cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
A new matroid lift construction and an application to group-labeled graphs
Creators: name: Walsh, Zach
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05B35

description: A well-known result of Brylawski constructs an elementary lift of a matroid $M$ from a linear class of circuits of $M$. We generalize this result by showing how to construct a rank-$k$ lift of $M$ from a rank-$k$ matroid on the set of circuits of $M$. We conjecture that every lift of $M$ arises via this construction. We then apply this result to group-labeled graphs, generalizing a construction of Zaslavsky. Given a graph $G$ with edges labeled by a group, Zaslavsky's lift matroid $K$ is an elementary lift of the graphic matroid $M(G)$ that respects the group-labeling; specifically, the cycles of $G$ that are circuits of $K$ coincide with the cycles that are balanced with respect to the group-labeling. For $k \ge 2$, when does there exist a rank-$k$ lift of $M(G)$ that respects the group-labeling in this same sense? For abelian groups, we show that such a matroid exists if and only if the group is isomorphic to the additive group of a non-prime finite field.
Additional file 1 of Large-scale 3D chromatin reconstruction from chromosomal contacts
Creators: name: Zhang, Yanlin
name: Liu, Weiwei
name: Lin, Yu
name: Ng, Yen
name: Li, Shuaicheng
Publisher: name: figshare
Year: 2019
Subjects: subject: Biochemistry
subject: Cell Biology
subject: Genetics
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Environmental Sciences not elsewhere classified
subject: Chemical Sciences not elsewhere classified
subject: Sociology
subject: FOS: Sociology
subject: Developmental Biology
subject: Cancer
subject: Infectious Diseases
subject: FOS: Health sciences

description: Large Scale 3D Chromatin Reconstruction From Chromosomal Contacts - Supplementary materials. This file contains the supplementary text and figures mentioned in the text. (PDF 6926 kb)
Competing Ordered Phases in URu2Si2: Hydrostatic Pressure and Re-substitution
Creators: name: Jeffries, J. R.
name: Butch, N. P.
name: Yukich, B. T.
name: Maple, M. B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A persistent kink in the pressure dependence of the \hidden order" (HO) transition temperature of URu2-xRexSi2 is observed at a critical pressure Pc=15 kbar for 0 < x < 0.08. In URu2Si2, the kink at Pc is accompanied by the destruction of superconductivity; a change in the magnitude of a spin excitation gap, determined from electrical resistivity measurements; and a complete gapping of a portion of the Fermi surface (FS), inferred from a change in scattering and the competition between the HO state and superconductivity for FS fraction.
Simplified Forms of the Transition Probabilities of the Two-Species ASEP with Some Initial Orders of Particles
Creators: name: Lee, Eunghyun
name: Raimbekov, Temirlan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: It has been known that the transition probability of the single species ASEP with $N$ particles is expressed as a sum of $N!$ $N$-fold contour integrals which are related to permutations in the symmetric group $S_N$. On other hand, the transition probabilities of the multi-species ASEP, in general, may be expressed as a sum of much more terms than $N!$. In this paper, we show that if the initial order of species is given by $2\cdots 21$, $12\cdots 2$, $1\cdots 12$ or $21\cdots 1$, then the transition probabilities can be expressed as a sum of at most $N!$ contour integrals, and provide their formulas explicitly.
Combinatorics of a disordered two-species ASEP on a torus
Creators: name: Ayyer, Arvind
name: Nadeau, Philippe
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: Probability (math.PR)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 05A15, 60C05, 60K35, 05A18

description: We define a new disordered asymmetric simple exclusion process (ASEP) with two species of particles, first-class particles labelled $\bullet$ and second-class particles labelled ${\scriptstyle \Box}$, on a two-dimensional toroidal lattice. The dynamics is controlled by particles labelled $\bullet$, which only move horizontally, with forward and backward hopping rates $p_i$ and $q_i$ respectively if the $\bullet$ is on row $i$. The motion of particles labelled ${\scriptstyle \Box}$ depends on the relative position of these with respect to $\bullet$'s, and can be both horizontal and vertical. We show that the stationary weight of any configuration is proportional to a monomial in the $p_i$'s and $q_i$'s. Our process projects to the disordered ASEP on a ring, and so explains combinatorially the stationary distribution of the latter first derived by Evans (Europhysics Letters, 1996). We compute the partition function, as well as densities and currents of $\bullet$'s and ${\scriptstyle \Box}$'s in the stationary state. We observe a novel mechanism we call the Scott Russell phenomenon: the current of ${\scriptstyle \Box}$'s in the vertical direction is the same as that of $\bullet$'s in the horizontal direction.
description: 29 pages, 12 figures, minor improvements in presentation, final version
Ion condensation on charged patterned surfaces
Creators: name: Velichko, Yuri S.
name: Solis, Francisco J.
name: Loverde, Sharon M.
