cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Minimal models of field theories: Chiral Higher Spin Gravity
Creators: name: Skvortsov, Evgeny
name: Van Dongen, Richard
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: There exists a unique class of local Higher Spin Gravities with propagating massless fields in $4d$ - Chiral Higher Spin Gravity. Originally, it was formulated in the light-cone gauge. We construct a covariant form of this theory as a Free Differential Algebra up to NLO, i.e. at the level of equations of motion. It also contains the recently discovered covariant forms of the higher spin extensions of SDYM and SDGR, as well as SDYM and SDGR themselves. From the mathematical viewpoint the result is equivalent to taking the minimal model (in the sense of $L_\infty$-algebras) of the jet-space extension of the BV-BRST formulation of Chiral Higher Spin Gravity, thereby, containing also information about (presymplectic AKSZ) action, counterterms, anomalies, etc.
description: 21 + Appendices + Refs = 34 pages; some typos fixed and comments added
Velocity Dispersion of Correlated Energy Spread Electron Beams in the Free Electron Laser
Creators: name: Campbell, L. T.
name: Maier, A. R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: The effects of a correlated linear energy/velocity chirp in the electron beam in the FEL, and how to compensate for its effects by using an appropriate taper (or reverse-taper) of the undulator magnetic field, is well known. The theory, as described thus far, ignores velocity dispersion from the chirp in the undulator, taking the limit of a `small' chirp. In the following, the physics of compensating for chirp in the beam is revisited, including the effects of velocity dispersion, or beam compression or decompression, in the undulator. It is found that the limit of negligible velocity dispersion in the undulator is different from that previously identified as the small chirp limit, and is more significant than previously considered. The velocity dispersion requires a taper which is non-linear to properly compensate for the effects of the detuning, and also results in a varying peak current (end thus a varying gain length) over the length of the undulator. The results may be especially significant for plasma driven FELs and low energy linac driven FEL test facilities.
Informed Consent? A Study of "Consent Dialogs" on Android and iOS
Creators: name: Altpeter, Benjamin
Publisher: name: Zenodo
Year: 2022
Subjects: android
ios
gdpr
eprivacy directive
mobile privacy
data protection
consent dialogs

description: Consent dialogs have become ubiquitous with seemingly every website and app pleading users to agree to their personal data being processed and their behaviour being tracked, often with the help of tens or even hundreds of third-party companies. They are an effort by website and app publishers to comply with data protection legislation like the GDPR, which imposes strict limits on how companies can process data. Previous research has established that companies often apply dark patterns to illegally nudge users into agreeing and that at the same time tracking is more common than ever with both websites and apps regularly automatically transmitting telemetry data. But so far, there has been almost no research into consent dialogs on mobile. In this thesis, we study consent dialogs on Android and iOS in an automated and dynamic manner, analysing 4,388 popular apps from both platforms. We identify different types of consent elements in the apps and analyse their prevalence. We also identify dark patterns and violations by the apps based on a list of criteria for a legally compliant consent dialog that we have compiled. Finally, we measure the effect of the user's choice in the consent dialog by comparing the traffic from before any interaction with the traffic after accepting and rejecting the dialog and analysing contacted trackers and transmitted data types.
 The results show that more than 90 % of consent dialogs implement at least one dark pattern and that a majority of apps transmits tracking data regardless of consent status.
Comparing Bayes factors and hierarchical inference for testing general relativity with gravitational waves
Creators: name: Isi, Maximiliano
name: Farr, Will M.
name: Chatziioannou, Katerina
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In the context of testing general relativity with gravitational waves, constraints obtained with multiple events are typically combined either through a hierarchical formalism or though a combined multiplicative Bayes factor. We show that the well-known dependence of Bayes factors on the analysis priors in regions of the parameter space without likelihood support can lead to strong confidence in favor of incorrect conclusions when one employs the multiplicative Bayes factor. Bayes factors $\mathcal{O}(1)$ are ambivalent as they depend sensitively on the analysis priors, which are rarely set in a principled way; additionally, combined Bayes factors $>\mathcal{O}(10^3)$ can be obtained in favor of the incorrect conclusion depending on the analysis priors when many $\mathcal{O}(1)$ Bayes factors are multiplied, and specifically when the priors are much wider than the underlying population. The hierarchical analysis that instead infers the ensemble distribution of the individual beyond-general-relativity constraints does not suffer from this problem, and generically converges to favor the correct conclusion. Rather than a naive multiplication, a more reliable Bayes factor can be computed from the hierarchical analysis. We present a number of toy models showing that the practice of multiplying Bayes Factors can lead to incorrect conclusions.
