cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
The ChaMP Extended Stellar Survey (ChESS): Photometric and Spectroscopic Properties of Serendipitously Detected Stellar X-ray Sources
Creators: name: Covey, K. R.
name: Agueros, M. A.
name: Green, P. J.
name: Haggard, D.
name: Barkhouse, W. A.
name: Drake, J.
name: Evans, N.
name: Kashyap, V.
name: Kim, D. -W.
name: Mossman, A.
name: Pease, D. O.
name: Silverman, J. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present 348 X-ray emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a serendipitous wide-area X-ray survey, with the Sloan Digital Sky Survey (SDSS). We use morphological star/galaxy separation, an SDSS quasar catalog, an optical color-magnitude cut, and X-ray data quality tests to create our catalog, the ChaMP Extended Stellar Survey (ChESS), from a sample of 2121 matched ChaMP/SDSS sources. Our cuts retain 92% of the spectroscopically confirmed stars while excluding 99.6% of the 684 spectoscopically confirmed extragalactic sources. Fewer than 3% of the sources in our final catalog are previously identified stellar X-ray emitters; we expect ~10% of the catalog is composed by giants, and identify seven giant stars and three cataclysmic variables. We derive distances, X-ray and bolometric luminosities for these stars, revealing that this catalog fills the gap between the nearby stars identified by the ROSAT All-Sky Survey and the more distant stars detected in deep Chandra and XMM-Newton surveys. For 36 newly identified X-ray emitting M stars we calculate L_(Halpha)/L_(bol). L_(Hα)/L_(bol) and L_(X)/L_(bol) are linearly related below L_(X)/L_(bol) ~ 3 x 10^(-4), while L_(Halpha)/L_(bol) appears to turn over at larger L_(X)/L_(bol) values. Stars with reliable SDSS photometry have an ~0.1 mag blue excess in (u-g), likely due to increased chromospheric continuum emission. Photometric metallicity estimates suggest the sample is split between the young and old disk populations of the Galaxy; the lowest activity sources belong to the old disk population, a clear signature of the decay of magnetic activity with age. Future papers will present analyses of source variability and comparisons of this catalog to models of stellar activity in the Galactic disk.
description: 21 pages, 12 figures, emulateapj format. Accepted for publication in ApJS. Tables 2 and 3 shown as stubs, and figures degraded to meet resolution limits. Full resolution version available from http://www.cfa.harvard.edu/~kcovey/ChESS.fullres.ps
Liouville Theory and Elliptic Genera
Creators: name: Taormina, Anne
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The structure and modular properties of N=4 superconformal characters are reviewed and exploited, in an attempt to construct elliptic genera-like functions by decompactifying K3. The construction is tested against expressions obtained in the context of strings propagating in background ALE spaces of type A(n-1), using the underlying superconformal theory, i.e the tensor product of N=2 minimal with N=2 Liouville theory.
description: 16 pages, Contribution to the Proceedings of the conference "30 Years of Mathematical Methods in High Energy Physics", Kyoto, March 2008, in honour of Prof. Tohru Eguchis 60th birthday; one reference added and clarification on the chronology of derivations of character modular transformations in Section 2
Tailoring Graphene with Metals on Top
Creators: name: Uchoa, B.
name: Lin, C. -Y.
name: Neto, A. H. Castro
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We study the effects of metallic doping on the electronic properties of graphene using density functional theory in the local density approximation in the presence of a local charging energy (LDA+U). The electronic properties are sensitive to whether graphene is doped with alkali or transition metals. We estimate the the charge transfer from a single layer of Potassium on top of graphene in terms of the local charging energy of the graphene sheet. The coating of graphene with a non-magnetic layer of Palladium, on the other hand, can lead to a magnetic instability in coated graphene due to the hybridization between the transition-metal and the carbon orbitals.
description: 5 pages, 4 figures
Direct simulations of a supernova-driven galactic dynamo
Creators: name: Gressel, Oliver
name: Elstner, Detlef
name: Ziegler, Udo
name: Rüdiger, Günther
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Supernovae are known to be the dominant energy source for driving turbulence in the interstellar medium. Yet, their effect on magnetic field amplification in spiral galaxies is still poorly understood. Previous analytical models, based on the evolution of isolated, non-interacting supernova remnants, predicted a dominant vertical pumping that would render dynamo action improbable. In the present work, we address the issue of vertical transport, which is thought to be the key process that inhibits dynamo action in the galactic context. We aim to demonstrate that supernova driving is a powerful mechanism to amplify galactic magnetic fields. We conduct direct numerical simulations in the framework of resistive magnetohydrodynamics. Our local box model of the interstellar medium comprises optically-thin radiative cooling, an external gravitational potential, and background shear. Dynamo coefficients for mean-field models are measured by means of passive test fields. Our simulations show that supernova-driven turbulence in conjunction with shear leads to an exponential amplification of the mean magnetic field. We found turbulent pumping to be directed inward and approximately balanced by a galactic wind.
