cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Towards a CPT Invariant Quantum Field Theory on Elliptic de Sitter Space
Creators: name: Chang, Zhe.
name: Li, Xin.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Consequences of Schrödinger's antipodal identification on quantum field theory in de Sitter space are investigated. The elliptic $\mathbb{Z}_2$ identification provides observers with complete information. We show that a suitable confinement on dimension of the elliptic de Sitter space guarantees the existence of globally defined spinors and orientable $dS/\mathbb{Z}_2$ manifold. In Beltrami coordinates, we give exact solutions of scalar and spinor fields. The CPT invariance of quantum field theory on the elliptic de Sitter space is presented explicitly.
description: 16 pages, some references have been added, the structure of paper have been revised, accepted for publication in Int. J. Mod. Phys. A
Silicon and hydrogen chemistry under laboratory conditions mimicking the atmosphere of evolved stars
Creators: name: Accolla, Mario
name: Santoro, Gonzalo
name: Merino, Pablo
name: Martínez, Lidia
name: Tajuelo-Castilla, Guillermo
name: Vázquez, Luis
name: Sobrado, Jesús M.
name: Agúndez, Marcelino
name: Jiménez-Redondo, Miguel
name: Herrero, Víctor J.
name: Tanarro, Isabel
name: Cernicharo, José
name: Martín-Gago, José Ángel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Silicon is present in interstellar dust grains, meteorites and asteroids, and to date thirteen silicon-bearing molecules have been detected in the gas-phase towards late-type stars or molecular clouds, including silane and silane derivatives. In this work, we have experimentally studied the interaction between atomic silicon and hydrogen under physical conditions mimicking those at the atmosphere of evolved stars. We have found that the chemistry of Si, H and H$_2$ efficiently produces silane (SiH$_4$), disilane (Si$_2$H$_6$) and amorphous hydrogenated silicon (a-Si:H) grains. Silane has been definitely detected towards the carbon-rich star IRC\,+10216, while disilane has not been detected in space yet. Thus, based on our results, we propose that gas-phase reactions of atomic Si with H and H$_2$ are a plausible source of silane in C-rich AGBs, although its contribution to the total SiH$_4$ abundance may be low in comparison with the suggested formation route by catalytic reactions on the surface of dust grains. In addition, the produced a-Si:H dust analogs decompose into SiH$_4$ and Si$_2$H$_6$ at temperatures above 500 K, suggesting an additional mechanism of formation of these species in envelopes around evolved stars. We have also found that the exposure of these dust analogs to water vapor leads to the incorporation of oxygen into Si-O-Si and Si-OH groups at the expense of SiH moieties, which implies that, if this type of grains are present in the interstellar medium, they will be probably processed into silicates through the interaction with water ices covering the surface of dust grains.
Small Extra Dimensions from the Interplay of Gauge and Supersymmetry Breaking
Creators: name: Buchmuller, Wilfried
name: Catena, Riccardo
name: Schmidt-Hoberg, Kai
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Higher-dimensional theories provide a promising framework for unified extensions of the supersymmetric standard model. Compactifications to four dimensions often lead to U(1) symmetries beyond the standard model gauge group, whose breaking scale is classically undetermined. Without supersymmetry breaking, this is also the case for the size of the compact dimensions. Fayet-Iliopoulos terms generically fix the scale M of gauge symmetry breaking. The interplay with supersymmetry breaking can then stabilize the compact dimensions at a size 1/M, much smaller than the inverse supersymmetry breaking scale 1/mu. We illustrate this mechanism with an SO(10) model in six dimensions, compactified on an orbifold.
description: 23 pages, 9 figures, to be published in Nuclear Physics, Section B
Parker Solar Probe Observations of Suprathermal Electron Flux Enhancements Originating from Coronal Hole Boundaries
Creators: name: Macneil, Allan R
name: Owens, Mathew J
name: Berčič, Laura
name: Finley, Adam J
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Reconnection between pairs of solar magnetic flux elements, one open and the other a closed loop, is theorised to be a crucial process for both maintaining the structure of the corona and producing the solar wind. This 'interchange reconnection' is expected to be particularly active at the open-closed boundaries of coronal holes (CHs). Previous analysis of solar wind data at 1AU indicated that peaks in the flux of suprathermal electrons at slow-fast stream interfaces may arise from magnetic connection to the CH boundary, rather than dynamic effects such as compression. Further, offsets between the peak and stream interface locations are suggested to be the result of interchange reconnection at the source. As a preliminary test of these suggestions, we analyse two solar wind streams observed during the first Parker Solar Probe (PSP) perihelion encounter, each associated with equatorial CH boundaries (one leading and one trailing with respect to rotation). Each stream features a peak in suprathermal electron flux, the locations and associated plasma properties of which are indicative of a solar origin, in agreement with previous suggestions from 1AU observations. Discrepancies between locations of the flux peaks and other features suggest these peaks may too be shifted by source region interchange reconnection. Our interpretation of each event is compatible with a global pattern of open flux transport, although random footpoint motions or other explanations remain feasible. These exploratory results highlight future opportunities for statistical studies regarding interchange reconnection and flux transport at CH boundaries with modern near-Sun missions.
