cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Clustering of periodic orbits and ensembles of truncated unitary matrices
Creators: name: Gutkin, Boris
name: Osipov, Vladimir Al.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 05C45, 37B10, 37D45, 37J45, 81Q20

description: Periodic orbits in chaotic systems form clusters, whose elements traverse approximately the same points of the phase space. The distribution of cluster sizes depends on the length n of orbits and the parameter p which controls closeness of orbits actions. We show that counting of cluster sizes in the baker's map can be turned into a spectral problem for an ensemble of truncated unitary matrices. Based on the conjecture of the universality for the eigenvalues distribution at the spectral edge of these ensembles, we obtain asymptotics of the second moment of cluster distribution in a regime where both n and p tend to infinity. This result allows us to estimate the average cluster size as a function of the number of encounters in periodic orbits.
description: 16 pages, 5 figures
Auroral Morphological Changes to the Formation of Auroral Spiral during the Late Substorm Recovery Phase: Polar UVI and Ground All-Sky Camera Observations
Creators: name: Nowada, Motoharu
name: Miyashita, Yukinaga
name: Partamies, Noora
name: Degeling, Alexander William
name: Shi, Quan-Qi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Space Physics (physics.space-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The ultraviolet imager (UVI) of the Polar spacecraft and an all-sky camera at Longyearbyen contemporaneously detected an auroral vortex structure (so-called "auroral spiral") on 10 January 1997. From space, the auroral spiral was observed as a "small spot" (one of an azimuthally-aligned chain of similar spots) in the poleward region of the main auroral oval from 18 h to 24 h magnetic local time. These auroral spots were formed while the substorm-associated auroral bulge was subsiding and several poleward-elongated auroral streak-like structures appeared during the late substorm recovery phase. During the spiral interval, the geomagnetically north-south and east-west components of the geomagnetic field, which were observed at several ground magnetic stations around Svalbard island, showed significant negative and positive bays caused by the field-aligned currents related with the aurora spiral appearance. The negative bays were reflected in the variations of local geomagnetic activity index (SML) which was provided from the SuperMAG magnetometer network at high latitudes. To pursue the spiral source region in the magnetotail, we trace each UVI image along field lines to the magnetic equatorial plane of the nightside magnetosphere using an empirical magnetic field model. Interestingly, the magnetotail region corresponding to the auroral spiral covered a broad region from Xgsm ~ -40 to -70 RE at Ygsm ~ 8 to 12 RE. The appearance of this auroral spiral suggests that extensive areas of the magnetotail (but local regions in the ionosphere) remain active even when the substorm almost ceases, and geomagnetic conditions are almost stable.
description: 40 Pages, 6 Figures (8 pages), 1 Table, and Supporting Information file (including 2 Figures (8 pages) and 1 Movie)
Searching for single-frame rapid X-ray transients detected with Chandra
Creators: name: Zhang, Yijia
name: Feng, Hua
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We propose a new method to identify rapid X-ray transients observed with focusing telescopes. They could be statistically significant if three or more photons are detected with Chandra in a single CCD frame within a point-spread-function region out of quiescent background. In the Chandra archive, 11 such events are discovered from regions without point-like sources, after discrimination of cosmic rays and background flares and control of false positives. Among them, two are spatially coincident with extended objects in the Milky Way, one with the Small Magellanic Cloud, and another one with M31; the rest have no or a dim optical counterpart ($\gtrsim 20$ mag), and are not clustered on the Galactic plane. Possible physical origins of the rapid transients are discussed, including short gamma-ray bursts (GRBs), short-lived hypermassive neutron stars produced by merger of neutron stars, accreting compact objects in the quiescent state, magnetars, and stellar flares. According to the short GRB event rate density, we expect to have detected $2.3_{-0.6}^{+0.7}$ such events in the Chandra archive. This method would also allow us to reveal quiescent black holes with only a few photons.
description: accepted for publication in Monthly Notices of the Royal Astronomical Society
title: Habitus – ein soziologisches Konzept in der Archäologie
Creators: name: Schreg, Rainer
name: Zerres, Jutta
name: Pantermehl, Heidi
name: Wefers, Stefanie
name: Grunwald, Lutz
name: Gronenborn, Detlef
Publisher: name: University Library Heidelberg
Year: 2014

