cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Inner Galaxy Abundance Patterns with APOGEE
Creators: name: Zasowski, Gail
Publisher: name: Zenodo
Year: 2019

description: Galactic bulges contain dense fossil records of star formation and galaxy assembly encoded in the chemodynamical patterns of the stars. The Milky Way's bar/bulge is the only one in which we can resolve the chemistry/kinematics of individual stars, but despite sophisticated models that can reproduce the bulk stellar patterns, we have not fully mapped the evolution of our bar/bulge's numerous populations. Recent surveys, particularly in the infrared, are providing opportunities to characterize ever-finer details of the inner Milky Way's velocity and chemical distributions, which are critical discriminants among models with different star formation and evolutionary histories.  Using APOGEE data, we will present an analysis of chemodynamical patterns observed in thousands of inner Galaxy stars, discuss implications for tracing the co-evolution of stellar morphological, dynamical, and chemical properties in external galaxies, and highlight future prospects for improvements in the 2020s.
Quasichemical Models of Multicomponent Nonlinear Diffusion
Creators: name: Gorban, A. N.
name: Sargsyan, H. P.
name: Wahab, H. A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Chemical Physics (physics.chem-ph)
subject: FOS: Physical sciences

description: Diffusion preserves the positivity of concentrations, therefore, multicomponent diffusion should be nonlinear if there exist non-diagonal terms. The vast variety of nonlinear multicomponent diffusion equations should be ordered and special tools are needed to provide the systematic construction of the nonlinear diffusion equations for multicomponent mixtures with significant interaction between components. We develop an approach to nonlinear multicomponent diffusion based on the idea of the reaction mechanism borrowed from chemical kinetics. Chemical kinetics gave rise to very seminal tools for the modeling of processes. This is the stoichiometric algebra supplemented by the simple kinetic law. The results of this invention are now applied in many areas of science, from particle physics to sociology. In our work we extend the area of applications onto nonlinear multicomponent diffusion. We demonstrate, how the mechanism based approach to multicomponent diffusion can be included into the general thermodynamic framework, and prove the corresponding dissipation inequalities. To satisfy thermodynamic restrictions, the kinetic law of an elementary process cannot have an arbitrary form. For the general kinetic law (the generalized Mass Action Law), additional conditions are proved. The cell--jump formalism gives an intuitively clear representation of the elementary transport processes and, at the same time, produces kinetic finite elements, a tool for numerical simulation.
description: 81 pages, Bibliography 118 references, a review paper (v4: the final published version)
Energy Spectrum and Exact Cover in an Extended Quantum Ising Model
Creators: name: Wakker, G. M. M.
name: Ockhorst, R.
name: Blaauboer, M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate an extended version of the quantum Ising model which includes beyond-nearest neighbour interactions and an additional site-dependent longitudinal magnetic field. Treating the interaction exactly and using perturbation theory in the longitudinal field, we calculate the energy spectrum and find that the presence of beyond-nearest-neighbour interactions enhances the minimal gap between the ground state and the first excited state, irrespective of the nature of decay of these interactions along the chain. The longitudinal field adds a correction to this gap that is independent of the number of qubits. We discuss the application of our model to implementing specific instances of 3-satisfiability problems (Exact Cover) and make a connection to a chain of flux qubits.
description: 9 pages, 3 figures, published version
Sum rule improved double parton distributions in position space
Creators: name: Diehl, M.
name: Gaunt, J. R.
name: Lang, D. M.
name: Plößl, P.
name: Schäfer, A.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Models for double parton distributions that are realistic and consistent with theoretical constraints are crucial for a reliable description of double parton scattering. We show how an ansatz that has the correct behaviour in the limit of small transverse distance between the partons can be improved step by step, such as to fulfil the sum rules for double parton distributions with an accuracy around 10%.
Prethermalization in quenched spinor condensates
Creators: name: Barnett, Ryan
name: Polkovnikov, Anatoli
name: Vengalattore, Mukund
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Motivated by recent experiments, we consider the dynamics of spin-one spinor condensates after a quantum quench from the polar to ferromagnetic state from varying the quadratic Zeeman field q. We apply the Truncated Wigner Approximation (TWA) to the spinor system, including all spatial and spin degrees of freedom. For short times, we find full agreement with the linearized Bogoliubov analysis. For longer times, where the Bogoliubov theory fails, we find that the system reaches a quasi-steady prethermalized state. We compute the Bogoliubov spectrum about the ferromagnetic state with general q and show that the resulting finite temperature correlation functions grossly disagree with the full TWA results, thus indicating that the system does not thermalize even over very long time scales. Finally we show that the absence of thermalization over realistic time scales is consistent with calculations of Landau damping rates of excitations in the finite-temperature condensate.
description: 7 pages
Generalized Geologic Map for Land-Use Planning: Magoffin County, Kentucky
Creators: name: Carey, Daniel I.