Learning with Knowledge of Structure: A Neural Network-Based Approach for MIMO-OFDM Detection
Creators: name: Zhou, Zhou
name: Jere, Shashank
name: Zheng, Lizhong
name: Liu, Lingjia
Publisher: name: arXiv
Year: 2020
Subjects: subject: Signal Processing (eess.SP)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: In this paper, we explore neural network-based strategies for performing symbol detection in a MIMO-OFDM system. Building on a reservoir computing (RC)-based approach towards symbol detection, we introduce a symmetric and decomposed binary decision neural network to take advantage of the structure knowledge inherent in the MIMO-OFDM system. To be specific, the binary decision neural network is added in the frequency domain utilizing the knowledge of the constellation. We show that the introduced symmetric neural network can decompose the original $M$-ary detection problem into a series of binary classification tasks, thus significantly reducing the neural network detector complexity while offering good generalization performance with limited training overhead. Numerical evaluations demonstrate that the introduced hybrid RC-binary decision detection framework performs close to maximum likelihood model-based symbol detection methods in terms of symbol error rate in the low SNR regime with imperfect channel state information (CSI).
Luminosity dependence of the spatial and velocity distributions of galaxies: Semi-analytic models versus the Sloan Digital Sky Survey
Creators: name: Li, Cheng
name: Jing, Y. P.
name: Kauffmann, Guinevere
name: Boerner, Gerhard
name: Kang, Xi
name: Wang, Lan
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: By comparing semi-analytic galaxy catalogues with data from the Sloan Digital Sky Survey (SDSS), we show that current galaxy formation models reproduce qualitatively the dependence of galaxy clustering and pairwise peculiar velocities on luminosity, but some subtle discrepancies with the data still remain. The comparisons are carried out by constructing a large set of mock galaxy redshift surveys that have the same selection function as the SDSS Data Release Four (DR4). The mock surveys are based on two sets of semi-analytic catalogues presented by Croton et al. and Kang et al. From the mock catalogues, we measure the redshift-space projected two-point correlation function, the power spectrum, and the pairwise velocity dispersion (PVD) in Fourier space and in configuration space, for galaxies in different luminosity intervals. We then compare these theoretical predictions with the measurements derived from the SDSS DR4. On large scales and for galaxies brighter than L*, both sets of mock catalogues agree well with the data. For fainter galaxies, however, both models predict stronger clustering and higher pairwise velocities than observed. We demonstrate that this problem can be resolved if the fraction of faint satellite galaxies in massive haloes is reduced by ~30% compared to the model predictions. A direct look into the model galaxy catalogues reveals that a signifcant fraction (15%) of faint galaxies ($-1810^{13}\msun$, and this population is predominantly red in colour. These faint red galaxies are responsible for the high PVD values of low-luminosity galaxies on small scales.
description: 16 pages, 12 figures, accepted for publication in Monthly Notices, typos corrected
An Intelligent Quantum Cyber-Security Framework for Healthcare Data Management
Creators: name: Gupta, Kishu
name: Saxena, Deepika
name: Rani, Pooja
name: Kumar, Jitendra
name: Makkar, Aaisha
name: Singh, Ashutosh Kumar
name: Lee, Chung-Nan
Publisher: name: arXiv
Year: 2024
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: Digital healthcare is essential to facilitate consumers to access and disseminate their medical data easily for enhanced medical care services. However, the significant concern with digitalization across healthcare systems necessitates for a prompt, productive, and secure storage facility along with a vigorous communication strategy, to stimulate sensitive digital healthcare data sharing and proactive estimation of malicious entities. In this context, this paper introduces a comprehensive quantum-based framework to overwhelm the potential security and privacy issues for secure healthcare data management. It equips quantum encryption for the secured storage and dispersal of healthcare data over the shared cloud platform by employing quantum encryption. Also, the framework furnishes a quantum feed-forward neural network unit to examine the intention behind the data request before granting access, for proactive estimation of potential data breach. In this way, the proposed framework delivers overall healthcare data management by coupling the advanced and more competent quantum approach with machine learning to safeguard the data storage, access, and prediction of malicious entities in an automated manner. Thus, the proposed IQ-HDM leads to more cooperative and effective healthcare delivery and empowers individuals with adequate custody of their health data. The experimental evaluation and comparison of the proposed IQ-HDM framework with state-of-the-art methods outline a considerable improvement up to 67.6%, in tackling cyber threats related to healthcare data security.