Viscosity in a Lepton-Photon Universe
Creators: name: Husdal, Lars
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We look at viscosity production in a universe consisting purely of leptons and photons. This is quite close to what the Universe actually look like when the temperature was between $10^{10}$ K and $10^{12}$ K ($1$ -- $100$ MeV). By taking the strong force and the hadronic particles out of the equation, we can examine how the viscous forces behave with all the 12 leptons present. By this we study how shear- and (more interestingly) bulk viscosity is affected during periods with particle annihilation. We use the theory given by Hoogeveen et. al. from 1986, replicate their 9-particle results and expanded it to include the muon and tau particles as well. This will impact the bulk viscosity immensely for high temperatures. We will show that during the beginning of the lepton era, when the temperature is around 100 MeV, the bulk viscosity will be roughly 100 million times larger with muons included in the model compared to a model without.
description: 14 pages, 10 figures + 2 tables in pdf format (= 12 figures)
Optical trapping of high-aspect-ratio NaYF hexagonal prisms for kHz-MHz gravitational wave detectors
Creators: name: Winstone, George
name: Wang, Zhiyuan
name: Klomp, Shelby
name: Felsted, Greg
name: Laeuger, Andrew
name: Grass, Daniel
name: Aggarwal, Nancy
name: Sprague, Jacob
name: Pauzauskie, Peter J.
name: Larson, Shane L.
name: Kalogera, Vicky
name: Geraci, Andrew A.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: We present experimental results on optical trapping of Yb-doped $β-$NaYF sub-wavelength-thickness high-aspect-ratio hexagonal prisms with a micron-scale radius. The prisms are trapped in vacuum using an optical standing wave, oriented with the normal vector to their face along the beam propagation direction, and exhibit characteristic modes of three translational and two torsional degrees of freedom. The measured motional spectra are compared with numerical simulations. This plate-like geometry simultaneously enables trapping with low photon-recoil-heating, high mass, and high trap frequency, potentially leading to advances in high frequency gravitational wave searches in the Levitated Sensor Detector (LSD), currently under construction. The material used here has previously been shown to exhibit internal cooling via laser refrigeration when optically trapped and illuminated with light of suitable wavelength. Employing such laser refrigeration methods in the context of our work may enable higher trapping intensity thus and higher trap frequencies for gravitational wave searches approaching the several hundred kHz range.
description: Title and Fig. 1 updated, minor changes, prepared for journal submission
Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime
Creators: name: Reymbaut, A.
name: Charlebois, M.
name: Asiani, M. Fellous
name: Fratino, L.
name: Sémon, P.
name: Sordi, G.
name: Tremblay, A. -M. S.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The nearest-neighbor superexchange-mediated mechanism for d_{x^2-y^2}-wave superconductivity in the one-band Hubbard model faces the challenge that nearest-neighbor Coulomb repulsion can be larger than superexchange. To answer this question, we use cellular dynamical mean-field theory (CDMFT) with a continuous-time quantum Monte Carlo solver to determine the superconducting phase diagram as a function of temperature and doping for on-site repulsion $U=9t$ and nearest-neighbor repulsion $V=0,2t,4t$. In the underdoped regime, $V$ increases the CDMFT superconducting transition temperature $T_c^d$ even though it decreases the superconducting order parameter at low temperature for all dopings. However, $V$ decreases $T_c^d$ in the overdoped regime. We gain insight into these paradoxical results through a detailed study of the frequency dependence of the anomalous spectral function, extracted at finite temperature via the MaxEntAux method for analytic continuation. A systematic study of dynamical positive and negative contributions to pairing reveals that even though $V$ has a high-frequency depairing contribution, it also has a low frequency pairing contribution since it can reinforce superexchange through $J=4t^2/(U-V)$. Retardation is thus crucial to understand pairing in doped Mott insulators, as suggested by previous zero-temperature studies. We also comment on the tendency to charge order for large $V$ and on the persistence of d-wave superconductivity over extended-$s$ or s+d-wave.
