cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A compact, integrated silicon device for the generation of spectrally-filtered, pair-correlated photons
Creators: name: Minkov, Momchil
name: Savona, Vincenzo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The third-order non-linearity of silicon gives rise to a spontaneous four-wave mixing process in which correlated photon pairs are generated. Sources based on this effect can be used for quantum computation and cryptography, and can in principle be integrated with standard CMOS fabrication technology and components. However, one of the major challenges is the on-chip demultiplexing of the photons, and in particular the filtering of the pump power, which is many orders of magnitude larger than that of the signal and idler photons. Here, we propose a photonic crystal coupled-cavity system designed so that the coupling of the pump mode to the output channel is strictly zero due to symmetry. We further analyze this effect in presence of fabrication disorder and find that, even then, a pump suppression of close to 40 dB can be achieved in state-of-the art systems. Due to the small mode volumes and high quality factors, our system is also expected to have a generation efficiency much higher than in standard micro-ring systems. Those two considerations make a strong case for the integration of our proposed design in future on-chip quantum technologies.
description: 7 pages, 7 figures
On the Metallicities and Kinematics of the Circumgalactic Media of Damped Ly$α$ Systems at $z \sim 2.5$
Creators: name: Stawinski, Stephanie M. Urbano
name: Rubin, Kate H. R.
name: Prochaska, J. Xavier
name: Hennawi, Joseph F.
name: Tejos, Nicolas
name: Fumagalli, Michele
name: Rafelski, Marc
name: Kirby, Evan N.
name: Lusso, Elisabeta
name: Hafen, Zachary
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Ly$α$ absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening DLA in the redshift range $1.610^{13}~\rm cm^{-2}$ within 100 kpc of DLAs are larger by $2σ$ than those measured in the CGM of Lyman break galaxies (C$_f(N_\text{CII})>0.89$ and C$_f(N_\text{SiII})=0.75_{-0.17}^{+0.12}$). Metallicity constraints derived from ionic ratios for nine CGM systems with negligible ionization corrections and $N_\text{HI}>10^{18.5}~\rm cm^{-2}$ show a significant degree of scatter (with metallicities/limits across the range $-2.06\lesssim\log Z/Z_{\odot}\lesssim-0.75$), suggesting inhomogeneity in the metal distribution in these environments. Velocity widths of $\text{CIV}\lambda1548$ and low-ionization metal species in the DLA vs. CGM sightlines are strongly ($>2σ$) correlated, suggesting they trace the potential well of the host halo over $R_\bot\lesssim300$ kpc scales. At the same time, velocity centroids for $\text{CIV}\lambda1548$ differ in DLA vs. CGM sightlines by $>100~\rm km\ s^{-1}$ for $\sim50\%$ of velocity components, but few components have velocities that would exceed the escape velocity assuming dark matter host halos of $\ge10^{12}M_\odot$.
description: 44 pages, 21 Figures, 5 Tables, accepted for publication in ApJ
Estimating relaxation times from a single trajectory
Creators: name: Akimoto, Takuma
name: Yamamoto, Eiji
name: Uneyama, Takashi
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: Complex systems such as protein conformational fluctuations and supercooled liquids exhibit a long relaxation time and are considered to posses multiple relaxation times. We analytically obtain the exact correlation function for stochastic processes with multiple relaxation times. We show that the time-averaged correlation function calculated by a trajectory whose length is shorter than the longest relaxation time exhibits an apparent aging behavior. We propose a method to extract relaxation times from a single trajectory. This method successfully extracts relaxation times of a stochastic process with multiple states when a state can be characterized by the values of the trajectory. As an application of this method, we estimate several relaxation times smaller than the longest relaxation time in conformational fluctuations of a small protein.
description: 10 pages, 4 figures
LSST Survey Strategy in the Galactic Plane and Magellanic Clouds
Creators: name: Street, R. A.
name: Li, X.
name: Khakpash, S.
name: Bellm, E.
name: Girardi, L.
name: Jones, L.
name: Abrams, N. S.
name: Tsapras, Y.
name: Hundertmark, M. P. G.
name: Bachelet, E.
name: Gandhi, P.
name: Szkody, P.
name: Clarkson, W. I.
name: Szabo, R.
name: Prisinzano, L.
name: Bonito, R.
name: Buckley, D. A. H.
name: Marais, J. P.
