nils-herrmann/clean_scirepeval huggingface dataset:
The birth of a galaxy – II. The role of radiation pressure

Massive stars provide feedback that shapes the interstellar medium of galaxies at all redshifts and their resulting stellar populations. Here we present three adaptive mesh refinement radiation hydrodynamics simulations that illustrate the impact of momentum transfer from ionising radiation to the absorbing gas on star formation in high-redshift dwarf galaxies. Momentum transfer is calculated by solving the radiative transfer equation with a ray tracing algorithm that is adaptive in spatial and angular coordinates. We find that momentum input partially affects star formation by increasing the turbulent support to a three-dimensional rms velocity equal to the circular velocity of early haloes. Compared to a calculation that neglects radiation pressure, the star formation rate is decreased by a factor of five to 1.8 × 10 −2 M⊙ yr −1 in a dwarf galaxy with a dark matter and stellar mass of 2.0 × 10 8 M⊙ and 4.5 × 10 5 M⊙, respectively, when radiation pressure is included. Its mean metallicity of 10 −2.1 Z⊙ is consistent with the observed dwarf galaxy luminosity-metallicity relation. However, what one may naively expect from the calculation without radiation pressure, the central region of the galaxy overcools and produces a compact, metalrich stellar population with an average metallicity of 0.3 Z⊙, indicative of an incorrect physical recipe. In addition to photo-heating in H ii regions, radiation pressure further drives dense gas from star forming regions, so supernovae feedback occurs in a warmer and more diffuse medium, launching metal-rich outflows. Capturing this aspect and a temporal separation between the start of radiative and supernova feedback are numerically important in the modeling of galaxies to avoid the “overcooling problem”. We estimate that dust in early low-mass galaxies is unlikely to aid in momentum transfer from radiation to the gas.
Modelling gravity on a hyper-cubic lattice

We present an elegant and simple dynamical model of symmetric, non-degenerate (n x n) matrices of fixed signature defined on a n-dimensional hyper-cubic lattice with nearest-neighbor interactions. We show how this model is related to General Relativity, and discuss multiple ways in which it can be useful for studying gravity, both classical and quantum. In particular, we show that the dynamics of the model when all matrices are close to the identity corresponds exactly to a finite-difference discretization of weak-field gravity in harmonic gauge. We also show that the action which defines the full dynamics of the model corresponds to the Einstein-Hilbert action to leading order in the lattice spacing, and use this observation to define a lattice analogue of the Ricci scalar and Einstein tensor. Finally, we perform a mean-field analysis of the statistical mechanics of this model.
No more pesky learning rates

The performance of stochastic gradient descent (SGD) depends critically on how learning rates are tuned and decreased over time. We propose a method to automatically adjust multiple learning rates so as to minimize the expected error at any one time. The method relies on local gradient variations across samples. In our approach, learning rates can increase as well as decrease, making it suitable for non-stationary problems. Using a number of convex and non-convex learning tasks, we show that the resulting algorithm matches the performance of SGD or other adaptive approaches with their best settings obtained through systematic search, and effectively removes the need for learning rate tuning.
Shortest paths in less than a millisecond

We consider the problem of answering point-to-point shortest path queries on massive social networks. The goal is to answer queries within tens of milliseconds while minimizing the memory requirements. We present a technique that achieves this goal for an extremely large fraction of path queries by exploiting the structure of the social networks. Using evaluations on real-world datasets, we argue that our technique offers a unique trade-off between latency, memory and accuracy. For instance, for the LiveJournal social network (roughly 5 million nodes and 69 million edges), our technique can answer 99.9 of the queries in less than a millisecond. In comparison to storing all pair shortest paths, our technique requires at least 550x less memory; the average query time is roughly 365 microseconds --- 430x faster than the state-of-the-art shortest path algorithm. Furthermore, the relative performance of our technique improves with the size (and density) of the network. For the Orkut social network (3 million nodes and 220 million edges), for instance, our technique is roughly 2588x faster than the state-of-the-art algorithm for computing shortest paths.
Negative Kelvin temperatures in stock markets

A spin model relating physical to financial variables is presented. This work is the first to introduce the concept of negative absolute temperature into stock market dynamics by establishing a rigorous formal analogy between physical and financial variables. Based on this model, an algorithm evaluating negative temperatures was applied to an analysis of New York Stock Exchange quotations from November 2002 up to the present. We found that the magnitude of negative temperature peaks correlates with subsequent index movement. Moreover, a certain autocorrelation function decays as temperature increases. An effort was directed to the search for patterns similar to known physical processes, since the model hypotheses pointed to the possibility of such a similarity. A number of cases resembling known processes in phenomenological thermodynamics were found, namely, population inversion and the magneto-caloric effect.
Neutrinos in IceCube/KM3NeT as probes of dark matter substructures in galaxy clusters