description: Latex, 16 pages, 8 figures
Synthesis of clonidine analogues for potassium channel blocking activity
Creators: name: Hay, Theresa K. C.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Surface reconstruction using digital photogrammetric techniques based on machine vision theory
Creators: name: Schwarze, Phillip John.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Using Dynamic Allocation of Write Voltage to Extend Flash Memory Lifetime
Creators: name: Wang, Haobo
name: Wong, Nathan
name: Chen, Tsung-Yi
name: Wesel, Richard D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: The read channel of a Flash memory cell degrades after repetitive program and erase (P/E) operations. This degradation is often modeled as a function of the number of P/E cycles. In contrast, this paper models the degradation as a function of the cumulative effect of the charge written and erased from the cell. Based on this modeling approach, this paper dynamically allocates voltage using lower-voltage write thresholds at the beginning of the device lifetime and increasing the thresholds as needed to maintain the mutual information of the read channel in the face of degradation. The paper introduces the technique in an idealized setting and then removes ideal assumptions about channel knowledge and available voltage resolution to conclude with a practical scheme with performance close to that of the idealized setting.
description: 13 pages, 11 figures. Accepted by IEEE Transactions on Communications
Consistent analytic approach to the efficiency of collisional Penrose process
Creators: name: Harada, Tomohiro
name: Ogasawara, Kota
name: Miyamoto, Umpei
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We propose a consistent analytic approach to the efficiency of collisional Penrose process in the vicinity of a maximally rotating Kerr black hole. We focus on a collision with arbitrarily high center-of-mass energy, which occurs if either of the colliding particles has its angular momentum fine-tuned to the critical value to enter the horizon. We show that if the fine-tuned particle is ingoing on the collision, the upper limit of the efficiency is $(2+\sqrt{3})(2-\sqrt{2})\simeq 2.186$, while if the fine-tuned particle is bounced back before the collision, the upper limit is $(2+\sqrt{3})^{2}\simeq 13.93$. Despite earlier claims, the former can be attained for inverse Compton scattering if the fine-tuned particle is massive and starts at rest at infinity, while the latter can be attained for various particle reactions, such as inverse Compton scattering and pair annihilation, if the fine-tuned particle is either massless or highly relativistic at infinity. We discuss the difference between the present and earlier analyses.
description: 9 pages, minor correction, accepted for publication in Physical Review D
Redshift Measurement and Spectral Classification for eBOSS Galaxies with the Redmonster Software
Creators: name: Hutchinson, Timothy A.
name: Bolton, Adam S.
name: Dawson, Kyle S.
name: Prieto, Carlos Allende
name: Bailey, Stephen
name: Bautista, Julian E.
name: Brownstein, Joel R.
name: Conroy, Charlie
name: Guy, Julien
name: Myers, Adam D.
name: Newman, Jeffrey A.
name: Prakash, Abhishek
name: Carnero-Rosell, Aurelio
name: Seo, Hee-Jong
name: Vivek, M.
name: Zhu, Guangtun Ben
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We describe the redmonster automated redshift measurement and spectral classification software designed for the extended Baryon Oscillation Spectroscopic Survey (eBOSS) of the Sloan Digital Sky Survey IV (SDSS-IV). We describe the algorithms, the template standard and requirements, and the newly developed galaxy templates to be used on eBOSS spectra. We present results from testing on early data from eBOSS, where we have found a 90.5% automated redshift and spectral classification success rate for the luminous red galaxy sample (redshifts 0.6$\lesssim z \lesssim$1.0). The redmonster performance meets the eBOSS cosmology requirements for redshift classification and catastrophic failures, and represents a significant improvement over the previous pipeline. We describe the empirical processes used to determine the optimum number of additive polynomial terms in our models and an acceptable $Δχ_r^2$ threshold for declaring statistical confidence. Statistical errors on redshift measurement due to photon shot noise are assessed, and we find typical values of a few tens of km s$^{-1}$. An investigation of redshift differences in repeat observations scaled by error estimates yields a distribution with a Gaussian mean and standard deviation of $μ\sim$0.01 and $σ\sim$0.65, respectively, suggesting the reported statistical redshift uncertainties are over-estimated by $\sim$54%. We assess the effects of object magnitude, signal-to-noise ratio, fiber number, and fiber head location on the pipeline's redshift success rate. Finally, we describe directions of ongoing development.
description: 19 pages, 16 figures. Corrected typos and added minor text clarifications relative to version 1. Accepted for publication in The Astronomical Journal
Bell inequality of frequency-bin entangled photon pairs with time-resolved detection
Creators: name: Guo, Xianxin
name: Mei, Yefeng
name: Du, Shengwang
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Entanglement, describing the inseparability of a quantum multiparty system, is one of the most intriguing features of quantum mechanics. Violation of Bell inequality, for ruling out the possibility of local hidden variable theories, is commonly used as a strong witness for quantum entanglement. In previous Bell test experiments with photonic entanglement based on two-photon coincidence measurement, the photon temporal wave packets are absorbed completely by the detectors. That is, the photon coherence time is much shorter than the detection time window. Here we demonstrate generation of frequency-bin entangled narrowband biphotons, and for the first time, test the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality |S|<= 2 for their nonlocal temporal correlations with time-resolved detection. We obtain a maximum |S| value of 2.52+/-0.48 that violates the CHSH inequality. Our result will have applications in quantum information processing involving time-frequency entanglement.