Publisher: name: Kentucky Geological Survey, University of Kentucky
Year: 2007

description: Abstract:
This map is not intended to be used for selecting individual sites. Its purpose is to inform land-use planners, government officials, and the public in a general way about geologic bedrock conditions that affect the selection of sites for various purposes. The properties of thick soils may supercede those of the underlying bedrock and should be considered on a site-to-site basis. At any site, it is important to understand the characteristics of both the soils and the underlying rock.
A K3 in phi4
Creators: name: Brown, Francis
name: Schnetz, Oliver
Publisher: name: arXiv
Year: 2010
Subjects: subject: Algebraic Geometry (math.AG)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 14J28, 81T18, 05C31

description: Inspired by Feynman integral computations in quantum field theory, Kontsevich conjectured in 1997 that the number of points of graph hypersurfaces over a finite field $\F_q$ is a (quasi-) polynomial in $q$. Stembridge verified this for all graphs with $\leq12$ edges, but in 2003 Belkale and Brosnan showed that the counting functions are of general type for large graphs. In this paper we give a sufficient combinatorial criterion for a graph to have polynomial point-counts, and construct some explicit counter-examples to Kontsevich's conjecture which are in $ϕ^4$ theory. Their counting functions are given modulo $pq^2$ ($q=p^n$) by a modular form arising from a certain singular K3 surface.
description: Final version
Non-perturbative contributions to vector-boson transverse momentum spectra in hadronic collisions
Creators: name: Hautmann, Francesco
name: Scimemi, Ignazio
name: Vladimirov, Alexey
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Experimental measurements of Drell-Yan (DY) vector-boson production are available from the Large Hadron Collider (LHC) and from lower-energy collider and fixed-target experiments. In the region of low vector-boson transverse momenta , which is important for the extraction of the W-boson mass at the LHC, QCD contributions from non-perturbative Sudakov form factors and intrinsic transverse momentum distributions become relevant. We study the potential for determining such contributions from fits to LHC and lower-energy experimental data, using the framework of low- factorization for DY differential cross sections in terms of transverse momentum dependent (TMD) distribution functions. We investigate correlations between different sources of TMD non-perturbative effects, and correlations with collinear parton distributions. We stress the relevance of accurate DY measurements at low masses and with fine binning in transverse momentum for improved determinations of long-distance contributions to Sudakov evolution processes and TMDs.
Dirac Matrices for Chern-Simons Gravity
Creators: name: Izaurieta, Fernando
name: Ramírez, Ricardo
name: Rodríguez, Eduardo
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: A genuine gauge theory for the Poincaré, de Sitter or anti-de Sitter algebras can be constructed in (2n-1)-dimensional spacetime by means of the Chern-Simons form, yielding a gravitational theory that differs from General Relativity but shares many of its properties, such as second order field equations for the metric. The particular form of the Lagrangian is determined by a rank n, symmetric tensor invariant under the relevant algebra. In practice, the calculation of this invariant tensor can be reduced to the computation of the trace of the symmetrized product of n Dirac Gamma matrices Γ_{ab} in 2n-dimensional spacetime. While straightforward in principle, this calculation can become extremely cumbersome in practice. For large enough n, existing computer algebra packages take an inordinate long time to produce the answer or plainly fail having used up all available memory. In this talk we show that the general formula for the trace of the symmetrized product of 2n Gamma matrices Γ_{ab} can be written as a certain sum over the integer partitions s of n, with every term being multiplied by a numerical coefficient α_{s}. We then give a general algorithm that computes the α-coefficients as the solution of a linear system of equations generated by evaluating the general formula for different sets of tensors B^{ab} with random numerical entries. A recurrence relation between different coefficients is shown to hold and is used in a second, "minimal" algorithm to greatly speed up the computations. Runtime of the minimal algorithm stays below 1 min on a typical desktop computer for up to n=25, which easily covers all foreseeable applications of the trace formula.
description: v2: 6 pages, no figures. Based on talk presented at I Cosmosul, Rio de Janeiro, Brazil, August 2011. v3: references added
Magnetic susceptibility of QCD matter and its decomposition from the lattice
Creators: name: Bali, Gunnar S.
name: Endrődi, Gergely
name: Piemonte, Stefano
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We determine the magnetic susceptibility of thermal QCD matter by means of first principles lattice simulations using staggered quarks with physical masses. A novel method is employed that only requires simulations at zero background field, thereby circumventing problems related to magnetic flux quantization. After a careful continuum limit extrapolation, diamagnetic behavior (negative susceptibility) is found at low temperatures and strong paramagnetism (positive susceptibility) at high temperatures. We revisit the decomposition of the magnetic susceptibility into spin- and orbital angular momentum- related contributions. The spin term — related to the normalization of the photon lightcone distribution amplitude at zero temperature — is calculated non-perturbatively and extrapolated to the continuum limit. Having access to both the full magnetic susceptibility and the spin term, we calculate the orbital angular momentum contribution for the first time. The results reveal the opposite of what might be expected based on a free fermion picture. We provide a simple parametrization of the temperature- and magnetic field-dependence of the QCD equation of state that can be used in phenomenological studies.