name: de la Cruz, Monica Olvera
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study ion condensation onto a patterned surface of alternating charges. The competition between self-energy and ion-surface interactions leads to the formation of ionic crystalline structures at low temperatures. We consider different arrangements of underlying ionic crystals, including single ion adsorption, as well as the formation of dipoles at the interface between charged domains. Molecular dynamic simulation illustrates existence of single and mixed phases. Our results contribute to understanding pattern recognition, and molecular separation and synthesis near patterned surfaces.
description: 3 figures
Emergence of noncollinear magnetic ordering in small magnetic clusters: Mn$_n$ and As@Mn$_n$
Creators: name: Kabir, Mukul
name: Kanhere, D. G.
name: Mookerjee, Abhijit
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: FOS: Physical sciences

description: Using first-principles density functional calculations, we have studied the magnetic ordering in pure Mn$_n$ ($n=2-$10, 13, 15, 19) and As@Mn$_n$ ($n=1-$10) clusters. Although, for both pure and doped manganese clusters, there exists many collinear and noncollinear isomers close in energy, the smaller clusters with $n\leqslant$5 have collinear magnetic ground state and the emergence of noncollinear ground states is seen for $n\geqslant$6 clusters. Due to strong $p-d$ hybridization in As@Mn$_n$ clusters, the binding energy is substantially enhanced and the magnetic moment is reduced compared to the corresponding pure Mn$_n$ clusters.
description: 10 Pages and 5 Figures
Gamma-Ray Burst Afterglows as Probes of Environment and Blastwave Physics II: the Distribution of p and Structure of the Circumburst Medium
Creators: name: Starling, R. L. C.
name: van der Horst, A. J.
name: Rol, E.
name: Wijers, R. A. M. J.
name: Kouveliotou, C.
name: Wiersema, K.
name: Curran, P. A.
name: Weltevrede, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We constrain blastwave parameters and the circumburst media of a subsample of ten BeppoSAX Gamma-Ray Bursts. For this sample we derive the values of the injected electron energy distribution index, p, and the density structure index of the circumburst medium, k, from simultaneous spectral fits to their X-ray, optical and nIR afterglow data. The spectral fits have been done in count space and include the effects of metallicity, and are compared with the previously reported optical and X-ray temporal behaviour. Using the blastwave model and some assumptions which include on-axis viewing and standard jet structure, constant blastwave energy and no evolution of the microphysical parameters, we find a mean value of p for the sample as a whole of 2.04 +0.02/-0.03. A statistical analysis of the distribution demonstrates that the p values in this sample are inconsistent with a single universal value for p at the 3-sigma level or greater, which has significant implications for particle acceleration models. This approach provides us with a measured distribution of circumburst density structures rather than considering only the cases of k=0 (homogeneous) and k=2 (wind-like). We find five GRBs for which k can be well constrained, and in four of these cases the circumburst medium is clearly wind-like. The fifth source has a value of 0
description: 25 pages (single column), 2 figures, ApJ accepted after minor revisions
More hilltop inflation models
Creators: name: Kohri, Kazunori
name: Lin, Chia-Min
name: Lyth, David H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Using analytic expressions, we explore the parameter space for hilltop inflation models with a potential of the form $V_0\pm m^2ϕ^2 -aϕ^p$. With the positive sign and p>2 this converts the original hybrid inflation model into a hilltop model, allowing the spectral index to agree with the observed value n=0.95. In some cases the observed value is theoretically favored, while in others there is only the generic prediction $|n-1|\lsim 1$.
description: 12 pages, 25 figures, to appear in JCAP
Development, validation and clinical usefulness of a prognostic model for relapse in relapsing-remitting multiple sclerosis
Creators: name: Chalkou, Konstantina
name: Steyerberg, Ewout
name: Bossuyt, Patrick
name: Subramanian, Suvitha
name: Benkert, Pascal
name: Kuhle, Jens
name: Disanto, Giulio
name: Kappos, Ludwig
name: Egger, Matthias
name: Salanti, Georgia
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: Prognosis on the occurrence of relapses in individuals with Relapsing-Remitting Multiple Sclerosis (RRMS), the most common subtype of Multiple Sclerosis (MS), could support individualized decisions and disease management and could be helpful for efficiently selecting patients in future randomized clinical trials. There are only three previously published prognostic models on this, all of them with important methodological shortcomings. We aim to present the development, internal validation, and evaluation of the potential clinical benefit of a prognostic model for relapses for individuals with RRMS using real world data. We followed seven steps to develop and validate the prognostic model. Finally, we evaluated the potential clinical benefit of the developed prognostic model using decision curve analysis. We selected eight baseline prognostic factors: age, sex, prior MS treatment, months since last relapse, disease duration, number of prior relapses, expanded disability status scale (EDSS), and gadolinium enhanced lesions. We also developed a web application where the personalized probabilities to relapse within two years are calculated automatically. The optimism-corrected c-statistic is 0.65 and the optimism-corrected calibration slope was 0.92. The model appears to be clinically useful between the range 15% and 30% of the threshold probability to relapse. The prognostic model we developed offers several advantages in comparison to previously published prognostic models on RRMS. Importantly, we assessed the potential clinical benefit to better quantify the clinical impact of the model. Our web application, once externally validated in the future, could be used by patients and doctors to calculate the individualized probability to relapse within two years and to inform the management of their disease.