The tectonic & metamorphic evolution of the high pressure schists of the Yambé-Colnett Region northeastern New Caledonia
Creators: name: Occhipinti, S. A. .
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
An affine Weyl group characterization of polynomial Heisenberg algebras
Creators: name: Morales-Salgado, V. S.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study deformations of the harmonic oscillator algebra known as polynomial Heisenberg algebras (PHAs), and establish a connection between them and extended affine Weyl groups of type $A^{(1)}_m$, where $m$ is the degree of the PHA. To establish this connection, we employ supersymmetric quantum mechanics to first connect a polynomial Heisenberg algebra to symmetric systems of differential equations. This connection has been previously used to relate quantum systems to non-linear differential equations; most notably, the fourth and fifth Painlevé equations. Once this is done, we use previous studies on the Bäcklund transformations of Painlevé equations and generalizations of their symmetric forms characterized by extended affine Weyl groups. This work contributes to better understand quantum systems and the algebraic structures characterizing them.
A theoretical investigation into steel surface emissivity
Creators: name: Bierbrauer, Frank.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Configuration interaction in symmetry-conserving covariant density functional theory
Creators: name: Zhao, P. W.
name: Ring, P.
name: Meng, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: A new method to calculate spectroscopic properties of deformed nuclei is proposed: configuration interaction on top of projected density functional theory (CI-PDFT). The general concept of this approach is discussed in the framework of covariant density functional theory and its validity is illustrated in an application to the yrast band of the nucleus Cr-54. It is found that the experimentally observed excitation energies for the yrast band in Cr-54 can be well reproduced. In contrast to conventional shell-model calculations, there is no core and only a relatively small number of configurations is sufficient for a satisfying description. No new parameters are necessary, because the effective interaction is derived from an universal density functional given in the literature.
description: 7 pages, 3 figures, 1 table
Material Suplementario
Creators: name: Espín-Sánchez, Daysi
name: Vizueta-Rubio, Carolina
name: Jaramillo-Guapisaca, Karen
name: Ramos-Aristimbay, María L.
name: Sánchez-Vaca, Andrés S.
name: Chico-Terán, Fernanda
name: Cerda-Mejía, Liliana
name: García, Mario D.
Publisher: name: Zenodo
Year: 2022

description: Material suplementario del artículo "Análisis de susceptibilidad a mutaciones que confieren resistencia a inhibidores de las enzimas proteasa principal (Mpro) y ARN polimerasa ARN-dependiente (RdRp) del SARS-CoV-2"
The influence of phonon harmonicity on spectrally pure resonant Stokes fields
Creators: name: Stoikos, Georgios
name: Granados, Eduardo
Publisher: name: arXiv
Year: 2022
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Thanks to their highly coherent emission and compact form factor, single axial mode diamond Raman lasers have been identified as a valuable asset for applications including integrated quantum technology, high resolution spectroscopy or coherent optical communications. While the fundamental emission linewidth of these lasers can be Fourier limited, their thermo-optic characteristics lead to drifts in their carrier frequency, posing important challenges for applications requiring ultra-stable emission. We propose here a method for measuring accurately the temperature-dependent index of refraction of diamond by employing standing Stokes waves produced in a monolithic Fabry-Perot (FP) diamond Raman resonator. Our approach takes into account the influence of the temperature on the first-order phonon line and the average lattice phonon frequency under intense stimulated Raman scattering (SRS) conditions. We further utilize this model to calculate the temperature-dependent thermo-optic coefficient and the Gruneisen parameter of diamond in the visible spectral range. The theory is accompanied by the demonstration of tunable Fourier-limited Stokes nanosecond pulses with a stabilized center frequency deviation of less than <4 MHz.
title: Trade mark licensing in England and Greece : a comparative approach.
Creators: name: Psarras, Alkiviadis C.