description: Das Hauptinteresse sozialgeschichtlicher Analysen in der Archäologie gilt der Identifikation sozialer Gruppen und Schichten, wobei eindeutig die Eliten im Mittelpunkt stehen. In jüngerer Zeit wurde vermehrt nach Identität und Distinktion gefragt, für die letztlich das Habitus-Konzept von Pierre Bourdieu wesentlich ist. Zugleich bietet das Habitus-Konzept aber auch eine interessante Perspektive für das Problem des Umweltdeterminismus. Vorliegender Artikel versucht einen Überblick zu geben, wie Archäologen bislang auf das Habitus-Konzept eingegangen sind. Berücksichtigt werden die Klassische und die Provinzialrömische Archäologie, die Prähistorische und die Historische Archäologie. Es wird deutlich, dass der Habitus ein Hintergrundkonzept bietet, das bei der Formulierung von Fragestellungen – und der Überwindung einfacher hierarchischer Gesellschaftsmodelle – hilft, aber nicht über eine explizite Methodik verfügt oder ein allgemeingültiges Interpretationsschema für eine Sozialarchäologie liefert.
description: Social archaeology is primarily engaged in the identification of social classes, focusing especially on the elites. In recent decades, identity and social distinction gained increasing interest. The concept of social habitus, elaborated by the French sociologist Pierre Bourdieu is essential to understand these social processes. However, there is a second field, which makes the habitus concept interesting for archaeology: It provides a perspective dealing with the problem of environmental determinism, which is crucial for current question on cultural reaction on environmental change. Within the present article we try to summarize archaeologists’ reflection of the habitus concept, in classical, prehistoric and historical archaeology, mainly focusing on the German situation. Obviously habitus provides a fruitful background concept to develop new research questions and alternative interpretations. It does not, however, provide a specific methodology or a universally valid interpretation.
Quality Assurance of Spectral Ultraviolet Measurements in Europe Through the Development of a Transportable Unit (QASUME)
Creators: name: Bais, Alkiviadis F.
name: Blumthaler, Mario
name: Gröbner, Julian
name: Seckmeyer, Gunther
name: Webb, Ann R.
name: Gorts, Peter
name: Koskela, Tapani
name: Rembges, Diana
name: Kazadzis, Stelios
name: Schreder, Josef
name: Cotton, Peter
name: Kelly, Peter
name: Kouremeti, Natalia
name: Rikkonen, Kimo
name: Studemund, H.
name: Tax, Rick
name: Wuttke, Sigrid
Publisher: name: Bellingham Wash. : SPIE
Year: 2003
Subjects: subject: UV spectroradiometric measurements
subject: weather patterns
subject: UV stations
subject: Konferenzschrift
subject: Dewey Decimal Classification::500 | Naturwissenschaften::551 | Geologie, Hydrologie, Meteorologie

description: QASUME is a European Commission funded project that aims to develop and test a transportable unit for providing quality assurance to UV spectroradiometric measurements conducted in Europe. The comparisons will be performed at the home sites of the instruments, thus avoiding the risk of transporting instruments to participate in intercomparison campaigns. Spectral measurements obtained at each of the stations will be compared, following detailed and objective comparison protocols, against collocated measurements performed by a thoroughly tested and validated travelling unit. The transportable unit comprises a spectroradiometer, its calibrator with a set of calibration lamps traceable to the sources of different Standards Laboratories, and devices for determining the slit function and the angular response of the local spectroradiometers. The unit will be transported by road to about 25 UV stations over a period of about two years. The spectroradiometer of the transportable unit is compared in an intercomparison campaign with six instruments to establish a relation, which would then be used as a reference for its calibration over the period of its regular operation at the European stations. Different weather patterns (from clear skies to heavy rain) were present during the campaign, allowing the performance of the spectroradiometers to be evaluated under unfavourable conditions (as may be experienced at home sites) as well as the more desirable dry conditions. Measurements in the laboratory revealed that the calibration standards of the spectroradiometers differ by up to 10%. The evaluation is completed through comparisons with the same six instruments at their homes sites.
Enhancing Clustering Algorithm to Plan Efficient Mobile Network
Creators: name: Ibrahim, Lamiaa Fattouh
name: Harby, Manal El
Publisher: name: arXiv
Year: 2013
Subjects: subject: Networking and Internet Architecture (cs.NI)
subject: FOS: Computer and information sciences

description: With the rapid development in mobile network effective network planning tool is needed to satisfy the need of customers. However, deciding upon the optimum placement for the base stations (BS) to achieve best services while reducing the cost is a complex task requiring vast computational resource. This paper addresses antenna placement problem or the cell planning problem, involves locating and configuring infrastructure for mobile networks. The Cluster Partitioning Around Medoids (PAM) original algorithm has been modified and a new algorithm M-PAM (Modified-Partitioning Around Medoids) has been proposed by the authors in a recent work. In the present paper, the M-PAM algorithm is modified and a new algorithm CWN-PAM (Clustering with Weighted Node-Partitioning Around Medoids) has been proposed to satisfy the requirements and constraints. Implementation of this algorithm to a real case study is presented. Results demonstrate the effectiveness and flexibility of the modifying algorithm in tackling the important problem of mobile network planning.
description: 7 Pages, 14 Figures. arXiv admin note: substantial text overlap with arXiv:1302.6602
title: Der Entdeckeranteil an einem nicht ausgegrabenen fränkischen Gräberfeld (OLG Frankfurt am Main, Urteil vom 20.08.2013 – 11 U 113/12) – Fluch und Segen für den Finder
Creators: name: Kemper, Till
Publisher: name: University Library Heidelberg
Year: 2014