On the stability of a semi-implicit scheme of Cahn-Hilliard type equations
Creators: name: Cheng, Xinyu
Publisher: name: University of British Columbia
Year: 2017

description: It is well known that Allen-Cahn equation and Cahn-Hilliard equation are essential to study the phase separation phenomenon of a two-phase or a multiple-phase mixture. An important property of the solutions to those two equations is that the energy functional, which is defined in this thesis, decreases in time. To study these solutions, researchers developed different numerical schemes to give accurate approximations, since analytic solutions are only available in a very few simple cases. However, not all schemes satisfy the energy-decay property, which is an important standard to determine whether the scheme is stable. In recent work, Li, Qiao and Tang developed a semi-implicit scheme for the Cahn-Hilliard equation and proved the energy-decay property. In this thesis, we extend the semi-implicit scheme to the Allen-Cahn equation and fractional Cahn-Hilliard equation with a proof of the energy-decay property. Moreover, this semi-implicit scheme is practical and could be applied to more general diffusion equations while preserving the energy-decay stability.
Privacy Preservation Technologies in Internet of Things
Creators: name: Sen, Jaydip
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cryptography and Security (cs.CR)
subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: Since the beginning of the Internet thirty years ago, we have witnessed a number of changes in the application of communication technologies. Today, the Internet can be described to a large extent as a ubiquitous infrastructure that is always accessible. After the era of connecting places and connecting people, the Internet of the future will also connect things. The idea behind the resulting Internet of Things is to seamlessly gather and use information about objects of the real world during their entire lifecycle. In this paper, we consider different approaches to technological protection of user data privacy in the world of Internet of Things. In particular,we consider what kind of security problems are being faced and what level of protection can be provided by applying approaches based on secure multi-party computations.
description: withdrawn by author. arXiv admin note: v1 significant text overlap with "Internet of things and privacy preserving technologies", by V. Oleshchuk, without attribution
Bilinear quark operators in the RI/SMOM scheme at three loops
Creators: name: Kniehl, Bernd A.
name: Veretin, Oleg L.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We consider the renormalization of the matrix elements of the bilinear quark operators ¯ψψ, ¯ ψγμψ, and ¯ ψσμνψat next-to-next-to-next-to-leading order in QCD perturbation theory at the symmetric subtraction point. This allows us to obtain conversion factors between the MSscheme and the regularization invariant symmetric momentum subtraction (RI/SMOM) scheme. The obtained results can be used to reduce the errors in determinations of quark masses from lattice QCD simulations. The results are given in Landau gauge.
Phenomenological implications of asymmetric AdS5 shock wave collision studies for heavy ion physics
Creators: name: Müller, Berndt
name: Rabenstein, Andreas
name: Schäfer, Andreas
name: Waeber, Sebastian
name: Yaffe, Laurence G.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: This paper discusses possible phenomenological implications for p+A and A+A collisions of the results of recent numerical AdS/CFT calculations examining asymmetric collisions of planar shocks. In view of the extreme Lorentz contraction, we model highly relativistic heavy ion collisions as a superposition of collisions between many near-independent transverse “pixels” with differing incident longitudinal momenta. It was found that also for asymmetric collisions the hydrodynamization time is in good approximation a proper time, just like for symmetric collisions, depending on the geometric mean of the longitudinally integrated energy densities of the incident projectiles. For realistic collisions with fluctuations in the initial energy densities, these results imply a substantial increase in the hydrodynamization time for highly asymmetric pixels. However, even in this case the local hydrodynamization time still is significantly smaller than perturbative results for the thermalization time.
Comprehensive Phenomenology of the Dirac Scotogenic Model: Novel Low Mass Dark Matter
Creators: name: Chuliá, Salvador Centelles
name: Srivastava, Rahul
name: Yadav, Sushant
Publisher: name: arXiv
Year: 2024
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The Dirac Scotogenic model provides an elegant mechanism for generating small Dirac neutrino masses at the one-loop level. A single abelian discrete $Z_{6}$ symmetry simultaneously protects the ``Diracness'' of the neutrinos and the stability of the dark matter candidate. This symmetry originates as an unbroken subgroup of the so-called 445 $U(1)_{B-L}$ symmetry. Here, we thoroughly explore the phenomenological implications of this construction, including an analysis of electroweak vacuum stability, charged lepton flavor violation, and the dark matter phenomenology. After considering all constraints, we also show that the model allows for the possibility of novel low-mass scalar and fermionic dark matter, a feature not shared by its canonical Majorana counterpart.
description: 49 pages, 29 figures, 5 tables. v2: reference added, improved main text and typos corrected
Lattice QCD Calculations of Transverse-Momentum-Dependent Soft Function through Large-Momentum Effective Theory
Creators: name: Zhang, Qi-An
name: Hua, Jun
name: Huo, Yikai
name: Ji, Xiangdong
name: Liu, Yizhuang
name: Liu, Yu-Sheng
name: Schlemmer, Maximilian
name: Schäfer, Andreas
name: Sun, Peng
name: Wang, Wei
name: Yang, Yi-Bo
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: The transverse-momentum-dependent (TMD) soft function is a key ingredient in QCD factorization of Drell-Yan and other processes with relatively small transverse momentum. We present a lattice QCD study of this function at moderately large rapidity on a 2+1 flavor CLS dynamic ensemble with a=0.098 fm. We extract the rapidity-independent (or intrinsic) part of the soft function through a large-momentum-transfer pseudoscalar meson form factor and its quasi-TMD wave function using leading-order factorization in large-momentum effective theory. We also investigate the rapidity-dependent part of the soft function—the Collins-Soper evolution kernel—based on the large-momentum evolution of the quasi-TMD wave function.