Publisher: name: University of Kent
Year: 2023

description: This is a comparative study of trade mark licensing in English and Greek law. Trade mark licensing is an activity which is fully compatible with the origin theory of trade marks. This theory is followed in both systems we examine. The understanding of the underlying theory of trade marks is necessary in order to understand the function of licensing, the conditions set by the law and the extent to which licensing is allowed. Ultimately the comparison made does not reveal considerable differences between the two legal systems. The English law seems to be rather more liberal, but in both legal systems there is room for alterations towards simplifying the procedure of licensing without endangering the ability of the trade mark to indicate a single source. Such alterations are proposed. Following the EC Directive and the White Paper, English law seems to be nearer to making such alterations. On the contrary no such sign is visible in Greek law. The two legal systems differ substantially regarding licensing of unregistered trade marks. This is due to the fact that the tort of passing off protects goodwill while in Greece the Unfair Competition Act protects the ability to indicate origin and reputation. The comparison of the different attitudes, and especially of goodwill and reputation, is necessary in order to understand the differences between the two systems and their ability to respond to new challenges such as merchandising etc. At this point no indication of harmonisation exists as no tort of unfair competition seems to be developing in England.
ATLASGAL-selected massive clumps in the inner Galaxy. X. Observations of atomic carbon at 492 GHz
Creators: name: Lee, Min-Young
name: Wyrowski, Friedrich
name: Menten, Karl
name: Tiwari, Maitraiyee
name: Guesten, Rolf
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: (Abridged) In this paper, we investigate the physical conditions of [CI]-traced gas in high-mass star-forming regions by analyzing APEX [CI] 492 GHz single-pointing observations of the ATLASGAL Top100 sources along with other multi-wavelength data. Our 98 sources are clearly detected in [CI] 492 GHz emission, and the observed integrated intensities and line widths tend to increase toward evolved stages of star formation. In addition to these "main" components that are associated with the Top100 sample, 41 emission and two absorption features are identified by their velocities toward 28 and two lines of sight respectively as "secondary" components. The secondary components have systematically smaller integrated intensities and line widths than the main components. We found that [CI] 492 GHz and 13CO(2-1) are well correlated with the 13CO(2-1)-to-[CI] 492 GHz integrated intensity ratio varying from 0.2 to 5.3. In addition, we derived the H2-to-[CI] conversion factor, X(CI), by dividing 870 micron-based H2 column densities by the observed [CI] 492 GHz integrated intensities and found that X(CI) ranges from 2.3e20 to 1.3e22 with a median of 1.7e21. In contrast to the strong correlation with 13CO(2-1), [CI] 492 GHz has a scattered relation with the 870 micron-traced molecular gas. Finally, we performed LTE and non-LTE analyses of the [CI] 492 GHz and 809 GHz data for a subset of the Top100 sample and inferred that [CI] emission likely originates from warm (kinetic temperature > 60 K), optically thin (opacity < 0.5), and highly pressurized (thermal pressure ~ e5 to e8 K/cm3) regions.
description: Accepted for publication in A&A
The calibration of radiocarbon dates
Creators: name: Chai, David K.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Regularized 3D spectroscopy with CubeFit: method and application to the Galactic Center Circumnuclear disk
Creators: name: Paumard, Thibaut
name: Ciurlo, Anna
name: Morris, Mark R.
name: Do, Tuan
name: Ghez, Andrea M.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Galactic Center black hole and the nuclear star cluster are surrounded by a clumpy ring of gas and dust (the circumnuclear disk, CND) that rotates about them at a standoff distance of ~1.5 pc. The mass and density of individual clumps in the CND are disputed. We seek to use H$_2$ to characterize the clump size distribution and to investigate the morphology and dynamics of the interface between the ionized interior layer of the CND and the molecular reservoir lying further out (corresponding to the inner rim of the CND, illuminated in ultraviolet light by the central star cluster). We have observed two fields of approximately 20"x20" in the CND at near-infrared wavelengths with the OSIRIS spectro-imager at the Keck Observatory. These two fields, located at the approaching and receding nodes of the CND, best display this interface. Our data cover two H$_2$ lines as well as the Br$γ$ line (tracing H ii). We have developed the tool CubeFit, an original method to extract maps of continuous physical parameters (such as velocity field and velocity dispersion) from integral-field spectroscopy data, using regularization to largely preserve spatial resolution in regions of low signal-to-noise ratio. This original method enables us to isolate compact, bright features in the interstellar medium of the CND. Several clumps in the southwestern field assume the appearance of filaments, many of which are parallel to each other. We conclude that these clumps cannot be self-gravitating.