description: Mit Urteil vom 20.08.2013 – 11 U 113/12 sprach das Oberlandesgericht Frankfurt am Main einem ehrenamtlich für das Landesamt für Denkmalpflege Hessen tätigen Sondengänger das hälftige Eigentum hinsichtlich aller Funde zu, die auf einem merowingerzeitlichen Gräberfeld in Hessen künftig gleich durch wen oder wann gemacht werden. Zwar wurden die Ausdehnung und Befunde mittels eines geomagnetischen Gutachtens festgestellt, Art und Anzahl der Funde aber blieb dagegen undefiniert. Dieses Urteil reiht sich in eine lange Tradition von Entscheidungen zum Anspruch auf den Entdeckeranteil aus der Hadrianischen Teilung gemäß § 984 BGB ein. Im Detail weicht es von den übrigen Urteilen jedoch ab. Dies ist nicht der Fall, weil es den Anspruch aus § 984 BGB auf noch nicht bloßgelegte Funde ausdehnt. Das Besondere ist, dass das Gericht den Anspruch auf eine enorme Fläche und Vielzahl von Funden ausdehnt und erstmals den Anspruch für einen ehrenamtlich für die Denkmalpflege Tätigen bejaht, ohne die Bedeutung oder Rechtsfolgen des Bestehens eines Ehrenamtsverhältnisses zur planmäßigen „Schatzsuche“ zu problematisieren. Zudem gibt das Urteil Anlass, auch die Rechtsfolgen des Entdeckeranteils für den Finder zu besprechen, die keineswegs nur positiv sind.
description: The Higher Regional Court of Frankfurt/Main pronounced the sentence of 20.08.2013 – 11 U 113/12 that a volunteer of the cultural heritage preservation department have the claim of estate on all non excavated corpus of finds existing in a pre-medieval burial ground he located. There are a lot of sentences by German courts which confirmed as well the claim of property of a finder of archaeological artefacts. But theses sentences affected isolated corpus of finds in a limited area. The discussed sentence of 2013 is special because it widen out the claim of a huge areal and an undefined number of artefacts. Also it ignored the fact that the finder was a volunteer of the cultural heritage preservation department and prospected the affected area in charge of that department. So the location of the burial ground was a result of a planed prospection in charge of the department. According to German law this facts give good reasons to deny the claim.
A Method for Measuring the $6S_{1/2} \leftrightarrow 5D_{3/2}$ Magnetic Dipole Transition Moment in {Ba}$^{+}$
Creators: name: Williams, Spencer R.
name: Jayakumar, Anupriya
name: Hoffman, Matthew R.
name: Blinov, Boris B.
name: Fortson, E. N.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We propose a method for measuring the magnetic dipole (M1) transition moment of the $6S_{1/2} \big(\mathrm{m}=-1/2\big)\leftrightarrow 5D_{3/2}\big(\mathrm{m}=-1/2\big)$ transition in single trapped Ba$^{+}$ by exploiting different symmetries in the electric quadrupole (E2) and M1 couplings between the states. The technique is adapted from a previously proposed method for measuring atomic parity nonconservation in a single trapped ion [Norval Fortson, Phys. Rev. Lett. \textbf{70}, 17 (1993)]. Knowledge of M1 is crucial for any parity nonconservation measurement in Ba$^{+}$, as laser coupling through M1 can mimic the parity-violating signal. The magnetic moment for the transition has been calculated by atomic theory and found to be dominated by electron-electron correlation effects [B.K. Sahoo et. al., Phys. Rev. A \textbf{74}, 6 (2006)]. To date the value has not been verified experimentally. This proposed measurement is therefore an essential step toward a parity nonconservation experiment in the ion that will also test current many-body theory. The technique can be adapted for similar parity nonconservation experiments using other atomic ions, where the magnetic dipole moment could present similar complications.
The shape of spins
Creators: name: Englert, Christoph
name: Goncalves, Dorival
name: Nail, Graeme
name: Spannowsky, Michael
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: After the discovery of a Higgs-like particle at the LHC, the determination of its spin quantum numbers across different channels will be the next step in arriving at a more precise understanding of the new state and its role in electroweak symmetry breaking. Event shape observables have been shown to provide extremely sensitive observables for the discrimination of the scalar Higgs boson's CP quantum numbers as a consequence of the different radiation patterns of Higgs production via gluon fusion vs. weak boson fusion in the $pp\to X+2j$ selection. We show that a similar strategy serves to constrain the spin quantum numbers of the discovered particle as a function of the involved couplings. We also discuss the prospects of applying a similar strategy to future discoveries of Higgs-like particles.
description: 11 pages, 7 figures
You Only Live Once: Single-Life Reinforcement Learning
Creators: name: Chen, Annie S.
name: Sharma, Archit
name: Levine, Sergey
name: Finn, Chelsea
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Reinforcement learning algorithms are typically designed to learn a performant policy that can repeatedly and autonomously complete a task, usually starting from scratch. However, in many real-world situations, the goal might not be to learn a policy that can do the task repeatedly, but simply to perform a new task successfully once in a single trial. For example, imagine a disaster relief robot tasked with retrieving an item from a fallen building, where it cannot get direct supervision from humans. It must retrieve this object within one test-time trial, and must do so while tackling unknown obstacles, though it may leverage knowledge it has of the building before the disaster. We formalize this problem setting, which we call single-life reinforcement learning (SLRL), where an agent must complete a task within a single episode without interventions, utilizing its prior experience while contending with some form of novelty. SLRL provides a natural setting to study the challenge of autonomously adapting to unfamiliar situations, and we find that algorithms designed for standard episodic reinforcement learning often struggle to recover from out-of-distribution states in this setting. Motivated by this observation, we propose an algorithm, $Q$-weighted adversarial learning (QWALE), which employs a distribution matching strategy that leverages the agent's prior experience as guidance in novel situations. Our experiments on several single-life continuous control problems indicate that methods based on our distribution matching formulation are 20-60% more successful because they can more quickly recover from novel states.
description: 17 pages
0.75 atoms improve the clock signal of 10,000 atoms
Creators: name: Kruse, I.
name: Lange, K.
name: Peise, J.
name: Lücke, Bernd
name: Pezzè, L.
name: Arlt, Jan J.
name: Ertmer, Wolfgang
name: Lisdat, C.
name: Santos, Luis
name: Smerzi, A.
name: Klempt, Carsten
Publisher: name: Bellingham, WA : S P I E - International Society for Optical Engineering
Year: 2017
Subjects: subject: Atomic clock
subject: Precision below the SQL
subject: Squeezed vacuum
subject: Atomic clocks
subject: Fountains
subject: Interferometers
subject: Units of measurement
subject: Atom interferometer
subject: Clock signal
subject: Precision metrology
subject: Squeezed vacuum state
subject: Standard quantum limits
subject: Technical limitations
subject: Slow light
subject: Konferenzschrift
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: Since the pioneering work of Ramsey, atom interferometers are employed for precision metrology, in particular to measure time and to realize the second. In a classical interferometer, an ensemble of atoms is prepared in one of the two input states, whereas the second one is left empty. In this case, the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.75 atoms to improve the clock sensitivity of 10,000 atoms by 2.05-.37 +.34 dB. The SQL poses a significant limitation for today's microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks based on atomic squeezed vacuum. © 2017 SPIE.
Early evolution of fully convective stars in scalar-tensor gravity
Creators: name: Gomes, Débora Aguiar
name: Wojnar, Aneta
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In this work, the early evolution of low-mass fully convective stars is studied in the context of DHOST (degenerate higher order scalar-tensor) theories of gravity. Although it is known that the hydrostatic equilibrium equation is modified for scalar-tensor gravity, the consequent modifications to the early evolution phases of a star were not explored in this framework. With this in mind, we consider three evolutionary phases - contraction to the main sequence, lithium burning and entrance to the main sequence - and investigate how each of these phases is affected by the theory's parameter. Taking these effects into account, we are able to show, among other things, that the Hayashi tracks are shifted and the star's age is considerably modified.
description: 11 pages, 1 figure, to appear in EPJC
Search for the CP violating $K_S \to 3π^0$ decay with the KLOE detector
Creators: name: Silarski, M.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We present a new search for the $K_S \to 3π^0$ decay performed with the KLOE detector operating at the DA$Φ$NE $ϕ$--factory. The $K_S$ mesons were tagged via registration of $K_L$ mesons which crossed the drift chamber without decaying and interacted with the KLOE electromagnetic calorimeter. The $K_S \to 3π^0$ decay was then searched requiring six prompt photons. To suppress background, originating from fake $K_S$ tags and $K_S \to 2π^0$ decays with additional two spurious clusters, we have performed a discriminant analysis based on kinematical fit, testing of the signal and background hypotheses and exploiting of the differences in kinematics of the $K_S$ decays into $2π^0$ and $3π^0$. In a sample of about 1.7$\cdot 10^9$ $ϕ\to K_S K_L$ events we have found no candidates in data and simulated background samples. Normalizing to the number of $K_S \to 2π^0$ events in the same sample, we have set the upper limit on the $K_S \to 3π^0$ branching ratio BR($K_S \to 3π^0) < 2.6 \cdot 10^{-8}$ at 90% C.L., five times lower than the previous limit. This upper limit can be translated into a limit on the modulus of the $η_{000}$ parameter amounting to $|η_{000}| < 0.0088$ at 90% C.L., improving by a factor two the latest direct measurement.
description: Proceedings of the DISCRETE 2012 conference, 8 pages, 7 figures
Reducing Collision Checking for Sampling-Based Motion Planning Using Graph Neural Networks
Creators: name: Yu, Chenning
name: Gao, Sicun
Publisher: name: arXiv
Year: 2022
Subjects: subject: Robotics (cs.RO)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Sampling-based motion planning is a popular approach in robotics for finding paths in continuous configuration spaces. Checking collision with obstacles is the major computational bottleneck in this process. We propose new learning-based methods for reducing collision checking to accelerate motion planning by training graph neural networks (GNNs) that perform path exploration and path smoothing. Given random geometric graphs (RGGs) generated from batch sampling, the path exploration component iteratively predicts collision-free edges to prioritize their exploration. The path smoothing component then optimizes paths obtained from the exploration stage. The methods benefit from the ability of GNNs of capturing geometric patterns from RGGs through batch sampling and generalize better to unseen environments. Experimental results show that the learned components can significantly reduce collision checking and improve overall planning efficiency in challenging high-dimensional motion planning tasks.
The LIZA cornerstone an ESA/NASA collaborative mission
Creators: name: Danzmann, Karsten
Publisher: name: Bellingham, WA : S P I E - International Society for Optical Engineering
Year: 2017
Subjects: subject: Audio acoustics
subject: Gravitational effects
subject: Audio frequencies
subject: Gravitational wave detectors
subject: Ground based
subject: Ground-based detectors
subject: Space-based detector
subject: Gravity waves
subject: Gravitationswelle
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Small prototypes of gravitational wave detectors have been under development for over 30 years. But it is only now that we have the necessary technology available to build large instruments with good sensitivity. After several years of construction, the first ground-based interferometers will go into operation in 2001 and a space-based detector is expected to be launched in 2010. These instruments will complement each other because the gravitational wave spectrum extends over many decades in frequency. Ground-based detectors can only observe the audio-frequency regime are only accessible from space because of the unshieldable background of local gravitational noise on the ground. © 2000 ESA and CNES.
Translation-Invariant Shrinkage/Thresholding of Group Sparse Signals
Creators: name: Chen, Po-Yu
name: Selesnick, Ivan W.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Sound (cs.SD)
subject: FOS: Computer and information sciences