name: Di Stefano, R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Galactic science encompasses a wide range of subjects in the study of the Milky Way and Magellanic Clouds, from Young Stellar Objects to X-ray Binaries. Mapping these populations, and exploring transient phenomena within them, are among the primary science goals of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST). While early versions of the survey strategy dedicated relatively few visits to the Galactic Plane region, more recent strategies under consideration envision higher cadence within selected regions of high scientific interest. The range of galactic science presents a challenge in evaluating which strategies deliver the highest scientific returns. Here we present metrics designed to evaluate Rubin survey strategy simulations based on the cadence of observations they deliver within regions of interest to different topics in galactic science, using variability categories defined by timescale. We also compare the fractions of exposures obtained in each filter with those recommended for the different science goals. We find that the baseline_v2.x simulations deliver observations of the high-priority regions at sufficiently high cadence to reliably detect variability on timescales >10 d or more. Follow-up observations may be necessary to properly characterize variability, especially transients, on shorter timescales. Combining the regions of interest for all the science cases considered, we identify those areas of the Galactic Plane and Magellanic Clouds of highest priority. We recommend that these refined survey footprints be used in future simulations to explore rolling cadence scenarios, and to optimize the sequence of observations in different bandpasses.
description: Accepted for publication in ApJS. 26 pages and 36 figures
Left- vs right-handed badminton slice shots: opposite shuttlecock spinning and Magnus effect
Creators: name: Collet, Eric
Publisher: name: arXiv
Year: 2023
Subjects: subject: Popular Physics (physics.pop-ph)
subject: FOS: Physical sciences

description: The chiral nature of a badminton shuttlecock is responsible for its anti-clockwise spinning as it naturally propagates through the air. This induces a dissymmetry between left-handed and right-handed players and the resulting trajectories of the shuttlecock, which were captured in real condition on the badminton court and in slow-motion at 3700 fps. The videos clearly evidence this dissymmetry as slice shots performed by righties accelerate the natural anti-clockwise spinning, while the one performed by lefties induces a clockwise to anti-clockwise spinning, making trajectories of shuttlecocks different. The slow-motion videos also caught a brief Magnus effect, often neglected in badminton, lifting up the shuttlecock for both lefties and righties and affecting the effectiveness of the slice shot.
description: Videos are available here: doi 10.5281/zenodo.10012876
Discovery of an Extended $γ$-ray Emission around the Supernova Remnant Candidate associated with PSR J0837$-$2454
Creators: name: Zhang, Pengfei
name: Xin, Yuliang
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Motivated by the recent discovery of a low surface brightness diffuse emission, a supernova remnant (SNR) candidate, surrounding the young pulsar PSR~J0837--2454, we carry out a likelihood analysis of the $γ$-ray data obtained by the \emph{Fermi} Gamma-ray Space Telescope from August 2008 to November 2022. Using a 2D Gaussian spatial template, we detect a significant extended $γ$-ray emission with a 68\% containment radius of $\sim1^{\circ}.8$, which is spatially coincident with the new SNR candidate at $\sim12σ$ confidence level. The spectrum of the extended $γ$-ray emission, obtained in the energy range of 0.1-500.0 GeV, shows a significant spectral curvature at $\sim$1 GeV, with a log-parabola spectral shape. Several scenarios, such as the SNR, pulsar wind nebula, and pulsar halo, are discussed as the potential origins of the extended $γ$-ray emission, and our model fitting results are preferred for the SNR scenario.
description: 8 pages, 5 figures, submitted to ApJ
Hilbert-Huang Transform analysis of quasi-periodic oscillations in MAXI J1820+070
Creators: name: Yu, Wei
name: Bu, Qing-Cui
name: Yang, Zi-Xu
name: Liu, He-Xin
name: Zhang, Liang
name: Huang, Yue
name: Zhou, Deng-Ke
name: Qu, Jin-Lu
name: Zhang, Shuang-Nan
name: Zhang, Shu
name: Song, Li-Ming
name: Jia, Shu-Mei
name: Ma, Xiang
name: Tao, Lian
name: Ge, Ming-Yu
name: Liu, Qing-Zhong
name: Yan, Jing-Zhi
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We present time-frequency analysis, based on the Hilbert-Huang transform (HHT), of the evolution on the low-frequency quasi-periodic oscillations (LFQPOs) observed in the black hole X-ray binary MAXI J1820+070. Through the empirical mode decomposition (EMD) method, we decompose the light curve of the QPO component and measure its intrinsic phase lag between photons from different energy bands. We find that the QPO phase lag is negative (low energy photons lag behind high energy photons), meanwhile the absolute value of the lag increases with energy. By applying the Hilbert transform to the light curve of the QPO, we further extract the instantaneous frequency and amplitude of the QPO. Compared these results with those from the Fourier analysis, we find that the broadening of the QPO peak is mainly caused by the frequency modulation. Through further analysis, we find that these modulations could share a common physical origin with the broad-band noise, and can be well explained by the internal shock model of the jet.
Real-time Aerial Detection and Reasoning on Embedded-UAVs
Creators: name: Lai, Tin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: We present a unified pipeline architecture for a real-time detection system on an embedded system for UAVs. Neural architectures have been the industry standard for computer vision. However, most existing works focus solely on concatenating deeper layers to achieve higher accuracy with run-time performance as the trade-off. This pipeline of networks can exploit the domain-specific knowledge on aerial pedestrian detection and activity recognition for the emerging UAV applications of autonomous surveying and activity reporting. In particular, our pipeline architectures operate in a time-sensitive manner, have high accuracy in detecting pedestrians from various aerial orientations, use a novel attention map for multi-activities recognition, and jointly refine its detection with temporal information. Numerically, we demonstrate our model's accuracy and fast inference speed on embedded systems. We empirically deployed our prototype hardware with full live feeds in a real-world open-field environment.
description: In TGRS
Entomacis laertes Nixon 1980
Creators: name: Notton, David G.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Diapriidae
Entomacis
Entomacis laertes

description: Entomacis laertes Nixon, 1980: 13.