description: 16 pages, 19 figures, accepted for publication in A&A
Diffusion-Weighted MR imaging: Clinical applications of kurtosis analysis to prostate cancer
Creators: name: Barucci, Andrea
name: Carpi, Roberto
name: Esposito, Marco
name: Olmastroni, Maristella
name: Zatelli, Giovanna
Publisher: name: arXiv
Year: 2016
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Magnetic resonance imaging technique known as DWI (diffusion-weighted imaging) allows measurement of water diffusivity on a pixel basis for evaluating pathology throughout the body and is now routinely incorporated into many body MRI protocols, mainly in oncology. Indeed water molecules motion reflects the interactions with other molecules, membranes, cells, and in general the interactions with the environment. Microstructural changes as e.g. cellular organization and/or integrity then affect the motion of water molecules, and consequently alter the water diffusion properties measured by DWI. Then DWI technique can be used to extract information about tissue organization at the cellular level indirectly from water motion. In general the signal intensity in DWI can be quantified by using a parameter known as ADC (Apparent Diffusion Coefficient) emphasizing that it is not the real diffusion coefficient, which is a measure of the average water molecular motion. In the simplest models, the distribu- tion of a water molecule diffusing in a certain period of time is considered to have a Gaussian form with its width proportional to the ADC. However, water in biological structures often displays non-Gaussian diffusion behavior, consequently the DWI signal shows a more complex behavior that need to be modeled following different approaches. In this work we explore the possibility to quantify the degree to which water diffusion in biologic tissues is non-Gaussian introducing the AKC parameter (Apparent Kurtosis Coefficient). In this work we have realized DWI non-Gaussian diffusion maps to be used in the clinical routine along with standard ADC maps, giving to the radiologist another tool to explore how much structure inside a voxel is organized. In particular in this work some prostate DWI examples have been analyzed and will be shown.
Eternal vs singular observers in interacting dark energy-dark matter models
Creators: name: Álvarez-Ortega, Diego
name: Olmo, Gonzalo J.
name: Rubiera-García, Diego
name: Gómez, Diego Sáez-Chillón
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Interacting dark energy-dark matter models have been widely analyzed in the literature in an attempt to find traces of new physics beyond the usual cosmological ($Λ$CDM) models. Such a coupling between both dark components is usually introduced in a phenomenological way through a flux in the continuity equation. However, models with a Lagrangian formulation are also possible. A class of the latter assumes a conformal/disformal coupling that leads to a fifth force on the dark matter component, which consequently does not follow the same geodesics as the other (baryonic, radiation, and dark energy) matter sources. Here we analyze how the usual cosmological singularities of the standard matter frame are seen from the dark matter one, concluding that by choosing an appropriate coupling, dark matter observers will see no singularities but a non-beginning, non-ending universe. By considering two simple phenomenological models we show that such a type of coupling can fit observational data as well as the usual $Λ$CDM model.
description: 14 pages, 3 figures
Ultrafast Magnetization Reversal by Picosecond Electrical Pulses
Creators: name: Yang, Yang
name: Wilson, R. B.
name: Gorchon, Jon
name: Lambert, Charles-Henri
name: Salahuddin, Sayeef
name: Bokor, Jeffrey
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The field of spintronics involves the study of both spin and charge transport in solid state devices with a view toward increasing their functionality and efficiency. Alternatively, the field of ultrafast magnetism focuses on the use of femtosecond laser pulses to excite electrons in magnetic materials, which allows the magnetic order to be dramatically changed on unprecedented sub-picosecond time-scales. Here, we unite these two distinct research activities by using picosecond electrical pulses to rapidly excite electrons in a magnetic metal. We are able to deterministically and repetitively reverse the magnetization of a GdFeCo film with sub-10 picosecond electrical pulses. The magnetization reverses in ~10ps, which is more than an order of magnitude faster than any other electrically controlled magnetic switching. We attribute the deterministic switching of the magnetization to ultrafast excitation of the electrons, a fundamentally different mechanism from other current driven switching mechanisms such as spin-transfer-torque (STT) or spin-orbit-torque (SOT). The energy density required for switching is measured and the process is found to be efficient, projecting to only 4 fJ needed to switch a (20 nm)^3 cell, which is comparable to other state-of-the-art STT-MRAM memory devices. This discovery will launch a new field of research into picosecond spintronic phenomena and devices.