description: This paper addresses signal denoising when large-amplitude coefficients form clusters (groups). The L1-norm and other separable sparsity models do not capture the tendency of coefficients to cluster (group sparsity). This work develops an algorithm, called 'overlapping group shrinkage' (OGS), based on the minimization of a convex cost function involving a group-sparsity promoting penalty function. The groups are fully overlapping so the denoising method is translation-invariant and blocking artifacts are avoided. Based on the principle of majorization-minimization (MM), we derive a simple iterative minimization algorithm that reduces the cost function monotonically. A procedure for setting the regularization parameter, based on attenuating the noise to a specified level, is also described. The proposed approach is illustrated on speech enhancement, wherein the OGS approach is applied in the short-time Fourier transform (STFT) domain. The denoised speech produced by OGS does not suffer from musical noise.
description: 33 pages, 7 figures, 5 tables
Accurate propagation of ultrashort pulses in nonlinear waveguides using propagation models for the analytic signal
Creators: name: Melchert, O.
name: Morgner, Uwe
name: Roth, B.
name: Babushkin, I.
name: Demircan, A.
Publisher: name: Bellingham, WA : SPIE - International Society for Optical Engineering
Year: 2018
Subjects: subject: analytic signal
subject: barrier scattering
subject: solitons
subject: Unidirectional field propagation
subject: Laser pulses
subject: Nonlinear optics
subject: Photonic crystal fibers
subject: Runge Kutta methods
subject: Solitons
subject: Waveguides
subject: Analytic signals
subject: Field propagation
subject: High order polynomial
subject: Interaction pictures
subject: Nonlinear waveguides
subject: Propagation equations
subject: Slowly varying envelope approximation
subject: Ultrashort optical pulse
subject: Dispersion (waves)
subject: Konferenzschrift
subject: Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik

description: We present a numerical approach for the accurate simulation of the complex propagation dynamics of ultrashort optical pulses in nonlinear waveguides, especially valid for few-cycle pulses. The propagation models are derived for the analytical signal, which includes the real optical field, exempt from the commonly adopted slowly varying envelope approximation. As technical basis for the representation of the medium dispersion we use rational Pade approximants instead of commonly employed high-order polynomial expansions. The implementation of the propagation equation is based on the Runge-Kutta in the interaction picture method. In addition, our modular approach easily allows to incorporate a Raman response and dispersion in the nonlinear term. As exemplary use-cases we illustrate our numerical approach for the simulation of a few-cycle pulse at various center frequencies for an exemplary photonic crystal fiber and demonstrate the collision of a soliton and two different dispersive waves mediated by their group-velocity event horizon.
Coexistence of the superconducting energy gap and pseudogap above and below the transition temperature of superconducting cuprates
Creators: name: Tallon, Jeffery L.
name: Barber, Felix
name: Storey, James G.
name: Loram, John W.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We express the superconducting gap, $Δ(T)$, in terms of thermodynamic functions in both $s$- and d-wave symmetries. Applying to Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$ and Y$_{0.8}$Ca$_{0.2}$Ba$_2$Cu$_3$O$_{7-δ}$ we find that for all dopings $Δ(T)$ persists, as a partial gap, high above $T_c$ due to strong superconducting fluctuations. Therefore in general two gaps are present above $T_c$, the superconducting gap and the pseudogap, effectively reconciling two highly polarized views concerning pseudogap physics.
description: Published as Rapid Communications in Phys. Rev. B. Five pages, 4 figures
The space-Time explorer and quantum test of the equivalence principle mission (STE-QUEST)
Creators: name: Gaaloul, Naceur
name: Ertmer, Wolfgang
name: Rasel, Ernst Maria
name: Braxmaier, Claus
name: Landragin, Arnaud
name: Bouyer, Philippe
name: Bongs, Kai
name: Tino, Guglielmo
Publisher: name: Bellingham, WA : S P I E - International Society for Optical Engineering
Year: 2017
Subjects: subject: Space-Time Explorer
subject: Equivalence Principle mission
subject: STEQUEST
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: The Space-Time Explorer and Quantum Test of the Equivalence Principle mission (STEQUEST) is devoted to a precise measurement of the effect of gravity on time and matter using an atomic clock and an atom interferometer. The mission was selected by ESA as one of four candidates for the M3 mission within the Cosmic Vision Program (launch in 2022).
title: The "free democratic constitutional structure" and its enemies – law and authority in Germany
Creators: name: Schulz, Sarah
Publisher: name: University Library Heidelberg
Year: 2014