Prevalence, Intensity, and Knowledge of Hookworm Infection Among Rural Fishermen and Farmers in Rivers State, Nigeria: An Occupational Health Perspective
Creators: name: Bruce, I
name: Alali, AA
name: Lawson, SD
name: Cookey-Gam, IF
name: Austin-Asomeji, I
name: Ogba, AA
name: Ogbonda, PI
name: Perri, T
Publisher: name: AMMS Journal
Year: 2024
Subjects: Fishermen
Farmers
Hookworm
Infection
Knowledge
Prevalence
Rural

description: Abstract

Background: Hookworm infestation adversely affect humans especially in developing countries. Agricultural workers are predisposed to acquiring hookworm infection due to direct exposure to soil or water where the filariform larvae which is the infective stage live and penetrate the skin. Objectives: To determine the prevalence, infection intensity and knowledge of hookworm infestation among rural fishermen and farmers in Rivers State, Nigeria. Method: A multi-stage sampling technique was used in selecting the participants. 200 fishermen and 200 farmers were recruited between May and November 2021. Stool samples were processed using the Kato- Katz technique. 19 possible answers were summed up to assess knowledge. Data was analyzed using SPSS version 26 and presented in charts and tables. Result: The age of respondents ranged from 18 to 70 years with a mean age of 46 ± 12years. More than 50% of respondents have worked for 10 years. About half of respondents had only primary level of education while the average income was 30,000 Naira monthly. The prevalence of hookworm was 14.5% among fishermen and 12.5% among farmers. Both groups had majority of respondents with light intensity infection. For knowledge of hookworm infection, 55.86% of fishermen were assessed as having poor knowledge while 44.14% were deemed to have good knowledge. Among farmers, 44.13% had good knowledge and 55.86% had poor knowledge of hookworm infections. Conclusion: The prevalence of hookworm was 14.5% among fishermen and 12.5% among farmers. Most respondents had low density hookworm infection while level of knowledge was generally poor. These figures are worrisome thus there is need for awareness of hookworm in particular and other soil-transmitted Helminthes in general in this informal occupational group.
A holographic proof of the strong subadditivity of entanglement entropy
Creators: name: Headrick, Matthew
name: Takayanagi, Tadashi
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: When a quantum system is divided into subsystems, their entanglement entropies are subject to an inequality known as "strong subadditivity". For a field theory this inequality can be stated as follows: given any two regions of space $A$ and $B$, $S(A) + S(B) \ge S(A \cup B) + S(A \cap B)$. Recently, a method has been found for computing entanglement entropies in any field theory for which there is a holographically dual gravity theory. In this note we give a simple geometrical proof of strong subadditivity employing this holographic prescription.
description: 9 pages, 3 figures
Communication protocol channel utilization and the design of the MAX2 data link protocol
Creators: name: Lee, Kenneth
Publisher: name: University of British Columbia
Year: 2010

description: In this thesis, we first surveyed and analyzed the Kermit, XMODEM, YMODEM, and ZMODEM file transfer protocols. A number of theoretical channel utilization equations were then developed that would predict the effective utilization, and hence effective throughput, of stop and wait protocols and streaming protocols. A series of experiments were performed that measured the effective throughput of the protocols at various baud rates and error rates and showed the utilization equations to be within ±5% of the measured values. Based upon these results, a full-streaming communications protocol, MAX2, was designed. A subset of the MAX2 protocol was then implemented and tested at different baud rates and error rates. These results were within ±1.5% of the theoretical values and showed that the MAX2 protocol to be more efficient than the Kermit, XMODEM, YMODEM, and ZMODEM protocols at all baud rates and error rates when using comparable maximum packet sizes . These results also indicated that in order to achieve maximum effective throughput, the packet size must change as the communication channel's error rate changes.
Structure, bonding and magnetism in cobalt clusters
Creators: name: Datta, S.
name: Kabir, M.
name: Ganguly, S.
name: Sanyal, B.
name: Saha-Dasgupta, T.
name: Mookerjee, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic and Molecular Clusters (physics.atm-clus)
subject: FOS: Physical sciences

description: The structural, electronic and magnetic properties of Co$_n$ clusters ($n=2-$20) have been investigated using density functional theory within the pseudopotential plane wave method. An unusual hexagonal growth pattern has been observed in the intermediate size range, $n=15-$20. The cobalt atoms are ferromagnetically ordered and the calculated magnetic moments are found to be higher than that of corresponding hcp bulk value, which are in good agreement with the recent Stern-Gerlach experiments. The average coordination number is found to dominate over the average bond length to determine the effective hybridization and consequently the cluster magnetic moment.
