Emergent states in dense systems of active rods: from swarming to turbulence

Dense suspensions of self-propelled rod-like particles exhibit a fascinating variety of non-equilibrium phenomena. By means of computer simulations of a minimal model for rigid self-propelled colloidal rods with variable shape we explore the generic diagram of emerging states over a large range of rod densities and aspect ratios. The dynamics is studied using a simple numerical scheme for the overdamped noiseless frictional dynamics of a many-body system in which steric forces are dominant over hydrodynamic ones. The different emergent states are identified by various characteristic correlation functions and suitable order parameter fields. At low density and aspect ratio, a disordered phase with no coherent motion precedes a highly-cooperative swarming state at large aspect ratio. Conversely, at high densities weakly anisometric particles show a distinct jamming transition whereas slender particles form dynamic laning patterns. In between there is a large window corresponding to strongly vortical, turbulent flow. The different dynamical states should be verifiable in systems of swimming bacteria and artificial rod-like micro-swimmers.Comment: 14 pages, 8 figure

Thermofield Dynamics of the Heterotic String - Physical Aspects of the Thermal Duality -

The thermofield dynamics of the D = 10 heterotic thermal string theory is described in proper reference to the thermal duality symmetry as well as the thermal stability of modular invariance in association with the global phase structure of the D = 10 heterotic thermal string ensemble.Comment: 8 pages, LaTeX, Minor correction

Density matrix of a finite sub-chain of the Heisenberg anti-ferromagnet

We consider a finite sub-chain on an interval of the infinite XXX model in the ground state. The density matrix for such a subsystem was described in our previous works for the model with inhomogeneous spectral parameters. In the present paper, we give a compact formula for the physically interesting case of the homogeneous model.Comment: 6 pages, some formulas are refine

Xenon forms stable compound with fluorine

Experiments show that xenon and fluorine combine readily at 400 deg C to form xenon tetrafluoride, which is colorless, crystalline, chemically stable and solid at room temperature. This process can be used for the separation of xenon from mixtures with other noble gases

Weak Quantum Theory: Complementarity and Entanglement in Physics and Beyond

The concepts of complementarity and entanglement are considered with respect to their significance in and beyond physics. A formally generalized, weak version of quantum theory, more general than ordinary quantum theory of material systems, is outlined and tentatively applied to some examples.Comment: Revised version. Chapter 5.2 (old counting) omitted for separate publication, chapter 5.2 (new counting) reformulate

Relation between mutation yield and cell lethality over a wide range of X-ray and fission neutron doses in maize

Dry maize seeds, of a genetic stock heterozygous for the yellow-green locus (Yg^ Λ ^ ) ι were irradiated with fission neutron doses up to 2700 rads and with 250 kVp X-rays to 40 000 rads. The frequency of yellow-green (yg) sectors in seedling leaves 4 and 5 is largely a measure of the frequency of breakage (or incomplete exchange) and loss of the part of the short arm of chromosome I X carrying Yj>. Plots of dose versus yj* sector frequency per leaf show a linear increase with neutrons which reaches a maximum (leaf 4 = S. 5, leaf 5 = 2. 5) followed by a rapid decline; and a curvilinear increase with X-rays reaching a higher maximum (leaf 4 = 8. 5, leaf 5 = 3.6) followed by a decrease. The observed rise and subsequent fall of numbers of yg_ mutations can be accounted for by a model in which the decline of the curves is due to cell killing which may also be due to chromosome breakage and deletion. The interpretation is based on the principles of the dual action theory, which explains radiobiological action in terms of microdosimetry. One of the observations accounted for is the higher maximum mutation rate for X-rays as compared to neutrons

Parallel plate viscometer Patent

Describing instrument capable of measuring true shear viscosity of liquids and viscoelastic material

Absolute viscosity measured using instrumented parallel plate system

An automatic system measures the true average shear viscosity of liquids and viscoelastic materials, using the parallel plate method and automatically displays the results on a graphic record. This eliminates apparatus setup and extensive calculations