description: Der folgende Beitrag geht anhand der aktuellen Diskussion um die ‚Extremismusklausel‛ in den Programmen gegen ‚Rechtsextremismus‛ der Bundesregierung und des sächsischen Innenministeriums der Frage nach, woher ein Bezug auf Recht und Verfassung bzw. Bundesverfassungsgericht in politischen Debatten Autorität gewinnt. Antworten auf diese Frage
werden in der deutschen Staatsrechtstheorie sowie den Annahmen zur politischen Kultur gesucht. Vor allem aber wird der theoretische Ansatz von Jacques Derrida herangezogen. Mittels seiner Aussagen lassen sich ein mystischer Grund der Autorität und eine aporetische Struktur des Rechts darstellen. Recht auto-autorisiert sich, benötigt dennoch stetige Bejahung. Diese Bejahung kann auch das geforderte Bekenntnis zur freiheitlichen demokratischen Grundordnung sein, dass in der ‚Extremismusklausel‛ unterschrieben werden soll. Dieses Bekenntnis soll Demokratie schützen. Versteht man aber Demokratie im Derridaschen Sinne als eine entgrenzte, kommende, wird klar, dass eine Beschränkung ebenjener – und sei es auf eine freiheitlich demokratische Grundordnung – das verursacht, was es vorgibt, vermeiden zu wollen: die Zerstörung der Demokratie.
description: The following article seeks to answer the question as to why there is such strong acceptance of "the law" as an authority in political debates. The recent conflict on the so-called "Extremismusklausel"
(extremism clause) between anti-right-wing NGOs and the German Ministry of Familiy, Youth, Women an Social Affairs as well as the Saxonian Ministry of Interior provides some examples of the questions considered in the following theoretical essay. The
"extremism provision" requires NGOs that receive government funding in the work against "right wing extremism" to sign a clause stating that neither they nor any of their cooperation partners would give anyone cause to suspect them of "extremism". Here, the "free democratic constitutional structure" is evoked as the quintessence of the German legal system. A Derridian critique of the conflict on the "extremism clause" might argue that to require the signature is to demand the inevitable affirmation of the necessity of the law to be in force. "The Law" has an aporetical structure and auto-authorizes itself. This aporetical structure enables democracy "to come". But the default attempt to shield democracy from its presumed enemies by reducing it to the "free democratic constitutional structure" destroys this enabling abilitiy – it destroys democracy.
Statistical Methods for Estimating Complexity from Competition Experiments between Two Populations
Creators: name: Montgomery-Smith, Stephen
name: Schmidt, Francis J.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantitative Methods (q-bio.QM)
subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: Often a screening or selection experiment targets a cell or tissue, which presents many possible molecular targets and identifies a correspondingly large number of ligands. We describe a statistical method to extract an estimate of the complexity or richness of the set of molecular targets from competition experiments between distinguishable ligands, including aptamers derived from combinatorial experiments (SELEX or phage display). In simulations, the nonparametric statistic provides a robust estimate of complexity from a 100x100 matrix of competition experiments, which is clearly feasible in high-throughput format. The statistic and method are potentially applicable to other ligand binding situations.
Ultrashort pulse CPA-free Ho:YLF linear amplifier
Creators: name: Hinkelmann, Moritz
name: Wandt, Dieter
name: Morgner, Uwe
name: Neumann, Jörg
name: Kracht, Dietmar
Publisher: name: Bellingham, WA : S P I E - International Society for Optical Engineering
Year: 2018
Subjects: subject: infrared lasers
subject: laser amplifiers
subject: mode-locked lasers
subject: solid-state lasers
subject: Ultrafast lasers
subject: ultrashort lasers
subject: Amplifiers (electronic)
subject: Fiber amplifiers
subject: Infrared lasers
subject: Optical parametric amplifiers
subject: Optical pumping
subject: Parametric amplifiers
subject: Pulse repetition rate
subject: Ultrashort pulses
subject: All-fiber system
subject: IR spectral regions
subject: Laser amplifiers
subject: Linear amplification
subject: Linear amplifiers
subject: Mode-locked laser
subject: Soliton oscillators
subject: Ultrashort Laser
subject: Solid state lasers
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: We present CPA-free linear amplification of 6:3 ps pulses in Ho:YLF crystals up to 100 μJ pulse energy at 10 kHz repetition rate. The seed pulses at a wavelength of 2:05 μm are provided by a Ho-based all-fiber system consisting of a soliton oscillator and a subsequent pre-amplifier followed by a free-space AOM as pulse-picker. Considering the achieved pulse peak power at MW-level, this system is a powerful tool for efficient pumping of parametric amplifiers addressing the highly demanded mid-IR spectral region. In detailed numerical simulations we verified our experimental results and discuss scaling options for pulse duration and energy. © 2018 SPIE.
Wavefront sensorless adaptive optics for optical coherence tomography guided femtosecond laser surgery in the posterior eye
Creators: name: Zabic, Miroslav
name: Matthias, Ben
name: Hahn, Jan
name: Heisterkamp, Alexander
name: Meyer, Heiko
name: Ripken, Tammo
Publisher: name: Bellingham : SPIE
Year: 2019
Subjects: subject: Fs-laser
subject: Ophthalmic laser surgery
subject: Optical coherence tomography
subject: Wavefront sensorless adaptive optics
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: Surgery with fs-laser in the posterior part of the eye could be useful for separation of tractional epiretinal membrane and vitreous floaters treatment. However, focus degradation occurs near the retina due to induced aberrations by cornea and lens. To overcome this issue, adaptive optics with wavefront sensor and wavefront modulator can be utilized. We demonstrate an alternative concept for image guided femto second laser (fs-laser) surgery in the posterior eye with wavefront sensorless adaptive optics (WFSLAO). Our laboratory setup consists of an 800 nm fs-laser and a superluminescent diode (SLD) with 897.2 nm central wavelength. The SLD is used for optical coherence tomography (OCT) whereby the light for the OCT sample arm and the fs-laser share the same optical path which contains a deformable mirror, scanner and focusing optics. Energy calibrated photodiodes are used to measure the threshold energy for a laser induced optical breakdown inside a water filled chamber that acts as simple eye model. OCT image based metrics were used to determine a set of Zernike polynomials that describe a near optimal deformable mirror state. Such a mirror state improved OCT resolution and at the same time lowered the required fs-laser energy for a laser induced optical breakdown inside the eye model substantially. © COPYRIGHT SPIE.
Transmission and reflection features of all-dielectrics metasurfaces with electric and magnetic resonances
Creators: name: Terekhov, Pavel D.
name: Babicheva, Viktoriia E.
name: Baryshnikova, Kseniia V.
name: Shalin, Alexander S.
name: Karabchevsky, Alina
name: Evlyukhin, Andrey B.
Publisher: name: Bellingham : SPIE
Year: 2019
Subjects: subject: Dielectric
subject: Infrared
subject: Metasurface
subject: Multipole
subject: Silicon
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: The effective multipole decomposition approach is applied to study the optical features of the silicon metasurface in the near-infrared. The spectral regions of perfect transmission and reflection have been analyzed using the Cartesian multipole decomposition. It is shown that transmission peaks appear due to the mutual interaction of multipole moments up to the third order, while reflection peaks are due to the dominant contribution of one of the multipole moments. The results of this work can be broadly applied to design novel metasurfaces, sensors, and optical filters. © 2019 SPIE.
Coupled skinny baker's maps and the Kaplan-Yorke conjecture
Creators: name: Gröger, Maik
name: Hunt, Brian R.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Dynamical Systems (math.DS)
subject: FOS: Mathematics
subject: 37C45 (Primary), 37C40, 37D45, 37C20, 28C20 (Secondary)