description: 12 pages and 9 figures
Potential and limitations of machine-learning approaches to inclusive $|V_{ub}|$ determinations
Creators: name: Biekötter, Anke
name: Kwok, Ka Wang
name: Pecjak, Benjamin D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The determination of $|V_{ub}|$ in inclusive semileptonic $B \to X_u \ell ν$ decays will be among the pivotal tasks of Belle II. In this paper we study the potential and limitations of machine learning approaches that attempt to reduce theory uncertainties by extending the experimentally accessible fiducial region of the $B\to X_u \ellν$ signal into regions where the $B\to X_c \ellν$ background is dominant. We find that a deep neural network trained on low-level single particle features offers modest improvement in separating signal from background, compared to BDT set-ups using physicist-engineered high-level features. We further illustrate that while the signal acceptance of such a deep neural network deteriorates in kinematic regions where the signal is small, such as at high hadronic invariant mass, neural networks which exclude kinematic features are flatter in kinematics but less inclusive in the sampling of exclusive hadronic final states at fixed kinematics. The trade-off between these two set-ups is somewhat Monte Carlo dependent, and we study this issue using the multipurpose event generator Sherpa in addition to the widely used $B$-physics tool EvtGen.
description: 20 pages, 11 figures; v2: Final version published in JHEP
Multiparameter Riesz Commutators
Creators: name: Lacey, Michael
name: Petermichl, Stefanie
name: Pipher, Jill
name: Wick, Brett
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics

description: It is shown that product BMO of Chang and Fefferman, defined on the product of Euclidean spaces can be characterized by the multiparameter commutators of Riesz transforms. This extends a classical one-parameter result of Coifman, Rochberg, and Weiss, and at the same time extends the work of Lacey and Ferguson and Lacey and Terwilleger on multiparameter commutators with Hilbert transforms. The method of proof requires the real-variable methods throughout, which is new in the multi-parameter context.
description: 38 Pages. References updated. To appear in American J Math
NASDUCK: New Constraints on Axion-like Dark Matter from Floquet Quantum Detector
Creators: name: Bloch, Itay M.
name: Ronen, Gil
name: Shaham, Roy
name: Katz, Ori
name: Volansky, Tomer
name: Katz, Or
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on the first results of the Noble and Alkali Spin Detectors for Ultralight Coherent darK matter (NASDUCK) collaboration. We search for the interactions of Axion-Like Particles (ALPs) with atomic spins using an earth-based precision quantum detector as it traverses through the galactic dark matter halo. The detector is composed of spin-polarized xenon gas which can coherently interact with a background ALP dark matter field and an in-situ rubidium Floquet optical-magnetometer. Conducting a five months-long search, we derive new constraints on ALP-proton and ALP-neutron interactions in the $4\times 10^{-15}-4\times 10^{-12}{~\rm eV/c^2}$ mass range. Our limits on the ALP-proton (ALP-neutron) couplings improve upon previous terrestrial bounds by up to 3 orders of magnitude for masses above $4\times 10^{-14}{~\rm eV/c^2}$ ($4\times 10^{-13}{~\rm eV/c^2}$). Moreover, barring the uncertain supernova constraints, the ALP-proton bound improves on all existing terrestrial and astrophysical limits, partially closing the unexplored region for couplings in the range $10^{-6}~{\rm GeV^{-1}}$ to $2\times 10^{-5}~{\rm GeV^{-1}}$. Finally, we also cast bounds on pseudo-scalar dark matter models in which dark matter is quadratically-coupled to the nucleons.
description: I.M.B. and G.R. contributed equally
Cosmic Rays: The Second Knee and Beyond
Creators: name: Bergman, Douglas R
name: Belz, John W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We conduct a review of experimental results on Ultra-High Energy Cosmic Rays (UHECR's) including measurements of the features of the spectrum, the composition of the primary particle flux and the search for anisotropy in event arrival direction. We find that while there is a general consensus on the features in the spectrum -- the Second Knee, the Ankle, and (to a lesser extent) the GZK Cutoff -- there is little consensus on the composition of the primaries that accompany these features. This lack of consensus on the composition makes interpretation of the agreed upon features problematic. There is also little direct evidence about potential sources of UHECRs, as early reports of arrival direction anisotropies have not been confirmed in independent measurements.
description: 46 pages, 30 figures. Topical Review to appear in J. Physics G
$\vert V_{cb} \vert$ and $R(D^{(*)})$ using lattice QCD and unitarity
Creators: name: Martinelli, G.
name: Simula, S.