description: minor changes, 4 pages, 4 figures, accepted for publication in A&A L
Real-Time Multi-Level Neonatal Heart and Lung Sound Quality Assessment for Telehealth Applications
Creators: name: Grooby, Ethan
name: Sitaula, Chiranjibi
name: Fattahi, Davood
name: Sameni, Reza
name: Tan, Kenneth
name: Zhou, Lindsay
name: King, Arrabella
name: Ramanathan, Ashwin
name: Malhotra, Atul
name: Dumont, Guy A.
name: Marzbanrad, Faezeh
Publisher: name: arXiv
Year: 2021
Subjects: subject: Audio and Speech Processing (eess.AS)
subject: Machine Learning (cs.LG)
subject: Sound (cs.SD)
subject: Signal Processing (eess.SP)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: Digital stethoscopes in combination with telehealth allow chest sounds to be easily collected and transmitted for remote monitoring and diagnosis. Chest sounds contain important information about a newborn's cardio-respiratory health. However, low-quality recordings complicate the remote monitoring and diagnosis. In this study, a new method is proposed to objectively and automatically assess heart and lung signal quality on a 5-level scale in real-time and to assess the effect of signal quality on vital sign estimation. For the evaluation, a total of 207 10s long chest sounds were taken from 119 preterm and full-term babies. Thirty of the recordings from ten subjects were obtained with synchronous vital signs from the Neonatal Intensive Care Unit (NICU) based on electrocardiogram recordings. As reference, seven annotators independently assessed the signal quality. For automatic quality classification, 400 features were extracted from the chest sounds. After feature selection using minimum redundancy and maximum relevancy algorithm, class balancing, and hyper-parameter optimization, a variety of multi-class and ordinal classification and regression algorithms were trained. Then, heart rate and breathing rate were automatically estimated from the chest sounds using adapted pre-existing methods. The results of subject-wise leave-one-out cross-validation show that the best-performing models had a mean squared error (MSE) of 0.49 and 0.61, and balanced accuracy of 57% and 51% for heart and lung qualities, respectively. The best-performing models for real-time analysis (<200ms) had MSE of 0.459 and 0.67, and balanced accuracy of 57% and 46%, respectively. Our experimental results underscore that increasing the signal quality leads to a reduction in vital sign error, with only high-quality recordings having a mean absolute error of less than 5 beats per minute, as required for clinical usage.
description: 13 pages, 8 figures, 3 tables. Paper submitted and under review in IEEE Access
Wavefront tolerances of space-based segmented telescopes at very high contrast: Experimental validation
Creators: name: Laginja, Iva
name: Sauvage, Jean-François
name: Mugnier, Laurent M.
name: Pueyo, Laurent
name: Perrin, Marshall D.
name: Noss, James
name: Will, Scott D.
name: Brooks, Keira J.
name: Por, Emiel H.
name: Petrone, Peter
name: Soummer, Rémi
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Context: The detection and characterization of Earth-like exoplanets (exoEarths) from space requires exquisite wavefront stability at contrast levels of $10^{-10}$. On segmented telescopes in particular, aberrations induced by cophasing errors lead to a light leakage through the coronagraph, deteriorating the imaging performance. These need to be limited in order to facilitate the direct imaging of exoEarths. Aims: We perform a laboratory validation of an analytical tolerancing model that allows us to determine wavefront error requirements in the $10^{-6} - 10^{-8}$ contrast regime, for a segmented pupil with a classical Lyot coronagraph. We intend to compare the results to simulations, and we aim to establish an error budget for the segmented mirror on the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed. Methods: We use the Pair-based Analytical model for Segmented Telescope Imaging from Space (PASTIS) to measure a contrast influence matrix of a real high contrast instrument, and use an analytical model inversion to calculate per-segment wavefront error tolerances. We validate these tolerances on the HiCAT testbed by measuring the contrast response of segmented mirror states that follow these requirements. Results: The experimentally measured optical influence matrix is successfully measured on the HiCAT testbed, and we derive individual segment tolerances from it that correctly yield the targeted contrast levels. Further, the analytical expressions that predict a contrast mean and variance from a given segment covariance matrix are confirmed experimentally.