description: The Kaplan-Yorke conjecture states that for "typical" dynamical systems with a physical measure, the information dimension and the Lyapunov dimension coincide. We explore this conjecture in a neighborhood of a system for which the two dimensions do not coincide because the system consists of two uncoupled subsystems. We are interested in whether coupling "typically" restores the equality of the dimensions. The particular subsystems we consider are skinny baker's maps, and we consider uni-directional coupling. For coupling in one of the possible directions, we prove that the dimensions coincide for a prevalent set of coupling functions, but for coupling in the other direction we show that the dimensions remain unequal for all coupling functions. We conjecture that the dimensions prevalently coincide for bi-directional coupling. On the other hand, we conjecture that the phenomenon we observe for a particular class of systems with uni-directional coupling, where the information and Lyapunov dimensions differ robustly, occurs more generally for many classes of uni-directionally coupled systems (also called skew-product systems) in higher dimensions.
description: 33 pages, 3 figures
Social Media App Usage in Relation with PHQ-9 Depression Scores during the COVID-19 Pandemic
Creators: name: Mulansky, Lena
name: Pryss, Rüdiger
name: Cohrdes, Caroline
name: Baumeister, Harald
name: Beierle, Felix
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computers and Society (cs.CY)
subject: Social and Information Networks (cs.SI)
subject: FOS: Computer and information sciences

description: With about 300 million affected people, major depressive disorder (MDD) is one of the most common diseases worldwide. During the COVID-19 pandemic, the number of cases increased even further, by 28%. Many factors may be correlated with MDD, including the excessive use of social media apps. In this paper, we investigated the relationship between the use of social media and communication apps and depressive symptoms during the COVID-19 pandemic. The pandemic and social distancing like lockdowns probably changed smartphone usage times and usage patterns. While previous studies have shown an association between depression and social media usage, we report about the situation during these special circumstances.We employed a log-linear regression to examine the association of social media and communication app usage and depression. To quantify the usage, we applied the total usage time in hours of social media apps (e.g., WhatsApp, Facebook) as well as communication apps (Phone and Messaging) within one week. To measure depressive symptoms, we used the PHQ-9 score. We discovered a significant association between the usage time and the PHQ-9 score (beta=0.0084, p-value=0.010). We conclude that social media usage is a robust marker for depression severity and future research should focus on a better understanding of the underlying causality and potential counter-measures.
description: Accepted for the UbiComp/ISWC 2022 conference
Milnor-Thurston homology groups of the Warsaw Circle
Creators: name: Przewocki, Janusz
Publisher: name: arXiv
Year: 2014
Subjects: subject: Geometric Topology (math.GT)
subject: K-Theory and Homology (math.KT)
subject: FOS: Mathematics
subject: Primary 55N35, Secondary 54G20