name: Vittorio, L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: The Cabibbo-Kobayashi-Maskawa (CKM) matrix element $|V_{cb}|$ is extracted from exclusive semileptonic $B \to D^{(*)}$ decays adopting a novel unitarity-based approach which allows to determine in a full non-perturbative way the relevant hadronic form factors (FFs) in the whole kinematical range. By using existing lattice computations of the $B \to D^{(*)}$ FFs at small recoil from FNAL/MILC and JLQCD Collaborations, we show that it is possible to extrapolate their behavior also at large recoil without assuming any specific momentum dependence and without constraining their shape using experimental data. Thus, we address the extraction of $|V_{cb}|$ from the experimental data on the semileptonic $B \to D^{(*)} \ell ν_\ell$ decays, obtaining $\vert V_{cb}\vert = (41.0 \pm 1.2 ) \cdot 10^{-3}$ from $B \to D$ using as input the final FNAL/MILC lattice data for the FFs and $|V_{cb}| = (40.4 \pm 1.8 ) \cdot 10^{-3}$ from $B \to D^*$ using the preliminary JLQCD lattice data. Our result from $B \to D$ is consistent within $\sim 1$ standard deviation with the most recent inclusive determination $|V_{cb}|_{incl} = (42.00 \pm 0.65) \cdot 10^{-3}$. The resulting uncertainty is comparable with those obtained in literature using experimental data to constrain the shape of the FFs. Our result from $B \to D^*$, though consistent with $|V_{cb}|_{incl} $, is still based on preliminary lattice data for the FFs and its uncertainty is greater than the ones obtained in literature using experimental data to constrain the shape of the FFs. We investigate also the issue of Lepton Flavor Universality thanks to new theoretical estimates of the ratios $R(D^{(*)})$, namely $R(D) = 0.296(8)$ using final FNAL/MILC lattice results, and $R(D^{*}) = 0.261(20)$ using preliminary JLQCD and FNAL/MILC lattice data. Our findings differ by $\sim 1.4σ$ from the latest experimental determinations.
description: 48 pages, 15 figures, 6 tables. Matches the published version in PRD
PEDAGOGICAL CONDITIONS AND INNOVATIVE TECHNOLOGIES FOR SPEECH DEVELOPMENT OF PRESCHOOL PUPILS IN EDUCATIONAL ORGANISATIONS
Creators: name: Dilova, Firuza
Publisher: name: Zenodo
Year: 2024

description: The present scientific research is devoted to the topic of ‘pedagogical conditions and innovative technologies for the development of speech of pupils of preschool educational organisations’. The main purpose of the research is to identify the pedagogical conditions necessary for the development of children's speech abilities in preschool educational organisations and to study the role of innovative technologies.
Microwave Optomechanically Induced Transparency and Absorption Between 250 and 450 mK
Creators: name: Kumar, Sumit
name: Cattiaux, Dylan
name: Collin, Eddy
name: Fefferman, Andrew
name: Zhou, Xin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: High-quality microwave amplifiers and notch-filters can be made from microwave optomechanical systems in which a mechanical resonator is coupled to a microwave cavity by radiation pressure. These amplifiers and filters rely on optomechanically induced transparency (OMIT) and absorption (OMIA), respectively. Such devices can amplify microwave signals with large, controllable gain, high dynamic range and very low noise. Furthermore, extremely narrowband filters can be constructed with this technique. We briefly review previous measurements of microwave OMIT and OMIA before reporting our own measurements of these phenomena, which cover a larger parameter space than has been explored in previous works. In particular, we vary probe frequency, pump frequency, pumping scheme (red or blue), probe power, pump power and temperature. We find excellent agreement between our measurements and the predictions of input/output theory, thereby guiding further development of microwave devices based on nanomechanics.
Reheating Closed String Inflation
Creators: name: Green, Daniel
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Protecting the inflationary potential from quantum corrections typically requires symmetries that constrain the form of couplings of the inflaton to other sectors. We will explore how these restrictions affect reheating in models with UV completions. In particular, we look at how reheating occurs when inflation is governed by closed strings, using N-flation as an example. We find that coupling the inflaton preferentially to the Standard Model is difficult, and hidden sectors are typically reheated. Observational constraints are only met by a fraction of the models. In some working models, relativistic relics in the hidden sector provide dark matter candidates with masses that range from keV to PeV, with lighter masses being preferred.
description: 17 pages, v2: fixed typos and added refs, v3: fixed typos, added refs and title change
Skyrmion Tubes in achiral nematic liquid crystals
Creators: name: De Matteis, G.
name: Martina, L.
name: Naya, C.
name: Turco, V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We analyze the interaction with uniform external fields of nematic liquid crystals within a recent generalized free-energy posited by Virga and falling in the class of quartic functionals in the spatial gradients of the nematic director. We review some known interesting solutions, i. e., uniform heliconical structures, which correspond to the so-called twist-bend nematic phase and we also study the transition between this phase and the standard uniform nematic one. Moreover, we find liquid crystal configurations, which closely resemble some novel, experimentally detected, structures called Skyrmion Tubes. Skyrmion Tubes are characterized by a localized cylindrically-symmetric pattern surrounded by either twist-bend or uniform nematic phase. We study the equilibrium differential equations and find numerical solutions and analytical approximations.
description: 23 pages, 11 figures. v2: published version
Direct Measurement of the Radius and Density of the Transiting Exoplanet HD 189733B with the CHARA Array
Creators: name: Baines, E. K.