Gravitational production of dark photon dark matter with mass generated by the Higgs mechanism
Creators: name: Sato, Takanori
name: Takahashi, Fuminobu
name: Yamada, Masaki
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the gravitational production of dark photon dark matter during inflation, when dark photons acquire mass by the Higgs mechanism. In the previous study, it was assumed that the dark photon has a Stückelberg mass, or a mass generated by the Higgs mechanism with a sufficiently heavy Higgs boson. In this paper we consider a case in which the Higgs boson is not fully decoupled; the Higgs field changes its vacuum expectation value after inflation. Then, the dark photon mass also changes with time after inflation, and the time evolution of the longitudinal mode is different from the case with a Stückelberg mass. Consequently, the spectrum of the dark photon energy density can have two peaks at an intermediate scale and a small scale. We show that the dark photon can explain the dark matter if its current mass is larger than $6 \, μ{\rm eV} \times (H_I / 10^{14} \, {\rm GeV})^{-4}$ and smaller than $0.8 \, {\rm GeV} \times (H_I / 10^{14} \, {\rm GeV})^{-3/2}$, with $H_I$ being the Hubble parameter during inflation. A higher mass is required if one considers a larger gauge coupling constant. The result for the Stückelberg mass can be reproduced in the limit of a small gauge coupling constant. We also comment on the constraints set by various conjectures in quantum gravity theory.
description: 22 pages, 5 figures
Remarks on the Taub-NUT solution in Chern-Simons modified gravity
Creators: name: Brihaye, Yves
name: Radu, Eugen
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We discuss the generalization of the NUT spacetime in General Relativity (GR) within the framework of the (dynamical) Einstein--Chern-Simons (ECS) theory with a massless scalar field. These configurations approach asymptotically the NUT spacetime and are characterized by the `electric' and `magnetic' mass parameters and a scalar `charge'. The solutions are found both analytically and numerically. The analytical approach is perturbative around the Einstein gravity background. Our results indicate that the ECS configurations share all basic properties of the NUT spacetime in GR. However, when considering the solutions inside the event horizon, we find that in contrast to the GR case, the spacetime curvature grows (apparently) without bound.
description: 10 pages, 3 figures
Tomographic inversion of reflection seismic amplitude data for interface geometry and velocity variation
Creators: name: Wang, Yanghua.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Practical Approaches for Acoustic Emission Attenuation Modelling to Enable the Process Monitoring of CFRP Machining
Creators: name: Uhlmann, Eckart
name: Holznagel, Tobias
name: Clemens, Robin
Publisher: name: Technische Universität Berlin
Year: 2022
Subjects: subject: 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
subject: attenuation
subject: acoustic emission
subject: CFRP
subject: milling
subject: process monitoring

description: Acoustic emission-based monitoring of the milling process holds the potential to detect undesired damages of fibre-reinforced plastic workpieces, such as delamination or matrix cracking. In addition, abrasive tool wear, tool breakage, or coating failures can be detected. As measurements of the acoustic emission are impacted by attenuation, dispersion, and reflection as it propagates from source to sensor, the waveforms, amplitudes, and frequency content of a wave packet differ depending on the propagation length in the workpiece. Since the distance between acoustic emission sources and a stationary sensor attached to the workpiece changes continually in circumferential milling, the extraction of meaningful information from the raw measurement data is challenging and requires appropriate signal processing and frequency-dependent amplification. In this paper, practical and robust approaches, namely experimentally identified transfer functions and frequency gain parameter tables for attenuation modelling, which in reverse enable the reconstruction of frequency spectra emitted at the acoustic emission source, are presented and discussed. From the results, it is concluded that linear signal processing can largely compensate for the influence of attenuation, dispersion, and reflection on the frequency spectra and can therefore enable acoustic emission based process monitoring.