Differences in the levels of role stress between registered nurses returning for their Baccalaureate degree in nursing and registered nurses in the work place
Creators: name: Foster, Sue
Publisher: name: University of British Columbia
Year: 2009

description: The purpose of this study is to compare the differences in the levels of role intensity and role disparity between registered nurses in the work place (RNs) and registered nurses returning for their baccalaureate degree in nursing (RRNs). Demographic variables were also captured and described. Three hundred and fifty female RNs in British Columbia were randomly selected to participate in the study. Each participant was mailed a Role Enactment Questionnaire and asked to return it to the researcher upon completion. The participants were aged 25-45, were married or partnered, had at least one child under the age of 6, and worked part-time. Two hundred of the group were also returning to university, part-time, for a baccalaureate degree in nursing. The "Role Enactment Questionnaire" and a demographic form were mailed to each participant. Sixty-eight questionnaires (19%) were returned and 38 (11%) were used in the analysis. Results indicate that generally the RRNs were a younger group than the RNs, with smaller numbers of children living with them full time. The RRNs reported having more children under the age of six living with them full time. Surprisingly, the RRN group also indicated that they worked more hours per week and had more flex time options available to them. Despite these demographic differences the RNs reported having more additional paid home help available. Personal income levels revealed that the RRN group had higher incomes than the RNs. However, for family income levels the RNs reported a higher level. When the groups were compared the RRNs perceived significantly lower levels of role intensity than the RNs. The RNs and RRNs reported perceiving similar levels of role disparity. Several implications for current and future RRNs, as well as nursing faculty and nurse administrators in relation to role intensity and role disparity have been derived from this study. The results indicate that RRNs who reduce their role demands and responsibilities will not necessarily experience low levels of role intensity and disparity. Therefore, attention to RRNs' cognitive perceptions of their role demands and responsibilities is needed before any actions can be implemented. Further research addressing the partner's involvement in family roles, and their level of role intensity and role disparity would provide insights into their perceptions. Longitudinal studies involving RNs and their partners, should be conducted comparing the RNs levels of role intensity and role disparity before and after they entered a baccalaureate program. This data would give us insight into perception changes in relation to role intensity and role disparity that occur when the RN adds the student role to the four roles of paid worker, parent, spouse/partner and individual.
Symmetry breaking induced magnon-magnon coupling in synthetic antiferromagnets
Creators: name: Lu, Jie
name: Li, Mei
name: He, Wei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We propose a general theory of microwave absorption spectroscopy for symmetry-breaking synthetic antiferromagnets (SAFs). Generally, inhomogeneity or different thickness of the two ferromagnetic sublayers of a SAF results in the intrinsic symmetry breaking, while out-of-plane components of dc magnetic fields lead to the extrinsic one. The broken symmetry of SAFs excludes the original symmetry-protected crossing between pure in-phase and out-of-phase resonance modes with opposite parity. Alternatively, new frequency branches become hybridization of original bare modes in terms of symmetry-breaking-induced magnon-magnon coupling, which results in an indirect gap in ferromagnetic resonance frequencies. Also, the dependence of gap width on the degree of symmetry breaking for several typical cases are presented and compared with existing experiments. Our theory provides a simple but physical understanding on the rich structure of ferromagnetic resonance spectra for asymmetric SAFs.
description: 6 pages, 2 figures
Two-dimensional Heisenberg antiferromagnet in a transverse field
Creators: name: Jensen, P. J.
name: Bennemann, K. H.
name: Morr, D. K.
name: Dreysse, H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We investigate the magnetic reorientation in a two-dimensional anisotropic antiferromagnet due to a transverse magnetic field. Using a many-body Green's function approach, we show that the magnetization component perpendicular to the applied field (and along the easy-axis of the antiferromagnet) initially increases with increasing field strength. We show that this unexpected result arises from the suppression of quantum and thermal fluctuations in the antiferromagnet. Above the Néel temperature, this effect leads to a reappearance of a magnetic moment along the easy-axis.
The inadequacy of a magnetohydrodynamic approach to the Biermann Battery
Creators: name: Ridgers, C. P.
name: Arran, C.
name: Bissell, J. J.
name: Kingham, R. J.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Magnetic fields can be generated in plasmas by the Biermann battery when the electric field produced by the electron pressure gradient has a curl. The commonly employed magnetohydrodynamic (MHD) model of the Biermann battery breaks down when the electron distribution function is distorted away from Maxwellian. Using both MHD and kinetic simulations of a laser-plasma interaction relevant to inertial confinement fusion we have shown that this distortion can reduce the Biermann-producing electric field by around 50\%. More importantly, the use of a flux limiter in an MHD treatment to deal with the effect of the non-Maxwellian electron distribution on electron thermal transport leads to a completely unphysical prediction of the Biermann-producing electric field and so results in erroneous predictions for the generated magnetic field.