name: van Belle, G. T.
name: Brummelaar, T. A. ten
name: McAlister, H. A.
name: Swain, M.
name: Turner, N. H.
name: Sturmann, L.
name: Sturmann, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have measured the angular diameter of the transiting extrasolar planet host star HD 189733 using the CHARA O/IR interferometric array. Combining our new angular diameter of 0.377+/-0.024 mas with the Hipparcos parallax leads to a linear radius for the host star of 0.779+/-0.052 Rsol and a radius for the planet of 1.19+/-0.08 RJup. Adopting the mass of the planet as derived by its discoverers, we derive a mean density of the planet of 0.91+/-0.18 g cm-3. This is the first determination of the diameter of an extrasolar planet through purely direct means.
description: 14 pages, 5 figures, to be published in Astrophysical Journal Letters
Near-Infrared Interferometric, Spectroscopic, and Photometric Monitoring of T Tauri Inner Disks
Creators: name: Eisner, J. A.
name: Hillenbrand, L. A.
name: White, R. J.
name: Bloom, J. S.
name: Akeson, R. L.
name: Blake, C. H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present high angular resolution observations with the Keck Interferometer, high dispersion spectroscopic observations with Keck/NIRSPEC, and near-IR photometric observations from PAIRITEL of a sample of 11 solar-type T Tauri stars in 9 systems. We use these observations to probe the circumstellar material within 1 AU of these young stars, measuring the circumstellar-to-stellar flux ratios and angular size scales of the 2.2 micron emission. Our sample spans a range of stellar luminosities and mass accretion rates, allowing investigation of potential correlations between inner disk properties and stellar or accretion properties. We suggest that the mechanism by which the dusty inner disk is truncated may depend on the accretion rate of the source; in objects with low accretion rates, the stellar magnetospheres may truncate the disks, while sublimation may truncate dusty disks around sources with higher accretion rates. We have also included in our sample objects that are known to be highly variable (based on previous photometric and spectroscopic observations), and for several sources, we obtained multiple epochs of spectroscopic and interferometric data, supplemented by near-IR photometric monitoring, to search for inner disk variability. While time-variable veilings and accretion rates are observed in some sources, no strong evidence for inner disk pulsation is found.
description: 33 pages, 6 figures. Accepted for publication in ApJ
Geometric hierarchies and parallel subdivision search
Creators: name: Dadoun, Nounou Norman
Publisher: name: University of British Columbia
Year: 2011

description: Geometric hierarchies have proven useful for the problems of point location in planar subdivisions and 2- and 3-dimensional convex polytope separation on a sequential model of computation. In this thesis, we formulate a geometric hierarchy paradigm (following the work of Dobkin and Kirkpatrick) and apply this paradigm to solve a number of computational geometry problems on a shared memory (PRAM) parallel model of computation. For certain problems, we describe what we call cooperative algorithms, algorithms which exploit parallelism in searching geometric hierarchies to solve their respective problems. For convex polygons, the geometric hierarchies are implicit and can be exploited in cooperative algorithms to compute convex polygon separation and to construct convex polygon separating/common tangents. The paradigm is also applied to the problem of tree contraction which is, in turn, applied to a number of specialized point location applications including the parallel construction of 2-dimensional Voronoi Diagrams. For point location in planar subdivisions, we present parallel algorithms to construct a subdivision hierarchy representation. A related convex polyhedra hierarchy is constructed similarly and applied to the parallel construction of 3-dimensional convex hulls. The geometric hierarchy paradigm is applied further to the design of a data structure which supports cooperative point location in general planar subdivisions. Again, a related polyhedral hierarchy can be used to exploit parallelism for a cooperative separation algorithm for convex polyhedra.
Dyson Indices and Hilbert-Schmidt Separability Functions and Probabilities
Creators: name: Slater, Paul B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A confluence of numerical and theoretical results leads us to conjecture that the Hilbert-Schmidt separability probabilities of the 15- and 9-dimensional convex sets of complex and real two-qubit states (representable by 4 x 4 density matrices rho) are 8/33 and 8/17, respectively. Central to our reasoning are the modifications of two ansatze, recently advanced (quant-ph/0609006), involving incomplete beta functions B_{nu}(a,b), where nu= (rho_{11} rho_{44})/(rho_{22} rho_{33}). We, now, set the separability function S_{real}(nu) propto B_{nu}(nu,1/2},2) =(2/3) (3-nu) sqrt{nu}. Then, in the complex case -- conforming to a pattern we find, manifesting the Dyson indices (1, 2, 4) of random matrix theory-- we take S_{complex}(nu) propto S_{real}^{2} (nu). We also investigate the real and complex qubit-qutrit cases. Now, there are two Bloore ratio variables, nu_{1}= (rho_{11} rho_{55})(rho_{22} rho_{44}), nu_{2}= (rho_{22} rho_{66})(rho_{33} rho_{55}), but they appear to remarkably coalesce into the product, eta = nu_1 nu_2 = rho_{11} ρ_{66}}{ρ_{33} ρ_{44}}, so that the real and complex separability functions are again univariate in nature.