Galaxy clusters are one of the most promising candidate sites for dark matter (DM) annihilation. We focus on DM ($\ensuremath{\chi}$) with mass in the range of 10 GeV\char21{}100 TeV, annihilating through the channels $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$, $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}t\overline{t}$, or $\ensuremath{\chi}\ensuremath{\chi}\ensuremath{\rightarrow}\ensuremath{\nu}\overline{\ensuremath{\nu}}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, and forecast the expected sensitivity to the annihilation cross section into these channels by observing galaxy clusters at IceCube/KM3NeT. Optimistically, the presence of DM substructures in galaxy clusters is predicted to enhance the signal by 2\char21{}3 orders of magnitude over the contribution from the smooth component of the DM distribution. Optimizing for the angular size of the region of interest for galaxy clusters, the sensitivity to the annihilation cross section, $⟨\ensuremath{\sigma}v⟩$, of heavy DM with mass in the range of 300 GeV\char21{}100 TeV will be $\mathcal{O}({10}^{\ensuremath{-}24}\text{ }\text{ }{\mathrm{cm}}^{3}\text{ } We find that neutrinos from cosmic ray interactions in the galaxy cluster, in addition to the atmospheric neutrinos, are a source of background. We show that significant improvement in the experimental sensitivity can be achieved for lower DM masses in the range of 10\char21{}300 GeV if neutrino-induced cascades can be reconstructed to $\ensuremath{\approx}5\ifmmode^\circ\else\textdegree\fi{}$ accuracy, as may be possible in KM3NeT. We, therefore, propose that a low-energy extension ``KM3NeT-Core,'' similar to DeepCore in IceCube, be considered for an extended reach at low DM masses.
Rindler quantum gravity

In this paper, we explain how asymptotically globally AdS spacetimes can be given an alternate dual description as entangled states of a pair of hyperbolic space CFTs, which are associated with complementary Rindler wedges of the AdS geometry. The reduced density matrix encoding the state of the degrees of freedom in one of these CFTs describes the physics in a single wedge, which we can think of as the region of spacetime accessible to an accelerated observer in AdS. For pure AdS, this density matrix is thermal, and we argue that the microstates in this thermal ensemble correspond to spacetimes that are almost indistinguishable from a Rindler wedge of pure AdS away from the horizon, but with the horizon replaced by some kind of singularity where the geometrical description breaks down. This alternate description of AdS, based on patches associated with particular observers, may give insight into the holographic description of cosmologies where no observer has access to the full spacetime.
Gross-Witten-Wadia transition in a matrix model of deconfinement

We study the deconfining phase transition at nonzero temperature in a SU(N) gauge theory, using a matrix model which was analyzed previously at small N. We show that the model is soluble at infinite N, and exhibits a Gross-Witten-Wadia transition. In some ways, the deconfining phase transition is of first order: at a temperature $T_d$, the Polyakov loop jumps discontinuously from 0 to1/2, and there is a nonzero latent heat $\sim N^2$. In other ways, the transition is of second order: e.g., the specific heat diverges as $C \sim 1/(T-T_d)^{3/5}$ when $T \rightarrow T_d^+$. Other critical exponents satisfy the usual scaling relations of a second order phase transition. In the presence of a nonzero background field $h$ for the Polyakov loop, there is a phase transition at the temperature $T_h$ where the value of the loop =1/2, with $T_h < T_d$. Since $\partial C/\partial T \sim 1/(T-T_h)^{1/2}$ as $T \rightarrow T_h^+$, this transition is of third order.
Gravitational wave background from rotating neutron stars

initial spin period distributions lead to very dierent results. For one of the models, with slow initial spins, the detection of the background by present or planned detectors can be rejected. However, other models do predict the detection of the background, that would be unresolvable, by the future ground-based gravitational wave detector ET. A robust upper limit for the background of rotating neutron stars is obtained; it does not exceed the detection threshold of two cross-correlated Advanced LIGO interferometers. If gravitars exist and constitute more than a few percent of the neutron star population, then they produce an unresolvable background that could be detected by ET. Under the most reasonable assumptions on the parameters characterizing a neutron star, the background is too faint to be detected. Previous papers have suggested neutron star models in which large magnetic elds (like the ones that characterize magnetars) induce big deformations in the star, which produce a stronger emission of gravitational radiation. Considering the most optimistic (in terms of the detection of gravitational waves) of these models, an upper limit for the background produced by magnetars is obtained; it could be detected by ET, but not by BBO or DECIGO. Simple approximate formulas to characterize both the total and the unresolvable backgrounds are given for the ensemble of rotating neutron stars, and, for completion, also for the ensemble of binary star systems.
Quantum Mechanics of Semiconductor Quantum Dots and Rings