MBIC – A Media Bias Annotation Dataset Including Annotator Characteristics
Creators: name: Spinde, Timo
name: Rudnitckaia, Lada
name: Sinha, Kanishka
name: Hamborg, Felix
name: Gipp, Bela
name: Donnay, Karsten
Publisher: name: figshare
Year: 2021
Subjects: subject: 80107 Natural Language Processing
subject: FOS: Computer and information sciences

description: Many people consider news articles to be a reliable source of information on current events. However, due to the range of factors influencing news agencies, such coverage may not always be impartial. Media bias, or slanted news coverage, can have a substantial impact on public perception of events, and, accordingly, can potentially alter the beliefs and views of the public. The main data gap in current research on media bias detection is a robust, representative, and diverse dataset containing annotations of biased words and sentences. In particular, existing datasets do not control for the individual background of annotators, which may affect their assessment and, thus, represents critical information for contextualizing their annotations. In this poster, we present a matrix-based methodology to crowdsource such data using a self-developed annotation platform. We also present MBIC (Media Bias Including Characteristics) - the first sample of 1,700 statements representing various media bias instances. The statements were reviewed by ten annotators each and contain labels for media bias identification both on the word and sentence level. MBIC is the first available dataset about media bias reporting detailed information on annotator characteristics and their individual background. The current dataset already significantly extends existing data in this domain providing unique and more reliable insights into the perception of bias. In future, we will further extend it both with respect to the number of articles and annotators per article.
On the robustness of the hybrid qubit computational gates through simulated randomized benchmarking protocols
Creators: name: Ferraro, Elena
name: De Michielis, Marco
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: One of the main challenges in building a quantum processor is to characterize the environmental noise. Noise characterization can be achieved by exploiting different techniques, such as randomization where several sequences of random quantum gates are applied to the qubit under test to derive statistical characteristics about the affecting noises. A scalable and robust algorithm able to benchmark the full set of Clifford gates using randomization techniques is called randomized benchmarking. In this study, we simulated randomized benchmarking protocols in a semiconducting all-electrical three-electron double-quantum dot qubit, i.e. hybrid qubit, under different error models, that include quasi-static Gaussian and the more realistic 1/f noise model, for the input controls. The average error of specific quantum computational gates is extracted through interleaved randomized benchmarking obtained including Clifford gates between the gate of interest. It provides an estimate of the fidelity as well as theoretical bounds for the average error of the gate under test.
description: 10 pages, 8 figures
Uncertainty in land allocation decisions for Vancouver Island : an application of fuzzy multiple objective programming
Creators: name: Ells, Arlene Kathryn
Publisher: name: University of British Columbia
Year: 2009

description: An increasing amount of weight is placed on non-timber values when management or allocation plans for woodlands are considered. In addition, the public is becoming more involved in the planning process. Both trends are evident on Vancouver Island, particularly in the recently completed work of the Commission on Resources and Environment (CORE), a multiple interest group process. A great deal of uncertainty is associated with decision-making situations of this type, due both to the complexity of the problem and the necessity to reconcile conflicting and poorly defined objectives. This study explored the use of fuzzy set theory as a tool for incorporating uncertainty into models used to inform decision-making processes. Two types of uncertainty were considered; vagueness in the identification and ranking of objectives and imprecision in the specification of problem parameters. Fuzzy set theory was used to construct a fuzzy multiple objective linear program (FMOLP) to capture the vagueness of objectives for the land-use allocation problem on Vancouver Island. This model was then extended through the use of possibility theory to a fuzzy possibilistic multiple objective linear program (FPMOLP), allowing consideration of the problem with imprecise parameters. Results were compared to those from a more traditional goal programming approach. Results from the FMOLP provided a better solution than did the goal programming approach when measured by the criteria of the degree of satisfaction of the problem's objectives. The FMOLP provided a higher degree of satisfaction to the majority of objectives considered, and yielded an allocation scheme where more of the land base was in multiple use and protected areas than did the goal program. Results from the FPMOLP were interpreted as a sensitivity analysis of the model with respect to uncertainty of parameter specification. It was demonstrated that the solution was sensitive to the level of parameter uncertainty considere. The methodology employed allowed only for general insights into this problem, proving a poor tool for this type of analysis.
