those models display quantum phase transitions. We find that a gapped bulk phase with local order corresponds to a boundary Hamiltonian with local interactions, whereas critical behavior in the bulk is reflected on a diverging interaction length of the boundary Hamiltonian. Furthermore, topologically ordered states yield non-local Hamiltonians. As our duality also associates a boundary operator to any operator in the bulk, it in fact provides a full holographic framework for the study of quantum many-body systems via their boundary.
description: 13 pages, 14 figures
WGC and WCCC of black holes with quintessence and cloud strings in RPS space
Creators: name: Alipour, Mohammad Reza
name: Sadeghi, Jafar
name: Shokri, Mehdi
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we first introduce the Riesner-Nordstrom AdS (RN-AdS) black hole in presence of quintessence and cloud of strings. And then we use the Restrict Phase Space $(RPS)$ formalism in the corresponding black holes at the critical point with equation state $ω_q =-\frac{1}{3},-\frac{2}{3},-1 $. We take advantage from the central charge and Newton's constant with form of variable and prove the compatibility between weak gravity conjecture (WGC) and weak cosmic censorship conjecture (WCCC). Here, we show that when we use the usual RN-AdS black hole with $\frac{Q}{M}>\sqrt{G}$ condition, we have weak gravity conjecture. But, in that case, the WCCC is violated by WGC conjecture. In order to avoid such violation, we consider the Riesner-Nordstrom AdS (RN-AdS) black hole in the presence of quintessence, quintessence, and cloud strings. Here, also one can say that, by using the special central charge, chemical potential, appropriate quintessence, cloud strings parameters, and the effective Newton's constant with suitable conditions one can arrive the compatibility between weak gravity conjecture and weak cosmic censorship conjecture.
description: to appear in Nucl. Phys. B
Untersuchungen zur Tränenfilmaufrisscharakteristik unter dem Einfluss eines benzalkoniumhaltigen Lokalanästhetikums
Creators: name: Förstner, Ellen Alexandra
Publisher: name: Universität Rostock
Year: 2019
Subjects: subject: 610 Medical sciences Medicine

description: Die Tränenfilmstabilität kann über die Tränenfilmaufrisszeit (BUT) gemessen werden. Insbesondere beeinflussen in Augentropfen enthaltene Konservierungsmittel die BUT. In dieser Arbeit wurde die BUT, unter Fluoresceineinbringung mit der Spaltlampe (FBUT) und mit dem Oculus® Keratograph 5M (NIKBUT), ermittelt, um den Einfluss von Konservierungsmitteln am Beispiel von Benzalkoniumchlorid in Bezug auf die Destabilisierung und die Dynamik des Tränenfilms zu untersuchen. Gleichzeitig wurde die Eignung des Oculus® Keratograph 5M für die Bestimmung der NIKBUT untersucht.
title: How to Design Games that Promote Racial Equity
Creators: name: Fan, Lai-Tze
name: Gray, Kishonna
name: Kadir, Aynur
Publisher: name: Electronic Book Review
Year: 2021

description: In this conversation and accompanying "How to Not" guide, Drs. Lai-Tze Fan, Kishonna Gray, and Aynur Kadir consider responsible theories and methods towards racial equity, racial justice, and anti-racism in game design. Their main focus is on how games can provide a platform for helping people understand and learn about these issues.
A truthful incentive mechanism for mobile crowdsourcing
Creators: name: Song, Boya
Publisher: name: University of British Columbia
Year: 2015

description: In a mobile crowdsourcing system, the platform utilizes ubiquitous smartphones to perform sensing tasks. For a successful mobile crowdsourcing application, the consideration of the heterogeneity of quality of sensing from different users as well as proper incentive mechanism to motivate users to contribute to the system are essential. In this thesis, we introduce quality of sensing into incentive mechanism design. Under a budget constraint, the platform aims to maximize the valuation of the performed tasks, which depends on the quality of sensing of the users. We propose ABSee, an auction-based budget feasible mechanism, which consists of a winning bid selection rule and a payment determination rule. We obtain the approximation ratio of ABSee, which significantly improves the approximation ratio of existing budget feasible mechanisms. ABSee also satisfies the properties of computational efficiency, truthfulness, individual rationality, and budget feasibility. Extensive simulation results show that ABSee provides a higher valuation to the platform when compared with an existing mechanism in the literature.
