Hurst-Kolmogorov dynamics as a result of extremal entropy production

It is demonstrated that extremization of entropy production of stochastic representations of natural systems, performed at asymptotic times (zero or infinity) results in constant derivative of entropy in logarithmic time and, in turn, in Hurst-Kolmogorov processes. The constraints used include preservation of the mean, variance and lag-1 autocovariance at the observation time step, and an inequality relationship between conditional and unconditional entropy production, which is necessary to enable physical consistency. An example with real world data illustrates the plausibility of the findings.     

Quartz from southern Africa: sensitivity changes as a result of thermal pretreatment

Sensitivity changes are known to occur in quartz during luminescence measurement procedures. Accurate single-aliquot equivalent dose (D_e) evaluations can be made only if the experimental procedure applied causes no sensitivity change, or can correct for it. The quartz single-aliquot regenerative-dose (SAR) protocol developed by Murray and Wintle (Murray, A.S., Wintle, A.G., 2000. Luminescence dating of quartz using an improved single-aliquot regenerative-close protocol. Radiation Measurements 32, 57–73) incorporates a sensitivity correction procedure that was developed using measurements made on a single sample from Australia. This paper presents experimental data designed to test the applicability of this correction procedure to quartz extracted from two southern African sediments. The results indicate that accurate corrections are made using this protocol irrespective of the direction and magnitude of the sensitivity change. The implications for routine D_e evaluation are discussed.     

Fast antibaryon production in pp collisions as a result of string fusion

The inclusion of string fusion in Dual Parton Model results in the appearance of diquark-antidiquark pairs in the sea with comparatively large Feynman-x. Such antidiquarks can fragment into fast antibaryons, thus increasing several times the corresponding yields in high energy pp collisions for x _F ～ 0.8 ÷ 0.9. String fusion also results in an unusual dependence of inclusive spectra on the multiplicity of secondaries. Some numerical estimations are presented.     

String theory as a universal language

Some new results and new speculations on various topics are submitted. They include discussion of open strings in the AdS space, unusual features of D branes, and conformal gauge theories in higher dimensions. The infrared screening of the cosmological constant and the “brane worlds” are also discussed.     

Measurement of radical production as a result of cavitation in medical ultrasound fields

This paper describes the use of the terephthalate dosimeter to measure the threshold and extent of cavitation arising from medical ultrasound sources at high frequencies. Significant hydroxyl radical production was noted from a physiotherapy source and low level activity was also detected when using a pulsed, diagnostic type transducer system. The effect of sound intensity and the type of field is described. The possibility of using polymer degradation to monitor the cavitation is also discussed.     

Entropy and specific heat as a measure of fluctuations in multiparticle production in relativistic nuclear collisions

An analysis to disentangle information about the occurrence of dynamical fluctuations in multiparticle production in high energy nucleus-nucleus collisions has been carried out in terms of fractal moments and entropy for the experimental and simulated data using FRITIOF, UrQMD and HIJING generators. Although there is a possibility to thermodynamically interpret the final state of multiparticle production by calculating the values of specific heat, c, using G _q - and F _q -moments. However, both these moments give markedly different values of c. The constancy observed in the values of specific heats calculated from either G _q - or F _q -moments is in accord with the predictions of constant specific heat approximation. Variations of multifractal and factorial moments and various other parameters calculated from these moments predict the presence of non-statistical fluctuations in high energy nuclear collisions.     

Electron shake probabilities of heavy elements as a result of M‐shell vacancy production

The electron shakeup‐plus‐shakeoff probabilities accompanying M‐shell vacancy creation have been calculated for elements between Z = 72 and 92. The calculations were performed relativistically in the sudden approximation by the use of the Dirac–Fock–Slater wave functions. The relativistic effects are demonstrated in comparison with the nonrelativistic calculations, and the validity of the approximation method based on the difference in the effective nuclear charge is discussed. The dependence of different initial M‐subshell vacancies on the shake probability is studied. Copyright © 2014 John Wiley & Sons, Ltd.     

Relation between quantum and thermal fluctuations

A relation between quantum and thermal fluctuations, called the generalized uncertainty relation, is derived and discussed. It is given in the terminology of thermo field dynamics. The relation enables us to separate the purely thermal fluctuation from the total fluctuation.     