Thermodynamics of apparent horizon in modified FRW universe with power-law corrected entropy
Creators: name: Karami, K.
name: Abdolmaleki, A.
name: Sahraei, N.
name: Ghaffari, S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Physics (physics.gen-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We derive the modified Friedmann equation corresponding to the power-law corrected entropy-area relation $S_{\rm A}=\frac{A}{4}[1-K_α A^{1-\fracα{2}}]$ which is motivated by the entanglement of quantum fields in and out of the apparent horizon. We consider a non-flat modified FRW universe containing an interacting viscous dark energy with dark matter and radiation. For the selected model, we study the effect of the power-law correction term to the entropy on the dynamics of dark energy. Furthermore, we investigate the validity of the generalized second law (GSL) of gravitational thermodynamics on the apparent horizon and conclude that the GSL is satisfied for $α<2$.
description: 12 pages, Accepted for Publication in JHEP
Evaluation of the effectiveness of two irrigation systems in reducing bacterial load in root canals in vitro by quantitative real-time polymerase chain reaction
Creators: name: Zhang, Duo
Publisher: name: University of British Columbia
Year: 2017

description: Introduction: Irrigation is regarded as having a key role in one of the main goals of endodontic treatment, the killing and removing bacteria from the infected root canal. Different methods and techniques have been used to deliver irrigating solutions and to facilitate the effectiveness of irrigation. The purpose of this in vitro study was, by using quantitative real-time PCR to determine the effectiveness of two irrigation and cleaning systems in removing multispecies oral biofilms from root canals. Methods: Fifteen extracted human molars were instrumented to size #15/.02 and then cleaned with the GentleWave System (GW; Sonendo Inc, Laguna Hills, CA). The teeth were autoclaved to provide the same sterile baseline. The molars were filled with mixed plaque suspended in brain-heart infusion broth and centrifuged to help the bacteria spread all over the root canal system. After two weeks of incubation, samples were divided randomly into two treatment groups and instrumented into size #15/.04 (GW) and #35/.04 (PiezoFlow group) under needle irrigation with sterile water. The teeth were then cleaned either with GentleWave System or ProUltra PiezoFlow Active Ultrasonic System (Dentsply Tulsa, Tulsa, OK) using 3% NaOCl, 8% EDTA and sterile water as irrigants. Root canals were sampled with paper points before and after instrumentation (S1, S2) and after GW or PF cleaning (S3). Quantitative real-time PCR was performed, the presence of microorganism in the samples was determined by using universal bacterial, a genus specific and species-specific primers. Statistical analysis was performed using the Mann-Whitney U test with the significance level set at P < 0.05. Result: A highly significant bacterial reduction was recorded for both groups (P < 0.001). GW group showed a significantly higher reduction than the PF group of total microbes (P < 0.01), Enterococcus faecalis (P < 0.01) and Streptococcus species (P < 0.05). GW resulted predictably in high reduction of over 99% of the microbes in every canal, whereas in the PF group the reduction of microbes varied between 87% and 99.99%. Conclusion: While both systems demonstrated effective reduction of intracanal bacteria, a high level of over 99% was more predictably achieved in the GW group.
Nucleon axial structure from lattice QCD
Creators: name: Bali, Gunnar S.
name: Barca, Lorenzo
name: Collins, Sara
name: Gruber, Michael
name: Löffler, Marius
name: Schäfer, Andreas
name: Söldner, Wolfgang
name: Wein, Philipp
name: Weishäupl, Simon
name: Wurm, Thomas
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We present a new analysis method that allows one to understand and model excited state contributions in observables that are dominated by a pion pole. We apply this method to extract axial and (induced) pseudoscalar nucleon isovector form factors, which satisfy the constraints due to the partial conservation of the axial current up to expected discretization effects. Effective field theory predicts that the leading contribution to the (induced) pseudoscalar form factor originates from an exchange of a virtual pion, and thus exhibits pion pole dominance. Using our new method, we can recover this behavior directly from lattice data. The numerical analysis is based on a large set of ensembles generated by the CLS effort, including physical pion masses, large volumes (with up to 963 × 192 sites and Lmπ = 6.4), and lattice spacings down to 0.039 fm, which allows us to take all the relevant limits. We find that some observables are much more sensitive to the choice of parametrization of the form factors than others. On the one hand, the z-expansion leads to significantly smaller values for the axial dipole mass than the dipole ansatz (Mz−expA = 1.02(10) GeV versus MdipoleA = 1.31(8) GeV). On the other hand, we find that the result for the induced pseudoscalar coupling at the muon capture point is almost independent of the choice of parametrization (g∗z−expP = 8.68(45) and g∗dipoleP = 8.30(24)), and is in good agreement with both, chiral perturbation theory predictions and experimental measurement via ordinary muon capture. We also determine the axial coupling constant gA.