description: 44 pages, 6 figures, modified title, trimmed abstract, to appear in J. Phys. A
Spin squeezing in optical lattice clocks via lattice-based QND measurements
Creators: name: Meiser, D.
name: Ye, Jun
name: Holland, M. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Quantum projection noise will soon limit the best achievable precision of optical atomic clocks based on lattice-confined neutral atoms. Squeezing the collective atomic pseudo-spin via measurement of the clock state populations during Ramsey interrogation suppresses the projection noise. We show here that the lattice laser field can be used to perform ideal quantum non-demolition measurements without clock shifts or decoherence and explore the feasibility of such an approach in theory with the lattice field confined in a ring-resonator. Detection of the motional sideband due to the atomic vibration in the lattice wells can yield signal sizes a hundredfold above the projection noise limit.
description: Substantially expanded version
A quantum cascade laser-pumped molecular laser tunable over 1 THz
Creators: name: Amirzhan, Arman
name: Chevalier, Paul
name: Rowlette, Jeremy
name: Stinson, H. Ted
name: Pushkarsky, Michael
name: Day, Timothy
name: Everitt, Henry O.
name: Capasso, Federico
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: By introducing methyl fluoride (CH$_3$F) as a new gain medium for a quantum cascade laser-pumped molecular laser (QPML), we demonstrate continuous-wave lasing from more than 120 discrete transitions spanning the frequency range 0.25 to 1.3 THz. The unprecedented degree of spectral tuning achieved with CH$_3$F also confirms the universality of the QPML concept: for all polar gas molecules, lasing can be induced on any dipole-allowed rotational transition by sufficient pumping of a related roto-vibrational transition using a continuously tunable quantum cascade laser.
description: main text: 4 pages, 4 figures, supplement: 7 pages, 5 figures. APL Photonics (2021)
A Model of Late Long-Term Potentiation Simulates Aspects of Memory Maintenance
Creators: name: Smolen, Paul
Publisher: name: arXiv
Year: 2007
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: Molecular Networks (q-bio.MN)
subject: FOS: Biological sciences

description: Late long-term potentiation (L-LTP) appears essential for the formation of long-term memory, with memories at least partly encoded by patterns of strengthened synapses. How memories are preserved for months or years, despite molecular turnover, is not well understood. Ongoing recurrent neuronal activity, during memory recall or during sleep, has been hypothesized to preferentially potentiate strong synapses, preserving memories. This hypothesis has not been evaluated in the context of a mathematical model representing biochemical pathways important for L-LTP. I incorporated ongoing activity into two such models: a reduced model that represents some of the essential biochemical processes, and a more detailed published model. The reduced model represents synaptic tagging and gene induction intuitively, and the detailed model adds activation of essential kinases by Ca. Ongoing activity was modeled as continual brief elevations of [Ca]. In each model, two stable states of synaptic weight resulted. Positive feedback between synaptic weight and the amplitude of ongoing Ca transients underlies this bistability. A tetanic or theta-burst stimulus switches a model synapse from a low weight to a high weight stabilized by ongoing activity. Bistability was robust to parameter variations. Simulations illustrated that prolonged decreased activity reset synapses to low weights, suggesting a plausible forgetting mechanism. However, episodic activity with shorter inactive intervals maintained strong synapses. Both models support experimental predictions. Tests of these predictions are expected to further understanding of how neuronal activity is coupled to maintenance of synaptic strength.
description: Accepted to PLoS One. 8 figures at end
The charge and spin sectors of the $t$-$t'$ Hubbard model
Creators: name: Avella, Adolfo
name: Mancini, Ferdinando
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The charge and spin sectors, which are intimately coupled to the fermionic one, of the $t$-$t'$ Hubbard model have been computed self-consistently within the two-pole approximation. The relevant unknown correlators appearing in the causal bosonic propagators have been computed by enforcing the constraints dictated by the hydrodynamics and the algebra of the composite operators coming into play. The proposed scheme of approximation extends previous calculations made for the fermionic sector of the $t$-$t'$ Hubbard model and the bosonic sector of the Hubbard model, which showed to be very effective to describe the overdoped region of cuprates (the former) and the magnetic response of their parent compounds (the latter).