Phase transitions induced by thermal fluctuations

The present study generalizes the model of extended stochastic systems with a field-dependent kinetic coefficient [M. Ibanes, J. Garcia-Ojalvo, R. Toral, J.M. Sancho, Phys. Rev. Lett. 87, 020601 (2001)] to systems with symmetric and asymmetric bistable potentials. It is found that in systems with a relaxational flow and a symmetric local potential, reentrant phase transitions can be observed. In the case of an asymmetric local potential, a hysteresis-like behaviour in the order parameter appears. It is shown that such phase transitions can be controlled by the constant that governs relaxation flow, noise intensity and spatial coupling intensity.     

Laser-pulse fluctuations due to thermal self-action in a turbulent atmosphere

Conclusions Refractive-index fluctuations caused by heating alter the intensity and phase fluctuation spectra arising from the turbulence. The large-scale part of the spectra is weakened, whereas the small-scale part is strengthened, and the spatial-frequency range in which the fluctuations are attenuated becomes narrower as the beam energy increases. Correspondingly, the fluctuation structure functions alter. For values of the arguments in those functions less than the radius of the first Fresnel zone , the thermal nonlinearity causes increases in the structural functions D_, with the energy. For , the dependence of D_, on energy is nonmonotone, with the fluctuations at first weakened but then strengthened. The reduction in fluctuation variance and the improvement in coherence is less pronounced over long lines than on short ones. The range in which geometrical optics can be used to derive the fluctuations is independent of the nonlinearity and is defined by k₂z/2k /4. The trend to the diffraction asymptote becomes slower as the nonlinearity increases.Atmospheric Physics Institute, Academy of Sciences of the USSR. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 32, No. 9, pp. 1063–1071, September, 1989.     

Fermi-surface truncation from thermal nematic fluctuations

We analyze how thermal fluctuations near a finite temperature nematic phase transition affect the spectral function A(k,ω) for single-electron excitations in a two-dimensional metal. Perturbation theory yields a splitting of the quasiparticle peak with a d-wave form factor, reminiscent of a pseudogap. We present a resummation of contributions to all orders in the Gaussian fluctuation regime. Instead of a splitting, the resulting spectral function exhibits a pronounced broadening of the quasiparticle peak, which varies strongly around the Fermi surface and vanishes upon approaching the Brillouin-zone diagonal. The Fermi surface obtained from a Brillouin-zone plot of A(k,0) seems truncated to Fermi arcs.     

Diffusive transport by thermal velocity fluctuations

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two identical fluids. We find good agreement between a simple fluctuating hydrodynamics theory and particle and finite-volume simulations. The enhancement of the diffusive transport depends on the system size L and grows as ln(L/L?) in quasi-two-dimensional systems, while in three dimensions it scales as L??1 - L?1, where L? is a reference length. Our results demonstrate that fluctuations play an important role in the hydrodynamics of small-scale systems.     

Dynamics of flux lines: thermal fluctuations

A relaxational dynamics for ad-dimensional model of flux lines is investigated. The flux lines are subject to thermal fluctuations such that they form a flux liquid rather than a flux lattice. We find that the density-density auto correlation function decays as (logt/t ²)² for large timest. In contrast, this correlation function decays for point-like vortices ast ^–2. At the transition to an empty lattice (Abrikosov-Meissner transition), the auto correlation function decays as a power law with dimension-dependent exponentsd+2 for flux lines andd for point-like vortices. Therefore, the fluctuations and the interactions of long flux lines have an accelerating effect on the relaxation.     

Selforganisation as a result of effective nonlocality

A one-component quasilinear kinetic system with nonlocal spatial coupling is considered. The long-range inhibition effect combined with a short-range activation is shown to provide a possibility of spontaneous dissipative structure formation. The effective nonlocality can be due to diffusion of an intermediate.     

The Thomas-Fermi-Theory as result of a strong-coupling-limit

The energy of non-relativistic neutral atoms is shown to approach asymptotically the Thomas-Fermi-energy, when the charge of the nucleus tends to infinity.