An obstacle to sub-AdS holography for SYK-like models
Creators: name: Zhang, Pengfei
name: Gu, Yingfei
name: Kitaev, Alexei
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We argue that "stringy" effects in a putative gravity-dual picture for SYK-like models are related to the branching time, a kinetic coefficient defined in terms of the retarded kernel. A bound on the branching time is established assuming that the leading diagrams are ladders with thin rungs. Thus, such models are unlikely candidates for sub-AdS holography. In the weak coupling limit, we derive a relation between the branching time, the Lyapunov exponent, and the quasiparticle lifetime using two different approximations.
description: 31 pages, 3 figures
Study of the HII regions in the spiral galaxy NGC6384
Creators: name: Hakobyan, A. A.
name: Petrosian, A. R.
name: Yeghiazaryan, A. A.
name: Boulesteix, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The galaxy NGC6384 has been observed with an IPCS through H alpha and [NII] narrow-band interference filters for direct imagery with the 2.6 m Byurakan telescope. We studied main physical parameters of identified 98 HII regions, their diameter and luminosity functions, as well [NII]/H alpha ratio distribution. The integrated distribution function of the HII region diameters can be well fitted by the exponential function. The characteristic diameter has the value (Do = 217 pc) predicted for a galaxy of its measured absolute luminosity. The luminosity function of HII regions has double power laws profile with relatively shallow slope at low luminosities (a = - 0.4), an abrupt turnover at log L(H alpha) = 38.75, and sharper slope at higher luminosities (a = - 2.3). Correlation between luminosity and diameter of HII regions confirms that in general they are constant density, radiation-bound systems. [NII]/H alpha ratio data for HII regions show that there is a negative radial gradient of [NII]/H alpha. In the central region of the galaxy, nitrogen abundance is higher than in the periphery. The properties of the HII regions population of this AGN galaxy does not differs significantly from the properties of the HII regions population of the "normal" galaxies. Reexamining the location of the type Ia SN 1971L in the galaxy, we confirm that it lies on the spiral arm at about 8.6" far from the closest HII region #53 (F81). Such a location can be taken as prove that the progenitor of this SN do not belong to an old, evolved stellar population.
description: 17 pages, 7 figures
Electrically driven thermal light emission from individual single-walled carbon nanotubes
Creators: name: Mann, David
name: Kato, Y. K.
name: Kinkhabwala, Anika
name: Pop, Eric
name: Cao, Jien
name: Wang, Xinran
name: Zhang, Li
name: Wang, Qian
name: Guo, Jing
name: Dai, Hongjie
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Light emission from nanostructures exhibits rich quantum effects and has broad applications. Single-walled carbon nanotubes (SWNTs) are one-dimensional (1D) metals or semiconductors, in which large number of electronic states in a narrow range of energies, known as van Hove singularities, can lead to strong spectral transitions. Photoluminescence and electroluminescence involving interband transitions and excitons have been observed in semiconducting SWNTs, but are not expected in metallic tubes due to non-radiative relaxations. Here, we show that in the negative differential conductance regime, a suspended quasi-metallic SWNT (QM-SWNT) emits light due to joule-heating, displaying strong peaks in the visible and infrared corresponding to interband transitions. This is a result of thermal light emission in 1D, in stark contrast with featureless blackbody-like emission observed in large bundles of SWNTs or multi-walled nanotubes. This allows for probing of the electronic temperature and non-equilibrium hot optical phonons in joule-heated QM-SWNTs.
The influence of line opacity treatment in STELLA on supernova light curves
Creators: name: Kozyreva, Alexandra
name: Shingles, Luke
name: Mironov, Alexey
name: Baklanov, Petr
name: Blinnikov, Sergey
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We systematically explore the effect of the treatment of line opacity on supernova light curves. We find that it is important to consider line opacity for both scattering and absorption (i.e. thermalisation which mimics the effect of fluorescence.) We explore the impact of degree of thermalisation on three major types of supernovae: Type Ia, Type II-peculiar, and Type II-plateau. For that we use radiative transfer code STELLA and analyse broad-band light curves in the context of simulations done with the spectral synthesis code ARTIS and in the context a few examples of observed supernovae of each type. We found that the plausible range for the ratio between absorption and scattering in the radiation hydrodynamics code STELLA is (0.8-1):(0.2-0), i.e. the recommended thermalisation parameter is 0.9.
description: Accepted for publication in MNRAS
Free energy and segregation dynamics of two channel-confined polymers of different length
Creators: name: Polson, James M.