Valid name
Entomacis graeffei Kieffer, 1909.
Summary of types
Holotype ♀, BMNH number 9.810, by original designation. Paratypes 5 ♀♀.
Primary type data
Sweden, Sk./ Ring sjö/ 27.vi.1938 / D.M.S.P. & J.F.P./ B.M.1938-414; Entomacis / laertes Nixon / type ♀, 197.
Type locality
Sweden, Skåne County, Ring Sjö.
Remarks
The holotype is mounted on a card point and is entire.
description: Published as part of Notton, David G., 2014, A catalogue of the types of Diapriinae (Hymenoptera, Diapriidae) at the Natural History Museum, London, pp. 1-123 in European Journal of Taxonomy 75 on pages 94-95, DOI: 10.5852/ejt.2014.75, http://zenodo.org/record/3862773
Viscoelastic dynamics of a soft strip subject to a large deformation
Creators: name: Delory, Alexandre
name: Kiefer, Daniel A.
name: Lanoy, Maxime
name: Eddi, Antonin
name: Prada, Claire
name: Lemoult, Fabrice
Publisher: name: arXiv
Year: 2023
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: To produce sounds, we adjust the tension of our vocal folds to shape their properties and control the pitch. This efficient mechanism offers inspiration for designing reconfigurable materials and adaptable soft robots. However, understanding how flexible structures respond to a significant static strain is not straightforward. This complexity also limits the precision of medical imaging when applied to tensioned organs like muscles, tendons, ligaments and blood vessels among others. In this article, we experimentally and theoretically explore the dynamics of a soft strip subject to a substantial static extension, up to 180%. Our observations reveal a few intriguing effects, such as the resilience of certain vibrational modes to a static deformation. These observations are supported by a model based on the incremental displacement theory. This has promising practical implications for characterizing soft materials but also for scenarios where external actions can be used to tune properties.
Switching of magnon parametric oscillation by magnetic field direction
Creators: name: Horibe, Sohei
name: Shimizu, Hiroki
name: Hoshi, Koujiro
name: Makiuchi, Takahiko
name: Hioki, Tomosato
name: Saitoh, Eiji
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Parametric oscillation occurs when the resonance frequency of an oscillator is periodically modulated. Owing to time-reversal symmetry breaking in magnets, nonreciprocal magnons can be parametrically excited when spatial-inversion symmetry breaking is provided. This means that magnons with opposite propagation directions have different amplitudes. Here we demonstrate switching on and off the magnon parametric oscillation by reversing the external field direction applied to a Y$_3$Fe$_5$O$_{12}$ micro-structured film. The result originates from the nonreciprocity of surface mode magnons, leading to field-direction dependence of the magnon accumulation under a nonuniform microwave pumping. Our numerical calculation well reproduces the experimental result.
description: 5 pages, 4 figures
Space-charge effects in high-energy photoemission
Creators: name: Verna, Adriano
name: Greco, Giorgia
name: Lollobrigida, Valerio
name: Offi, Francesco
name: Stefani, Giovanni
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Pump-and-probe photoelectron spectroscopy (PES) with femtosecond pulsed sources opens new perspectives in the investigation of the ultrafast dynamics of physical and chemical processes at the surfaces and interfaces of solids. Nevertheless, for very intense photon pulses a large number of photoelectrons are simultaneously emitted and their mutual Coulomb repulsion is sufficiently strong to significantly modify their trajectory and kinetic energy. This phenomenon, referred as space-charge effect, determines a broadening and shift in energy for the typical PES structures and a dramatic loss of energy resolution. In this article we examine the effects of space charge in PES with a particular focus on time-resolved hard X-ray (~10 keV) experiments. The trajectory of the electrons photoemitted from pure Cu in a hard X-ray PES experiment has been reproduced through $N$-body simulations and the broadening of the photoemission core-level peaks has been monitored as a function of various parameters (photons per pulse, linear dimension of the photon spot, photon energy). The energy broadening results directly proportional to the number $N$ of electrons emitted per pulse (mainly represented by secondary electrons) and inversely proportional to the linear dimension $a$ of the photon spot on the sample surface, in agreement with the literature data about ultraviolet and soft X-ray experiments. The evolution in time of the energy broadening during the flight of the photoelectrons is also studied. Despite its detrimental consequences on the energy spectra, we found that space charge has negligible effects on the momentum distribution of photoelectrons and a momentum broadening is not expected to affect angle-resolved experiments. Strategy to reduce the energy broadening and the feasibility of hard X-ray PES experiments at the new free-electron laser facilities are discussed.