Optical/X-ray/radio view of Abell 1213: A galaxy cluster with anomalous diffuse radio emission
Creators: name: Boschin, W.
name: Girardi, M.
name: De Grandi, S.
name: Riva, G.
name: Feretti, L.
name: Giovannini, G.
name: Govoni, F.
name: Vacca, V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Context. Abell 1213, a low-richness galaxy system, is known to host an anomalous radio halo detected in data of the VLA. It is an outlier with regard to the relation between the radio halo power and the X-ray luminosity of the parent clusters. Aims. Our aim is to analyze the cluster in the optical, X-ray, and radio bands to characterize the environment of its diffuse radio emission and to shed new light on its nature. Methods. We used optical data from the SDSS to study the internal dynamics of the cluster. We also analyzed archival XMM-Newton X-ray data to unveil the properties of its hot intracluster medium. Finally, we used recent data from LOFAR at 144 MHz, together with VLA data at 1.4 GHz, to study the spectral behavior of the diffuse radio source. Results. Both our optical and X-ray analysis reveal that this low-mass cluster exhibits disturbed dynamics. In fact, it is composed of several galaxy groups in the peripheral regions and, in particular, in the core, where we find evidence of substructures oriented in the NE-SW direction, with hints of a merger nearly along the line of sight. The analysis of the X-ray emission adds further evidence that the cluster is in an unrelaxed dynamical state. At radio wavelengths, the LOFAR data show that the diffuse emission is ~510 kpc in size. Moreover, there are hints of low-surface-brightness emission permeating the cluster center. Conclusions. The environment of the diffuse radio emission is not what we would expect for a classical halo. The spectral index map of the radio source is compatible with a relic interpretation, possibly due to a merger in the N-S or NE-SW directions, in agreement with the substructures detected through the optical analysis. The fragmented, diffuse radio emissions at the cluster center could be attributed to the surface brightness peaks of a faint central radio halo.
description: 14 pages, 16 figures, 5 tables. In press on Astronomy & Astrophysics. Paper resubmitted after revision by the language editor
Nombres, Indeterminación y Sentido en un ejemplo de la mecánica cuántica
Creators: name: Dib, Eduardo Daniel
Publisher: name: Zenodo
Year: 2019
Subjects: Semantics
Philosophy of science

description: Student monography written for a seminar on Semantics many years ago. Recovered from an old copy which regrettably lacks bibliography. It deals with the problem that arises when you try to specify the meaning of certain scientific terms in spite of their inherent ambiguity
Metallicities, Age--Metallicity relationships, and Kinematics of Red Giant Branch Stars in the Outer Disk of the Large Magellanic Cloud
Creators: name: Carrera, R.
name: Gallart, C.
name: Aparicio, A.
name: Hardy, E.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The outer disk of the LMC is studied in order to unveil clues about its formation and evolution. Complementing our previous studies in innermost fields (3
description: 50 pages, 12 figures, accepted for publication in AJ
Solving Schrodinger equations using physically constrained neural network
Creators: name: Pu, Kai-Fang
name: Li, Hanlin
name: Lu, Hong-Liang
name: Pang, Long-Gang
Publisher: name: arXiv
Year: 2023
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Deep neural network (DNN) and auto differentiation have been widely used in computational physics to solve variational problems. When DNN is used to represent the wave function to solve quantum many-body problems using variational optimization, various physical constraints have to be injected into the neural network by construction, to increase the data and learning efficiency. We build the unitary constraint to the variational wave function using a monotonic neural network to represent the Cumulative Distribution Function (CDF) $F(x) = \int_{-\infty}^{x} ψ^*ψdx'$. Using this constrained neural network to represent the variational wave function, we solve Schrodinger equations using auto-differentiation and stochastic gradient descent (SGD), by minimizing the violation of the trial wave function $ψ(x)$ to the Schrodinger equation. For several classical problems in quantum mechanics, we obtain their ground state wave function and energy with very low errors. The method developed in the present paper may pave a new way in solving nuclear many body problems in the future.