description: 16 pages, 16 figures, accepted for publication in A&A
Comparison of Cluster Lensing Profiles with Lambda CDM Predictions
Creators: name: Broadhurst, Tom
name: Umetsu, Keiichi
name: Medezinski, Elinor
name: Oguri, Masamune
name: Rephaeli, Yoel
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We derive lens distortion and magnification profiles of four well known clusters observed with Subaru. Each cluster is very well fitted by the general form predicted for Cold Dark Matter (CDM) dominated halos, with good consistency found between the independent distortion and magnification measurements. The inferred level of mass concentration is surprisingly high, 8 = 10.4 \pm 0.9), compared to the relatively shallow profiles predicted by the Lambda CDM model, c_{vir}=5.1 \pm 1.1 (for =1.25\times 10^{15}M_{\odot}/h). This represents a 4sigma discrepancy, and includes the relatively modest effects of projection bias and profile evolution derived from N-body simulations, which oppose each other with little residual effect. In the context of CDM based cosmologies, this discrepancy implies clusters collapse earlier (z\geq 1) than predicted (z<0.5), when the Universe was correspondingly denser.
description: Accepted version in ApJL, minor changes
Design and analysis of multi-channel protocols in local area networks
Creators: name: Khoshnevis, Hamid
Publisher: name: University of British Columbia
Year: 2010

description: Current implementations of local area networks utilize a single channel for packet transmission. The need for multi-channel networks arises whenever (a) the population of users is large, and the extra hardware cost incurred by increasing the data rates in response to higher user demands, is not justified, (b) the bandwidth is available only in segments (such as in CATV systems), or (c) the use of high data rates causes an unacceptably high bit-error probability. We propose two different multi-channel access control protocols. The first, SRMA/m, utilizes a distributed scheme for request, and a central scheme for message packet scheduling. The second protocol, MCMA/m, is totally distributed, avoiding much of the hardware complexity of SRMA/m. The performance of the protocols is studied using a combination of analytical and simulation methods. The performance criteria are efficient bandwidth utilization and small average delays. The same system parameters are used for both protocols, making a comparative study possible. The delay vs. throughput performances of the two protocols are compared. The comparison indicates that for light to intermediate loads, MCMA/m shows a better performance (i.e. lower delays for the same throughputs). For higher loads, the relative performance depends on m, the number of channels. For small values of m (1£m£4), the overall performance of MCMA/m is superior. However as m increases, SRMA/m shows a better performance in the form of lower delays and fixed capacity (versus decreasing capacity of MCMA/m). In conclusion, the choice between SRMA/m and MCMA/m is based on a direct cost/performance tradeoff. For most ranges of parameters, SRMA/m achieves a superior performance at the expense of higher hardware complexity and cost.
Backreacting Flavors in the Klebanov-Strassler Background
Creators: name: Benini, Francesco
name: Canoura, Felipe
name: Cremonesi, Stefano
name: Nunez, Carlos
name: Ramallo, Alfonso V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we present new analytic solutions of pure Type IIB supergravity plus D7-branes describing the addition of an arbitrary number of flavors to the Klebanov-Tseytlin and Klebanov-Strassler backgrounds. We provide a precise field theory dual and a detailed analysis of the duality cascade which describes its RG flow. Matchings of beta functions and anomalies between the field theory and the string setup are presented. We give an understanding of Seiberg duality as a large gauge transformation on the RR and NSNS potentials. We also analyze the UV behavior of the field theory, that as suggested by the string background can be associated with a duality wall.
description: 33 pages, 2 figures;v2: typos corrected
The precursor state to superconductivity in CeIrIn${_5}$: Unusual scaling of magnetotransport
Creators: name: Nair, Sunil
name: Nicklas, M.
name: Steglich, F.
name: Sarrao, J. L.
name: Thompson, J. D.
name: Schofield, A. J.
name: Wirth, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We present an analysis of the normal-state Hall effect and magnetoresistance in the heavy fermion superconductor CeIrIn${_5}$. It is demonstrated that the modified Kohler's scaling--which relates the magnetoresistance to the Hall angle--breaks down prior to the onset of superconductivity due to the presence of a precursor state to superconductivity in this system. A model-independent, single-parameter scaling of the Hall angle governed solely by this precursor state is observed. Neither the Hall coefficient nor the resistivity exhibit this scaling implying that this precursor state preferentially influences the Hall channel.
On the distance of PG 1553+11. A lineless BL Lac object active in the TeV band
Creators: name: Treves, Aldo
name: Falomo, Renato
name: Uslenghi, Michela
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Context: The redshift of PG 1553+11, a bright BL Lac object (V~14), is still unknown. It has been recently observed in the TeV band, a fact that offers an upper limit for the redshift z<0.4. Aims: We intend to provide a lower limit for the distance of the object. Methods: We used a chi^2 procedure to constrain the apparent magnitude of the host galaxy in archived HST images. Supposing that the host galaxy is typical of BL Lac objects (M_{R} -22.8), a lower limit to the distance can be obtained from the limit on the apparent magnitude of the host galaxy. Results: Using the 3 sigma limit on the host galaxy magnitude, the redshift is found to be greater or equal to 0.25. Conlusions: The redshift of PG 1553+11 is probably in the range z=0.3-0.4, making this object the most distant extragalactic source so far detected in the TeV energies. We suggest that other bright BL Lac objects of unknown redshift and similar spectroscopic characteristics may be interesting targets for TeV observations.