Unitary representations of a loop ax+b group, Wiener measure and Gamma-function
Creators: name: Zeitlin, Anton M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We construct a family of irreducible unitary representations of the loop affine group of a line (ax+b group) with central extension on the Hilbert space of square integrable functions with respect to the Wiener measure. We relate the matrix coefficients of the elements of the loop ax+b group to the loop analogue of the Gamma-function.
description: 20 pages, minor revisions due to referees' comments, Journal of Functional Analysis, in press
Chameleonic Generalized Brans--Dicke model and late-time acceleration
Creators: name: Farajollahi, H.
name: Farhoudi, M.
name: Salehi, A.
name: Shojaie, H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this paper we consider Chameleonic Generalized Brans--Dicke Cosmology in the framework of FRW universes. The bouncing solution and phantom crossing is investigated for the model. Two independent cosmological tests: Cosmological Redshift Drift (CRD) and distance modulus are applied to test the model with the observation.
description: 20 pages, 15 figures, to be published in Astrophys. Space Sci. (2011)
Renormalization of parton quasi-distributions beyond the leading order: spacelike vs. timelike
Creators: name: Braun, V. M.
name: Chetyrkin, K. G.
name: Kniehl, B. A.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We argue that the renormalization factors for non-local quark-antiquark and gluon operators at space-like and time-like separations connected by a Wilson line coincide to all orders in perturbation theory. We calculate the anomalous dimensions and renormalization constants of quark-antiquark and gluon operators to three- and two-loop accuracy, respectively, and also compute vacuum expectation values of these operators to three-loop accuracy.
Can we fit nuclear PDFs with the high-x CLAS data?
Creators: name: Paukkunen, Hannu
name: Zurita, Pia
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Nuclear parton distribution functions (nuclear PDFs) are non-perturbative objects that encode the partonic behaviour of bound nucleons. To avoid potential higher-twist contributions, the data probing the high-x end of nuclear PDFs are sometimes left out from the global extractions despite their potential to constrain the fit parameters. In the present work we focus on the kinematic corner covered by the new high-x data measured by the CLAS/JLab collaboration. By using the Hessian re-weighting technique, we are able to quantitatively test the compatibility of these data with globally analyzed nuclear PDFs and explore the expected impact on the valence-quark distributions at high x. We find that the data are in a good agreement with the EPPS16 and nCTEQ15 nuclear PDFs whereas they disagree with TuJu19. The implications on flavour separation, higher-twist contributions and models of EMC effect are discussed.
Entangled Photon Pair Generation in Hybrid Superconductor-Semiconductor Quantum Dot Devices
Creators: name: Khoshnegar, Milad
name: Majedi, A. Hamed
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We investigate the effect of Cooper pair injection in shifting biexciton energy level of low-symmetry (C2v) quantum dots (QDs) exhibiting nontrivial fine structure splitting. Coupling QDs to the superconducting coherent state forms extra fine structures by intermixing the ground and biexcitonic states where spectroscopic separation of neutral exciton and biexciton can be diminished, yielding a system to be utilized in time reordering scheme. The separability of exciton and biexciton energy levels is ascribed to the corresponding direct, exchange and correlation energies calculated here through configuration interaction method. We demonstrate the possibility of enhancing photon entanglement concurrence via providing an energy coincidence for biexciton-exciton (XX \rightarrow X) and exciton-ground (X \rightarrow 0) emissions within the weak coupling regime.
description: 19 pages, 4 figures
Bulge formation scenarios …perspectives from a high-z observer
Creators: name: Tacchella, Sandro
Publisher: name: Zenodo
Year: 2019

description: I will present observational theoretical work on the formation bulges and pseudo-bulges in galaxies at high and low redshifts. Specifically, using the cosmological zoom-in simulations VELA, I will show how typical galaxies on the star-forming main sequence at redshift 2 can form a bulge component through rapid gas inflows, triggered by mergers, counter-rotating accretion streams, or violent disk instabilities. A comparison with our SINFONI-HST observations of stellar mass and star-formation rate profiles support this picture. In the second part, I will present how bulges and pseudo-bulges assemble in the new cosmological simulation IllustrisTNG. In particular, I discuss which physical processes are important to set the diversity of bulges in Milky Way like halos.