Dispersive analysis of excited glueball states
Creators: name: Li, Hsiang-nan
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Motivated by the determination for the spin-parity quantum numbers of the $X(2370)$ meson at BESIII, we extend our dispersive analysis on hadronic ground states to excited states. The idea is to start with the dispersion relation which a correlation function obeys, and subtract the known ground-state contribution from the involved spectral density. Solving the resultant dispersion relation as an inverse problem with available operator-product-expansion inputs, we extract excited-state masses from the subtracted spectral density. This formalism is verified by means of the application to the series of $ρ$ resonances, which establishes the $ρ(770)$, $ρ(1450)$ and $ρ(1700)$ mesons one by one under the sequential subtraction procedure. Our previous study has suggested the admixture of the $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ mesons (the $η(1760)$ meson) to be the lightest scalar (pseudoscalar) glueball. The present work predicts that the $f_0(2200)$ ($X(2370)$) meson is the first excited scalar (pseudoscalar) glueball.
description: 16 pages, 5 figures, journal version
An Improved Pair Method to Probe the Dust Extinction Law
Creators: name: Wang, Yuxi
name: Gao, Jian
name: Ren, Yi
name: Li, Jun
Publisher: name: arXiv
Year: 2023
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Dust extinction law is crucial to recover the intrinsic energy distribution of celestial objects and infer the characteristics of interstellar dust. Based on the traditional pair method, an improved pair method is proposed to model the dust extinguished spectral energy distribution (SED) of an individual star. Instead of the mathematically parameterizing extinction curves, the extinction curves in this work are directly from the silicate-graphite dust model, so that the dust extinction law can be obtained and the dust properties can be analyzed simultaneously. The ATLAS9 stellar model atmosphere is adopted for the intrinsic SEDs in this work, while the silicate-graphite dust model with a dust size distribution of $dn/da \sim a^{-α}{\rm exp}(-a/a_c),~0.005 < a < 5~μ{\rm m}$ for each component is adopted for the model extinction curves. One typical extinction tracer in the dense region (V410 Anon9) and one in the diffuse region (Cyg OB2 \#12) of the MW are chosen to test the reliability and the practicability of the improved pair method in different stellar environments. The results are consistent with their interstellar environments and are in agreement with the previous observations and studies, which prove that the improved pair method is effective and applicable in different stellar environments. In addition to the reliable extinction results, the derived parameters in the dust model can be used to analyze the dust properties, which cannot be achieved by other methods with the mathematical extinction models. With the improved pair method, the stellar parameters can also be inferred and the extinction law beyond the wavelengths of observed data can be predicted based on the dust model as well.
Phase transitions : applications to physics beyond the Standard Model
Creators: name: Blinov, Nikita
Publisher: name: University of British Columbia
Year: 2015

description: Despite their phenomenological successes, the Standard Models (SMs) of particle physics and cosmology remain incomplete. Several theoretical and observational problems cannot be explained within this framework, including the hierarchy problem, dark matter (DM), and the baryon asymmetry of the Universe. The objective of this thesis is to investigate phenomenological and theoretical aspects of the solutions to these issues. We consider two kinds of phase transitions that can occur in the early or late Universe in extensions of the SM, that can be either responsible for dark matter and/or baryon asymmetry production or may be used to constrain possible models of new physics. In the first part we analyze string theory-inspired models where the Universe transitions from matter- to radiation-dominated evolution just before Big Bang Nucleosynthesis through out-of-equilibrium decays of a scalar modulus field. We employ these decays to produce DM and for baryogenesis. We study the phenomenology of these scenarios and its implications for high-scale physics. The second part of this thesis is dedicated to thermodynamic and quantum phase transitions in the early and late Universe, respectively. In the former case, we investigate the dynamics of the electroweak phase transition when the electroweak symmetry is broken down to electromagnetism in the Inert Doublet Model, a simple extension of the SM that can account for DM. Such transitions can generate the baryon asymmetry in a process called electroweak baryogenesis. Some extensions of the SM also predict similar transitions through quantum tunneling that break the colour and electromagnetic symmetries, indicating that our ground state is unstable. We use these arguments to put new constraints on the Minimal Supersymmetric Standard Model.
The subword complexity of smooth words on 2-letter alphabets
Creators: name: Huang, Yun Bao
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: Let $γ_{a,b}(n)$ be the number of smooth words of length $n$ over the alphabet $\{a,b\}$ with $a
description: 20 Pages
The Black Hole Candidate Swift J1728.9$-$3613 and the Supernova Remnant G351.9$-$0.9
Creators: name: Balakrishnan, Mayura
name: Draghis, Paul A.
name: Miller, Jon M.
name: Bright, Joe
name: Fender, Robert
name: Ng, Mason
name: Cackett, Edward
name: Fabian, Andrew
name: Kuntz, Kip
name: Miller-Jones, James C. A.
name: Proga, Daniel
name: Ray, Paul S.