description: Accepted for publication in A&A letters, 4 pages, 5 figures
First-principles analysis of the optical properties of lead halide perovskite solution precursors
Creators: name: Procida, Giovanni
name: Schier, Richard
name: Valencia, Ana M.
name: Cocchi, Caterina
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Lead halide perovskites (LHPs) are promising materials for opto-electronics and photovoltaics, thanks to favorable characteristics and low manufacturing costs enabled by solution processing. In light of this, it is crucial to assess the impact of solvent-solute interactions on the electronic and optical properties of LHPs and of their solution precursors. In a first-principles work based on time-dependent density-functional theory coupled with the polarizable continuum model, we investigate the electronic and optical properties of a set of charge-neutral compounds with chemical formula, PbX$_2$(Sol)$_4$, where X=Cl, Br, and I, and Sol are the six common solvents. We find that single-particle energies and optical gaps depend on the halogen species as well as on the solvent molecules, which also affect the energy and the spatial distribution of the molecular orbitals, thereby impacting on the excitations. We clarify that dark states at the absorption onset are promoted by electron-withdrawing solvents, and we show the correlation between oscillator strength and HOMO$\rightarrow$LUMO contribution to the excitations. Our results provide microscopic insight into the electronic and optical properties of LHP solution precursors, complementing ongoing experimental research on these systems and on their evolution to photovoltaic thin films.
description: Supporting Information available free of charge at the journal webpage
ФОРМУЛА КАРЛЕМАНА ДЛЯ ОБОБЩЕННОЙ СИСТЕМЫ КОШИ-РИМАНА С КВАТЕРНИОННЫМ ПАРАМЕТРОМ
Creators: name: Сатторов, Э.Н.
name: Рустамов, С.У.
Publisher: name: Zenodo
Year: 2023

description: В данной работе получено формула Карлемана для решений обобщенной системы Коши-Римана с кватернионным параметром  в ограниченной трехмерной области.
At ease with your tics: A guided relaxation (GR) 12th European conference on Tourette syndrome and tic disorders
Creators: name: Anderson, Seonaid
name: Murphy, Tara
name: Griendt, Jolande Van Der
name: Verdellen, Cara
name: Murray, Liz
Publisher: name: F1000 Research Limited
Year: 2019

description: Behavioural interventions for tics are recommended as first-line treatments and often preferred by patients to
medication. Relaxation is common in evidence-based packages of treatment e.g. Exposure with Response Prevention (ERP) and Comprehensive Behavioural Intervention for Tics (CBITS).

A guided relaxation ‘At ease with your tics: A Guided Relaxation’ (GR) aimed to help patients with TS access a mindfulness/relaxation technique.  Underlying mechanisms of tic-alleviating processes are unknown, but a focus on internal processes may be effective. Favourable effects of mindfulness-based reduction on tics for adults with TS/CTD have been reported. This third wave behavioural therapy has gained empirical support across a range of conditions.
title: Injector Optimization at the Superconducting Darmstadt Linear Electron Accelerator S-DALINAC
Creators: name: Weih, Simon
Publisher: name: UNSPECIFIED
Year: 2022

description: The former 5-cell capture cavity of the S-DALINAC injector was insufficiently adapted to the beam energies provided by the electron sources. This led to an inefficient energy gain and a deterioration of the beam quality in this acceleration structure. In order to optimize the performance of the injector, especially with regard to an accelerator operation in the energy-recovery mode, it was therefore necessary to replace the 5-cell cavity with a dedicated β-adapted capture structure. This project was implemented within the scope of this dissertation. A new β-reduced 6-cell structure was manufactured, tested and installed at the accelerator. Tuner frame components had to be adapted to the novel geometry and mechanical features of the cavity. To achieve an exchange of the cavities within a regular maintenance shutdown, full compatibility with the existing cryostat was prioritized during the design of the modified cryomodule components. In addition, a beam diagnostic setup was conceptualized, installed and commissioned upstream of the capture cavity. This setup was used to characterize momentum spreads of the beam along the normal-conducting injector section with a relative uncertainty of ±2 %. Furthermore, parameters of the beam entering the superconducting injector section, which have a significant influence on the achievable injector beam quality, could be optimized. After the cool-down of the installed capture cavity, full functionality of the upgraded cryomodule was shown. First beam parameter studies were conducted at the optimized injector. The results were benchmarked against the former injector setup. Besides a reduction of the momentum spread by a factor of around four, a substantially improved energy gain of up to 1.4 MeV was achieved in the new capture structure for an incident beam energy of 250 keV. Furthermore, a decreased bunch length was observed at the injector beam, which had already proven beneficial for the overall S-DALINAC performance during ERL experiments following the commissioning. The optimized injector is fully operational and is now available for further beam operation at the S-DALINAC.