We consider the several phenomena which are taking place in Quantum Dots (QD) and Quantum Rings (QR): The connection of the Quantum Chaos (QC) with the reflection symmetry of the QD, Disappearance of the QC in the tunnel coupled chaotic QD, electron localization and transition between Double Concentric QR in the transverse magnetic field, transition of electron from QR to the QD located in the center of QR. Basis of this consideration is the effective Schr\"odinger equation for the corresponding systems.
KELT-2Ab: A HOT JUPITER TRANSITING THE BRIGHT (V = 8.77) PRIMARY STAR OF A BINARY SYSTEM

We report the discovery of KELT-2Ab, a hot Jupiter transiting the bright (V = 8.77) primary star of the HD 42176 binary system. The host is a slightly evolved late F-star likely in the very short-lived “blue-hook” stage of evolution, with Teff = 6148 ± 48 K, log g = 4.030+0.015− 0.026 and [Fe/H] = 0.034 ± 0.78. The inferred stellar mass is M* = 1.314+0.063− 0.060 M☉ and the star has a relatively large radius of R* = 1.836+0.066− 0.046R☉. The planet is a typical hot Jupiter with period 4.1137913 ± 0.00001 days and a mass of MP = 1.524 ± 0.088 MJ and radius of RP = 1.290+0.064− 0.050 RJ. This is mildly inflated as compared to models of irradiated giant planets at the ∼4 Gyr age of the system. KELT-2A is the third brightest star with a transiting planet identified by ground-based transit surveys, and the ninth brightest star overall with a transiting planet. KELT-2Ab's mass and radius are unique among the subset of planets with V < 9 host stars, and therefore increases the diversity of bright benchmark systems. We also measure the relative motion of KELT-2A and -2B over a baseline of 38 years, robustly demonstrating for the first time that the stars are bound. This allows us to infer that KELT-2B is an early K dwarf. We hypothesize that through the eccentric Kozai mechanism KELT-2B may have emplaced KELT-2Ab in its current orbit. This scenario is potentially testable with Rossiter-McLaughlin measurements, which should have an amplitude of ∼44 m s−1.
Aggregating content and network information to curate twitter user lists

Twitter introduced user lists in late 2009, allowing users to be grouped according to meaningful topics or themes. Lists have since been adopted by media outlets as a means of organising content around news stories. Thus the curation of these lists is important - they should contain the key information gatekeepers and present a balanced perspective on a story. Here we address this list curation process from a recommender systems perspective. We propose a variety of criteria for generating user list recommendations, based on content analysis, network analysis, and the "crowdsourcing" of existing user lists. We demonstrate that these types of criteria are often only successful for datasets with certain characteristics. To resolve this issue, we propose the aggregation of these different "views" of a news story on Twitter to produce more accurate user recommendations to support the curation process.
The baryonic Tully–Fisher relation and galactic outflows

Most of the baryons in the Universe are not in the form of stars and cold gas in galaxies. Galactic outflows driven by supernovae/stellar winds are the leading mechanisms for explaining this fact. The scaling relation between galaxy mass and outer rotation velocity (also known as the baryonic Tully–Fisher relation, BTF) has recently been used as evidence against this viewpoint. We use a Λ cold dark matter (ΛCDM)-based semi-analytic disc galaxy formation model to investigate these claims. In our model, galaxies with less efficient star formation and higher gas fractions are more efficient at ejecting gas from galaxies. This somewhat counter intuitive result is due to the (observational) fact that galaxies with less efficient star formation and higher gas fractions tend to live in dark matter haloes with lower circular velocities, from which less energy is required to escape the potential well. In our model the intrinsic scatter in the BTF is ≃0.15 dex, and mostly reflects scatter in dark halo concentration. The scatter is largely independent of galaxy structure because of the large radius within which galaxy rotation velocities are measured. The observed scatter, equal to ≃0.24 dex, is dominated by measurement errors. The best estimate for the intrinsic scatter is that it is less than 0.15 dex, and thus our ΛCDM-based model (which does not include all possible sources of scatter) is only just consistent with this. Future observations of the BTF scatter could be made with a more stringent measurement of the intrinsic scatter, and thus provide a strong constraint to galaxy formation models. In our model, gas-rich galaxies, at fixed virial velocity (Vvir), with lower stellar masses have lower baryonic masses. This is consistent with the expectation that galaxies with lower stellar masses have had less energy available to drive an outflow. However, when the outer rotation velocity (Vflat) is used the correlation has the opposite sign, with a slope in agreement with observations. This is due to the fact there is scatter in the relation between Vflat and Vvir. In summary, contrary to some previous claims, we show that basic features of the BTF are consistent with a ΛCDM-based model in which the low efficiency of galaxy formation is determined by galactic outflows.
Multi-scale link prediction