description: 15 pages, 2 tables, 8 figures
The TOP counter and determination of bunch-crossing time at Belle II
Creators: name: Staric, Marko
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: At the Belle II experiment a Time-of-Propagation (TOP) counter is used for particle identification in the barrel region. This novel type of particle identification device combines the Cherenkov ring imaging technique with the time-of-flight and therefore it relies on a precise knowledge of the time of collision in each triggered event. We discuss the performance of the counter and present a maximum likelihood based method for the determination of event collision time from the measured data.
description: 4 pages, 6 figures
[C I] and [C II] emission in the circumstellar envelope of IRC +10216 I. Observational data and NLTE modeling of the [C I] emission
Creators: name: Jeste, Manali
name: Wiesemeyer, Helmut
name: Menten, Karl M.
name: Wyrowski, Friedrich
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Aims: The study at hand aims to describe the distribution of atomic carbon, C0, throughout the envelope, in support of an improved understanding of its photo-chemistry. Additionally, we also briefly discuss the observation of [CII] emission towards the star. Methods: We obtain spectra of the [CI] $\mathrm{^3P_1} \rightarrow \mathrm{^3P_0}$ fine structure line at projected distances of up to 78" from the star. The line profiles are characterized by both direct fitting of Gaussian components, and by modeling the observed line of the [CI] triplet. We also report the detection of the $\mathrm{^2P_{3/2}} \rightarrow \mathrm{^2P_{1/2}}$ line from the C+ fine structure singlet at the central position and at 32" from the star. Results: The overall picture of the [CI] emission from IRC +10216 agrees with more limited previous studies. The satisfying agreement between the observed and modeled line profiles, with emission at the systemic velocity appearing beyond one beam from the star, rules out that the C0 is located in a thin shell. Given that the bond energy of CO falls only 0.1 eV below the ionization threshold of C0, the absence of observable [CII] emission from sightlines beyond a projected distance of $\sim 10^{17}$ cm from the star (adopting a distance of 130 pc) does not contradict a scenario where the bulk of C0 is located between that of CO and C+, as expected for an external FUV radiation field. This conjecture is also corroborated by a model in which the C0 shell is located farther outside, failing to reproduce the [CI] line profiles at intermediate sky-plane distances from the star. Comparing a photo-chemical model adopted from literature with the simplifying assumption of a constant C0 abundance with respect to the $\mathrm{H}_2$ density, we constrain the inner boundary of the [CI] emitting shell, located at $\sim 10^{16}$ cm from the star.
description: 10 pages, 7 figures, accepted for publication in A&A
Two-fluid Physical Modeling of Superconducting Resonators in the ARTEMIS Framework
Creators: name: Jambunathan, Revathi
name: Yao, Zhi
name: Lombardini, Richard
name: Rodriguez, Aaron
name: Nonaka, Andrew
Publisher: name: arXiv
Year: 2023
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: In this work, we implement a new London equation module for superconductivity in the GPU-enabled ARTEMIS framework, and couple it to a finite-difference time-domain solver for Maxwell's equations. We apply this two-fluid approach to model a superconducting coplanar waveguide (CPW) resonator. We validate our implementation by verifying that the theoretical skin depth and reflection coefficients can be obtained for several superconductive materials, with different London penetration depths, over a range of frequencies. Our convergence studies show that the algorithm is second-order accurate in both space and time, except at superconducting interfaces where the approach is spatially first-order. In our CPW simulations, we leverage the GPU scalability of our code to compare the two-fluid model to more traditional approaches that approximate superconducting behavior and demonstrate that superconducting physics can show comparable performance to the assumption of quasi-infinite conductivity as measured by the Q-factor.
Layer-by-layer disentangling two-dimensional topological quantum codes
Creators: name: Zarei, Mohammad Hossein
name: Haghighi, Mohsen Rahmani
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: While local unitary transformations are used for identifying quantum states which are in the same topological class, non-local unitary transformations are also important for studying the transition between different topological classes. In particular, it is an important task to find suitable non-local transformations that systematically sweep different topological classes. Here, regarding the role of dimension in the topological classes, we introduce partially local unitary transformations namely Greenberger-Horne-Zeilinger (GHZ) disentanglers which reduce the dimension of the initial topological model by a layer-by-layer disentangling mechanism. We apply such disentanglers to two-dimensional (2D) topological quantum codes and show that they are converted to many copies of Kitaev's ladders. It implies that the GHZ disentangler causes a transition from an intrinsic topological phase to a symmetry-protected topological phase. Then, we show that while Kitaev's ladders are building blocks of both color code and toric code, there are different patterns of entangling ladders in 2D color code and toric code. It shows that different topological features of these topological codes are reflected in different patterns of entangling ladders. In this regard, we propose that the layer-by-layer disentangling mechanism can be used as a systematic method for classification of topological orders based on finding different patterns of the long-range entanglement in topological lattice models.