name: Zhu, Qinxin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: Polymers confined to a narrow channel are subject to strong entropic forces that tend to drive the molecules apart. In this study, we use Monte Carlo computer simulations to study the segregation behavior of two flexible hard-sphere polymers under confinement in a cylindrical channel. We focus on the effects of using polymers of different lengths. We measure the variation of the conformational free energy, $F$, with the center-of-mass separation distance, $λ$. The simulations reveal four different separation regimes, characterized by different scaling properties of the free energy with respect to the polymer lengths and the channel diameter, $D$. We propose a regime map in which the state of the system is determined by the values of the quantities $N_2/N_1$ and $λ/(N_1+N_2)D^{-β}$, where $N_1$ and $N_2$ are the polymer lengths, and where $β\approx 0.64$. The observed scaling behavior of $F(λ)$ in each regime is in reasonable agreement with predictions using a simple theoretical model. In addition, we use MC dynamics simulations to study the segregation dynamics of initially overlapping polymers by measurement of the incremental mean first-passage time with respect to $λ$. For systems characterized by a wide range of $λ$ in which a short polymer is nested within a longer one, the segregation dynamics are close to that expected for two noninteracting 1D random walkers undergoing unbiased diffusion. When the free energy gradient is large segregation is rapid and characterized by out-of-equilibrium effects.
description: 15 pages, 12 figures
Entropy of gravitating systems: scaling laws versus radial profiles
Creators: name: Pesci, Alessandro
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Through the consideration of spherically symmetric gravitating systems consisting of perfect fluids with linear equation of state constrained to be in a finite volume, an account is given of the properties of entropy at conditions in which it is no longer an extensive quantity (it does not scale with system's size). To accomplish this, the methods introduced by Oppenheim [1] to characterize non-extensivity are used, suitably generalized to the case of gravitating systems subject to an external pressure. In particular when, far from the system's Schwarzschild limit, both area scaling for conventional entropy and inverse radius law for the temperature set in (i.e. the same properties of the corresponding black hole thermodynamical quantities), the entropy profile is found to behave like 1/r, being r the area radius inside the system. In such circumstances thus entropy heavily resides in internal layers, in opposition to what happens when area scaling is gained while approaching the Schwarzschild mass, in which case conventional entropy lies at the surface of the system. The information content of these systems, even if it globally scales like the area, is then stored in the whole volume, instead of packed on the boundary.
description: 16 pages, 11 figures. v2: addition of some references; the stability of equilibrium configurations is readdressed
Towards TMA-Based Transmissive RIS Transceiver Enabled Downlink Communication Networks: A Consensus-ADMM Approach
Creators: name: Li, Zhendong
name: Chen, Wen
name: Qin, Haoran
name: Wu, Qingqing
name: Zhu, Xusheng
name: Zhang, Ziheng
name: Li, Jun
Publisher: name: arXiv
Year: 2024
Subjects: subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper presents a novel multi-stream downlink communication system that utilizes a transmissive reconfigurable intelligent surface (RIS) transceiver. Specifically, we elaborate the downlink communication scheme using time-modulated array (TMA) technology, which enables high order modulation and multi-stream beamforming. Then, an optimization problem is formulated to maximize the minimum signal-to-interference-plusnoise ratio (SINR) with user fairness, which takes into account the constraint of the maximum available power for each transmissive element. Due to the non-convex nature of the formulated problem,finding optimal solution is challenging. To mitigate the complexity,we propose a linear-complexity beamforming algorithm based on consensus alternating direction method of multipliers (ADMM).Specifically, by introducing a set of auxiliary variables, the problem can be decomposed into multiple sub-problems that are amenable to parallel computation, where the each sub-problem can yield closed-form expressions, bringing a significant reduction in the computational complexity. The overall problem achieves convergence by iteratively addressing these sub-problems in an alternating manner. Finally, the convergence of the proposed algorithm and the impact of various parameter configurations on the system performance are validated through numerical simulations.
A Multiwavelength Survey of Wolf-Rayet Nebulae in the Large Magellanic Cloud
Creators: name: Hung, Clara Shang
name: Ou, Po-Sheng
name: Chu, You-Hua
name: Gruendl, Robert A.