Comparing correlation components and approximations in Hartree-Fock and Kohn-Sham theories via an analytical test case study
Creators: name: Giarrusso, Sara
name: Pribram-Jones, Aurora
Publisher: name: arXiv
Year: 2022
Subjects: subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: The asymmetric Hubbard dimer is a model that allows for explicit expressions of the Hartree-Fock (HF) and Kohn-Sham (KS) states as analytical functions of the external potential, $Δv$, and of the interaction strength, $U$. We use this unique circumstance to establish a rigorous comparison between the individual contributions to the correlation energies stemming from the two theories in the $\{U,Δv\}$ parameter space. Within this analysis of the Hubbard dimer, we observe a change in the sign of the HF kinetic correlation energy, compare the indirect repulsion energies, and derive an expression for the 'traditional' correlation energy, i.e. the one that corrects the HF estimate, in a pure site-occupation function theory spirit [Eq. (43)]. Next, we test the performances of the Liu-Burke and the Seidl-Perdew-Levy functionals, which model the correlation energy based on its weak- and strong-interaction limit expansions and can be used for both the traditional and the KS correlation energies. Our results show that, in the Hubbard dimer setting, they typically work better for the HF reference, despite having been originally devised for KS. These conclusions are somewhat in line with prior assessments of these functionals on various chemical data sets. However, the Hubbard dimer model allows us to show the extent of the error that may occur in using the strong-interaction ingredient for the KS reference in place of the one for the HF reference, as has been carried out in most of the prior assessments.
Quantitative immunofluorescent analysis of surface molecules on mononuclear phagocytes
Creators: name: Hutchinson, Paul.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
Angular dependence of primordial trispectra and CMB spectral distortions
Creators: name: Shiraishi, Maresuke
name: Bartolo, Nicola
name: Liguori, Michele
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Under the presence of anisotropic sources in the inflationary era, the trispectrum of the primordial curvature perturbation has a very specific angular dependence between each wavevector that is distinguishable from the one encountered when only scalar fields are present, characterized by an angular dependence described by Legendre polynomials. We examine the imprints left by curvature trispectra on the $TTμ$ bispectrum, generated by the correlation between temperature anisotropies (T) and chemical potential spectral distortions ($μ$) of the Cosmic Microwave Background (CMB). Due to the angular dependence of the primordial signal, the corresponding $TTμ$ bispectrum strongly differs in shape from $TTμ$ sourced by the usual $g_{\rm NL}$ or $τ_{\rm NL}$ local trispectra, enabling us to obtain an unbiased estimation. From a Fisher matrix analysis, we find that, in a cosmic-variance-limited (CVL) survey of $TTμ$, a minimum detectable value of the quadrupolar Legendre coefficient is $d_2 \sim 0.01$, which is 4 orders of magnitude better than the best value attainable from the $TTTT$ CMB trispectrum. In the case of an anisotropic inflationary model with a $f(ϕ)F^2$ interaction (coupling the inflaton field $ϕ$ with a vector kinetic term $F^2$), the size of the curvature trispectrum is related to that of quadrupolar power spectrum asymmetry, $g_*$. In this case, a CVL measurement of $TTμ$ makes it possible to measure $g_*$ down to $10^{-3}$.
description: 20 pages, 5 figures; version matching publication in JCAP
Growth, development and reproductive structure in the brown alga, Hormosira banksii, (fucales, phaeophyta)
Creators: name: Wenno, Petrus A.
Publisher: name: Monash University
Year: 2022

description: This thesis was scanned from the print manuscript for digital preservation and is copyright the author.
 Researchers can access this thesis by asking their local university, institution or public library to
 make a request on their behalf. Monash staff and postgraduate students can use the link in the References field.
BeAGLE: Benchmark $e$A Generator for LEptoproduction in high energy lepton-nucleus collisions
Creators: name: Chang, Wan
name: Aschenauer, Elke-Caroline
name: Baker, Mark D.
name: Jentsch, Alexander
name: Lee, Jeong-Hun
name: Tu, Zhoudunming
name: Yin, Zhongbao
name: Zheng, Liang
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computational Physics (physics.comp-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The upcoming Electron-Ion Collider (EIC) will address several outstanding puzzles in modern nuclear physics. Topics such as the partonic structure of nucleons and nuclei, the origin of their mass and spin, among others, can be understood via the study of high energy electron-proton ($ep$) and electron-nucleus ($e$A) collisions. Achieving the scientific goals of the EIC will require a novel electron-hadron collider and detectors capable to perform high-precision measurements, but also dedicated tools to model and interpret the data. To aid in the latter, we present a general-purpose $e$A Monte Carlo (MC) generator - BeAGLE. In this paper, we provide a general description of the models integrated into BeAGLE, applications of BeAGLE in $e$A physics, implications for detector requirements at the EIC, and the tuning of the parameters in BeAGLE based on available experimental data. Specifically, we focus on a selection of model and data comparisons in particle production in both $ep$ and $e$A collisions, where baseline particle distributions provide essential information to characterize the event. In addition, we investigate the collision geometry determination in $e$A collisions, which could be used as an experimental tool for varying the nuclear density.
description: Manuscript with 20 pages, 16 figures, and 3 tables