Convergence of nonlocal threshold dynamics approximations to front propagation
Creators: name: Caffarelli, Luis A.
name: Souganidis, Panagiotis E.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35J60; 35J15; 35Q40

description: In this note we prove that appropriately scaled threshold dynamics-type algorithms corresponding to the fractional Laplacian of order $α\in (0,2)$ converge to moving fronts. When $α\geqq 1$ the resulting interface moves by weighted mean curvature, while for $α<1$ the normal velocity is nonlocal of ``fractional-type.'' The results easily extend to general nonlocal anisotropic threshold dynamics schemes.
description: 19 pages
A Review of Text Style Transfer using Deep Learning
Creators: name: Toshevska, Martina
name: Gievska, Sonja
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Style is an integral component of a sentence indicated by the choice of words a person makes. Different people have different ways of expressing themselves, however, they adjust their speaking and writing style to a social context, an audience, an interlocutor or the formality of an occasion. Text style transfer is defined as a task of adapting and/or changing the stylistic manner in which a sentence is written, while preserving the meaning of the original sentence. A systematic review of text style transfer methodologies using deep learning is presented in this paper. We point out the technological advances in deep neural networks that have been the driving force behind current successes in the fields of natural language understanding and generation. The review is structured around two key stages in the text style transfer process, namely, representation learning and sentence generation in a new style. The discussion highlights the commonalities and differences between proposed solutions as well as challenges and opportunities that are expected to direct and foster further research in the field.
Water vapour and hydrogen in the terrestrial-planet-forming region of a protoplanetary disk
Creators: name: Eisner, J. A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Planetary systems, ours included, are formed in disks of dust and gas around young stars. Disks are an integral part of the star and planet formation process, and knowledge of the distribution and temperature of inner disk material is crucial for understanding terrestrial planet formation, giant planet migration, and accretion onto the central star. While the inner regions of protoplanetary disks in nearby star forming regions subtend only a few nano-radians, near-IR interferometry has recently enabled the spatial resolution of these terrestrial zones. Most observations have probed only dust, which typically dominates the near-IR emission. Here I report spectrally dispersed near-IR interferometric observations that probe gas (which dominates the mass and dynamics of the inner disk), in addition to dust, within one astronomical unit of the young star MWC 480. I resolve gas, including water vapor and atomic hydrogen, interior to the edge of the dust disk; this contrasts with results of previous spectrally dispersed interferometry observations. Interactions of this accreting gas with migrating planets may lead to short-period exoplanets like those detected around main-sequence stars. The observed water vapor is likely produced by the sublimation of migrating icy bodies, and provides a potential reservoir of water for terrestrial planets.
description: 15 pages, 3 figures. Appeared in Nature May 31. Supplementary information available at http://www.nature.com/nature
Synchrotron radiation from a charge moving along a helix around a dielectric cylinder
Creators: name: Saharian, A. A.
name: Kotanjyan, A. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Other Condensed Matter (cond-mat.other)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: In this paper we investigate the radiation emitted by a charged particle moving along a helical orbit around a dielectric cylinder immersed into a homogeneous medium. Formulae are derived for the electromagnetic potentials, electric and magnetic fields, and for the spectral-angular distribution of the radiation in the exterior medium. It is shown that under the Cherenkov condition for dielectric permittivity of the cylinder and the velocity of the particle image on the cylinder surface, strong narrow peaks appear in the angular distribution for the number of quanta radiated on a given harmonic. At these peaks the radiated energy exceeds the corresponding quantity for a homogeneous medium by several dozens of times. Simple analytic estimates are given for the heights and widths of these peaks. The results of numerical calculations for the angular distribution of the radiated quanta are presented and they are compared with the corresponding quantities for the radiation from a charge moving along a helical trajectory inside a dielectric cylinder.