description: 9 pages, 9 figures, submitted to PRB
Spins of primordial black holes formed with a soft equation of state
Creators: name: Saito, Daiki
name: Harada, Tomohiro
name: Koga, Yasutaka
name: Yoo, Chul-Moon
Publisher: name: arXiv
Year: 2023
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We investigate the probability distribution of the spins of primordial black holes (PBHs) formed in the universe dominated by a perfect fluid with the linear equation of state $p=wρ$, where $p$ and $ρ$ are the pressure and energy density of the fluid, respectively. We particularly focus on the parameter region $0
description: 21 pages, 6 figures, references added: version accepted for publication in JCAP
Investigations on the molecular basis of temperature response in plants
Creators: name: YADAV, AVILASH SINGH
Publisher: name: Monash University
Year: 2021
Subjects: Genetics not elsewhere classified
Plant biology not elsewhere classified

description: This thesis is about understanding molecular mechanisms that regulate plant morphology in response to mild fluctuations in temperature within non-stressful range. In my thesis, I attempted to understand the mechanism by which POWERDRESS (PWR), a component required for histone deacetylation regulates temperature response. I have undertaken a bioinformatics approach to understand how PWR regulates genomewide transcription profile in response to temperature, and what effect it potentially has on additional histone modifications. I have also performed a genetic screen to identify addition genetic interactors of PWR, and have used forward genetics based approach to map potential loci in two independent mutants.
The Complex Magmatic Evolution and Crustal Processes of Asteroid 4 Vesta
Creators: name: MITCHELL, JENNIFER TALLIS
Publisher: name: Monash University
Year: 2021
Subjects: Geochemistry not elsewhere classified
Planetary science (excl. solar system and planetary geology)
Geology not elsewhere classified
Planetary geology

description: Asteroid 4 Vesta is a surprisingly complex body, recording a vast range of processes and lithologies with many more likely unsampled by the global meteorite collection. Through multiple modelling and experimental techniques, I have explored Vesta’s magmatic evolution and crustal processes with reference to observations from NASA’s Dawn mission and the howardite-eucrite-diogenite meteorite suite in order to answer longstanding questions regarding the petrogenesis of diogenites and their relationship to eucrites, as well as suggesting what would be expected of the unsampled Vestan mantle.
Topological state engineering by potential impurities on chiral superconductors
Creators: name: Kaladzhyan, Vardan
name: Röntynen, Joel
name: Simon, Pascal
name: Ojanen, Teemu
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In this work we consider the influence of potential impurities deposited on top of two-dimensional chiral superconductors. As discovered recently, magnetic impurity lattices on an $s$-wave superconductor may give rise to a rich topological phase diagram. We show that similar mechanism takes place in chiral superconductors decorated by non-magnetic impurities, thus avoiding the delicate issue of magnetic ordering of adatoms. We illustrate the method by presenting the theory of potential impurity lattices embedded on chiral $p$-wave superconductors. While a prerequisite for the topological state engineering is a chiral superconductor, the proposed procedure results in vistas of nontrivial descendant phases with different Chern numbers.
description: 4.5+5 pages
Evolution of the Radial Size and Expansion of Coronal Mass Ejections Investigated by Combining Remote and In-Situ Observations
Creators: name: Zhuang, Bin
name: Lugaz, Noé
name: Al-Haddad, Nada
name: Winslow, Réka M.
name: Scolini, Camilla
name: Farrugia, Charles J.
name: Galvin, Antoinette B.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: A fundamental property of coronal mass ejections (CMEs) is their radial expansion, which determines the increase in the CME radial size and the decrease in the CME magnetic field strength as the CME propagates. CME radial expansion can be investigated either by using remote observations or by in-situ measurements based on multiple spacecraft in radial conjunction. However, there have been only few case studies combining both remote and in-situ observations. It is therefore unknown if the radial expansion estimated remotely in the corona is consistent with that estimated locally in the heliosphere. To address this question, we first select 22 CME events between the years 2010 and 2013, which were well observed by coronagraphs and by two or three spacecraft in radial conjunction. We use the graduated cylindrical shell model to estimate the radial size, radial expansion speed, and a measure of the dimensionless expansion parameter of CMEs in the corona. The same parameters and two additional measures of the radial-size increase and magnetic-field-strength decrease with heliocentric distance of CMEs based on in-situ measurements are also calculated. For most of the events, the CME radial size estimated by remote observations is inconsistent with the in-situ estimates. We further statistically analyze the correlations of these expansion parameters estimated using remote and in-situ observations, and discuss the potential reasons for the inconsistencies and their implications for the CME space weather forecasting.
description: Accepted by ApJ
Large N Thirring Matter in Three Dimensions
Creators: name: Goykhman, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper we calculate properties of the three-dimensional system of N species of fermions at zero temperature and finite chemical potential, with the four-fermionic interaction of the Thirring type. We observe that this model fits consistently into framework of the Landau Fermi liquid theory, and possesses a non-trivial zeroth and first Landau parameters. Our result is derived to all orders of the Thirring coupling constant and to the leading order of the large-N expansion. In particular we solve for the exact current-current correlation function, and show that it exhibits a singular behavior at zero frequency and twice of the Fermi momentum.
