Thermodynamics of condensed matter with strong pressure-energy correlations

We show that for any liquid or solid with strong correlation between its $NVT$ virial and potential-energy equilibrium fluctuations, the temperature is a product of a function of excess entropy per particle and a function of density, $T=f(s)h(\rho)$. This implies that 1) the system's isomorphs (curves in the phase diagram of invariant structure and dynamics) are described by $h(\rho)/T={\rm Const.}$, 2) the density-scaling exponent is a function of density only, 3) a Gr{\"u}neisen-type equation of state applies for the configurational degrees of freedom. For strongly correlating atomic systems one has $h(\rho)=\sum_nC_n\rho^{n/3}$ in which the only non-zero terms are those appearing in the pair potential expanded as $v(r)=\sum_n v_n r^{-n}$. Molecular dynamics simulations of Lennard-Jones type systems confirm the theory

Analysing Political Biases in Danish Newspapers Using Sentiment Analysis

Traditionally, the evaluation of political biases in Danish newspapers has been carried out throughhighly subjective methods. The conventional approach has been surveys asking samples of thepopulation to place various newspapers on the political spectrum, coupled with analysing votinghabits of the newspapers’ readers (Hjarvard, 2007). This paper seeks to examine whether it ispossible to use sentiment analysis to objectively assess political biases in Danish newspapers. Byusing the sentiment dictionary AFINN (Nielsen et al., 2011), the mean sentiment scores for 360articles was calculated. The articles were published in the Danish newspapers Berlingske andInformation and were all regarding the political parties Alternativet and Liberal Alliance. Asignificant interaction effect between the parties and newspapers was discovered. This effect wasmainly driven by Information’s coverage of the two parties. Moreover, Berlingske was found topublish a disproportionately greater number of articles concerning Liberal Alliance thanAlternativet. Based on these findings, an integration of sentiment analysis into the evaluation ofbiases in news outlets is proposed. Furthermore, future studies are suggested to construct datasetsfor evaluation of AFINN on news and to utilize web-mining methods to gather greater amounts ofdata in order to analyse more parties and newspapers

Fluctuations and scaling in creep deformation

The spatial fluctuations of deformation are studied in creep in the Andrade's power-law and the logarithmic phases, using paper samples. Measurements by the Digital Image Correlation technique show that the relative strength of the strain rate fluctuations increases with time, in both creep regimes. In the Andrade creep phase characterized by a power law decay of the strain rate $\epsilon_t \sim t^{-\theta}$, with $\theta \approx 0.7$, the fluctuations obey $\Delta \epsilon_t \sim t^{-\gamma}$, with $\gamma \approx 0.5$. The local deformation follows a data collapse appropriate for an absorbing state/depinning transition. Similar behavior is found in a crystal plasticity model, with a jamming or yielding phase transition

Isomorphs in the phase diagram of a model liquid without inverse power law repulsion

It is demonstrated by molecular dynamics simulations that liquids interacting via the Buckingham potential are strongly correlating, i.e., have regions of their phase diagram where constant-volume equilibrium fluctuations in the virial and potential energy are strongly correlated. A binary Buckingham liquid is cooled to a viscous phase and shown to have isomorphs, which are curves in the phase diagram along which structure and dynamics in appropriate units are invariant to a good approximation. To test this, the radial distribution function, and both the incoherent and coherent intermediate scattering function are calculated. The results are shown to reflect a hidden scale invariance; despite its exponential repulsion the Buckingham potential is well approximated by an inverse power-law plus a linear term in the region of the first peak of the radial distribution function. As a consequence the dynamics of the viscous Buckingham liquid is mimicked by a corresponding model with purely repulsive inverse-power-law interactions. The results presented here closely resemble earlier results for Lennard-Jones type liquids, demonstrating that the existence of strong correlations and isomorphs does not depend critically on the mathematical form of the repulsion being an inverse power law.Comment: 7 pages, 9 figure

Scaling of viscous dynamics in simple liquids:theory, simulation and experiment

Supercooled liquids are characterized by relaxation times that increase dramatically by cooling or compression. Many liquids have been shown to obey power-law density scaling, according to which the relaxation time is a function of density to some power over temperature. We show that power-law density scaling breaks down for larger density variations than usually studied. This is demonstrated by simulations of the Kob-Andersen binary Lennard-Jones mixture and two molecular models, as well as by experimental results for two van der Waals liquids. A more general form of density scaling is derived, which is consistent with results for all the systems studied. An analytical expression for the scaling function for liquids of particles interacting via generalized Lennard-Jones potentials is derived and shown to agree very well with simulations. This effectively reduces the problem of understanding the viscous slowing down from being a quest for a function of two variables to a search for a single-variable function.Comment: 7 pages, 5 figure