Competition between Two Kinds of Correlations in Literary Texts

A theory of additive Markov chains with long-range memory is used for description of correlation properties of coarse-grained literary texts. The complex structure of the correlations in texts is revealed. Antipersistent correlations at small distances, L 300 define this nontrivial structure. For some concrete examples of literary texts, the memory functions are obtained and their power-law behavior at long distances is disclosed. This property is shown to be a cause of self-similarity of texts with respect to the decimation procedure.Comment: 7 pages, 7 figures, Submitted to Physica

Segregation by thermal diffusion in granular shear flows

Segregation by thermal diffusion of an intruder immersed in a sheared granular gas is analyzed from the (inelastic) Boltzmann equation. Segregation is induced by the presence of a temperature gradient orthogonal to the shear flow plane and parallel to gravity. We show that, like in analogous systems without shear, the segregation criterion yields a transition between upwards segregation and downwards segregation. The form of the phase diagrams is illustrated in detail showing that they depend sensitively on the value of gravity relative to the thermal gradient. Two specific situations are considered: i) absence of gravity, and ii) homogeneous temperature. We find that both mechanisms (upwards and downwards segregation) are stronger and more clearly separated when compared with segregation criteria in systems without shear.Comment: 8 figures. To appear in J. Stat. Mec

Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Surface Josephson Plasma Waves in Layered Superconductors above the Plasma Frequency: Evidence for a Negative Index of Refraction

We predict a new branch of surface Josephson plasma waves (SJPWs) in layered superconductors for frequencies higher than the Josephson plasma frequency. In this frequency range, the permittivity tensor components along and transverse to the layers have different signs, which is usually associated with negative refraction. However, for these frequencies, the bulk Josephson plasma waves cannot be matched with the incident and reflected waves in the vacuum, and, instead of the negative-refractive properties, abnormal surface modes appear within the frequency band expected for bulk modes. We also discuss the excitation of high-frequency SJPWs by means of the attenuated-total-reflection method. DOI: 10.1103/PhysRevLett.104.187003 PACS numbers: 74.25.NÀ, 42.25.Bs, 74.25.Gz, 78.20.Ci High-T c layered cuprate superconductors are important candidates for negative-refractive-index (NRI) metamaterials (see, e.g., Experiments for the c-axis conductivity in layered superconductors prove the use of a model in which the superconducting CuO 2 layers are coupled by the intrinsic Josephson effect through the layers The Josephson current along the c-axis couples with the electromagnetic field inside the insulating dielectric layers, forming Josephson plasma waves (JPWs) (see the review [5] and references therein). Thus, the propagation of electromagnetic waves through the layers is favored by the layered structure. The study of these waves is very important because of their terahertz frequency range, which is still hardly reachable for electronic and optical devices. As in common plasma waves, JPWs propagate with frequencies above some threshold value (the Josephson plasma frequency ! J ). However, in the frequency range below ! J , the presence of the sample boundary can produce surface Josephson plasma waves (SJPWs) At frequencies ! higher than the Josephson plasma frequency ! J , the normal-to-the-layers components of both the group velocity and the Poynting vector of propagating JPWs have signs opposite to the sign of the normal component of the wave vector k s . This corresponds to a NRI. However, the condition ! > ! J is not sufficient for NRI. This NRI effect can be observed at the vacuumlayered superconductor boundary only in a relatively narrow frequency range, , where " is the interlayer dielectric constant. A similar limitation exists for any insulator-layeredsuperconductor boundary, if the dielectric constant " ext of the insulator is less than ". The above conditions follow from the dispersion relation for the JPWs and the natural limitation for the tangential component q (q ¼ k sin < k, k ¼ !=c) of the wave vector for a wave incident at an angle from the vacuum onto the layered superconductor. A simple analysis shows that the above inequality is compatible with the dispersion relation for JPWs only for frequencies ! J < ! < ! PRL 104, 187003 (2010