Application of Super-Resolution Microscopies for Subcellular Biology
Creators: name: ROZARIO, ASHLEY MICHAEL
Publisher: name: Monash University
Year: 2021
Subjects: Animal physiology - biophysics
Human biophysics
Optical technology
Virology
Biochemistry and cell biology not elsewhere classified
Plant cell and molecular biology
Animal cell and molecular biology
Image processing
Immunology not elsewhere classified

description: Fluorescence microscopy has a resolution limit due to the diffraction of light, which hinders accurate visualisation of nanoscopic organelles and features within the cell. Super-resolution microscopies overcome this limitation using innovative strategies, including single molecule localisations, correlating fluorescence fluctuations, and physical expansion. Each provides a unique advantage for subcellular biology research, such as achieving resolutions as good as 20 nm, the ability to capture live cell dynamics, and decrowd the dense cellular environment. This thesis presents the development of super-resolution microscopy methods dSTORM, SOFI and ExM, and their applications in studying viral protein mechanisms, anticancer drug effects, and genomic organization.
Field-direction-dependent skyrmion crystals in noncentrosymmetric cubic magnets: A comparison between point groups $(O,T)$ and $T_{\rm d}$
Creators: name: Hayami, Satoru
name: Yambe, Ryota
Publisher: name: arXiv
Year: 2023
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the instability toward a skyrmion crystal (SkX) in noncentrosymmetric cubic magnets with an emphasis on a comparison between point groups $(O,T)$ and $T_{\rm d}$. By constructing low-temperature magnetic phase diagrams under an external magnetic field for three directions based on numerically simulated annealing, we find that the system under the point group $(O,T)$ exhibits different two types of SkXs depending on the field direction, while that under $T_{\rm d}$ does not show such an instability. The difference between them is understood from the difference in the momentum-dependent Dzyaloshinskii-Moriya interaction under each point group. Meanwhile, we show that the system under $T_{\rm d}$ leads to the SkX instability by considering an additional effect of the uniaxial strain, which lowers the symmetry to $D_{\rm 2d}$. We obtain two different SkXs: Néel-type and anti-type SkXs, the former of which is stabilized in the presence of the interactions at the three-dimensional ordering wave vectors. The present results provide rich topological spin textures in the three-dimensional systems, which are sensitive to the magnetic-field direction and point-group symmetry.
description: 11 pages, 11 figures, accepted for publication in PRB
Combining direct and indirect sparse data for learning generalizable turbulence models
Creators: name: Zhang, Xin-Lei
name: Xiao, Heng
name: Luo, Xiaodong
name: He, Guowei
Publisher: name: arXiv
Year: 2023
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Learning turbulence models from observation data is of significant interest in discovering a unified model for a broad range of practical flow applications. Either the direct observation of Reynolds stress or the indirect observation of velocity has been used to improve the predictive capacity of turbulence models. In this work, we propose combining the direct and indirect sparse data to train neural network-based turbulence models. The backpropagation technique and the observation augmentation approach are used to train turbulence models with different observation data in a unified ensemble-based framework. These two types of observation data can explore synergy to constrain the model training in different observation spaces, which enables learning generalizable models from very sparse data. The present method is tested in secondary flows in a square duct and separated flows over periodic hills. Both cases demonstrate that combining direct and indirect observations is able to improve the generalizability of the learned model in similar flow configurations, compared to using only indirect data. The ensemble-based method can serve as a practical tool for model learning from different types of observations due to its non-intrusive and derivative-free nature.
description: 42 pages, 16 figures
Spin-orbit-coupling induced torque in ballistic domain walls: equivalence of charge-pumping and nonequilibrium magnetization formalisms
Creators: name: Yuan, Zhe
name: Kelly, Paul J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: To study the effect of spin-orbit coupling (SOC) on spin-transfer torque in magnetic materials, we have implemented two theoretical formalisms that can accommodate SOC. Using the "charge-pumping" formalism, we find two contributions to the out-of-plane spin-transfer torque parameter $β$ in ballistic Ni domain walls (DWs). For short DWs, the nonadiabatic reflection of conduction electrons caused by the rapid spatial variation of the exchange potential results in an out-of-plane torque that increases rapidly with decreasing DW length. For long DWs, the Fermi level conduction channel anisotropy that gives rise to an intrinsic DW resistance in the presence of SOC leads to a linear dependence of $β$ on the DW length. To understand this counterintuitive divergence of $β$ in the long DW limit, we use the "nonequilibrium magnetization" formalism to examine the spatially resolved spin-transfer torque. The SOC-induced out-of-plane torque in ballistic DWs is found to be quantitatively consistent with the values obtained using the charge-pumping calculations indicating the equivalence of the two theoretical methods.