The automated analysis of social networks has become an important problem due to the proliferation of social networks, such as LiveJournal, Flickr and Facebook. The scale of these social networks is massive and continues to grow rapidly. An important problem in social network analysis is proximity estimation that infers the closeness of different users. Link prediction, in turn, is an important application of proximity estimation. However, many methods for computing proximity measures have high computational complexity and are thus prohibitive for large-scale link prediction problems. One way to address this problem is to estimate proximity measures via low-rank approximation. However, a single low-rank approximation may not be sufficient to represent the behavior of the entire network. In this paper, we propose Multi-Scale Link Prediction (MSLP), a framework for link prediction, which can handle massive networks. The basic idea of MSLP is to construct low-rank approximations of the network at multiple scales in an efficient manner. To achieve this, we propose a fast tree-structured approximation algorithm. Based on this approach, MSLP combines predictions at multiple scales to make robust and accurate predictions. Experimental results on real-life datasets with more than a million nodes show the superior performance and scalability of our method.
Shaping the international financial system in century of globalization

We educe a perspective on how best to regulate the bank of tomorrow in frames of debate launched by the International Centre for Financial Regulation and Financial Times. Our goal is to create a conceptual framework for policymakers and regulators to shape the international financial system in century of globalization using the 1888 FT's motto: "Without fear and without favour." Our prospect employs an analytical approach, which focuses on the origins and evolution of banking system, its transformation over the recent decades, subsequent encountering the limits to growth and redefinition of new strategic boundaries of emerging financial industry. We identify the main reasons and limitations, which led to the global financial crisis. We propose the new research agendas with the aim to understand the situation in finances, evaluate the created systemic damages, and find the possible ways to resolve the existing problems through introduction of new banking regulation. We think that the global economic and financial systems are highly nonlinear systems. In our opinion, the frequency, phase and amplitude modulation during the mixing of waves, which characterize the Kitchin, Juglar, Kuznets, Kondratiev economic cycles, may result in origination of strong nonlinear dynamics in financial system, accompanied by chaos- induced phenomena. These nonlinear effects have to be taken to the account, when adding the liquidity to the financial system in small quantas in series over time period during the Quantitative Easing policy execution by central banks. We propose the Random Tax to be selectively imposed on the profits, obtained by market agents during high-risk high-profit speculative transactions. We expect that the Random Tax will stabilize the financial system in conditions of free market capitalism.
Complementarity of Galactic radio and collider data in constraining WIMP dark matter models

In this work we confront dark matter models to constraints that may be derived from radio synchrotron radiation from the Galaxy, taking into account the astrophysical uncertainties and we compare these to bounds set by accelerator and complementary indirect dark matter searches. Specifically we apply our analysis to three popular particle physics models. First, a generic effective operator approach, in which case we set bounds on the corresponding mass scale, and then, two specific UV completions, the Z' and Higgs portals. We show that for many candidates, the radio synchrotron limits are competitive with the other searches, and could even give the strongest constraints (as of today) with some reasonable assumptions regarding the astrophysical uncertainties.
A Physical Theory of Economic Growth

Economic growth is unpredictable unless demand is quantified. We solve this problem by introducing the demand for unpaid spare time and a user quantity named human capacity. It organizes and amplifies spare time required for enjoying affluence like physical capital, the technical infrastructure for production, organizes and amplifies working time for supply. The sum of annual spare and working time is fixed by the universal flow of time. This yields the first macroeconomic equilibrium condition. Both storable quantities form stabilizing feedback loops. They are driven with the general and technical knowledge embodied with parts of the supply by education and construction. Linear amplification yields S-functions as only analytic solutions. Destructible physical capital controls medium-term recoveries from disaster. Indestructible human capacity controls the collective long-term industrial evolution. It is immune even to world wars and runs from 1800 to date parallel to the unisex life expectancy in the pioneering nations. This is the first quantitative information on long-term demand. The theory is self-consistent. It reproduces all peaceful data from 1800 to date without adjustable parameter. It has full forecasting power since the decisive parameters are constants of the human species. They predict an asymptotic maximum for the economic level per capita. Long-term economic growth appears as a part of natural science.
Assessing the Quality of Wikipedia Pages Using Edit Longevity and Contributor Centrality

In this paper we address the challenge of assessing the quality of Wikipedia pages using scores derived from edit contribution and con- tributor authoritativeness measures. The hypothesis is that pages with significant contributions from authoritative contributors are likely to be high-quality pages. Contributions are quantified using edit longevity measures and contributor authoritativeness is scored using centrality metrics in either the Wikipedia talk or co-author networks. The results suggest that it is useful to take into account the contributor authori- tativeness when assessing the information quality of Wikipedia content. The percentile visualization of the quality scores provides some insights about the anomalous articles, and can be used to help Wikipedia editors to identify Start and Stub articles that are of relatively good quality.