Fair Allocation of Conflicting Items
Creators: name: Hummel, Halvard
name: Hetland, Magnus Lie
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: FOS: Computer and information sciences
subject: 91B32

description: We study fair allocation of indivisible items, where the items are furnished with a set of conflicts, and agents are not permitted to receive conflicting items. This kind of constraint captures, for example, participating in events that overlap in time, or taking on roles in the presence of conflicting interests. We demonstrate, both theoretically and experimentally, that fairness characterizations such as EF1, MMS and MNW still are applicable and useful under item conflicts. Among other existence, non-existence and computability results, we show that a $1/Δ$-approximate MMS allocation for $n$ agents may be found in polynomial time when $n>Δ>2$, for any conflict graph with maximum degree $Δ$, and that, if $n > Δ$, a 1/3-approximate MMS allocation always exists.
description: 33 pages; Revised manuscript; Experiment code included; Published in JAAMAS
Pion-mass dependence of three-nucleon observables
Creators: name: Hammer, H. -W.
name: Phillips, D. R.
name: Platter, L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We use an effective field theory (EFT) which contains only short-range interactions to study the dependence of a variety of three-nucleon observables on the pion mass. The pion-mass dependence of input quantities in our ``pionless'' EFT is obtained from a recent chiral EFT calculation. To the order we work at, these quantities are the 1S0 scattering length and effective range, the deuteron binding energy, the 3S1 effective range, and the binding energy of one three-nucleon bound state. The chiral EFT input we use has the inverse 3S1 and 1S0 scattering lengths vanishing at mpi_c=197.8577 MeV. At this ``critical'' pion mass, the triton has infinitely many excited states with an accumulation point at the three-nucleon threshold. We compute the binding energies of these states up to next-to-next-to-leading order in the pionless EFT and study the convergence pattern of the EFT in the vicinity of the critical pion mass. Furthermore, we use the pionless EFT to predict how doublet and quartet nd scattering lengths depend on mpi in the region between the physical pion mass and mpi=mpi_c.
description: 24 pages, 9 figures
Spinning solutions for the bosonic M2-brane with $C_{\pm}$ fluxes
Creators: name: Alvarez, Pedro D.
name: García, Pedro
name: del Moral, Maria Pilar Garcia
name: Peña, Joselen M.
name: Prado, Reginaldo
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this work we obtain classical solutions of the bosonic sector of the supermembrane theory with two-form fluxes associated to a quantized constant $C_{\pm}$ background. This theory satisfies a flux condition on the worldvolume that induces monopoles over it. Classically it is stable as it does not contain string-like spikes with zero energy in distinction with the general case. At quantum level the bosonic membrane has a purely discrete spectrum but the relevance is that the same property holds for its supersymmetric spectrum. We find for this theory spinning membrane solutions, some of them including the presence of a non-vanishing symplectic gauge connection defined on its worldvolume in different approximations. By using the duality found between this theory and the so-called supermembrane with central charges, rotating membrane solutions found in that case, are also solutions of the M2-brane with $C_{\pm}$ fluxes. We generalize this result to other embeddings. We find new distinctive rotating membrane solutions, some of them including the presence of a non-vanishing symplectic gauge connection defined on its worldvolume. We obtain numerical and analytical solutions in different approximations characterizing the dynamics of the membrane with fluxes $C_{\pm}$ for different ansätze of the dynamical degrees of freedom. Finally we discuss the physical admissibility of some of these ansätze to model the components of the symplectic gauge field.
description: Some clarifications added to section 2 and the discussion session has been enriched. Some references added. Results unchanged. Some change letter size. Latex, 33 pages, 5 figures. Accepted in JHEP
Intertwined Weyl phases emergent from higher-order topology and unconventional Weyl fermions via crystalline symmetry
Creators: name: Rui, W. B.
name: Zheng, Zhen
name: Hirschmann, Moritz M.
name: Zhang, Song-Bo
name: Wang, Chenjie
name: Wang, Z. D.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We discover three-dimensional intertwined Weyl phases, by developing a theory to create topological phases. The theory is based on intertwining existing topological gapped and gapless phases protected by the same crystalline symmetry. The intertwined Weyl phases feature both unconventional Weyl semimetallic (monopole charge>1) and higher-order topological phases, and more importantly, their exotic intertwining. While the two phases are independently stabilized by the same symmetry, their intertwining results in the specific distribution of them in the bulk. The construction mechanism allows us to combine different kinds of unconventional Weyl semimetallic and higher-order topological phases to generate distinct phases. Remarkably, on 2D surfaces, the intertwining causes the Fermi-arc topology to change in a periodic pattern against surface orientation. This feature provides a characteristic and feasible signature to probe the intertwining Weyl phases. Moreover, we provide guidelines for searching candidate materials, and elaborate on emulating the intertwined double-Weyl phase in cold-atom experiments.
description: 8 pages, 4 figures
Itô versus Stratonovich in a stochastic cosmological model
Creators: name: Escudero, Carlos
name: Manada, Carlos
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Probability (math.PR)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: In this work we study a stochastic version of the Friedmann acceleration equation. This model has been proposed in the cosmology literature as a possible explanation of the uncertainty found in the experimental quantification of the Hubble parameter. Its noise has been tacitly interpreted in the Stratonovich sense. Herein we prove that this interpretation leads to a positive probability of finite time blow-up of the solution, that is, of the Hubble parameter. In contrast, if we just modify the noise interpretation to that of Itô, then the solution globally exists almost surely. Moreover, the expected asymptotic behavior is found under this interpretation too.