name: Raymond, John
name: Reynolds, Mark
name: Zoghbi, Abderahmen
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: A number of neutron stars have been observed within the remnants of the core-collapse supernova explosions that created them. In contrast, black holes are not yet clearly associated with supernova remnants. Indeed, some observations suggest that black holes are ``born in the dark'', i.e. without a supernova explosion. Herein, we present a multi-wavelength analysis of the X-ray transient Swift J1728.9$-$3613, based on observations made with Chandra, ESO-VISTA, MeerKAT, NICER, NuSTAR, Swift, and XMM-Newton. Three independent diagnostics indicate that the system likely harbors a black hole primary. Infrared imaging signals a massive companion star that is broadly consistent with an A or B spectral type. Most importantly, the X-ray binary lies within the central region of the catalogued supernova remnant G351.9$-$0.9. Our deep MeerKAT image at 1.28~GHz signals that the remnant is in the Sedov phase; this fact and the non-detection of the soft X-ray emission expected from such a remnant argue that it lies at a distance that could coincide with the black hole. Utilizing a formal measurement of the distance to Swift J1728.9$-$3613 ($d = 8.4\pm 0.8$ kpc), a lower limit on the distance to G351.9$-$0.9 ($d \geq 7.5$ kpc), and the number and distribution of black holes and supernova remnants within the Milky Way, extensive simulations suggest that the probability of a chance superposition is $<1.7\%$ ($99.7\%$ credible interval). The discovery of a black hole within a supernova remnant would support numerical simulations that produce black holes and remnants, and thus provide clear observational evidence of distinct black hole formation channels. We discuss the robustness of our analysis and some challenges to this interpretation.
description: 25 pages, 10 figures, accepted for publication to ApJ
title: River: Forking Paths, Monsters, Simultaneous Timelines and Continuity over 25 Years of Creative Practice
Creators: name: Fisher, Caitlin
Publisher: name: Electronic Book Review
Year: 2021

description: In this essay, Caitlin Fisher reflects on the ideas, processes, and approaches that have shaped and influenced her work in digital storytelling and electronic literature for over 25 years. She invokes theorists like Borges, Haraway, and Aristotle and critical concepts of hybridity, string theory, hypermedia, and spatial narratives to illuminate readers about the simultaneous timelines, continuity, and forking paths that run through the river of her work.
The impact of endogenous acetylation on the deconstruction of Populus trichocarpa wood during pretreatment
Creators: name: Johnson, Amanda M.
Publisher: name: University of British Columbia
Year: 2015

description: Wood is a renewable, sustainable and economic resource. Non-cellulosic wood polysaccharides are acetylated in a species-dependent and spatially-regulated manner. Acetyl groups comprise approximately 5% of the dry weight of poplar wood. Biologically, acetyl groups increase xylan chain solubility and may therefore influence secondary cell wall formation by affecting the association of hemicelluloses with the other cell wall components, such as cellulose, lignin, and the pectic and proteinaceous constituents of the adjacent primary cell wall. In this research, we found that acetyl content correlated positively with lignin (R = 0.28) and negatively with cellulose (R = -0.41) in wood samples from a common garden of over 200 unrelated Populus trichocarpa individuals. During the pretreatment of biomass, acetyl groups are hydrolyzed from wood to form free acetic acid in the reaction media. The present research examined the relationships between wood composition and pretreatment sugar yield of 19 P. trichocarpa genotypes with varying levels of acetylation. The results clearly show a strong correlation (R > 0.77) between acetic acid and polysaccharide dissolution. Fast-reacting xylan had a degree of acetylation of 0.35, while slow-reacting xylan had a degree of acetylation of 0.73. Hydrophobic interactions could explain the negative correlation between lignin content and acetic acid released (R = -0.59). This research highlights the impact acetylation may have on the large-scale industrial utility of plants.