Two-loop coefficient function for DVCS: vector contributions
Creators: name: Braun, V. M.
name: Manashov, A. N.
name: Moch, S.
name: Schoenleber, J.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Using the approach based on conformal symmetry we calculate the two-loop coefficient function for the vector flavor-nonsinglet contribution to deeply-virtual Compton scattering (DVCS). The analytic expression for the coefficient function in momentum fraction space is presented in the MS¯¯¯¯¯¯¯ scheme. The corresponding next-to-next-to-leading order correction to the Compton form factor ℋ for a simple model of the generalized parton distribution appears to be rather large: a factor two smaller than the next-to-leading order correction, approximately ∼ 10% of the tree level result in the bulk of the kinematic range, for Q2 = 4 GeV2.
title: Metformin and guanylurea in aquatic environments: an overview and improved analysis
Creators: name: Tao, Yunwen
Publisher: name: Memorial University of Newfoundland
Year: 2020

description: Metformin, a biguanide in chemical classification, is widely used as one of the most effective first-line oral drugs for type 2 diabetes. It is difficult to be metabolized by the human body and exists in both urine and faeces samples. Guanylurea is metformin’s biotransformation product. Consequently, significant concentrations of metformin and guanylurea have been reported in wastewater treatment plants (WWTPs) and coastal aquatic environments. In this thesis, a comprehensive overview is conducted to discuss the occurrence, impact, analysis and treatment of metformin and guanylurea in coastal aquatic environments of Canada, USA and Europe. The maximum concentrations of metformin and guanylurea in surface water samples were as high as 59,000 and 4,502 ng L⁻¹, respectively. Metformin can be absorbed in non-target organisms by plants and in Atlantic salmon (Salmo salar). Guanylurea has a confirmed mitotic activity in plant cells. Analysis methods of metformin are currently developed based on high-performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry (GC-MS). The removal of metformin from aquatic environments in the target regions is summarized. The review helps to fill a knowledge gap and provides insights for regulatory considerations. The potential options for managing these emerging pollutants are outlined too. To help better track the occurrence of the two non-volatile biguanide compounds in liquid samples, the improvement of existing GC-MS based methods for reliable metformin and guanylurea analysis is also conducted in this thesis. Derivatization of metformin and guanylurea is the key pre-treatment procedure before the associated GC-MS analysis. Four selected factors affecting for the derivatization were evaluated, and the optimal factors include temperature (90oC), reacting time (40 minutes), solvent (1,4-dioxane), and ratio (1.5:1) of reagent to target component. Buformin and N-methyl-bis(trifluoroacetamide) (MBTFA) were used as the internal standard (IS) and the derivatization reagent, respectively. Calibration curves were made based on the optimal conditions of derivatization for metformin and guanylurea with the R² values of calibration linearity achieved as 99.35% and 99.2%, respectively. The values of relative standard deviation (RSD%) of metformin and guanylurea based on seven repeated trails are 2.67% and 15.37%, respectively. The optimal conditions for enhancing the sensitization of metformin and guanylurea derivatization performance were obtained. The improved GC-MS analysis method was eventually applied for metformin and guanylurea analysis in real water samples. Detection of metformin and guanylurea in other types of real water samples could be conducted in the future like final effluents of wastewater treatment plants.
Forward trijet production in p-p and p-Pb collisions at LHC
Creators: name: Bury, Marcin
name: van Hameren, Andreas
name: Kotko, Piotr
name: Kutak, Krzysztof
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We calculate various azimuthal angle distributions for three jets produced in the forward rapidity region with transverse momenta pT > 20 GeV in proton-proton (p-p) and proton-lead (p-Pb) collisions at center of mass energy 5.02 TeV. We use the multiparton extension of the so-called small-x Improved Transverse Momentum Dependent factorization (ITMD). We study effects related to change from the standard kT -factorization to ITMD factorization as well as changes as one goes from p-p collision to p-Pb. We observe rather large differences in the distribution when we change the factorization approach, which allows to both improve the small-x TMD gluon distributions as well as validate and improve the factorization approach. We also see significant depletion of the nuclear modification ratio, indicating a possibility of searches for saturation effects using trijet final states in a more exclusive way than for dijets.
Z tetraquark channel from lattice QCD and Born-Oppenheimer approximation
Creators: name: Prelovsek, S.
name: Bahtiyar, H.
name: Petković, J.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Two Zbhadrons with exotic quark structure ¯bb¯duwere discovered by Belle experiment. We present a lattice QCD study of the ¯bb¯dusystem in the approximation of static bquarks, where the total spin of heavy quarks is fixed to one. The energies of eigenstates are determined as a function of the separation rbetween band ¯ b. The lower eigenstates are related to a bottomonium and a pion. The eigenstate dominated by B¯ B∗has energy significantly below mB+mB∗, which points to a sizable attraction for small r. The attractive potential V(r)between Band ¯ B∗is extracted assuming that this eigenstate is related exclusively to B¯ B∗. The Schrödinger equation for B¯ B∗within the extracted potential leads to a virtual bound state, whose mass depends on the parametrization of the lattice potential. For certain parametrizations, we find a virtual bound state slightly below B¯ B∗threshold and a narrow peak in the B¯ B∗rate above threshold -these features could be related to Zb(10610)in the experiment. We surprisingly find also a deep bound state within the undertaken approximations.