description: Milnor-Thurston homology theory is a construction of homology theory that is based on measures. It is known that it is equivalent to singular homology theory in case of manifolds and complexes. Its behaviour for non-tame spaces is still unknown. This paper provides results in this direction. We prove that Milnor-Thurston homology groups for the Warsaw Circle are trivial except for the zeroth homology group which is uncountable dimensional. Additionally, we prove that the zeroth homology group is non-Hausdorff for this space with respect a natural topology that was proposed by Berlanga.
Dissipative Dicke model with non-linear atom-photon interaction
Creators: name: Grimsmo, A L
name: Parkins, A S
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study a generalized Dicke model, as recently realized in an atomic quantum gas experiment, describing the collective interaction of N two-level atoms with a single cavity mode. The model takes account of dissipation of the cavity field, and includes a non-linear atom-photon coupling, not present in the conventional Dicke model. We extend previous theoretical investigations of a semiclassical model by including all quantum effects and considering finite atom number N . Our results show good agreement between quantum expectation values and the semiclassical model as N is increased, but also show exotic behaviour for the corresponding quantum state as the non-linear atom-photon coupling is varied.
description: 25 pages, 16 figures
Amplification of ultrafast pulses in an extended Mamyshev regenerator
Creators: name: Repgen, Paul
name: Wandt, Dieter
name: Morgner, Uwe
name: Neumann, Jörg
name: Kracht, Dietmar
Publisher: name: Bellingham : SPIE
Year: 2020
Subjects: subject: Femtosecond fiber laser
subject: Mamyshev oscillator
subject: Nonlinear amplifier
subject: Konferenzschrift
subject: Dewey Decimal Classification::600 | Technik::620 | Ingenieurwissenschaften und Maschinenbau

description: We present the characteristics of a high-energy ultrafast Yb-fiber laser system, based on a Mamyshev oscillator and a subsequently arranged fiber amplifier stage. The Mamyshev oscillator emits pulses at a repetition rate of 11 MHz and pulse energies of 31 nJ. These pulses are spectrally filtered and amplified in a Yb-doped fiber up to 1 μJ pulse energy which could be temporally dechirped to less than 50 fs autocorrelation duration. We discuss the scaling as well as limiting options related to pulse energies and duration. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
title: Blick-Wünsche. Eine Nachschrift
Creators: name: Schade, Sigrid
Publisher: name: University Library Heidelberg
Year: 2014

description: kritische berichte - Zeitschrift für Kunst- und Kulturwissenschaften, Bd. 12, Nr. 4 (1984): kritische berichte, Beginn und Erscheinungsfrequenz: Ausgaben pro Band: 4
Hilbert Series of Residual Intersections
Creators: name: Chardin, Marc
name: Eisenbud, David
name: Ulrich, Bernd
Publisher: name: arXiv
Year: 2013
Subjects: subject: Commutative Algebra (math.AC)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: Primary, 13D40, 13C40, Secondary, 13H15, 13M06, 14C17, 14N15

description: We find explicit formulas for the Hilbert series of residual intersections of a scheme in terms of the Hilbert series of its conormal modules. In a previous paper we proved that such formulas should exist. We give applications to the dimension of secant varieties of surfaces and three-folds.
title: »Barockkunst und Rhetorik«. Zur Tagung des Ulmer-Vereins in Bamberg, 28.5.-31.5.1987
Creators: name: Locher, Hubert
Publisher: name: University Library Heidelberg
Year: 2014

description: kritische berichte - Zeitschrift für Kunst- und Kulturwissenschaften, Bd. 15, Nr. 3/4 (1987): kritische berichte, Beginn und Erscheinungsfrequenz: Ausgaben pro Band: 4
A Simplified Algorithm for Identifying Abnormal Changes in Dynamic Networks
Creators: name: Azamir, Bouchaib
name: Bennis, Driss
name: Michel, Bertrand
Publisher: name: arXiv
Year: 2022
Subjects: subject: Algebraic Topology (math.AT)
subject: Combinatorics (math.CO)
subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 55N35, 55U99, 91B84

description: Topological data analysis has recently been applied to the study of dynamic networks. In this context, an algorithm was introduced and helps, among other things, to detect early warning signals of abnormal changes in the dynamic network under study. However, the complexity of this algorithm increases significantly once the database studied grows. In this paper, we propose a simplification of the algorithm without affecting its performance. We give various applications and simulations of the new algorithm on some weighted networks. The obtained results show clearly the efficiency of the introduced approach. Moreover, in some cases, the proposed algorithm makes it possible to highlight local information and sometimes early warning signals of local abnormal changes.