description: 11+pages, 10 figures
Studies in stellar oscillations and rotation with applications to compact objects
Creators: name: McNeill, Lucy
Publisher: name: Monash University
Year: 2021
Subjects: High energy astrophysics and galactic cosmic rays
Astroparticle physics and particle cosmology

description: When stars die, they leave behind extremely dense remnants such as neutron stars and white dwarfs. These dead stars offer a wealth of information on, and provide observational tools to explore, questions related to cosmology, stellar evolution, and even the ripples in spacetime predicted from general relativity. Motivated by both electromagnetic and gravitational wave observations of compact objects, this thesis explores questions related to stellar evolution and interiors. In particular, we investigate waves excited by convective burning in stars, and study stellar rotation, just before supernova, and also waves excited through tidal interactions between pairs of white dwarfs.
An Atypical Plateau-like Extreme-ultraviolet Late-phase Solar Flare Driven by the Non-radial Eruption of a Magnetic Flux Rope
Creators: name: Chen, Yuehong
name: Dai, Yu
name: Ding, Mingde
Publisher: name: arXiv
Year: 2023
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares, which is characterized by a second peak in the warm coronal emissions (about 3 MK) occurring several tens of minutes to a few hours after the corresponding main flare peak. We aim to clarify the physical origin of an atypical plateau-like EUV late phase in an X1.8-class solar flare occurring on 2011 September 7 from active region (AR) 11283. We first characterize the plateau-like late phase using EUV Variability Experiment (EVE) full-disk integrated irradiance observations and Atmospheric Imaging Assembly (AIA) spatially-resolved imaging observations on board the Solar Dynamics Observatory (SDO). Then we perform a nonlinear force-free-field (NLFFF) extrapolation, from which a filament-hosting magnetic flux rope (MFR) is revealed. The eruption of the MFR is tracked both in the plane of the sky (POS) and along the line of sight (LOS) through visual inspection and spectral fitting, respectively. Finally, we carry out differential emission measure (DEM) analysis to explore the thermodynamics of the late-phase loops. The MFR shows a non-radial eruption from a fan-spine magnetic structure. The eruption of the MFR and its interaction with overlying arcades invoke multiple magnetic reconnections, which are responsible for the production of different groups of late-phase loops. Afterwards, the late-phase loops enter a long-lasting cooling stage, appearing sequentially in AIA passbands of decreasing response temperatures. Due to their different lengths, the different groups of late-phase loops cool down at different cooling rates, which makes their warm coronal emission peaks temporally separated from each other. Combing the emissions from all late-phase loops together, an elongated plateau-like late phase is formed.
description: Accepted by A&A
The Chemical Signature of Primordial Hypernovae
Creators: name: GRIMMETT, JAMES JOSEPH
Publisher: name: Monash University
Year: 2021
Subjects: High energy astrophysics and galactic cosmic rays
Astroparticle physics and particle cosmology

description: The first massive stars to form after the big bang mark the departure from a chemically and structurally simple Universe, towards one of increasing richness and complexity. Exploding as supernovae, the first massive stars provided the Universe with the initial enrichment of the first significant amounts of carbon and heavier elements necessary to life. The first stars are not directly observable by current instruments, and their nature remains a mystery. In this thesis we investigate the nucleosynthesis that can be achieved with models of high energy supernova for the first stars, and make comparison with the chemical signature preserved in ancient metal-poor stars.
Formation of complex organic molecules on interstellar CO ices? Insights from computational chemistry simulations
Creators: name: Ferrero, Stefano
name: Ceccarelli, Cecilia
name: Ugliengo, Piero
name: Sodupe, Mariona
name: Rimola, Albert
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Carbon ($^3$P) atom is a reactive species that, according to laboratory experiments and theoretical calculations, condensates with interstellar ice components. This fact is of uttermost importance for the chemistry in the interstellar medium (ISM) because the condensation reaction is barrierless and the subsequent species formed are still reactive given their open-shell character. Carbon condensation on CO-rich ices forms the \ch{C=C=O} ($^3$$Σ$$^-$) species, which can be easily hydrogenated twice to form ketene (H$_2$CCO). Ketene is very reactive in terrestrial conditions, usually found as an intermediate hard to be isolated in chemical synthesis laboratories. These characteristics suggest that ketene can be a good candidate to form interstellar complex organic molecules (iCOMs) via a two-step process, i.e., its activation followed by a radical-radical coupling. In this work, reactions between ketene and atomic H, and the OH and NH$_2$ radicals on a CO-rich ice model have been explored by means of quantum chemical calculations complemented by kinetic calculations to evaluate if they are favourable in the ISM. Results indicate that H addition to ketene (helped by tunneling) to form the acetyl radical (CH$_3$CO) is the most preferred path, as the reactions with OH and NH$_2$ possess activation energies ($\geq$ 9kJ/mol) hard to surmount in the ISM conditions, unless external processes provide energy to the system. Thus, acetaldehyde (CH$_3$CHO) and, probably, ethanol (CH$_3$CH$_2$OH) formation via further hydrogenations are the possible unique operating synthetic routes. Moreover, from the computed relatively large binding energies of OH and NH$_2$ on CO ice, slow diffusion is expected, hampering possible radical-radical couplings with CH$_3$CO. The astrophysical implications of these findings are discussed considering the incoming James Webb Space Telescope observations.