description: 14 pages, 2 figures
Detection loophole in quantum causality and its countermeasures
Creators: name: Cao, Zhu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Quantum causality violates classical intuitions of cause and effect and is a unique quantum feature different from other quantum phenomena such as entanglement and quantum nonlocality. In order to avoid the detection loophole in quantum causality, we initiate the study of the detection efficiency requirement for observing quantum causality. We first show that previous classical causal inequalities require detection efficiency at least 95.97% (89.44%) to show violation with quantum (nonsignaling) correlations. Next we derive a classical causal inequality I_{222} and show that it requires lower detection efficiency to be violated, 92.39% for quantum correlations and 81.65% for nonsignaling correlations, hence substantially reducing the requirement on detection. Then we extend this causal inequality to the case of multiple measurement settings and analyze the corresponding detection efficiency. After that, we show that previous quantum causal inequalities require detection efficiency at least 94.29% to violate with nonsignaling correlations. We subsequently derive a quantum causal bound J_{222} that has a lower detection efficiency requirement of 91.02% for violation with nonsignaling correlations. Our work paves the way towards an experimental demonstration of quantum causality and shows that causal inequalities significantly differ from Bell inequalities in terms of the detection efficiency requirement.
description: 18 pages, 7 figures
Search for fast radio transients using Arecibo drift-scan observations at 1.4 GHz
Creators: name: Perera, B. B. P.
name: Smith, A. J.
name: Vaddi, S.
name: Carballo-Rubio, R.
name: McGilvray, A.
name: Venkataraman, A.
name: Roshi, D. Anish
name: Manoharan, P. K.
name: Perillat, P.
name: Lieb, E.
name: Lorimer, D. R.
name: McLaughlin, M. A.
name: Agarwal, D.
name: Aggarwal, K.
name: Ransom, S. M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We conducted a drift-scan observation campaign using the 305-m Arecibo telescope in January and March 2020 when the observatory was temporarily closed during the intense earthquakes and the initial outbreak of the COVID-19 pandemic, respectively. The primary objective of the survey was to search for fast radio transients, including Fast Radio Bursts (FRBs) and Rotating Radio Transients (RRATs). We used the 7-beam ALFA receiver to observe different sections of the sky within the declination region $\sim$(10$-$20) deg on 23 nights and collected 160 hours of data in total. We searched our data for single-pulse transients, covering up to a maximum dispersion measure of 11 000 pc cm$^{-3}$ at which the dispersion delay across the entire bandwidth is equal to the 13 s transit length of our observations. The analysis produced more than 18 million candidates. Machine learning techniques sorted the radio frequency interference and possibly astrophysical candidates, allowing us to visually inspect and confirm the candidate transients. We found no evidence for new astrophysical transients in our data. We also searched for emission from repeated transient signals, but found no evidence for such sources. We detected single pulses from two known pulsars in our observations and their measured flux densities are consistent with the expected values. Based on our observations and sensitivity, we estimated the upper limit for the FRB rate to be $
description: 11 pages, 8 figures. Accepted 2021 October 27 for publication in MNRAS
Phenomenology of D-Brane Inflation with General Speed of Sound
Creators: name: Peiris, Hiranya V.
name: Baumann, Daniel
name: Friedman, Brett
name: Cooray, Asantha
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: A characteristic of D-brane inflation is that fluctuations in the inflaton field can propagate at a speed significantly less than the speed of light. This yields observable effects that are distinct from those of single-field slow roll inflation, such as a modification of the inflationary consistency relation and a potentially large level of non-Gaussianities. We present a numerical algorithm that extends the inflationary flow formalism to models with general speed of sound. For an ensemble of D-brane inflation models parameterized by the Hubble parameter and the speed of sound as polynomial functions of the inflaton field, we give qualitative predictions for the key inflationary observables. We discuss various consistency relations for D-brane inflation, and compare the qualitative shapes of the warp factors we derive from the numerical models with analytical warp factors considered in the literature. Finally, we derive and apply a generalized microphysical bound on the inflaton field variation during brane inflation. While a large number of models are consistent with current cosmological constraints, almost all of these models violate the compactification constraint on the field range in four-dimensional Planck units. If the field range bound is to hold, then models with a detectable level of non-Gaussianity predict a blue scalar spectral index, and a tensor component that is far below the detection limit of any future experiment.
description: 23 pages, 11 figures, v2: version accepted by PRD; minor clarifications and references added to the text. Higher resolution figures are available in the published version. v3: post-publication correction of typo in Eq. 87. No results/conclusions changed
Study on higher moments of net-charge multiplicity distributions using a multiphase transport model
Creators: name: Huang, Ling
name: Ma, Guo-Liang
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The moments and moment products of conserved charges are believed to be sensitive to critical fluctuations, which have been adopted in determining the QCD critical point. Using a dynamical multiphase transport model, we reproduce the centrality and energy dependences of moments and moment products of net-charge multiplicity distributions in Au+Au collisions measured by the Beam Energy Scan program at the RHIC. No non-monotonic energy dependence is observed. We infer that the moment products develop during the dynamical evolution of heavy-ion collisions. The observed difference based on the expectation of the Poisson baseline indicates a positive two-particle correlation between positively and negatively charged particles, which can arise from different dynamical processes at different stages. Therefore, to adopt moments and moment products of net-charge multiplicity distributions in determining the QCD critical point of relativistic heavy-ion collisions, it is essential to take the dynamical evolution.