Collider Constraints on Dipole-Interacting Dark Matter
Creators: name: Fortin, Jean-François
name: Tait, Tim M. P.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Dark matter which interacts through a magnetic or electric dipole moment is an interesting possibility which may help to resolve the discrepancy between the DAMA annual modulation signal and the null results of other searches. In this article we examine relic density and collider constraints on such dark matter, and find that for couplings needed to explain DAMA, the thermal relic density is generically in the right ballpark to account for cosmological measurements. Collider constraints are relevant for light WIMPs, but less constraining that direct searches for masses above about 10 GeV.
description: 11 pages, 2 figures, extended discussion, added references, conclusion unchanged
Consistency of hadronic vacuum polarization between lattice QCD and the R ratio
Creators: name: Lehner, Christoph
name: Meyer, Aaron S.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: There are emerging tensions for theory results of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment both within recent lattice QCD calculations and between some lattice QCD calculations and R-ratio results. In this paper, we work toward scrutinizing critical aspects of these calculations. We focus in particular on a precise calculation of Euclidean position-space windows defined by RBC/UKQCD that are ideal quantities for cross-checks within the lattice community and with R-ratio results. We perform a lattice QCD calculation using physical up, down, strange, and charm sea quark gauge ensembles generated in the staggered formalism by the MILC Collaboration. We study the continuum limit using inverse lattice spacings from a−1≈1.6 GeV to 3.5 GeV, identical to recent studies by FNAL/HPQCD/MILC and Aubin et al. and similar to the recent study of BMW. Our calculation exhibits a tension for the particularly interesting window result of aud,conn.,isospin,Wμ from 0.4 to 1.0 fm with previous results obtained with a different discretization of the vector current on the same gauge configurations. Our results may indicate a difficulty related to estimating uncertainties of the continuum extrapolation that deserves further attention. In this work, we also provide results for aud,conn.,isospinμ, as,conn.,isospinμ, aSIB,conn.μ for the total contribution and a large set of windows. For the total contribution, we find aHVP LOμ=714(27)(13)10−10, aud,conn.,isospinμ=657(26)(12)10−10, as,conn.,isospinμ=52.83(22)(65)10−10, and aSIB,conn.μ=9.0(0.8)(1.2)10−10, where the first uncertainty is statistical and the second systematic. We also comment on finite-volume corrections for the strong-isospin-breaking corrections.
Derogating others in the face of death : applications of the mortality salience hypothesis of terror management theory
Creators: name: Hutchinson, Shirley May Gallon
Publisher: name: University of British Columbia
Year: 2017

description: One goal in life is survival even when faced with the certainty of death. To defend against the fear of eventual death, individuals are strongly motivated to maintain faith in cultural worldviews, or beliefs about the nature of their reality. Terror Management Theory (TMT) argues that cultural worldviews act to protect individuals from the terror that is brought on by the knowledge of their own mortality. Cultural worldviews provide structure, order, and significance to an individual’s reality insulating them from the inevitability of death. Validation of these cultural worldviews by others increases their level of effectiveness as a buffer against the anxiety caused by the reality of death. However, when others disagree with an individual’s notion of reality, their faith in these concepts becomes threatened, and their ability to cope with the anxiety of impending death is weakened. This research examined one of the four responses to a threatened worldview – derogation against those who hold conflicting cultural worldviews. Specifically, this research examined how reminders of impending death (i.e., mortality salience) influenced the derogation of others in both healthcare and criminal justice domains. It was hypothesized that reminders of death would lead to greater derogation of others in both of these domains; in general, results did not support these hypotheses. Further the established effect in the literature regarding the influence of traditional mortality salience manipulations on the derogation of others was not replicated in this research. Two novel mortality salience manipulations were created and tested as alternatives to the traditional methods; only one of which showed a promising effect (i.e., AgingBooth software). This research contributes to our understanding of the mortality salience hypothesis and the need to continue to develop and test mortality salience manipulations as alternatives to traditional methods in a variety of domains.
Direct CP violation and the ΔI=1/2 rule in K→ππ decay from the standard model
Creators: name: Abbott, R.
name: Blum, T.
name: Boyle, P. A.
name: Bruno, M.
name: Christ, N. H.
name: Hoying, D.
name: Jung, C.
name: Kelly, C.
name: Lehner, C.
name: Mawhinney, R. D.
name: Murphy, D. J.
name: Sachrajda, C. T.
name: Soni, A.
name: Tomii, M.
name: Wang, T.