Surface plasmon-polaritons in graphene, embedded into medium with gain and losses
Creators: name: Zhernovnykova, O. A.
name: Popova, O. V.
name: Deynychenko, G. V.
name: Deynichenko, T. I.
name: Bludov, Yuliy V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The paper deals with the theoretical consideration of surface plasmon-polaritons in the graphene monolayer, embedded into dielectric with spatially separated gain and losses. It is demonstrated, that presence of gain and losses in the system leads to the formation of additional mode of graphene surface plasmon-polaritons, which does not have its counterpart in the conservative system. When the gain and losses are mutually balanced, the position of exceptional point -- transition point between unbroken and broken $\mathcal{PT}$-symmetry -- can be effectively tuned by graphene's doping. In the case of unbalanced gain and losses the spectrum of surface plasmon-polaritons contains spectral singularity, whose frequency is also adjustable through the electrostatic gating of graphene.
description: 13 pages, 5 figures
Orbital characteristics of planetesimals captured by circumplanetary gas disks
Creators: name: Suetsugu, Ryo
name: Ohtsuki, Keiji
name: Fujita, Tetsuya
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Sufficiently massive growing giant planets have circumplanetary disks, and the capture of solid bodies by the disks would likely influence the growth of the planets and formation of satellite systems around them. In addition to dust particles that are supplied to the disk with inflowing gas, recent studies suggest the importance of capture of planetesimals whose motion is decoupled from the gas, but orbital evolution of captured bodies in circumplanetary gas disks has not been studied in detail. In the present work, using three-body orbital integration and analytic calculations, we examine orbital characteristics and subsequent dynamical evolution of planetesimals captured by gas drag from circumplanetary gas disks. We find that the semi-major axes of the planet-centered orbits of planetesimals at the time of permanent capture are smaller than about one third of the planet's Hill radius in most cases. Typically, captured bodies rapidly spiral into the planet, and the rate of the orbital decay is faster for the retrograde orbits due to the strong headwind from the circumplanetary gas. When a planetesimal captured into a retrograde orbit suffers from sufficiently strong gas drag before spiraling into the planet, its orbit turns to the prograde direction at a radial location that can be explained using the Stokes number. We also find that those captured into certain types of orbits can survive for a long period of time even under gas drag both in the prograde and retrograde cases, which may be important for the origin of irregular satellites of giant planets.
description: 37 pages, 11 figures, accepted for publication in AJ
An $M$-ary Concentration Shift Keying with Common Detection Thresholds For Multitransmitter Molecular Communication
Creators: name: Shitiri, Ethungshan
name: Cho, Ho-Shin
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Theory (cs.IT)
subject: Emerging Technologies (cs.ET)
subject: FOS: Computer and information sciences

description: Concentration shift keying (CSK) is a widely studied modulation technique for molecular communication-based nanonetworks, which is a key enabler for the Internet of Bio-NanoThings (IoBNT). Existing CSK methods, while offering optimal error performance, suffer from increased operational complexity that scales poorly as the number of transmitters, $K$, grows. In this study, a novel $M$-ary CSK method is proposed: CSK with common detection thresholds (CSK-CT). CSK-CT uses \textit{common} thresholds, set sufficiently low to guarantee the reliable detection of symbols from all transmitters, regardless of distance. Closed-form expressions are derived to obtain the common thresholds and release concentrations. To further enhance error performance, the release concentration is optimized using a scaling exponent that also optimizes the common thresholds. The performance of CSK-CT is evaluated against the benchmark CSK across various $K$ and $M$ values. CSK-CT has an error probability between $10^{-7}$ and $10^{-4}$, which is a substantial improvement from that of the benchmark CSK (from $10^{-4}$ to $10^{-3}$). In terms of complexity, CSK-CT is $\mathcal{O}\big(n\big)$ and does not scale with $K$ but $M$ ($M\ll K$), whereas the benchmark is $\mathcal{O}\big(n^2\big)$. Furthermore, CSK-CT can mitigate inter-symbol interference (ISI), although this facet merits further investigation. Owing to its low error rates, improved scalability, reduced complexity, and potential ISI mitigation features, CSK-CT is particularly advantageous for IoBNT applications focused on data gathering. Its effectiveness is especially notable in scenarios where a computationally limited receiver is tasked with collecting vital health data from multiple transmitters.
description: Submitted to IEEE for possible publication