Cooperative beamforming for cognitive radio systems in presence of asynchronous interference
Creators: name: Hassan, Mai Mohamed
Publisher: name: University of British Columbia
Year: 2015

description: Cognitive radio (CR) is considered a key enabling technology to exploit the underutilized and non-utilized radio spectrum bands. On the other hand, cooperative communication among nodes in CR networks, can improve the overall performance of CR systems, in terms of increasing data rates, attainable coverage range and overall energy efficiency, providing some diversity against shadow fading, and having low deployment costs. In a CR network, cooperative transmit beamforming can be achieved via a number of single antenna-based CR nodes organizing themselves in a virtual antenna array and focusing their transmission in the direction of intended CR receiver. However, deploying the beamforming in such a cooperative manner faces several implementation challenges. Therefore, in this thesis, we tackle some of these critical challenges facing the design and implementation of cooperative CR networks. The first challenge is referred to as asynchronous interference, that results from asynchronous arrival of the same signal from the set of cooperating CR nodes at primary receivers. Next, we address the problem of feedback overhead needed for cooperative beamforming. Specifically, each cooperating CR node requires knowing global information including other nodes' locations, in addition to accurate and instantaneous knowledge of their channel state information (CSI). We also tackle the problem of imperfect CSI estimation. Another important aspect of implementing cooperative CR networks is studied in this thesis, which is described as follows. Since the cooperating nodes can be located in different locations, they contribute differently to received signals at the CR receivers, as well as to interference signals at the primary receivers. Therefore, we propose different cooperating CR node selection strategies, to be applied in conjunction with cooperative beamforming. Finally, we study different participation decision making strategies that enable each CR user to independently decide whether to participate in the cooperative transmission or not, based on an offered incentive for cooperation and estimated cost of participation in cooperative transmission represented in transmit power. At the end of each chapter, we present some numerical examples to show the implications of ignoring different implementation challenges in the design of cooperative CR networks, and to assess the performance of the proposed solutions.
On the magnetic field through the Upper Centaurs-Lupus Super bubble, in the vicinity of the Southern Coalsack
Creators: name: Bhat, N. D. Ramesh
name: Andersson, B-G
Publisher: name: arXiv
Year: 2010
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Southern Coalsack is located in the interior of the Upper Centaurus-Lupus (UCL) super bubble and shows many traits that point to a much more energetic environment than might be expected from a dark, starless molecular cloud. A hot, X-ray emitting, envelope surrounds the cloud, it has a very strong internal magnetic field and its darkest core seems to be on astronomical time scales "just about" to start forming stars. In order to probe the magnetic environment of the cloud and to compare with the optical/near infrared polarimetry-based field estimates for the cloud, we have acquired Faraday Rotation measurements towards the pulsar PSR J1210$-$6550, probing the magnetic field in the vicinity of the cloud, and a comparison target, PSR J1435$-$5954, at a similar line of sight distance but several degrees from the cloud. Both lines of sight hence primarily probe the UCL super bubble. The earlier estimates of the magnetic field inside the Coalsack, using the Chandrasekhar-Fermi method on optical and near-infrared polarimetry, yield B$_\perp$ = 64--93 $μ$G. However, even though PSR J1210$-$6550 is located only $\sim$30 arc minutes from the (CO) edge of the cloud, the measured field strength is only B$_\parallel$ = 1.1$\pm$0.2 $μ$G. While thus yielding a very high field contrast to the cloud we argue that this might be understood as due to the effects on the cloud by the super bubble.
description: 8 pages, 6 figures, Accepted for publication in ApJ
The Spin of a Newborn Black Hole: Swift J1728.9-3613
Creators: name: Draghis, Paul A.
name: Balakrishnan, Mayura
name: Miller, Jon M.
name: Cackett, Edward
name: Fabian, Andrew C.
name: Miller-Jones, James C. A.
name: Ng, Mason
name: Raymond, John C.
name: Reynolds, Mark
name: Zoghbi, Abderahmen
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The origin and distribution of stellar-mass black hole spins are a rare window into the progenitor stars and supernova events that create them. Swift J1728.9-3613 is an X-ray binary, likely associated with the supernova remnant G351.9-0.9 (Balakrishnan et al. 2023). A NuSTAR X-ray spectrum of this source during its 2019 outburst reveals reflection from an accretion disk extending to the innermost stable circular orbit. Modeling of the relativistic Doppler shifts and gravitational redshifts imprinted on the spectrum measures a dimensionless spin parameter of $a=0.86\pm0.02$ ($1σ$ confidence), a small inclination angle of the inner accretion disk $θ<10$ degrees, and a sub-solar iron abundance in the disk $A_{\rm Fe}<0.84$. This high spin value rules out a neutron star primary at the $5\;σ$ level of confidence. If the black hole is located in a still visible supernova remnant, it must be young. Therefore, we place a lower limit on the natal black hole spin of $a>0.82$, concluding that the black hole must have formed with a high spin. This demonstrates that black hole formation channels that leave a supernova remnant, and those that do not (e.g. Cyg X-1), can both lead to high natal spin with no requirement for subsequent accretion within the binary system. Emerging disparities between the population of high-spin black holes in X-ray binaries and the low-spin black holes that merge in gravitational wave events may therefore be explained in terms of different stellar conditions prior to collapse, rather than different environmental factors after formation.
description: 11 pages, 3 appendices, 10 figures. Accepted for publication in ApJ