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: We present a lattice QCD calculation of the ΔI=1/2, K→ππ decay amplitude A0 and ϵ′, the measure of direct CP violation in K→ππ decay, improving our 2015 calculation [1] of these quantities. Both calculations were performed with physical kinematics on a 323×64 lattice with an inverse lattice spacing of a−1=1.3784(68) GeV. However, the current calculation includes nearly 4 times the statistics and numerous technical improvements allowing us to more reliably isolate the ππ ground state and more accurately relate the lattice operators to those defined in the standard model. We find Re(A0)=2.99(0.32)(0.59)×10−7 GeV and Im(A0)=−6.98(0.62)(1.44)×10−11 GeV, where the errors are statistical and systematic, respectively. The former agrees well with the experimental result Re(A0)=3.3201(18)×10−7 GeV. These results for A0 can be combined with our earlier lattice calculation of A2 [2] to obtain Re(ϵ′/ϵ)=21.7(2.6)(6.2)(5.0)×10−4, where the third error represents omitted isospin breaking effects, and Re(A0)/Re(A2)=19.9(2.3)(4.4). The first agrees well with the experimental result of Re(ϵ′/ϵ)=16.6(2.3)×10−4. A comparison of the second with the observed ratio Re(A0)/Re(A2)=22.45(6), demonstrates the standard model origin of this “ΔI=1/2 rule” enhancement.
On Delannoy numbers and Schröder numbers
Creators: name: Sun, Zhi-Wei
Publisher: name: arXiv
Year: 2010
Subjects: subject: Number Theory (math.NT)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 11A07, 11B75, 05A15, 11B39, 11B68, 11E25

description: The n-th Delannoy number and the n-th Schröder number given by $D_n=\sum_{k=0}^n\binom{n}{k}\binom{n+k}{k}$ and $S_n=\sum_{k=0}^n\binom{n}{k}\binom{n+k}{k}/(k+1)$ respectively arise naturally from enumerative combinatorics. Let p be an odd prime. We mainly show that $$\sum_{k=1}^{p-1}D_k/k^2=2(-1/p)E_{p-3} (mod p)$$ and $$\sum_{k=1}^{p-1}S_k/m^k=(m^2-6m+1)/(2m)*(1-((m^2-6m+1)/p) (mod p),$$ where (-) is the Legendre symbol, E_0,E_1,E_2,... are Euler numbers and m is any integer not divisible by p. We also conjecture that $\sum_{k=1}^{p-1}D_k^2/k^2=-2q_p(2)^2 (mod p)$, where $q_p(2)=(2^{p-1}-1)/p$.
Monte Carlo simulations of overlap Majorana fermions
Creators: name: Piemonte, Stefano
name: Bergner, Georg
name: López, Camilo
Publisher: name: Universität Regensburg
Year: 2020
Subjects: subject: 530 Physik

description: Supersymmetric Yang-Mills (SYM) theories in four dimensions exhibit many interesting nonperturbative phenomena that can be studied by means of Monte Carlo lattice simulations. However, the lattice regularization breaks supersymmetry explicitly, and in general a fine-tuning of a large number of parameters is required to correctly extrapolate the theory to the continuum limit. From this perspective, it is important to preserve on the lattice as many symmetries of the original continuum action as possible. Chiral symmetry for instance prevents an additive renormalization of the fermion mass. A (modified) version of chiral symmetry can be preserved exactly if the Dirac operator fulfills the Ginsparg-Wilson relation. In this contribution, we present an exploratory nonperturbative study of N=1 supersymmetric Yang-Mills theory using the overlap formalism to preserve chiral symmetry at nonzero lattice spacings. N=1 SYM is an ideal benchmark toward the extension of our studies to more complex supersymmetric theories, as the only parameter to be tuned is the gluino mass. Overlap fermions allow us therefore to simulate the theory without fine-tuning. We compare our approach to previous investigations of the same theory, and we present clear evidences for gluino condensation.
Finding radio transients with anomaly detection and active learning based on volunteer classifications
Creators: name: Andersson, Alex
name: Lintott, Chris
name: Fender, Rob
name: Lochner, Michelle
name: Woudt, Patrick
name: Eijnden, Jakob van den
name: van der Horst, Alexander
name: Horesh, Assaf
name: Saikia, Payaswini
name: Sivakoff, Gregory R.
name: Tremou, Lilia
name: Vaccari, Mattia
Publisher: name: arXiv
Year: 2024
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: In this work we explore the applicability of unsupervised machine learning algorithms to finding radio transients. Facilities such as the Square Kilometre Array (SKA) will provide huge volumes of data in which to detect rare transients; the challenge for astronomers is how to find them. We demonstrate the effectiveness of anomaly detection algorithms using 1.3 GHz light curves from the SKA precursor MeerKAT. We make use of three sets of descriptive parameters ('feature sets') as applied to two anomaly detection techniques in the Astronomaly package and analyse our performance by comparison with citizen science labels on the same dataset. Using transients found by volunteers as our ground truth, we demonstrate that anomaly detection techniques can recall over half of the radio transients in the 10 per cent of the data with the highest anomaly scores. We find that the choice of anomaly detection algorithm makes a minor difference, but that feature set choice is crucial, especially when considering available resources for human inspection and/or follow-up. Active learning, where human labels are given for just 2 per cent of the data, improves recall by up to 20 percentage points, depending on the combination of features and model used. The best performing results produce a factor of 5 times fewer sources requiring vetting by experts. This is the first effort to apply anomaly detection techniques to finding radio transients and shows great promise for application to other datasets, and as a real-time transient detection system for upcoming large surveys.
description: Version 2, Accepted to MNRAS, 18 pages, 9 figures