name: Li, Chuan-Jui
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Surveys of Wolf-Rayet (WR) stars in the Large Magellanic Cloud (LMC) have yielded a fairly complete catalog of 154 known stars. We have conducted a comprehensive, multiwavelength study of the interstellar/circumstellar environments of WR stars, using the Magellanic Cloud Emission Line Survey (MCELS) images in the H$α$, [O III], and [S II] lines; Spitzer Space Telescope 8 and 24 $μ$m images; Blanco 4m Telescope H$α$ CCD images; and Australian Telescope Compact Array (ATCA) + Parkes Telescope H I data cube of the LMC. We have also examined whether the WR stars are in OB associations, classified the H II environments of WR stars, and used this information to qualitatively assess the WR stars' evolutionary stages. The 30 Dor giant H II region has active star formation and hosts young massive clusters, thus we have made statistical analyses for 30 Dor and the rest of the LMC both separately and altogether. Due to the presence of massive young clusters, the WR population in 30 Dor is quite different from that from elsewhere in the LMC. We find small bubbles ($
description: 32 pages, 5 figures, accepted for publication in The Astrophysical Journal Supplement Series
Photonic Astronomy and Quantum Optics
Creators: name: Dravins, Dainis
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Quantum optics potentially offers an information channel from the Universe beyond the established ones of imaging and spectroscopy. All existing cameras and all spectrometers measure aspects of the first-order spatial and/or temporal coherence of light. However, light has additional degrees of freedom, manifest in the statistics of photon arrival times, or in the amount of photon orbital angular momentum. Such quantum-optical measures may carry information on how the light was created at the source, and whether it reached the observer directly or via some intermediate process. Astronomical quantum optics may help to clarify emission processes in natural laser sources and in the environments of compact objects, while high-speed photon-counting with digital signal handling enables multi-element and long-baseline versions of the intensity interferometer. Time resolutions of nanoseconds are required, as are large photon fluxes, making photonic astronomy very timely in an era of large telescopes.
description: Review; 32 pages, 15 figures, 167 references. Book chapter to appear in: D.Phelan, O.Ryan & A.Shearer, eds.: High Time Resolution Astrophysics (Astrophysics and Space Science Library, Springer, 2007). The original publication will be available at www.springerlink.com
One-Form Abelian Gauge Theory As The Hodge Theory
Creators: name: Malik, R. P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We demonstrate that the two (1 + 1)-dimensional (2D) free 1-form Abelian gauge theory provides an interesting field theoretical model for the Hodge theory. The physical symmetries of the theory correspond to all the basic mathematical ingredients that are required in the definition of the de Rham cohomological operators of differential geometry. The conserved charges, corresponding to the above continuous symmetry transformations, constitute an algebra that is reminiscent of the algebra obeyed by the de Rham cohomological operators. The topological features of the above theory are discussed in terms of the BRST and co-BRST operators. The super de Rham cohomological operators are exploited in the derivation of the nilpotent (anti-)BRST, (anti-)co-BRST symmetry transformations and the equations of motion for all the fields of the theory, within the framework of the superfield formulation. The derivation of the equations of motion, by exploiting the super Laplacian operator, is a completely new result in the framework of the superfield approach to BRST formalism. In an Appendix, the interacting 2D Abelian gauge theory (where there is a coupling between the U(1) gauge field and the Dirac fields) is also shown to provide a tractable field theoretical model for the Hodge theory.
description: LaTeX file, 39 pages, brief review, journal version
Strongly correlated bistable sublattice and temperature hysteresis of elastic and thermal crystal properties
Creators: name: Saiko, A. P.
name: Gusakov, V. E.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: It is shown that in crystal lattices with a basis the cooperative behavior of a certain type of atoms performing optical long-wavelength vibrations in a double-well potential of the field of the matrix lattice may lead to the formation of a bistable sublattice. As a result of the interaction of the metastable states of such a sublattice with the vibrational states of the matrix lattice, the elastic and thermal properties of the crystal acquire anomalous, hysteresis-like, temperature curves. The concepts developed in the paper make it possible to obtain a qualitative interpretation, which agrees with the experimental data, of the hysteresis-like temperature dependence of the speed and absorption of ultrasonic waves, the specific heat, and the thermal conductivity in superconducting yttrium and bismuth cuprates.
description: 15 pages, 9 figures
3D Segmentation of Neuronal Nuclei and Cell-Type Identification using Multi-channel Information
Creators: name: LaTorre, Antonio
name: Alonso-Nanclares, Lidia
name: Peña, José María
name: De Felipe, Javier
Publisher: name: arXiv
Year: 2024
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Background Analyzing images to accurately estimate the number of different cell types in the brain using automatic methods is a major objective in neuroscience. The automatic and selective detection and segmentation of neurons would be an important step in neuroanatomical studies. New method We present a method to improve the 3D reconstruction of neuronal nuclei that allows their segmentation, excluding the nuclei of non-neuronal cell types. Results We have tested the algorithm on stacks of images from rat neocortex, in a complex scenario (large stacks of images, uneven staining, and three different channels to visualize different cellular markers). It was able to provide a good identification ratio of neuronal nuclei and a 3D segmentation. Comparison with Existing Methods: Many automatic tools are in fact currently available, but different methods yield different cell count estimations, even in the same brain regions, due to differences in the labeling and imaging techniques, as well as in the algorithms used to detect cells. Moreover, some of the available automated software methods have provided estimations of cell numbers that have been reported to be inaccurate or inconsistent after evaluation by neuroanatomists. Conclusions It is critical to have a tool for automatic segmentation that allows discrimination between neurons, glial cells and perivascular cells. It would greatly speed up a task that is currently performed manually and would allow the cell counting to be systematic, avoiding human bias. Furthermore, the resulting 3D reconstructions of different cell types can be used to generate models of the spatial distribution of cells.