description: 10 pages, 14 figures
Emergent Universe and Phantom Tachyon Model
Creators: name: Debnath, Ujjal
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this work, I have considered that the universe is filled with normal matter and phantom field (or tachyonic field). If the universe is filled with scalar field, Ellis et al have shown that emergent scenario is possible only for $k=+1$ i.e. for closed universe and here I have shown that the emergent scenario is possible for closed universe if the universe contains normal tachyonic field. But for phantom field (or tachyonic field), the negative kinetic term can generate the emergent scenario for all values of $k ~(=0,\pm 1)$. From recently developed statefinder parameters, the behaviour of different stages of the evolution of the emergent universe have been studied. The static Einstein universe and the stability analysis have been briefly discussed for both phantom and tachyon models.
description: 7 Latex pages, 7 figures, RevTex style
(GL(n+1,F),GL(n,F)) is a Gelfand pair for any local field F
Creators: name: Aizenbud, Avraham
name: Gourevitch, Dmitry
name: Sayag, Eitan
Publisher: name: arXiv
Year: 2007
Subjects: subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 22E,22E45,20G05,20G25,46F99

description: Let F be an arbitrary local field. Consider the standard embedding of GL(n,F) into GL(n+1,F) and the two-sided action of GL(n,F) \times GL(n,F) on GL(n+1,F). In this paper we show that any GL(n,F) \times GL(n,F)-invariant distribution on GL(n+1,F) is invariant with respect to transposition. We show that this implies that the pair (GL(n+1,F),GL(n,F)) is a Gelfand pair. Namely, for any irreducible admissible representation $(π,E)$ of (GL(n+1,F), $$dimHom_{GL(n,F)}(E,\cc) \leq 1.$$ For the proof in the archimedean case we develop several new tools to study invariant distributions on smooth manifolds.
description: v3: Archimedean Localization principle excluded due to a gap in its proof. Another version of Localization principle can be found in arXiv:0803.3395v2 [RT]. v4: an inaccuracy with Bruhat filtration fixed. See Theorem 4.2.1 and Appendix B
Topological Sigma B Model in 4-Dimensions
Creators: name: Jun, Hyun-Keun
name: Park, Jae-Suk
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We propose a 4-dimensional version of topological sigma B-model, governing maps from a smooth compact 4-manifold M to a Calabi-Yau target manifold X. The theory depends on on complex structure of X, while is independent of Kaehler metric of X. The theory is also a 4-dimensiona topological field theory in the sense that the theory is independent of variation of Riemannian metric of the source 4-manifold M, potentially leading to new smooth invariant of 4-manifolds. We argue that the theory also comes with a topological family parametrized by the extended moduli space of complex structures.
description: 16 pages, JHEP style (minor corrections)
Inside-Out Evacuation of Transitional Protoplanetary Disks by the Magneto-Rotational Instability
Creators: name: Chiang, Eugene I.
name: Murray-Clay, Ruth A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: How do T Tauri disks accrete? The magneto-rotational instability (MRI) supplies one means, but protoplanetary disk gas is typically too poorly ionized to be magnetically active. Here we show that the MRI can, in fact, explain observed accretion rates for the sub-class of T Tauri disks known as transitional systems. Transitional disks are swept clean of dust inside rim radii of ~10 AU. Stellar coronal X-rays ionize material in the disk rim, activating the MRI there. Gas flows from the rim to the star, at a rate limited by the depth to which X-rays ionize the rim wall. The wider the rim, the larger the surface area that the rim wall exposes to X-rays, and the greater the accretion rate. Interior to the rim, the MRI continues to transport gas; the MRI is sustained even at the disk midplane by super-keV X-rays that Compton scatter down from the disk surface. Accretion is therefore steady inside the rim. Blown out by radiation pressure, dust largely fails to accrete with gas. Contrary to what is usually assumed, ambipolar diffusion, not Ohmic dissipation, limits how much gas is MRI-active. We infer values for the transport parameter alpha on the order of 0.01 for GM Aur, TW Hyd, and DM Tau. Because the MRI can only afflict a finite radial column of gas at the rim, disk properties inside the rim are insensitive to those outside. Thus our picture provides one robust setting for planet-disk interaction: a protoplanet interior to the rim will interact with gas whose density, temperature, and transport properties are definite and decoupled from uncertain initial conditions. Our study also supplies half the answer to how disks dissipate: the inner disk drains from the inside out by the MRI, while the outer disk photoevaporates by stellar ultraviolet radiation.
description: Accepted to Nature Physics June 7, 2007. The manuscript for publication is embargoed per Nature policy. This arxiv.org version contains more technical details and discussion, and is distributed with permission from the editors. 10 pages, 4 figures
Hamiltonian statistical mechanics
Creators: name: Brody, Dorje C.
name: Ellis, David C. P.
name: Holm, Darryl D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: A framework for statistical-mechanical analysis of quantum Hamiltonians is introduced. The approach is based upon a gradient flow equation in the space of Hamiltonians such that the eigenvectors of the initial Hamiltonian evolve toward those of the reference Hamiltonian. The nonlinear double-bracket equation governing the flow is such that the eigenvalues of the initial Hamiltonian remain unperturbed. The space of Hamiltonians is foliated by compact invariant subspaces, which permits the construction of statistical distributions over the Hamiltonians. In two dimensions, an explicit dynamical model is introduced, wherein the density function on the space of Hamiltonians approaches an equilibrium state characterised by the canonical ensemble. This is used to compute quenched and annealed averages of quantum observables.
description: 8 pages, 2 figures, references added
Valley contrasting physics in graphene: magnetic moment and topological transport
Creators: name: Xiao, Di
name: Yao, Wang
name: Niu, Qian
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate physical properties that can be used to distinguish the valley degree of freedom in systems where inversion symmetry is broken, using graphene systems as examples. We show that the pseudospin associated with the valley index of carriers has an intrinsic magnetic moment, in close analogy with the Bohr magneton for the electron spin. There is also a valley dependent Berry phase effect that can result in a valley contrasting Hall transport, with carriers in different valleys turning into opposite directions transverse to an in-plane electric field. These effects can be used to generate and detect valley polarization by magnetic and electric means, forming the basis for the so-called valley-tronics applications.
On finite-index extensions of subgroups of free groups
Creators: name: Silva, Pedro
name: Weil, Pascal
Publisher: name: arXiv
Year: 2008
Subjects: subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 20E05

description: We study the lattice of finite-index extensions of a given finitely generated subgroup $H$ of a free group $F$. This lattice is finite and we give a combinatorial characterization of its greatest element, which is the commensurator of $H$. This characterization leads to a fast algorithm to compute the commensurator, which is based on a standard algorithm from automata theory. We also give a sub-exponential and super-polynomial upper bound for the number of finite-index extensions of $H$, and we give a language-theoretic characterization of the lattice of finite-index subgroups of $H$. Finally, we give a polynomial time algorithm to compute the malnormal closure of $H$.
The effects of mobile sodium contamination on MOS structures
Creators: name: Bouthillier, Thomas Michael
Publisher: name: University of British Columbia
Year: 2010

description: As the present trend to larger scales of integration of chips continues an increasing demand on reliability must be met. One source of premature device failure is contamination by mobile sodium ions. This thesis is a study of some of the effects of sodium contamination in silicon dioxide using internal photoemission and self healing breakdown. Lateral inhomogeneities in the barrier height at the Si-Si02 interface were probed by scanning a focussed beam of ultraviolet light along a MOS capacitor. It was found that barrier height was uniform unless highly contaminated samples were subjected both to a high temperature and also to a positive bias on the field plate for a short time at moderate temperatures. Qualitative features of lateral inhomogeneities in the surface potential were characterized by high frequency capacitance-voltage measurements showing similar effects. A model for the photoemission process was proposed. The effect of illumination while measuring photoemission was found to affect the band bending substantially so that a relatively simple model neglecting band bending in the silicon was used. Barrier height lowering caused by sodium contamination was measured on samples having a uniform photocurrent. By measuring samples at different contamination levels an experimental relationship between sodium concentration and barrier height lowering was found. A simple model taking into account Schottky barrier lowering resulting from the dipole field was found to be in good agreement with the results for low levels of surface concentration. Good experimental agreement was found with previous work. Self healing breakdown of the sample was also performed showing a convincing correlation between photoemission peaks and areas of early breakdown.
Subtractive renormalization of the NN scattering amplitude at leading order in chiral effective theory
Creators: name: Yang, C. -J.
name: Elster, Ch.
name: Phillips, D. R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The leading-order nucleon-nucleon (NN) potential derived from chiral perturbation theory consists of one-pion exchange plus a short-distance contact interaction. We show that in the 1S0 and 3S1-3D1 channels renormalization of the Lippmann-Schwinger equation for this potential can be achieved by performing one subtraction. This subtraction requires as its only input knowledge of the NN scattering lengths. This procedure leads to a set of integral equations for the partial-wave NN t-matrix which give cutoff-independent results for the corresponding NN phase shifts. This reformulation of the NN scattering equation offers practical advantages, because only observable quantities appear in the integral equation. The scattering equation may then be analytically continued to negative energies, where information on bound-state energies and wave functions can be extracted.
description: 16 pages, 11 figures