Frequency evaluation of the doubly forbidden $^1S_0\to ^3P_0$ transition in bosonic $^{174}$Yb
Creators: name: Poli, N.
name: Barber, Z. W.
name: Lemke, N. D.
name: Oates, C. W.
name: Ma, L. S.
name: Stalnaker, J. E.
name: Fortier, T. M.
name: Diddams, S. A.
name: Hollberg, L.
name: Bergquist, J. C.
name: Brusch, A.
name: Jefferts, S.
name: Heavner, T.
name: Parker, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: We report an uncertainty evaluation of an optical lattice clock based on the $^1S_0\leftrightarrow^3P_0$ transition in the bosonic isotope $^{174}$Yb by use of magnetically induced spectroscopy. The absolute frequency of the $^1S_0\leftrightarrow^3P_0$ transition has been determined through comparisons with optical and microwave standards at NIST. The weighted mean of the evaluations is $ν$($^{174}$Yb)=518 294 025 309 217.8(0.9) Hz. The uncertainty due to systematic effects has been reduced to less than 0.8 Hz, which represents $1.5\times10^{-15}$ in fractional frequency.
description: 4 pages, 3 figure -Submitted to PRA Rapid Communications
Remote Joint Strong Coordination and Reliable Communication
Creators: name: Cervia, Giulia
name: Oechtering, Tobias J.
name: Skoglund, Mikael
Publisher: name: arXiv
Year: 2020
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We consider a three-node network, in which two agents wish to communicate over a noisy channel, while controlling the distribution observed by a third external agent. We use strong coordination to constrain the distribution, and we provide a complete characterization of the "remote strong coordination and reliable communication" region.
Supersymmetric states of N=4 Yang-Mills from giant gravitons
Creators: name: Biswas, Indranil
name: Gaiotto, Davide
name: Lahiri, Subhaneil
name: Minwalla, Shiraz
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Mikhailov has constructed an infinite family of 1/8 BPS D3-branes in AdS(5) x S**5. We regulate Mikhailov's solution space by focussing on finite dimensional submanifolds. Our submanifolds are topologically complex projective spaces with symplectic form cohomologically equal to 2 pi N times the Fubini-Study Kahler class. Upon quantization and removing the regulator we find the Hilbert Space of N noninteracting Bose particles in a 3d Harmonic oscillator, a result previously conjectured by Beasley. This Hilbert Space is isomorphic to the classical chiral ring of 1/8 BPS states in N=4 Yang-Mills theory. We view our result as evidence that the spectrum of 1/8 BPS states in N=4 Yang Mills theory, which is known to jump discontinuously from zero to infinitesimal coupling, receives no further renormalization at finite values of the `t Hooft coupling.
description: 66 pages, Latex. v2: typos fixed, references added. v3: more typos and references
Patellogastropoda Lindberg 1986
Creators: name: Hansen, Thomas
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Patellogastropoda

description: Subclass Patellogastropoda Lindberg, 1986  Superfamily Lottioidea Gray, 1840a
description: Published as part of Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, pp. 1-196 in Zootaxa 4654 (1) on page 56, DOI: 10.11646/zootaxa.4654.1.1, http://zenodo.org/record/3365803
Feedback induced locking in semiconductor lasers with strong amplitude-phase coupling
Creators: name: Hausen, Jan
name: Herzog, Bastian
name: Nelde, Alexander
name: Meinecke, Stefan
name: Owschimikow, Nina
name: Lüdge, Kathy
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: The influence of optical feedback on semiconductor lasers has been a widely studied field of research due to fundamental interests as well as the optimization of optical data transmission and computing. Recent publications have shown that it is possible to induce a periodic pulsed like output in quantum-dot and quantum-well laser diodes utilizing the locking of the external cavity modes and the relaxation oscillation frequency. We present an in-depth analysis of this effect. We choose submonolayer quantum dots as a gain system, as these provide a relatively strong amplitude-phase coupling, which has proven to be very beneficial for these locking effects to occur. Introducing a new theoretical model we can correctly reproduce the essential features of the gain system and validate them by comparison to our experimental results. From this starting point we can further explore how the staircase behavior of the oscillation frequency with increasing pump current can be influenced by changing various laser parameters. The staircase behavior is induced by a reordering of the Hopf bifurcations giving birth to the regular pulsed-like oscillations.
description: 12 pages, 9 figures